LT1304 [Linear]
Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown; 微功耗DC /对于低电池电压检测器DC转换器活跃在关断型号: | LT1304 |
厂家: | Linear |
描述: | Micropower DC/DC Converters with Low-Battery Detector Active in Shutdown |
文件: | 总16页 (文件大小:348K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
LT1304/LT1304-3.3/LT1304-5
Micropower
DC/DC Converters with
Low-Battery Detector
Active in Shutdown
U
DESCRIPTION
FEATURES
The LT®1304 is a micropower step-up DC/DC converter
ideal for use in small, low voltage, battery-operated sys-
tems. The devices operate from a wide input supply range
of 1.5V to 8V. The LT1304-3.3 and LT1304-5 generate
regulated outputs of 3.3V and 5V and the adjustable
LT1304 can deliver output voltages up to 25V. Quiescent
current, 120µA in active mode, decreases to just 10µA in
shutdown with the low-battery detector still active. Peak
switch current, internally set at 1A, can be reduced by
adding a single resistor from the ILIM pin to ground. The
high speed operation of the LT1304 allows the use of
small, surface-mountable inductors and capacitors. The
LT1304 is available in an 8-lead SO package.
■
5V at 200mA from Two Cells
■
10µA Quiescent Current in Shutdown
■
Operates with VIN as Low as 1.5V
■
Low-Battery Detector Active in Shutdown
■
Low Switch VCESAT: 370mV at 1A Typical
■
120µA Quiescent Current in Active Mode
■
Switching Frequency Up to 300kHz
■
Programmable Peak Current with One Resistor
8-Lead SO Package
■
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APPLICATIONS
■
2-, 3-, or 4-Cell to 5V or 3.3V Step-Up
■
Portable Instruments
, LTC and LT are registered trademarks of Linear Technology Corporation.
■
Bar Code Scanners
■
Palmtop Computers
■
Diagnostic Medical Instrumentation
Personal Data Communicators/Computers
■
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TYPICAL APPLICATION
2-Cell to 5V Step-Up Converter with Low-Battery Detect
Efficiency
D1**
22µH*
90
80
3
4
499k
V
SW
SENSE
LT1304-5
IN
8
2
1
6
5V
LBI
200mA
+
+
100k
100µF
70
60
50
40
100µF
2 CELLS
604k
NC
LBO
I
LBO
GND
5
LIM
LOW WHEN
SHDN
7
V
BAT
< 2.2V
V
IN
V
IN
V
IN
= 3.3V
= 2.5V
= 1.8V
SHUTDOWN
*SUMIDA CD54-220
**1N5817
1304 TA01
0.1
1
10
100
500
LOAD CURRENT (mA)
1304 TA02
1
LT1304/LT1304-3.3/LT1304-5
W W U W
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ABSOLUTE MAXIMUM RATINGS
PACKAGE/ORDER INFORMATION
VIN Voltage ................................................................ 8V
SW Voltage ............................................... –0.4V to 25V
FB Voltage (LT1304)...................................... VIN + 0.3V
Sense Voltage (LT1304-3.3/LT1304-5) ..................... 8V
ORDER PART
NUMBER
TOP VIEW
LT1304CS8
LT1304CS8-3.3
LT1304CS8-5
LBI
1
2
3
4
FB (SENSE)*
SHDN
8
7
6
5
ILIM Voltage .............................................................. 5V
LBO
SHDN Voltage ............................................................ 6V
LBI Voltage ............................................................... VIN
LBO Voltage............................................................... 8V
Maximum Power Dissipation ............................. 500mW
Junction Temperature.......................................... 125°C
Operating Temperature Range ..................... 0°C to 70°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
V
IN
I
LIM
SW
GND
S8 PART MARKING
S8 PACKAGE
8-LEAD PLASTIC SO
*FIXED OUTPUT VERSION
1304
13043
13045
TJMAX = 125°C, θJA = 150°C/W
Consult factory for Industrial and Military grade parts.
ELECTRICAL CHARACTERISTICS
VIN = 2V, VSHDN = 2V unless otherwise noted.
MIN
PARAMETER
CONDITIONS
TYP
MAX
1.65
8
UNITS
Minimum Operating Voltage
Operating Voltage Range
Quiescent Current
●
●
●
1.5
V
V
V
SHDN
= 2V, Not Switching
120
200
µA
Quiescent Current in Shutdown
V
SHDN
V
SHDN
= 0V, V = 2V
●
●
7
27
15
50
µA
µA
IN
= 0V, V = 5V
IN
Comparator Trip Point
FB Pin Bias Current
LT1304
LT1304
●
●
●
1.22
1.24
10
1.26
25
1
V
nA
µA
Sense Pin Leakage in Shutdown
Output Sense Voltage
V
SHDN
= 0V, Fixed Output Versions
0.002
LT1304-3.3
LT1304-5
●
●
3.17
4.80
3.3
5.05
3.43
5.25
V
V
Line Regulation
1.8V ≤ V ≤ 8V
●
●
●
●
●
●
0.04
1.17
6
0.15
1.25
20
%/V
V
IN
LBI Input Threshold
LBI Bias Current
Falling Edge
1.10
nA
mV
V
LBI Input Hysteresis
LBO Output Voltage Low
LBO Output Leakage Current
35
65
I
= 500µA
0.2
0.01
0.4
0.1
SINK
LBI = 1.5V, LBO = 5V
µA
SHDN Input Voltage High
SHDN Input Voltage Low
●
●
1.4
V
V
0.4
8
SHDN Pin Bias Current
V
V
= 5V
= 0V
●
●
5
µA
µA
SHDN
SHDN
–5
1
–2
Switch OFF Time
●
●
●
1.5
6
2
8
µs
µs
%
Switch ON Time
Current Limit Not Asserted
Current Limit Not Asserted
4
Maximum Duty Cycle
Peak Switch Current
76
0.8
80
88
1.2
I
Pin Open, V = 5V
1
500
A
mA
LIM
IN
20k from I to GND
LIM
2
LT1304/LT1304-3.3/LT1304-5
ELECTRICAL CHARACTERISTICS VIN = 2V, VSHDN = 2V unless otherwise noted.
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Switch Saturation Voltage
I
I
= 1A
0.37
0.26
V
V
SW
SW
= 700mA
●
●
0.35
7
Switch Leakage
Switch Off, V = 5V
0.01
µA
SW
The
● denotes specifications which apply over the 0°C to 70°C operating
temperature range.
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TYPICAL PERFORMANCE CHARACTERISTICS
Switch Saturation Voltage
Peak Switch Current Limit
On- and Off-Times
500
400
300
200
100
0
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
8
7
6
5
4
3
2
1
0
T
= 25°C
A
MAXIMUM ON-TIME
OFF-TIME
75
0
0.4
0.6
0.8
1.0
1.2
–50
–25
0
25
50
100
0.2
–50
0
25
50
75
100
–25
TEMPERATURE (°C)
SWITCH CURRENT (A)
TEMPERATURE (°C)
1304 G01
1304 G02
1304 G03
Supply Current
Feedback Pin Bias Current
Feedback Voltage
1.250
1.245
1.240
1.235
1.230
1.225
1.220
1.215
1.210
1.205
1.200
300
250
200
150
100
50
20
18
T
A
= 25°C
16
14
12
V
SHDN
= V
IN
NOT SWITCHING
10
8
6
4
2
0
V
= 0V
4
SHDN
0
–50
0
25
50
75
100
0
1
2
3
5
6
7
8
–25
–50 –25
25
50
75
100
0
TEMPERATURE (°C)
INPUT VOLTAGE (V)
TEMPERATURE (°C)
1304 G04
1304 G06
1304 G05
3
LT1304/LT1304-3.3/LT1304-5
U W
TYPICAL PERFORMANCE CHARACTERISTICS
Burst ModeTM Operation
Load Transient Response
VOUT
100mV/DIV
VOUT
100mV/DIV
AC COUPLED
AC COUPLED
VSW
5V/DIV
ILOAD
200mA
0
IL
500mA/DIV
100µs/DIV
1304 G07
20µs/DIV
1304 G08
VIN = 2.5V
OUT = 5V
LOAD = 185mA
L = 22µH
V
I
Burst Mode is a trademark of Linear Technology Corporation.
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PIN FUNCTIONS
ILIM (Pin6):CurrentLimitSetPin. Floatfor1Apeakswitch
current; a resistor to ground will lower peak current.
LBI (Pin 1): Low-Battery Detector Input. When voltage on
this pin is less than 1.17V, detector output is low.
SHDN (Pin 7): Shutdown Input. When low, switching
regulator is turned off. The low-battery detector remains
active. The SHDNinput should not be left floating. IfSHDN
is not used, tie the pin to VIN.
LBO (Pin 2): Low-Battery Detector Output. Open collector
cansinkupto500µA. Low-batterydetectorremainsactive
when device is shut down.
VIN (Pin 3): Input Supply. Must be bypassed close (<0.2")
FB/SENSE (Pin 8): On the LT1304 (adjustable) this pin
goes to the comparator input. On the fixed-output ver-
sions, the pin connects to the resistor divider which sets
output voltage. The divider is disconnected from the pin
during shutdown.
to the pin. See required layout in the Typical Applications.
SW(Pin4):CollectorofPowerNPN.Keepcoppertraceson
this pin short and direct to minimize RFI.
GND (Pin 5): Device Ground. Must be low impedance;
solder directly to ground plane.
4
LT1304/LT1304-3.3/LT1304-5
W
BLOCK DIAGRA S
V
IN
V
OUT
L1
+
+
D1
C1
C2
V
IN
LB0
SW
2
3
4
1.5V
UNDERVOLTAGE
LOCKOUT
36mV
LBI
1
+
+
–
R1
7.2Ω
R2
1k
A2
–
A3
1.17V
BIAS
~1V
Q3
OFF
R3
R4
FB
1k
8
–
TIMERS
ENABLE
Q1
×200
6µs ON
A1
Q2
×1
1.5µs OFF
+
DRIVER
1.24V
V
REF
SHUTDOWN
SHDN
7
I
GND
LIM
6
5
1304 F01
Figure 1. LT1304 Block Diagram. Independent Low-Battery Detector A3 Remains Alive When Device Is in Shutdown
V
IN
3
LBI
1
LB0
2
SW
4
1.5V
UNDERVOLTAGE
LOCKOUT
36mV
SENSE
8
+
+
–
R1
7.2Ω
R2
1k
A2
–
A3
1.17V
BIAS
~1V
Q3
OFF
590k
R1
1k
–
TIMERS
ENABLE
Q1
×200
6µs ON
A1
Q2
×1
1.5µs OFF
+
DRIVER
1.24V
V
REF
SHUTDOWN
SHDN
7
I
GND
LIM
6
5
1304 F02
R1 = 355k (LT1304-3.3), 195k (LT1304-5)
Figure 2. LT1304-3.3/LT1304-5 Block Diagram
5
LT1304/LT1304-3.3/LT1304-5
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OPERATIO
tion in efficiency. For the majority of 2-cell or 3-cell input
LT1304 applications, a 22µH or 20µH inductor such as the
SumidaCD54-220(drum)orCoiltronicsCTX20-1(toroid)
will suffice. If switch current is reduced using the ILIM pin,
smaller inductors such as the Sumida CD43 series or
Coilcraft DO1608 series can be used. Minimizing DCR is
important for best efficiency. Ideally, the inductor DCR
should be less than 0.05Ω, although the physical size of
such an inductor makes its use prohibitive in many space
conscious applications. If EMI is a concern, such as when
sensitive analog circuitry is present, a toroidal inductor
such as the Coiltronics CTX20-1 is suggested.
The LT1304’s operation can best be understood by exam-
ining the block diagram in Figure 1. Comparator A1
monitors the output voltage via resistor divider string
R3/R4 at the FB pin. When VFB is higher than the 1.24V
reference, A2 and the timers are turned off. Only the
reference, A1 and A3 consume current, typically 120µA.
As VFB drops below 1.24V plus A1’s hysteresis (about
6mV), A1 enables the rest of the circuit. Power switch Q1
is then cycled on for 6µs, or until current comparator A2
turns off the ON timer, whichever comes first. Off-time is
fixed at approximately 1.5µs. Q1’s switching causes cur-
rent to alternately build up in inductor L1 and discharge
into output capacitor C2 via D1, increasing the output
voltage. As VFB increases enough to overcome C1’s hys-
teresis, switching action ceases. C2 is left to supply
current to the load until VOUT decreases enough to force
A1’s output high, and the entire cycle repeats.
A special case exists where the VOUT/VIN differential is
high, such as a 2V to 12V boost converter. If the required
duty cycle for continuous mode operation is higher than
the LT1304 can provide, the converter must be designed
for discontinuous operation. This means that the inductor
current decreases to zero during the switch OFF time. For
a simple step-up (boost) converter, duty cycle can be
calculated by the following formula:
If switch current reaches 1A, causing A2 to trip, switch
ON time is reduced. This allows continuous mode opera-
tion during bursts. A2 monitors the voltage across 7.2Ω
resistor R1, which is directly related to the switch current.
Q2’s collector current is set by the emitter-area ratio to
0.5% of Q1’s collector current. R1’s voltage drop exceeds
36mV, corresponding to 1A switch current, A2’s output
goes high, truncating the ON time part of the switch cycle.
The 1A peak current can be reduced by tying a resistor
between the ILIM pin and ground, causing a voltage drop
to appear across R2. The drop offsets some of the 36mV
reference voltage, lowering peak current. A 22k resistor
limits current to approximately 550mA. A capacitor con-
nected between ILIM and ground provides soft start. Shut-
down is accomplished by grounding the SHDN pin.
DC = 1 – [(VIN – VSAT)/(VOUT + VD)]
where,
VIN = Minimum input voltage
VSAT = Switch saturation voltage (0.3V)
VOUT = Output voltage
VD = Diode forward voltage (0.4V)
If the calculated duty cycle exceeds the minimum LT1304
duty cycle of 76%, the converter should be designed for
discontinuous mode operation. The inductance must be
low enough so that current in the inductor reaches the
peak current in a single cycle. Inductor value can be
calculated by:
The low-battery detector A3 has its own 1.17V reference
andisalwayson.Theopencollectoroutputdevicecansink
up to 500µA. Approximately 35mV of hysteresis is built
into A3 to reduce “buzzing” as the battery voltage reaches
the trip level.
L = (VIN – VSAT)(tON/1A)
where,
tON = Minimum on-time of LT1304 (4µs)
Inductor Selection
One advantage of discontinuous mode operation is that
inductor values are usually quite low so very small units
can be used. Ripple current is higher than with continuous
mode designs and efficiency will be somewhat less.
Inductors used with the LT1304 must be capable of
handling the worst-case peak switch current of 1.2A
without saturating. Open flux rod or drum core units may
be biased into saturation by 20% with only a small reduc-
6
LT1304/LT1304-3.3/LT1304-5
U
OPERATIO
Table1listsinductorsuppliersalongwithappropriatepart
numbers.
ILIM Function
The LT1304’s current limit (ILIM) pin can be used for soft
start. Upon start-up, the LT1304 will draw maximum
current (about 1A) from the supply to charge the output
capacitor. Figure 3 shows VOUT and VIN waveforms as the
device is turned on. The high current flow can create IR
drops along supply and ground lines or cause the input
supply to drop out momentarily. By adding R1 and C1 as
shown in Figure 4, the switch current is initially limited to
well under 1A as detailed in Figure 5. Current flowing into
C1 from R1 and the ILIM pin will eventually charge C1 and
R1 effectively takes C1 out of the circuit. R1 also provides
a discharge path for C1 when SHUTDOWN is brought low
for turn-off.
Table 1. Recommended Inductors
VENDOR
Sumida
Coiltronics
Dale
SERIES
PHONE NUMBER
(708) 956-0666
(407) 241-7876
(605) 665-9301
(708) 639-6400
CD54, CD43
CTX20-1
LPT4545
Coilcraft
DO3316, DO1608, DO3308
Capacitor Selection
LowESR(EquivalentSeriesResistance)capacitorsshould
be used at the output of the LT1304 to minimize output
ripple voltage. High quality input bypassing is also re-
quired. For surface mount applications AVX TPS series
tantalum capacitors are recommended. These have been
specifically designed for switch mode power supplies and
have low ESR along with high surge current ratings. A
100µF, 10V AVX TPS surface mount capacitor typically
limits output ripple voltage to 70mV when stepping up
from 2V to 5V at a 200mA load. For through hole applica-
tions Sanyo OS-CON capacitors offer extremely low ESR
in a small package size. Again, if peak switch current is
reduced using the ILIM pin, capacitor requirements can be
eased and smaller, higher ESR units can be used. Sug-
gested capacitor sources are listed in Table 2.
VOUT
2V/DIV
IIN
500mA/DIV
VSHDN
10V/DIV
1ms/DIV
1304 F03
Figure 3. Start-Up Response. Input Current Rises Quickly to
1A. VOUT Reaches 5V in Approximately 1ms. Output Drives
20mA Load
MBRS130L
22µH*
Table 2. Recommended Capacitors
VENDOR
AVX
SERIES
TPS
TYPE
PHONE NUMBER
(803) 448-9411
(619) 661-6835
(603) 225-1961
Surface Mount
Through Hole
Surface Mount
V
SW
IN
5V
200mA
Sanyo
OS-CON
595D
LBI
SENSE
+
Sprague
LT1304-5
100µF
2 CELLS
LB0
GND
SHDN
+
I
LIM
R1
1M
Diode Selection
100µF
Best performance is obtained with a Schottky rectifier
such as the 1N5818. Motorola makes the MBRS130L
Schottky which is slightly better than the 1N5818 and
comes in a surface mount package. For lower switch
currents, the MBR0530 is recommended. It comes in a
verysmallSOD-123package. Multiple1N4148sinparallel
can be used in a pinch, although efficiency will suffer.
+
C1
1µF
SHUTDOWN
*SUMIDA CD54-220
1304 F04
Figure 4. 2-Cell to 5V/200mA Boost Converter Takes Four
External Parts. Components with Dashed Lines Are for
Soft Start (Optional)
7
LT1304/LT1304-3.3/LT1304-5
U
OPERATIO
If the full power capability of the LT1304 is not required, bypass capacitor is required. If the input supply is close to
peakswitchcurrentcanbelimitedbyconnectingaresistor the IC, a 1µF ceramic capacitor can be used instead. The
RLIM from the ILIM pin to ground. With RLIM = 22k, peak LT1304switchescurrentin1Apulses, soalowimpedance
switchcurrentisreducedtoapproximately500mA.Smaller supplymustbeavailable.Ifthepowersource(forexample,
power components can then be used. The graph in Figure a 2 AA cell battery) is within 1 or 2 inches of the IC, the
6 shows switch current vs RLIM resistor value.
battery itself provides bulk capacitance and the 1µF ce-
ramic capacitor acts to smooth voltage spikes at switch
turn-on and turn-off. If the power source is far away from
theIC,inductanceinthepowersourceleadsresultsinhigh
impedance at high frequency. A local high capacitance
bypassisthenrequiredtorestorelowimpedanceattheIC.
VOUT
2V/DIV
IIN
500mA/DIV
VSHDN
10V/DIV
SHUTDOWN
1ms/DIV
1304 F05
Figure 5. Start-Up Response with 1µF/1MΩ Components
in Figure 2 Added. Input Current Is More Controlled. VOUT
Reaches 5V in 6ms. Output Drives 20mA Load
1
2
3
4
8
7
6
5
LT1304
1000
900
800
700
600
500
400
V
IN
C
IN
+
V
OUT
C
OUT
+
GND (BATTERY AND LOAD RETURN)
1304 F07
10
100
(kΩ)
1000
R
LIM
Figure 7. Suggested Layout for Best Performance. Input
Capacitor Placement as Shown Is Highly Recommended.
Switch Trace (Pin 4) Copper Area Is Minimized
1304 F06
Figure 6. Peak Switch Current vs RLIM Value
Low-Battery Detector
Layout/Input Bypassing
TheLT1304containsanindependentlow-batterydetector
that remains active when the device is shut down. This
detector, actually a hysteretic comparator, has an open
collector output that can sink up to 500µA. The compara-
tor also operates below the switcher’s undervoltage lock-
out threshold, operating until VIN reaches approximately
1.4V. Figure 8 illustrates the input/output characteristic of
the detector. Hysteresis is clearly evident in the figure.
The LT1304’s high speed switching mandates careful
attentiontoPCboardlayout.Suggestedcomponentplace-
mentisshowninFigure7. Theinputsupplymusthavelow
impedance at AC and the input capacitor should be placed
as indicated in the figure. The value of this capacitor
depends on how close the input supply is to the IC. In
situations where the input supply is more than a few
inches away from the IC, a 47µF to 100µF solid tantalum
8
LT1304/LT1304-3.3/LT1304-5
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OPERATIO
1000
100
10
VLBO
2V/DIV
VLBI
200mV/DIV
1304 F08
1
Figure 8. Low-Battery Detector Transfer Function.
Pull-Up R = 22k, VIN = 2V, Sweep Frequency = 10Hz
1
10
100 200
LOAD CURRENT (mA)
1304 F10
Figure 10. Battery Life vs Load Current. Dots Specify
Actual Measurements
Battery Life
How may hours does it work? This is the bottom line
question that must be asked of any efficiency study. AA
alkaline cells are not perfect power sources. For efficient
power transfer, energy must be taken from AA cells at a
rate that does not induce excessive loss. AA cells internal
impedance,about0.2Ωfreshand0.5Ωend-of-life,results
insignificantefficiencylossathighdischargerates.Figure
10 illustrates battery life vs load current of Figure 9’s
LT1304, 2-cell to 5V DC/DC converter. Note the acceler-
ated decrease in hours at higher power levels. Figure 11
plots total watt hours vs load current. Watt hours are
determined by the following formula:
6
5
4
3
2
1
0
1
10
100 200
LOAD CURRENT (mA)
1304 F11
WH = ILOAD(5V)(H)
Figure 11. Output Watt Hours vs Load Current. Note
Rapid Fall-Off at Higher Discharge Rates
L1
22µH
D1
V
SW
IN
V
OUT
Figure 11’s graph varies significantly from electrical effi-
ciency plot pictured on the first page of this data sheet.
Why? As more current is drawn from the battery, voltage
drop across the cells’ internal impedance increases. This
causes internal power loss (heating), reducing cell termi-
nal voltage. Since the regulator input acts as a negative
resistance, more current is drawn from the battery as the
terminal voltage decreases. This positive feedback action
compounds the problem.
SHDN
SENSE
5V
200mA
B1
LT1304-5
2 CELLS
+
C2
100µF
LB1
LB0
GND
+
C1
100µF
I
LIM
B1 = 2× EVEREADY INDUSTRIAL
ALKALINE AA CELLS #EN91
C1, C2 = AVX TPSD107M010R0100
D1 = MOTOROLA MBRS130L
L1 = SUMIDA CD54-220
1304 F09
Figure 9. 2-Cell to 5V Converter Used in Battery Life Study
9
LT1304/LT1304-3.3/LT1304-5
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OPERATIO
100
90
80
70
60
50
40
30
20
10
0
Figure 12 shows overall energy conversion efficiency,
assuming availability of 6.5WH of battery energy. This
efficiency approximates the electrical efficiency at load
current levels from 1mA to 10mA, but drops severely at
loadcurrentsabove10mA(loadpowerabove50mW).The
moral of the story is this: if your system needs 5V at more
than 40mA to 50mA, consider using a NiCd battery (1/10
the internal impedance) instead of a AA cell alkaline
battery.
1
10
100 200
LOAD CURRENT (mA)
1304 F12
Figure 12. Overall System Efficiency Including Battery Efficiency
vs Load Current. Internal Impedance of Alkaline AA Cells
Accounts for Rapid Drop in Efficiency at Higher Load Current
U
TYPICAL APPLICATIONS
Super BurstTM Low IQ DC/DC Converter
Super Burst Efficiency
MBR0530
I
Q
≈ 10µA
33µH**
90
200k
47k
0.01µF
V
= 3V
= 2V
IN
IN
2N3906
80
70
60
50
40
V
SW
IN
3.83M*
5V
LBO
LBI
100mA
+
V
2 CELLS
100µF
LT1304
FB
I
+
LIM
1.21M*
220µF
SHDN
GND
47k
22k
0.01
0.1
1.0
10
100
*1% METAL FILM
**SUMIDA CD54-330
1304 TA03
LOAD CURRENT (mA)
1304 TA04
Super Burst is a trademark of Linear Technology Corporation.
10
LT1304/LT1304-3.3/LT1304-5
U
TYPICAL APPLICATIONS
2-Cell to 3.3V Converter Efficiency
2-Cell to 3.3V Boost Converter
L1*
MBRS130L
90
80
70
60
50
22µH
V
SW
IN
3.3V
SENSE
300mA
+
C1**
100µF
LT1304-3.3
2 CELLS
SHDN
C2**
100µF
10V
+
I
GND
LIM
V
IN
V
IN
V
IN
= 3.3V
= 2.5V
= 1.8V
NC
SHUTDOWN
40
*SUMIDA CD54-220
**AVX TPSD107M010R0100
30
1304 TA05
0.1
1
10
100
1000
LOAD CURRENT (mA)
1304 TA06
3.3V SEPIC (Step-Up/Step-Down Converter)
3.3V SEPIC Efficiency
C1**
1µF
80
75
70
65
60
55
50
L1A*
V
IN
2.5V TO 8V
1
2
4
3
†
V
SW
IN
C2
+
47µF
16V
L1B*
MBRS130L
LT1304-3.3
3.3V
300mA
SENSE
GND
SHDN
SHUTDOWN
I
LIM
††
C3
+
100µF
10V
V
V
V
= 4.5V
= 3.5V
= 2.5V
IN
IN
IN
NC
*
COILTRONICS CTX20-1
1
10
100
500
1304 TA07
** TOKIN 1E105ZY5U-C103-F
†
LOAD CURRENT (mA)
AVX TPSD476M016R0150
††
1304 TA08
AVX TPSD107M010R0100
5V SEPIC Efficiency
5V SEPIC (Step-Up/Step-Down Converter)
C1**
1µF
80
75
70
65
60
55
50
L1A*
V
IN
3V TO 8V
1
2
4
3
V
IN
SW
+
†
47µF
16V
L1B*
MBRS130L
LT1304-5
5V
200mA
SENSE
GND
SHDN
SHUTDOWN
I
LIM
V
V
V
V
= 6V
= 5V
= 4V
= 3V
+
IN
IN
IN
IN
††
100µF
10V
NC
*
COILTRONICS CTX20-1
1
10
100
500
1304 TA09
** TOKIN 1E105ZY5U-C103-F
†
LOAD CURRENT (mA)
AVX TPSD476M016R0150
††
1304 TA10
AVX TPSD107M010R0100
11
LT1304/LT1304-3.3/LT1304-5
U
TYPICAL APPLICATIONS
5V to 12V DC/DC Converter
5V to 12V Converter Efficiency
L1*
†
D1
90
85
80
75
70
65
22µH
5V
V
SW
IN
+
47µF**
LT1304
1.07M
1%
12V
FB
GND
SHDN
SHUTDOWN
200mA
+
124k
1%
47µF**
16V
*
SUMIDA CD54-220
1304 TA11
300
1
10
100
** AVX TPSD476M016R0150
†
MOTOROLA MBRS130L
LOAD CURRENT (mA)
1304 TA12
Single Li-Ion Cell to 5V Converter with Load Disconnect at VIN < 2.7V
MBRS130LT3
22µH**
(2.7V to 4.2V)
(5V)
5V
1µF
+
+
100µF
16V
562k
1%
220k
NC
V
SW
V
V
OUT
IN
OUT
I
SENSE
LT1304CS8-5
V
V
V
NC
NC
LIM
IN1
IN2
IN3
+
†
SINGLE
Li-Ion
CELL*
LTC1477
100µF
10V
LBI
SHDN
V
INS
432k
1%
LBO
EN
GND
GND
1304 TA13
*
PRIMARY Li-Ion BATTERY PROTECTION MUST BE
PROVIDED BY AN INDEPENDENT CIRCUIT
** SUMIDA CD54-220
†
AVX TPSD107M010R0100
12
LT1304/LT1304-3.3/LT1304-5
U
TYPICAL APPLICATIONS
Negative LCD Bias Generator
L1*
10µH
1µF
CERAMIC
**
1.69M
1%
V
SW
IN
–V
OUT
–14V TO –22V
1mA TO 10mA
FB
+
**
LT1304
1M
1%
47µF
2 CELLS
90.9k
1%
110k
1%
10µF
35V
1000pF
**
I
+
LIM
GND
EFFICIENCY = 70% TO 75%
+
AT I
≥ 2mA
LOAD
3.3µF
22k
* SUMIDA CD43-100
** MOTOROLA MBR0530
VOLTAGE ADJUST
1kHz PWM INPUT
0V TO 5V
1304 TA14
≤ 20nF
1304 TA15
Electroluminescent Panel Driver with 200Hz Oscillator
1µF
200V
MUR160
600V
1:12*
V
IN
2V TO 7V
3
4
+
47µF
EL PANEL
PANEL
C
1
6
MBR0530
DANGER!10HMIGH VOLTAGE
V
SW
FB
IN
(3.3M × 3)
5V = OPERATE
0V = SHUTDOWN
SHDN
FMMT458
22k
22k
75k
22k
51k
LBO
LT1304
2N3906
1nF
22k
22k
50k
LBI
I
INTENSITY
ADJUST
LIM
GND
3.3k
0.01µF
1/2 BAW56
1/2 BAW56
NC
200Hz
* DALE LPE3325-A205 TRANSFORMER MEASURES 6.5mm × 8.2mm × 5.2mm (H)
(605) 665-9301
13
LT1304/LT1304-3.3/LT1304-5
U
TYPICAL APPLICATIONS
2- to 4-Cell to 1kV Step-Up Converter
0.01µF
0.01µF
0.01µF
0.01µF
0.01µF
T1*
4
V
IN
2V TO 6V
3
1
+
0.01µF
0.01µF
0.01µF
0.01µF
47µF
6
MBR0530
DANGER! HIGH VOLTAGE
R1**
500M
V
SW
FB
IN
V
OUT
1kV
0.1µF
250µA
R2
620k
LT1304
R1
R2
V
= 1.24V 1+
OUT
(
)
SHUTDOWN
SHDN
I
LIM
GND
* DALE LPE3325-A205 TRANSFORMER MEASURES
6.5mm × 8.2mm × 5.2mm (H)
(605) 665-9301
NC
** IRC CGX-1/2
ALL 0.01µF CAPACITORS 250WVDC
1304 TA16
BAS21 OR MUR130
2- to 4-Cell to 5V Converter with Output Disconnect
2k
L1**
22µH
MBRS130L
V
IN
2V TO 6V
ZTX788B
V
SW
IN
5V
100mA
SENSE
+
LT1304-5
47µF*
+
+
SHDN
22µF*
220µF*
I
GND
LIM
SHUTDOWN
NC
*AVX TPS SERIES TANTALUM
OR SANYO OS-CON
**SUMIDA CD54-220
1304 TA17
14
LT1304/LT1304-3.3/LT1304-5
U
TYPICAL APPLICATIONS
2-Cell to 5V Converter with Auxiliary 10V Output
MBR0530
MBR0530
10V
20mA
+
1µF
CERAMIC
10µF
L1*
22µH
MBRS130L
V
SW
IN
5V
150mA
SENSE
+
LT1304-5
2 CELLS
100µF
+
SHDN
100µF
I
GND
LIM
SHUTDOWN
NC
*SUMIDA CD54-220
1304 TA18
2-Cell to 5V Converter with Auxiliary –5V Output
L1*
22µH
MBRS130L
V
SW
IN
5V
150mA
SENSE
+
1µF
CERAMIC
+
LT1304-5
2 CELLS
100µF
100µF
SHDN
MBR0530
–5V
20mA
I
GND
LIM
MBR0530
10µF
SHUTDOWN
NC
+
1304 TA19
*SUMIDA CD54-220
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-
tation that the interconnection of circuits as described herein will not infringe on existing patent rights.
15
LT1304/LT1304-3.3/LT1304-5
U
PACKAGE DESCRIPTION Dimension in inches (millimeter) unless otherwise noted.
S8 Package
8-Lead Plastic Small Outline (Narrow 0.150)
(LTC DWG # 05-08-1610)
0.189 – 0.197*
(4.801 – 5.004)
7
5
8
6
0.150 – 0.157**
(3.810 – 3.988)
0.228 – 0.244
(5.791 – 6.197)
1
3
4
2
0.010 – 0.020
(0.254 – 0.508)
× 45°
0.053 – 0.069
(1.346 – 1.752)
0.004 – 0.010
(0.101 – 0.254)
0.008 – 0.010
(0.203 – 0.254)
0°– 8° TYP
0.016 – 0.050
0.406 – 1.270
0.050
(1.270)
BSC
0.014 – 0.019
(0.355 – 0.483)
*DIMENSION DOES NOT INCLUDE MOLD FLASH. MOLD FLASH
SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE
SO8 0695
**DIMENSION DOES NOT INCLUDE INTERLEAD FLASH. INTERLEAD
FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE
RELATED PARTS
PART NUMBER
LTC®1163
LT1239
DESCRIPTION
COMMENTS
Triple High Side Driver for 2-Cell Inputs
Backup Battery Management System
Fixed 5V/12V Step-Up Micropower DC/DC Converter
High Output Current Micropower DC/DC Converter
Micropower DC/DC Converter
1.8V Minimum Input, Drives N-Channel MOSFETs
Easy-to-Use, Fail-Safe Backup Protection
LT1301
12V/200mA from 5V, 120µA I , 88% Efficiency
Q
LT1302
5V/600mA from 2V, 2A Internal Switch, 200µA I
Q
LT1303
Low-Battery Detector Inactive in Shutdown
LTC1477
LT1521
Protected Switch
Ultralow R
Switch: 0.07Ω
DS(ON)
300mA, 12µA I Low Dropout Regulator
500mV Dropout at Full Load
Q
LT/GP 1195 10K • PRINTED IN USA
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
16
●
●
(408) 432-1900 FAX: (408) 434-0507 TELEX: 499-3977
LINEAR TECHNOLOGY CORPORATION 1995
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