ISL6443_06 [INTERSIL]
300kHz Dual, 180∑ Out-of-Phase, Step- Down PWM and Single Linear Controller; 300kHz的双通道， 180Σ出异相，降压PWM和单点线性控制器
| 型号： | ISL6443_06 |
| 厂家： | 
Intersil |
| 描述： | 300kHz Dual, 180∑ Out-of-Phase, Step- Down PWM and Single Linear Controller |
| 文件： | 总18页 (文件大小：341K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
ISL6443
®
Data Sheet
August 9, 2006
FN9044.2
300kHz Dual, 180° Out-of-Phase, Step-
Down PWM and Single Linear Controller
Features
• Wide Input Supply Voltage Range
- Variable 5.6V to 24V
The ISL6443 is a high-performance, triple-output controller
optimized for converting wall adapter, battery or network
intermediate bus DC input supplies into the system supply
voltages required for a wide variety of applications. Each
output is adjustable down to 0.8V. The two PWMs are
synchronized 180° out of phase reducing the RMS input
current and ripple voltage.
- Fixed 4.5V to 5.6V
• Three Independently Programmable Output Voltages
• Switching Frequency . . . . . . . . . . . . . . . . . . . . . . .300kHz
• Out of Phase PWM Controller Operation
- Reduces Required Input Capacitance and Power
Supply Induced Loads
The ISL6443 incorporates several protection features. An
adjustable overcurrent protection circuit monitors the output
current by sensing the voltage drop across the lower
MOSFET. Hiccup mode overcurrent operation protects the
DC/DC components from damage during output
• No External Current Sense Resistor
- Uses Lower MOSFET’s r
DS(ON)
• Bidirectional Frequency Synchronization for
Synchronizing Multiple ISL6443s
overload/short circuit conditions. Each PWM has an
independent logic-level shutdown input (SD1 and SD2).
• Programmable Soft-Start
A single PGOOD signal is issued when soft-start is complete
on both PWM controllers and their outputs are within 10% of
the set point and the linear regulator output is greater than
75% of its setpoint. Thermal shutdown circuitry turns off the
device if the junction temperature exceeds +150°C.
• Extensive circuit protection functions
- PGOOD
- UVLO
- Overcurrent
- Over-temperature
- Independent Shutdown for Both PWMs
Ordering Information
• Excellent Dynamic Response
PART
PART
TEMP.
PKG.
- Voltage Feed-Forward with Current Mode Control
NUMBER MARKING RANGE (°C) PACKAGE
DWG. #
ISL6443IR ISL6443IR
-40 to 85 28 Ld 5x5 QFN L28.5x5
• QFN Packages:
ISL6443IRZ ISL6443IRZ
(See Note)
-40 to 85 28 Ld 5x5 QFN L28.5x5
(Pb-free)
- QFN - Compliant to JEDEC PUB95 MO-220
QFN - Quad Flat No Leads - Package Outline
Add “-T” or “-TK” suffix for tape and reel.
- Near Chip Scale Package footprint, which improves
PCB efficiency and has a thinner profile
NOTE: Intersil Pb-free plus anneal products employ special Pb-free
material sets; molding compounds/die attach materials and 100%
matte tin plate termination finish, which are RoHS compliant and
compatible with both SnPb and Pb-free soldering operations. Intersil
Pb-free products are MSL classified at Pb-free peak reflow
temperatures that meet or exceed the Pb-free requirements of
IPC/JEDEC J STD-020.
• Pb-Free Plus Anneal Available (RoHS Compliant)
Applications
• Power Supplies with Multiple Outputs
• xDSL Modems/Routers
• DSP, ASIC, and FPGA Power Supplies
• Set-Top Boxes
• Dual Output Supplies for DSP, Memory, Logic, µP Core
and I/O
• Telecom Systems
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1
1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2005-2006. All Rights Reserved
All other trademarks mentioned are the property of their respective owners.
ISL6443
Pinouts
ISL6443 (QFN)
TOP VIEW
28 27 26 25 24 23 22
PHASE2
ISEN2
ISEN1
PGND
1
2
3
4
5
6
7
21
20
19
PGOOD
VCC_5V
SD2
SD1
18 SS1
SGND
17
SS2
16 OCSET1
15
OCSET2
FB1
8
9
10 11 12 13 14
FN9044.2
August 9, 2006
2
Block Diagram
BOOT1
UGATE1
PHASE1
VCC_5V
LGATE1
PGND
BOOT2
UGATE2
PHASE2
VCC
PGOOD
SD1
VIN SGND
SD2
VCC
ADAPTIVE DEAD-TIME
DIODE EMULATION
V/I SAMPLE TIMING
ADAPTIVE DEAD-TIME
DIODE EMULATION
V/I SAMPLE TIMING
LGATE2
POR
PGND
ENABLE
0.8V REFERENCE
BIAS SUPPLIES
REFERENCE
FAULT LATCH
SOFT-START
+
GATE3
FB3
+
V
E
g
*V
E
m
-
UV
UV
PGOOD
PGOOD
18.5pF
1400kΩ
18.5pF
1400kΩ
VSEN2
SOFT2
180kΩ
180kΩ
-
FB1
-
OC1
OC2
16kΩ
16kΩ
PWM1
PWM2
-
-
+
+
ERROR AMP 2
+
ERROR AMP 1
0.8V
REF
+
+
SS1
+
0.8V
REF
DUTY CYCLE RAMP GENERATOR
PWM CHANNEL PHASE CONTROL
ISEN1
ISEN2
-
-
CURRENT
SAMPLE
CURRENT
SAMPLE
CURRENT
SAMPLE
CURRENT
SAMPLE
+
+
OCSET2
OCSET1
0.8V REFERENCE
+
+
0.8V REFERENCE
-
-
OC1
OC2
+
+
VIN
VCC
SYNC
SAME STATE FOR
2 CLOCK CYCLES
SAME STATE FOR
2 CLOCK CYCLES
REQUIRED TO LATCH
REQUIRED TO LATCH
OVERCURRENT FAULT
OVERCURRENT FAULT
ISL6443
Typical Application Schematic
+12V
+
C1
56µF
C2
4.7µF
VIN
10
VCC_5V
D1
BAT54HT1
D2
BAT54HT1
SS1
SS2
4
6
18
C4
0.1µF
C5
0.1µF
C3
1µF
C6
1µF
BOOT1
BOOT2
24
27
C7
0.1µF
C8
0.1µF
UGATE1
PHASE1
UGATE2
PHASE2
23
22
28
1
L1
R3
L2
VOUT1
R4
VOUT2
ISEN1
ISEN2
21
2
6.4µH
1.4K
+
6.4µH
C9
330µF
+3.3V, 2A
+1.2V, 2A
1.4K
C10
330µF
+
ISL6443
26
LGATE1
PGND
LGATE2
FB2
25
20
R5
31.6K
Q1
(See Note)
Q2
FDS6990S
R1
4.99k
FDS6990S
8
FB1
SD1
SGND
SGND
15
9
14
13
R6
10k
R2
10K
19
5
GATE3
FB3
C11
0.1µF
SD2
VOUT2
+3.3V
12
OCSET1
OCSET2
7
R12
100
16
R8
120K
17 11
SGND
3
R7
120K
Q3
IRF7404
SYNC
VOUT3
PGOOD
PGOOD
+2.5V, 500mA
R9
10K
R10
21.5K
C12
10µF
VCC_5V
R11
10K
FN9044.2
August 9, 2006
4
ISL6443
Absolute Maximum Ratings
Thermal Information
Supply Voltage (VCC_5V Pin) . . . . . . . . . . . . . . . . . . . .-0.3V to +7V
Thermal Resistance (Typical)
θ
(°C/W)
36
θ
(°C/W)
5.5
JA
JC
Input Voltage (V Pin). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+27V
IN
28 Lead QFN (Note 1) . . . . . . . . . . .
BOOT1, 2 and UGATE1, 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . +35V
PHASE1, 2 and ISEN1, 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . +27V
BOOT1, 2 with Respect to PHASE1, 2 . . . . . . . . . . . . . . . . . . +6.5V
UGATE1, 2. . . . . . . . . . . . (PHASE1, 2 - 0.3V) to (BOOT1, 2 +0.3V)
Maximum Junction Temperature (Plastic Package) .-55°C to 150°C
Maximum Storage Temperature Range. . . . . . . . . . .-65°C to 150°C
Temperature Range. . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to 85°C
CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the
device at these or any other conditions above those indicated in the operational sections of this specification is not implied.
NOTE:
1. θ is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. For θ
JC
JA
the “case temp” location is the center of the exposed metal pad on the underside of the package. See Tech Brief TB379.
Electrical Specifications Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application
Schematic. V = 5.6V to 24V, or VCC_5V = 5V ±10%, T = -40°C to 85°C (Note 2),
IN
Typical values are at T = 25°C
A
A
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
VIN SUPPLY
Input Voltage Range
5.6
12
24
V
VCC_5V SUPPLY (Note 3)
Input Voltage
4.5
4.5
60
5.0
5.0
-
5.6
5.5
-
V
V
Output Voltage
V
V
> 5.6V, I = 20mA
L
IN
IN
Maximum Output Current
SUPPLY CURRENT
= 12V
mA
Shutdown Current (Note 4)
Operating Current (Note 5)
REFERENCE SECTION
Nominal Reference Voltage
Reference Voltage Tolerance
POWER-ON RESET
SD1 = SD2 = GND
-
-
50
375
4.0
µA
2.0
mA
-
0.8
-
-
V
-1.0
1.0
%
Rising VCC_5V Threshold
Falling VCC_5V Threshold
OSCILLATOR
4.25
3.95
4.45
4.2
4.5
4.4
V
V
Total Frequency Variation
Peak-to-Peak Sawtooth Amplitude (Note 6)
260
300
340
kHz
V
V
V
= 12V
= 5V
-
1.6
-
IN
IN
-
-
0.667
-
V
Ramp Offset (Note 7)
1.0
-
10.0
5.44
-
V
SYNC Input Rise/Fall Time (Note 7)
SYNC Frequency Range
-
-
ns
MHz
V
4.16
3.5
-
4.8
SYNC Input HIGH Level
-
-
-
-
SYNC Input LOW Level
1.5
-
V
SYNC Input Minimum Pulse Width (Note 7)
SYNC Output HIGH Level
10
ns
V
V
- 0.6V
-
CC
SHUTDOWN1/SHUTDOWN2
HIGH Level (Converter Enabled)
LOW Level (Converter Disabled)
Internal Pull-up (3µA)
2.0
-
-
-
-
V
V
0.8
FN9044.2
August 9, 2006
5
ISL6443
Electrical Specifications Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application
Schematic. V = 5.6V to 24V, or VCC_5V = 5V ±10%, T = -40°C to 85°C (Note 2),
IN
A
Typical values are at T = 25°C (Continued)
A
PARAMETER
PWM CONVERTERS
TEST CONDITIONS
MIN
TYP
MAX
UNITS
Output Voltage
-
-
0.8
-
V
nA
%
FB Pin Bias Current
-
-
150
Maximum Duty Cycle
C
= 1000pF, T = 25°C
93
-
-
-
OUT
A
Minimum Duty Cycle
4
%
PWM CONTROLLER ERROR AMPLIFIERS
DC Gain (Note 7)
80
5.9
-
88
-
dB
MHz
V/µs
V
Gain-Bandwidth Product (Note 7)
Slew Rate (Note 7)
-
2.0
-
-
-
Maximum Output Voltage (Note 7)
Minimum Output Voltage (Note 7)
PWM CONTROLLER GATE DRIVERS (Note 8)
Sink/Source Current
0.9
-
-
-
3.6
V
-
-
-
-
-
-
-
400
8
-
-
-
-
-
-
-
mA
Upper Drive Pull-Up Resistance
Upper Drive Pull-Down Resistance
Lower Drive Pull-Up Resistance
Lower Drive Pull-Down Resistance
Rise Time
VCC_5V = 4.5V
VCC_5V = 4.5V
VCC_5V = 4.5V
VCC_5V = 4.5V
3.2
8
1.8
18
18
C
C
= 1000pF
= 1000pF
ns
ns
OUT
Fall Time
OUT
LINEAR CONTROLLER
Drive Sink Current
50
-
-
-
mA
V
FB3 Feedback Threshold
I = 21mA
0.8
75
45-
2
-
Undervoltage Threshold
V
-
-
150
-
%
FB
FB3 Input Leakage Current (Note 7)
Amplifier Transconductance
POWER GOOD AND CONTROL FUNCTIONS
PGOOD LOW Level Voltage
PGOOD Leakage Current
PGOOD Upper Threshold, PWM 1 and 2
PGOOD Lower Threshold, PWM 1 and 2
PGOOD for Linear Controller
ISEN and CURRENT LIMIT
Full Scale Input Current (Note 9)
Overcurrent Threshold (Note 9)
OCSET (Current Limit) Voltage
SOFT-START
-
nA
A/V
V
= 0.8V, I = 21mA
-
FB
Pull-up = 100kΩ
-
-
0.1
0.5
±1.0
120
95
V
µA
%
%
%
-
-
Fraction of set point
Fraction of set point
105
80
70
-
75
80
-
-
-
32
64
-
-
-
µA
µA
V
ROCSET = 110kΩ
1.75
Soft-Start Current
-
5
-
µA
FN9044.2
August 9, 2006
6
ISL6443
Electrical Specifications Recommended operating conditions unless otherwise noted. Refer to Block Diagram and Typical Application
Schematic. V = 5.6V to 24V, or VCC_5V = 5V ±10%, T = -40°C to 85°C (Note 2),
IN
A
Typical values are at T = 25°C (Continued)
A
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
PROTECTION
Thermal Shutdown
Rising
-
-
150
20
-
-
°C
°C
Hysteresis
NOTES:
2. Specifications at -40°C and 85°C are guaranteed by design, not production tested.
3. In normal operation, where the device is supplied with voltage on the V pin, the VCC_5V pin provides a 5V output capable of 60mA (min).
IN
When the VCC_5V pin is used as a 5V supply input, the internal LDO regulator is disabled and the V input pin must be connected to the
IN
VCC_5V pin. (Refer to the Pin Descriptions section for more details.)
4. This is the total shutdown current with V = VCC_5V = PVCC = 5V.
IN
5. Operating current is the supply current consumed when the device is active but not switching. It does not include gate drive current.
6. The peak-to-peak sawtooth amplitude is production tested at 12V only; at 5V this parameter is guaranteed by design.
7. Guaranteed by design; not production tested.
8. Not production tested; guaranteed by characterization only.
9. Guaranteed by design. The full scale current of 32µA is recommended for optimum current sample and hold operation. See the Feedback Loop
Compensation Section below.
FN9044.2
August 9, 2006
7
ISL6443
Typical Performance Curves
(Oscilloscope Plots are Taken Using the ISL6443EVAL Evaluation Board, VIN = 12V Unless Otherwise Noted.)
3.4
3.39
3.38
3.37
3.36
3.35
3.34
3.4
3.39
3.38
3.37
3.36
3.35
3.34
3.33
3.32
3.33
3.32
3.31
3.3
3.31
3.3
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
LOAD CURRENT (A)
LOAD CURRENT (A)
FIGURE 1. PWM1 LOAD REGULATION
FIGURE 2. PWM2 LOAD REGULATION
PGOOD 5V/DIV
0.85
0.84
0.83
0.82
V
2V/DIV
2V/DIV
OUT3
OUT2
0.81
0.8
V
0.79
0.78
0.77
0.76
0.75
V
2V/DIV
OUT1
60
-40
-20
20
40
80
0
TEMPERATURE (°C)
FIGURE 3. REFERENCE VOLTAGE VARIATION OVER
TEMPERATURE
FIGURE 4. SOFT-START WAVEFORMS WITH PGOOD
V
20mV/DIV, AC COUPLED
OUT2
V
20mV/DIV, AC COUPLED
OUT1
I
0.5A/DIV, AC COUPLED
L1
I
0.5A/DIV, AC COUPLED
L2
PHASE1 10V/DIV
PHASE2 10V/DIV
FIGURE 5. PWM1 WAVEFORMS
FIGURE 6. PWM2 WAVEFORMS
FN9044.2
August 9, 2006
8
ISL6443
Typical Performance Curves (Continued)
(Oscilloscope Plots are Taken Using the ISL6443EVAL Evaluation Board, VIN = 12V Unless Otherwise Noted.)
V
200mV/DIV
OUT2
AC COUPLED
V
200mV/DIV
OUT1
AC COUPLED
I
1A/DIV
OUT2
I
1A/DIV
OUT1
FIGURE 7. LOAD TRANSIENT RESPONSE VOUT1 (3.3V)
FIGURE 8. LOAD TRANSIENT RESPONSE VOUT2 (3.3V)
VCC_5V 1V/DIV
V
2V/DIV
OUT1
I
L1
2A/DIV
SS1 2V/DIV
V
1V/DIV
OUT1
FIGURE 10. OVERCURRENT HICCUP MODE OPERATION
FIGURE 9. PWM SOFT-START WAVEFORM
100
90
100
90
80
80
70
60
70
60
0
1
2
3
4
0
1
2
3
4
LOAD CURRENT (A)
LOAD CURRENT (A)
FIGURE 11. PWM1 EFFICIENCY vs LOAD (3.3V), VIN = 12V
FIGURE 12. PWM2 EFFICIENCY vs LOAD (3.3V), VIN = 12V
FN9044.2
August 9, 2006
9
ISL6443
Pin Descriptions
BOOT2, BOOT1 - These pins power the upper MOSFET
drivers of each PWM converter. Connect this pin to the
junction of the bootstrap capacitor and the cathode of the
bootstrap diode. The anode of the bootstrap diode is
connected to the VCC_5V pin.
REQUIRED outputs are within regulation AND soft-start
(SS1/SS2) is complete.
The last case is when both of the SD1 and SD2 are LOW.
PGOOD will be low.
SGND - (Pin 20 on the TSSOP; Pin 17 on the QFN)
This is the small-signal ground, common to all 3 controllers,
and must be routed separately from the high current ground
(PGND). All voltage levels are measured with respect to this
pin. Connect the additional SGND pins to this pin. If using a
5V supply, connect this pin to VCC_5V. A small ceramic
capacitor should be connected right next to this pin for noise
decoupling.
UGATE2, UGATE1 - These pins provide the gate drive for
the upper MOSFETs.
PHASE2, PHASE1 - These pins are connected to the junction
of the upper MOSFETs source, output filter inductor and lower
MOSFETs drain.
LGATE2, LGATE1 - These pins provide the gate drive for
the lower MOSFETs.
VIN - Use this pin to power the device with an external
supply voltage with a range of 5.6V to 24V. For 5V ±10%
operation, connect this pin to VCC_5V.
PGND - This pin provides the power ground connection for
the lower gate drivers for both PWM1 and PWM2. This pin
should be connected to the sources of the lower MOSFETs
and the (-) terminals of the external input capacitors.
VCC_5V - This pin is the output of the internal 5V linear
regulator. This output supplies the bias for the IC, the low
side gate drivers, and the external boot circuitry for the high
side gate drivers. The IC may be powered directly from a
single 5V (±10%) supply at this pin. When used as a 5V
FB3, FB2, FB1 - These pins are connected to the feedback
resistor divider and provide the voltage feedback signals for
the respective controller. They set the output voltage of the
converter. In addition, the PGOOD circuit uses these inputs
to monitor the output voltage status.
supply input, this pin must be externally connected to V
The VCC_5V pin must be always decoupled to power
.
IN
ISEN2, ISEN1 - These pins are used to monitor the voltage
drop across the lower MOSFET for current loop feedback
and overcurrent protection.
ground with a minimum of 4.7µF ceramic capacitor, placed
very close to the pin.
SYNC - This pin may be used to synchronize two or more
ISL6443 controllers. This pin requires a 1K resistor to
ground if used; connect directly to VCC_5V if not used.
PGOOD - This is an open drain logic output used to indicate
the status of the output voltages. This pin is pulled low when
either of the two PWM outputs is not within 10% of the
respective nominal voltage, or if the linear controller output is
less than 75% of it’s nominal value.
SS1, SS2 - These pins provide a soft-start function for their
respective PWM controllers. When the chip is enabled, the
regulated 5µA pull-up current source charges the capacitor
connected from this pin to ground. The error amplifier
reference voltage ramps from 0 to 0.8V while the voltage on
the soft-start pin ramps from 0 to 0.8V.
Table 1 shows detailed status of PGOOD which can be
classified into 4 cases under different combinations of SD1
and SD2 inputs.
The first case is when both SD1 and SD2 are HIGH.
PGOOD will be HIGH if all FB pins from the 3 REQUIRED
outputs are within regulation AND soft-starts (SS1 AND SS2)
are complete.
SD1, SD2 - These pins provide an enable/disable function
for their respective PWM output. The output is enabled when
this pin is floating or pulled HIGH, and disabled when the pin
is pulled LOW.
The other two cases are when either of SD1 or SD2 is LOW
which means the system wants to shut down one of the
PWM outputs but still wants to keep another output working.
PGOOD will be HIGH if all the FB pins from the 2
GATE3 - This pin is the open drain output of the linear
regulator controller.
OCSET2, OCSET1 - A resistor from this pin to ground sets
the overcurrent threshold for the respective PWM.
TABLE 1.
90%<FB2<110%? SS1 COMPLETED? SS2 COMPLETED? PGOOD
SD1
SD2
LDO>75%?
90%<FB1<110%?
1
1
0
0
1
0
1
0
Y
Y
Y
x
Y
Y
x
Y
x
Y
Y
x
Y
x
1
1
1
0
Y
x
Y
x
x
x
“x“ means “don’t care“.
FN9044.2
August 9, 2006
10
ISL6443
main outputs at start-up. The soft-start time can be obtained
from the following equation:
Functional Description
General Description
C
SS
⎛
⎝
⎞
⎠
-----------
T
= 0.8V
SOFT
The ISL6443 integrates control circuits for two synchronous
buck converters and one linear controller. The two
synchronous bucks operate out of phase to substantially
reduce the input ripple and thus reduce the input filter
requirements. The chip has four control lines (SS1, SD1,
SS2, and SD2), which provide independent control for each
of the synchronous buck outputs.
5µA
VCC_5V 1V/DIV
V
1V/DIV
OUT1
The buck PWM controllers employ a free-running frequency
of 300kHz. The current mode control scheme with an input
voltage feed-forward ramp input to the modulator provides
excellent rejection of input voltage variations and provides
simplified loop compensations.
The linear controller can drive either a PNP or PFET to provide
ultra low-dropout regulation with programmable voltages.
SS1 1V/DIV
Internal 5V Linear Regulator (VCC_5V)
FIGURE 13. SOFT-START OPERATION
All ISL6443 functions are internally powered from an on-
chip, low dropout 5V regulator. The maximum regulator input
voltage is 24V. Bypass the regulator’s output (VCC_5V) with
a 4.7µF capacitor to ground. The dropout voltage for this
LDO is typically 600mV, so when VCC_5V is greater than
5.6V, VCC_5V is typically 5V. The ISL6443 also employs an
undervoltage lockout circuit that disables both regulators
when VCC_5V falls below 4.4V.
The soft-start capacitors can be chosen to provide startup
tracking for the two PWM outputs. This can be achieved by
choosing the soft-start capacitors such that the soft-start
capacitor ration equals the respective PWM output voltage
ratio. For example, if I use PWM1 = 1.2V and PWM2 = 3.3V
then the soft-start capacitor ratio should be, C =
/C
SS1 SS1
1.2/3.3 = 0.364. Figure 14 shows that soft-start waveform
with C = 0.01µF and C = 0.027µF.
The internal LDO can source over 60mA to supply the IC,
power the low side gate drivers, charge the external boot
capacitor and supply small external loads. When driving
large FETs especially at 300kHz frequency, little or no
regulator current may be available for external loads.
SS1 SS2
V
1V/DIV
1V/DIV
OUT1
For example, a single large FET with 15nC total gate charge
requires 15nC x 300kHz = 4.5mA. Also, at higher input
voltages with larger FETs, the power dissipation across the
internal 5V will increase. Excessive dissipation across this
regulator must be avoided to prevent junction temperature
rise. Larger FETs can be used with 5V ±10% input
V
OUT2
applications. The thermal overload protection circuit will be
triggered, if the VCC_5V output is short circuited. Connect
VCC_5V to V for 5V ±10% input applications.
IN
Soft-Start Operation
FIGURE 14. PWM1 AND PWM2 OUTPUT TRACKING DURING
STARTUP
When soft-start is initiated, the voltage on the SS pin of the
enabled PWM channels starts to ramp gradually, due to the
5µA current sourced into the external capacitor. The output
voltage follows the soft-start voltage.
Output Voltage Programming
A resistive divider from the output to ground sets the output
voltage of either PWM channel. The center point of the
divider shall be connected to FBx pin. The output voltage
value is determined by the following equation.
When the SS pin voltage reaches 0.8V, the output voltage of
the enabled PWM channel reaches the regulation point, and
the soft-start pin voltage continues to rise. At this point the
PGOOD and fault circuitry is enabled. This completes the
soft-start sequence. Any further rise of SS pin voltage does
not affect the output voltage. By varying the values of the
soft-start capacitors, it is possible to provide sequencing of the
R1 + R2
R2
⎛
⎝
⎞
⎠
----------------------
V
= 0.8V
OUTx
where R1 is the top resistor of the feedback divider network
and R2 is the resistor connected from FBx to ground.
FN9044.2
August 9, 2006
11
ISL6443
Shoot-through control logic provides a 20ns deadtime to ensure
Out-of-Phase Operation
that both the upper and lower MOSFETs will not turn on
simultaneously and cause a shoot-through condition.
The two PWM controllers in the ISL6443 operate 180o out-of-
phase to reduce input ripple current. This reduces the input
capacitor ripple current requirements, reduces power supply-
induced noise, and improves EMI. This effectively helps to
lower component cost, save board space and reduce EMI.
Gate Drivers
The low-side gate driver is supplied from VCC_5V and
provides a peak sink/source current of 400mA. The high-side
gate driver is also capable of 400mA current. Gate-drive
voltages for the upper N-Channel MOSFET are generated by
the flying capacitor boot circuit. A boot capacitor connected
from the BOOT pin to the PHASE node provides power to the
high side MOSFET driver. To limit the peak current in the IC,
an external resistor may be placed between the UGATE pin
and the gate of the external MOSFET. This small series
resistor also damps any oscillations caused by the resonant
tank of the parasitic inductances in the traces of the board an
the FET’s input capacitance.
Dual PWMs typically operate in-phase and turn on both upper
FETs at the same time. The input capacitor must then support
the instantaneous current requirements of both controllers
simultaneously, resulting in increased ripple voltage and
current. The higher RMS ripple current lowers the efficiency
due to the power loss associated with the ESR of the input
capacitor. This typically requires more low-ESR capacitors in
parallel to minimize the input voltage ripple and ESR-related
losses, or to meet the required ripple current rating.
With dual synchronized out-of-phase operation, the high-side
MOSFETs of the ISL6443 turn on 180o out-of-phase. The
instantaneous input current peaks of both regulators no longer
overlap, resulting in reduced RMS ripple current and input
voltage ripple. This reduces the required input capacitor ripple
current rating, allowing fewer or less expensive capacitors, and
reducing the shielding requirements for EMI. The typical
operating curves show the synchronized 180° out-of-phase
operation.
VIN
VCC_5V
BOOT
UGATE
PHASE
Input Voltage Range
The ISL6443 is designed to operate from input supplies
ranging from 4.5V to 24V. However, the input voltage range
can be effectively limited by the available maximum duty
ISL6443
cycle (D
= 93%).
MAX
FIGURE 15.
V
+ V
d1
0.93
OUT
⎛
⎝
⎞
⎠
--------------------------------
V
=
+ V – V
d1
IN(min)
d2
At start-up the low-side MOSFET turns on and forces
PHASE to ground in order to charge the BOOT capacitor to
5V. After the low-side MOSFET turns off, the high-side
MOSFET is turned on by closing an internal switch between
BOOT and UGATE. This provides the necessary gate-to-
source voltage to turn on the upper MOSFET, an action that
boosts the 5V gate drive signal above VIN. The current
required to drive the upper MOSFET is drawn from the
internal 5V regulator.
where,
Vd1 = Sum of the parasitic voltage drops in the inductor
discharge path, including the lower FET, inductor and PC
board.
Vd2 = Sum of the voltage drops in the charging path,
including the upper FET, inductor and PC board resistances.
The maximum input voltage and minimum output voltage is
limited by the minimum on-time (t
).
ON(min)
Protection Circuits
V
OUT
× 300kHz
---------------------------------------------------
V
≤
IN(max)
t
The converter output is monitored and protected against
overload, short circuit and undervoltage conditions. A
sustained overload on the output sets the PGOOD low and
initiates hiccup mode.
ON(min)
where, t
= 30ns
ON(min)
Gate Control Logic
The gate control logic translates generated PWM signals into
gate drive signals providing amplification, level shifting and
shoot-through protection. The gate drivers have some circuitry
that helps optimize the ICs performance over a wide range of
operational conditions. As MOSFET switching times can vary
dramatically from type to type and with input voltage, the gate
control logic provides adaptive dead time by monitoring real
gate waveforms of both the upper and the lower MOSFETs.
Overcurrent Protection
Both PWM controllers use the lower MOSFET’s on-
resistance, r
, to monitor the current in the converter.
DS(ON)
The sensed voltage drop is compared with a threshold set by
a resistor connected from the OCSETx pin to ground.
(7)(R
)
CS
R
= ------------------------------------------
OCSET
(I )(R
)
DS(on)
OC
FN9044.2
August 9, 2006
12
ISL6443
where, I
is the desired overcurrent protection threshold,
Feedback Loop Compensation
OC
is a value of the current sense resistor connected
and R
CS
To reduce the number of external components and to simplify
the process of determining compensation components, both
PWM controllers have internally compensated error
amplifiers. To make internal compensation possible several
design measures were taken.
to the ISENx pin. If an overcurrent is detected for 2
consecutive clock cycles then the IC enters a hiccup mode
by turning off the gate drivers and entering into soft-start.
The IC will cycle 2 times through soft-start before trying to
restart. The IC will continue to cycle through soft-start until
the overcurrent condition is removed. Hiccup mode is active
during soft-start so care must be taken to ensure that the
peak inductor current does not exceed the overcurrent
threshold during soft-start.
First, the ramp signal applied to the PWM comparator is
proportional to the input voltage provided via the VIN pin.
This keeps the modulator gain constant with variation in the
input voltage. Second, the load current proportional signal is
derived from the voltage drop across the lower MOSFET
during the PWM time interval and is subtracted from the
amplified error signal on the comparator input. This creates
an internal current control loop. The resistor connected to
the ISEN pin sets the gain in the current feedback loop. The
following expression estimates the required value of the
current sense resistor depending on the maximum operating
Because of the nature of this current sensing technique, and
to accommodate a wide range of r
variations, the
DS(ON)
value of the overcurrent threshold should represent an
overload current about 150% to 180% of the maximum
operating current. If more accurate current protection is
desired place a current sense resistor in series with the
lower MOSFET source.
load current and the value of the MOSFET’s r
DS(ON)
.
Over-Temperature Protection
(I
)(R
)
DS(ON)
MAX
The IC incorporates an over-temperature protection circuit
that shuts the IC down when a die temperature of 150°C is
reached. Normal operation resumes when the die
temperatures drops below 130°C through the initiation of a
full soft-start cycle.
------------------------------------------------
≥
R
CS
32µA
Choosing R
to provide 32µA of current to the current
CS
sample and hold circuitry is recommended but values down
to 2µA and up to 100µA can be used.
Implementing Synchronization
Due to the current loop feedback, the modulator has a single
pole response with -20dB slope at a frequency determined
by the load.
The SYNC pin may be used to synchronize two or more
controllers. When the SYNC pins of two controllers are
connected together, one controller becomes the master and
the other controller synchronizes to the master. A pull-down
resistor is required and must be sized to provide a low
enough time constant to pass the SYNC pulse. Connect this
pin to VCC_5V if not used. Figure 16 shows the SYNC pin
waveform operating at 16 times the switching frequency.
1
--------------------------------
F
=
PO
2π ⋅ R ⋅ C
O
O
where R is load resistance and C is load capacitance. For
O
O
this type of modulator, a Type 2 compensation circuit is
usually sufficient.
Figure 17 shows a Type 2 amplifier and its response along
with the responses of the current mode modulator and the
converter. The Type 2 amplifier, in addition to the pole at
origin, has a zero-pole pair that causes a flat gain region at
frequencies in between the zero and the pole.
1
F
= ------------------------------ = 6kHz
Z
2π ⋅ R ⋅ C
2
1
1
F
= ------------------------------ = 600kHz
2π ⋅ R ⋅ C
P
1
2
FIGURE 16. SYNC WAVEFORM
FN9044.2
August 9, 2006
13
ISL6443
feedback resistor drains the excess charge. However,
charge may build up on the output capacitor making V
rise above its set point. Care must be taken to insure that the
feedback resistor’s current exceeds the pass transistors
leakage current over the entire temperature range.
LDO
C2
C1
R2
CONVERTER
R1
The linear regulator output can be supplied by the output of
one of the PWMs. When using a PFET, the output of the
linear will track the PWM supply after the PWM output rises
to a voltage greater than the threshold of the PFET pass
device. The voltage differential between the PWM and the
EA
TYPE 2 EA
G
= 17.5dB
M
G
= 18dB
EA
MODULATOR
linear output will be the load current times the r
.
F
DS(ON)
F
Z
P
Figure 18 shows the linear regulator (2.5V) startup waveform
and the PWM (3.3V) startup waveform.
F
PO
F
C
FIGURE 17. FEEDBACK LOOP COMPENSATION
The zero frequency, the amplifier high-frequency gain, and
the modulator gain are chosen to satisfy most typical
applications. The crossover frequency will appear at the
point where the modulator attenuation equals the amplifier
high frequency gain. The only task that the system designer
has to complete is to specify the output filter capacitors to
position the load main pole somewhere within one decade
lower than the amplifier zero frequency. With this type of
compensation plenty of phase margin is easily achieved due
to zero-pole pair phase ‘boost’.
V
1V/DIV
1V/DIV
OUT2
V
OUT3
Conditional stability may occur only when the main load pole
is positioned too much to the left side on the frequency axis
due to excessive output filter capacitance. In this case, the
ESR zero placed within the 1.2kHz to 30kHz range gives
some additional phase ‘boost’. Some phase boost can also
FIGURE 18. LINEAR REGULATOR STARTUP WAVEFORM
be achieved by connecting capacitor C in parallel with the
Z
60
50
upper resistor R1 of the divider that sets the output voltage
value. Please refer to the output inductor and capacitor
selection sections for further details.
40
30
Linear Regulator
The linear regulator controller is a transconductance
amplifier with a nominal gain of 2A/V. The N-channel
MOSFET output device can sink a minimum of 50mA. The
reference voltage is 0.8V. With zero volts differential at it’s
input, the controller sinks 21mA of current. An external PNP
transistor or PFET pass element can be used. The dominant
pole for the loop can be placed at the base of the PNP (or
gate of the PFET), as a capacitor from emitter to base
(source to gate of a PFET). Better load transient response is
achieved however, if the dominant pole is placed at the
output, with a capacitor to ground at the output of the
regulator.
20
10
0
0.84
0.79
0.8
0.82
0.83
0.85
0.81
FEEDBACK VOLTAGE (V)
FIGURE 19. LINEAR CONTROLLER GAIN
Base-Drive Noise Reduction
The high-impedance base driver is susceptible to system
noise, especially when the linear regulator is lightly loaded.
Capacitively coupled switching noise or inductively coupled
Under no-load conditions, leakage currents from the pass
transistors supply the output capacitors, even when the
transistor is off. Generally this is not a problem since the
FN9044.2
August 9, 2006
14
ISL6443
EMI onto the base drive causes fluctuations in the base
current, which appear as noise on the linear regulator’s
5. Place The PWM controller IC close to lower FET. The
LGATE connection should be short and wide. The IC can
be best placed over a quiet ground area. Avoid switching
ground loop current in this area.
output. Keep the base drive traces away from the step-down
converter, and as short as possible, to minimize noise
coupling. A resistor in series with the gate drivers reduces
the switching noise generated by PWM. Additionally, a
bypass capacitor may be placed across the base-to-emitter
resistor. This bypass capacitor, in addition to the transistor’s
input capacitor, could bring in second pole that will de-
stabilize the linear regulator. Therefore, the stability
requirements determine the maximum base-to-emitter
capacitance.
6. Place VCC_5V bypass capacitor very close to VCC_5V
pin of the IC and connect its ground to the PGND plane.
7. Place the gate drive components BOOT diode and BOOT
capacitors together near controller IC
8. The output capacitors should be placed as close to the
load as possible. Use short wide copper regions to
connect output capacitors to load to avoid inductance and
resistances.
9. Use copper filled polygons or wide but short trace to
connect junction of upper FET. Lower FET and output
inductor. Also keep the PHASE node connection to the IC
short. Do not unnecessary oversize the copper islands for
PHASE node. Since the phase nodes are subjected to
very high dv/dt voltages, the stray capacitor formed
between these islands and the surrounding circuitry will
tend to couple switching noise.
Layout Guidelines
Careful attention to layout requirements is necessary for
successful implementation of a ISL6443 based DC/DC
converter. The ISL6443 switches at a very high frequency
and therefore the switching times are very short. At these
switching frequencies, even the shortest trace has
significant impedance. Also the peak gate drive current rises
significantly in extremely short time. Transition speed of the
current from one device to another causes voltage spikes
across the interconnecting impedances and parasitic circuit
elements. These voltage spikes can degrade efficiency,
generate EMI, increase device overvoltage stress and
ringing. Careful component selection and proper PC board
layout minimizes the magnitude of these voltage spikes.
10. Route all high speed switching nodes away from the
control circuitry.
11. Create separate small analog ground plane near the IC.
Connect SGND pin to this plane. All small signal
grounding paths including feedback resistors, current
limit setting resistors, SYNC/SDx pull down resistors
should be connected to this SGND plane.
There are two sets of critical components in a DC/DC
converter using the ISL6443. The switching power
components and the small signal components. The
switching power components are the most critical from a
layout point of view because they switch a large amount of
energy so they tend to generate a large amount of noise.
The critical small signal components are those connected to
sensitive nodes or those supplying critical bias currents. A
multi-layer printed circuit board is recommended.
12. Ensure the feedback connection to output capacitor is
short and direct.
Component Selection Guidelines
MOSFET Considerations
The logic level MOSFETs are chosen for optimum efficiency
given the potentially wide input voltage range and output
power requirements. Two N-Channel MOSFETs are used in
each of the synchronous-rectified buck converters for the
PWM1 and PWM2 outputs. These MOSFETs should be
Layout Considerations
selected based upon r
and thermal management considerations.
, gate supply requirements,
DS(ON)
1. The Input capacitors, Upper FET, Lower FET, Inductor
and Output capacitor should be placed first. Isolate these
power components on the topside of the board with their
ground terminals adjacent to one another. Place the input
high frequency decoupling ceramic capacitor very close
to the MOSFETs.
The power dissipation includes two loss components;
conduction loss and switching loss. These losses are
distributed between the upper and lower MOSFETs
according to duty cycle (see the following equations). The
conduction losses are the main component of power
dissipation for the lower MOSFETs. Only the upper MOSFET
has significant switching losses, since the lower device turns
on and off into near zero voltage. The equations assume
linear voltage-current transitions and do not model power
loss due to the reverse-recovery of the lower MOSFET’s
body diode.
2. Use separate ground planes for power ground and small
signal ground. Connect the SGND and PGND together
close of the IC. Do not connect them together anywhere
else.
3. The loop formed by Input capacitor, the top FET and the
bottom FET must be kept as small as possible.
4. Insure the current paths from the input capacitor to the
MOSFET; to the output inductor and output capacitor are
as short as possible with maximum allowable trace
widths.
2
(I )(r
)(V
)
(I )(V )(t
)(F
)
SW
O
DS(ON)
OUT
O
IN SW
P
= -------------------------------------------------------------- + -----------------------------------------------------------
UPPER
V
2
IN
FN9044.2
August 9, 2006
15
ISL6443
High frequency decoupling capacitors should be placed as
2
(I )(r
)(V – V
)
OUT
close to the power pins of the load as physically possible. Be
careful not to add inductance in the circuit board wiring that
could cancel the usefulness of these low inductance
components. Consult with the manufacturer of the load
circuitry for specific decoupling requirements.
O
DS(ON)
IN
P
= ------------------------------------------------------------------------------
LOWER
V
IN
A large gate-charge increases the switching time, t
,
SW
which increases the upper MOSFET switching losses.
Ensure that both MOSFETs are within their maximum
junction temperature at high ambient temperature by
calculating the temperature rise according to package
thermal-resistance specifications.
Use only specialized low-ESR capacitors intended for
switching-regulator applications at 300kHz for the bulk
capacitors. In most cases, multiple small-case electrolytic
capacitors perform better than a single large-case capacitor.
Output Capacitor Selection
The stability requirement on the selection of the output
The output capacitors for each output have unique
capacitor is that the ‘ESR zero’, f , be between 1.2kHz and
requirements. In general, the output capacitors should be
selected to meet the dynamic regulation requirements
including ripple voltage and load transients. Selection of
output capacitors is also dependent on the output inductor,
so some inductor analysis is required to select the output
capacitors.
Z
30kHz. This range is set by an internal, single compensation
zero at 6kHz. The ESR zero can be a factor of five on either
side of the internal zero and still contribute to increased
phase margin of the control loop. Therefore,
1
C
= ------------------------------------
OUT
2Π(ESR)(f )
Z
One of the parameters limiting the converter’s response to a
load transient is the time required for the inductor current to
slew to it’s new level. The ISL6443 will provide either 0% or
71% duty cycle in response to a load transient.
In conclusion, the output capacitors must meet three criteria:
1. They must have sufficient bulk capacitance to sustain the
output voltage during a load transient while the output
inductor current is slewing to the value of the load
transient,
The response time is the time interval required to slew the
inductor current from an initial current value to the load
current level. During this interval the difference between the
inductor current and the transient current level must be
supplied by the output capacitor(s). Minimizing the response
time can minimize the output capacitance required. Also, if
the load transient rise time is slower than the inductor
response time, as in a hard drive or CD drive, it reduces the
requirement on the output capacitor.
2. The ESR must be sufficiently low to meet the desired
output voltage ripple due to the output inductor current,
and
3. The ESR zero should be placed, in a rather large range,
to provide additional phase margin.
The recommended output capacitor value for the ISL6443 is
between 150µF to 680µF, to meet stability criteria with
external compensation. Use of aluminum electrolytic,
POSCAP, or tantalum type capacitors is recommended. Use
of low ESR ceramic capacitors is possible but would take
more rigorous loop analysis to ensure stability.
The maximum capacitor value required to provide the full,
rising step, transient load current during the response time of
the inductor is:
2
(L )(I
)
TRAN
O
C
= ----------------------------------------------------------
OUT
2(V – V )(DV )
OUT
Output Inductor Selection
IN
O
The PWM converters require output inductors. The output
inductor is selected to meet the output voltage ripple
requirements. The inductor value determines the converter’s
ripple current and the ripple voltage is a function of the ripple
current and output capacitor(s) ESR. The ripple voltage
expression is given in the capacitor selection section and the
ripple current is approximated by the following equation:
where, C
OUT
is the output capacitor(s) required, L is the
O
output inductor, I
is the transient load current step, V
TRAN
is the input voltage, V is output voltage, and DV
IN
is the
O
OUT
drop in output voltage allowed during the load transient.
High frequency capacitors initially supply the transient
current and slow the load rate-of-change seen by the bulk
capacitors. The bulk filter capacitor values are generally
determined by the ESR (Equivalent Series Resistance) and
voltage rating requirements as well as actual capacitance
requirements.
(V – V
)(V
)
OUT
IN
OUT
∆I = ---------------------------------------------------------
L
(f )(L)(V
)
IN
S
For the ISL6443, Inductor values between 6.4µH to 10µH is
recommended when using the Typical Application
Schematic. Other values can be used but a thorough stability
study should be done.
The output voltage ripple is due to the inductor ripple current
and the ESR of the output capacitors as defined by:
V
= ∆I (ESR)
L
RIPPLE
where, I is calculated in the Inductor Selection section.
L
FN9044.2
August 9, 2006
16
ISL6443
Input Capacitor Selection
5
4.5
4
The important parameters for the bulk input capacitor(s) are
the voltage rating and the RMS current rating. For reliable
operation, select bulk input capacitors with voltage and
current ratings above the maximum input voltage and largest
RMS current required by the circuit. The capacitor voltage
rating should be at least 1.25 times greater than the
maximum input voltage and 1.5 times is a conservative
guideline. The AC RMS Input current varies with the load.
The total RMS current supplied by the input capacitance is:
IN PHASE
3.5
3
2.5
2
OUT OF PHASE
1.5
1
5V
3.3V
2
2
I
=
I
+ I
0.5
0
RMS
RMS1
RMS2
0
1
2
3
4
5
where,
3.3V AND 5V LOAD CURRENT
2
I
=
DC – DC ⋅ I
RMSx
O
FIGURE 20. INPUT RMS CURRENT vs LOAD
DC is duty cycle of the respective PWM.
Use a mix of input bypass capacitors to control the voltage
ripple across the MOSFETs. Use ceramic capacitors for the
high frequency decoupling and bulk capacitors to supply the
RMS current. Small ceramic capacitors can be placed very
close to the upper MOSFET to suppress the voltage induced
in the parasitic circuit impedances.
Depending on the specifics of the input power and its
impedance, most (or all) of this current is supplied by the
input capacitor(s). Figure 20 shows the advantage of having
the PWM converters operating out of phase. If the
converters were operating in phase, the combined RMS
current would be the algebraic sum, which is a much larger
value as shown. The combined out-of-phase current is the
square root of the sum of the square of the individual
reflected currents and is significantly less than the combined
in-phase current.
For board designs that allow through-hole components, the
Sanyo OS-CON® series offer low ESR and good
temperature performance. For surface mount designs, solid
tantalum capacitors can be used, but caution must be
exercised with regard to the capacitor surge current rating.
These capacitors must be capable of handling the surge-
current at power-up. The TPS series available from AVX is
surge current tested.
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.
Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
FN9044.2
August 9, 2006
17
ISL6443
Quad Flat No-Lead Plastic Package (QFN)
L28.5x5
Micro Lead Frame Plastic Package (MLFP)
28 LEAD QUAD FLAT NO-LEAD PLASTIC PACKAGE
(COMPLIANT TO JEDEC MO-220VHHD-1 ISSUE I)
2X
0.15
C A
MILLIMETERS
D
A
SYMBOL
MIN
NOMINAL
MAX
1.00
0.05
1.00
NOTES
9
D/2
A
A1
A2
A3
b
0.80
0.90
-
D1
-
-
0.02
-
D1/2
2X
0.65
9
N
0.15 C
B
6
0.20 REF
9
INDEX
AREA
1
2
3
E1/2
E/2
9
0.18
2.95
2.95
0.25
0.30
3.25
3.25
5,8
D
5.00 BSC
-
E1
E
B
D1
D2
E
4.75 BSC
9
3.10
7,8
2X
0.15 C
B
5.00 BSC
-
2X
TOP VIEW
E1
E2
e
4.75 BSC
9
0.15 C
A
3.10
7,8
0
A2
4X
C
0.50 BSC
-
A
/ /
0.10 C
0.08 C
k
0.20
0.50
-
0.60
28
7
-
-
L
0.75
8
SEATING PLANE
A1
A3
SIDE VIEW
9
N
2
Nd
Ne
P
3
5
NX b
0.10 M C A B
7
3
4X P
D2
D2
8
7
-
-
-
0.60
12
9
NX k
(DATUM B)
θ
-
9
2
N
Rev. 1 11/04
4X P
1
NOTES:
(DATUM A)
2
3
1. Dimensioning and tolerancing conform to ASME Y14.5-1994.
2. N is the number of terminals.
(Ne-1)Xe
REF.
E2
6
INDEX
AREA
7
8
3. Nd and Ne refer to the number of terminals on each D and E.
4. All dimensions are in millimeters. Angles are in degrees.
E2/2
NX L
8
N
5. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.
e
9
(Nd-1)Xe
REF.
CORNER
OPTION 4X
6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
BOTTOM VIEW
A1
NX b
5
7. Dimensions D2 and E2 are for the exposed pads which provide
improved electrical and thermal performance.
8. Nominal dimensionsare provided toassistwith PCBLandPattern
Design efforts, see Intersil Technical Brief TB389.
SECTION "C-C"
C
L
9. Features and dimensions A2, A3, D1, E1, P & θ are present when
Anvil singulation method is used and not present for saw
singulation.
C
L
L
L
10
10
L1
L1
e
e
C
C
TERMINAL TIP
FOR ODD TERMINAL/SIDE
FOR EVEN TERMINAL/SIDE
FN9044.2
August 9, 2006
18
相关型号：
ISL6446AIAZ
Dual (180° Out-of-Phase) PWM and Linear Controller; QSOP24; Temp Range: -40° to 85°C
RENESAS
ISL6446AIAZ-TK
Dual (180° Out-of-Phase) PWM and Linear Controller; QSOP24; Temp Range: -40° to 85°C
RENESAS
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