LTC3261IMSE#PBF [Linear]
LTC3261 - High Voltage, Low Quiescent Current Inverting Charge Pump; Package: MSOP; Pins: 12; Temperature Range: -40°C to 85°C;
| 型号： | LTC3261IMSE#PBF |
| 厂家： | 
Linear |
| 描述： | LTC3261 - High Voltage, Low Quiescent Current Inverting Charge Pump; Package: MSOP; Pins: 12; Temperature Range: -40°C to 85°C 光电二极管 |
| 文件： | 总14页 (文件大小：1827K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
LTC3261
High Voltage,
Low Quiescent Current
Inverting Charge Pump
FeaTures
DescripTion
The LTC®3261 is a high voltage inverting charge pump
that operates over a wide 4.5V to 32V input range and
is capable of delivering up to 100mA of output current.
n
4.5V to 32V V Range
IN
n
n
n
n
Inverting Charge Pump Generates –V
IN
60µA Quiescent Current in Burst Mode® Operation
Charge Pump Output Current Up to 100mA
50kHz to 500kHz Programmable Oscillator
Frequency
The charge pump employs either low quiescent current
Burst Mode operation or low noise constant frequency
mode. In Burst Mode operation the charge pump V
OUT
n
n
Short-Circuit/Thermal Protection
Low Profile Thermally Enhanced 12-Pin MSOP
Package
regulates to –0.94 • V and the LTC3261 draws only 60µA
IN
ofquiescentcurrent.Inconstantfrequencymodethecharge
pump produces an output equal to –V and operates at
IN
a fixed 500kHz or to a programmed frequency between
50kHz to 500kHz using an external resistor. The LTC3261
isavailableinathermallyenhanced12-pinMSOPpackage.
applicaTions
n
Bipolar/Inverting Supplies
n
Industrial/Instrumentation Bias Generators
L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks
and ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the
property of their respective owners.
n
Portable Medical Equipment
n
Portable Instruments
Typical applicaTion
15V to –15V Inverter
1µF
VOUT Ripple
+
–
C
C
V
OUT
MODE = L
MODE = H
V
V
= –14.8V
= –14.1V
OUT
OUT
10mV/DIV
–15V
15V
V
V
OUT
IN
AC-COUPLED
10µF
10µF
LTC3261
V
EN
MODE
OUT
200mV/DIV
AC-COUPLED
RT
GND
3261 TA01a
100µs/DIV
V
= 15V
= 500kHz
= 5mA
3261 TA01
IN
f
I
OSC
OUT
3261fb
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For more information www.linear.com/3261
LTC3261
absoluTe MaxiMuM raTings
pin conFiguraTion
(Notes 1, 3)
TOP VIEW
V , EN, MODE.. ......................................... –0.3V to 36V
OUT
RT................................................................ –0.3V to 6V
IN
1
2
3
4
5
6
NC
RT
NC
12 NC
11 MODE
10 EN
V
........................................................... –36V to 0.3V
13
GND
V
9
8
7
V
C
NC
OUT
IN
–
+
V
Short-Circuit Duration............................. Indefinite
C
OUT
NC
Operating Junction Temperature Range
MSE PACKAGE
(Note 2).................................................. –55°C to 150°C
Storage Temperature Range ................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec)...................300°C
12-LEAD PLASTIC MSOP
T
EXPOSED PAD (PIN 13) IS GND, MUST BE SOLDERED TO PCB
= 150°C, θ = 40°C/W
JA
JMAX
orDer inForMaTion
LEAD FREE FINISH
LTC3261EMSE#PBF
LTC3261IMSE#PBF
LTC3261HMSE#PBF
LTC3261MPMSE#PBF
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LTC3261EMSE#TRPBF
LTC3261IMSE#TRPBF
LTC3261HMSE#TRPBF
3261
3261
3261
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
12-Lead Plastic MSOP
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–55°C to 150°C
LTC3261MPMSE#TRPBF 3261
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
3261fb
2
For more information www.linear.com/3261
LTC3261
elecTrical characTerisTics The l denotes the specifications which apply over the specified operating
junction temperature range, otherwise specifications are at TA = 25°C (Note 2). VIN = EN = 12V, MODE = 0V, RT = 200kΩ.
SYMBOL
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Charge Pump
l
V
V
Input Voltage Range
4.5
3.4
32
4
V
IN
l
l
V
Undervoltage Lockout Threshold
V
IN
V
IN
Rising
Falling
3.8
3.6
V
V
UVLO
IN
I
V
Quiescent Current
Shutdown, = EN = 0V
2
60
3.5
5
120
5.5
µA
µA
mA
VIN
IN
MODE = V , I
= 0mA
= 0mA
IN VOUT
MODE = 0V, I
VOUT
V
V
RT Regulation Voltage
Regulation Voltage
1.200
V
RT
V
MODE = 12V
MODE = 0V
–0.94 • V
IN
V
V
OUT
OUT
–V
IN
f
Oscillator Frequency
RT = GND
450
100
0.4
500
32
550
KHz
Ω
OSC
R
Charge Pump Output Impedance
MODE = 0V, RT = GND
OUT
l
l
l
I
Max I
Short-Circuit Current
V
V
V
= GND, RT = GND
160
1.1
1.0
0.7
1.1
1.0
0.7
250
2
mA
V
SHORT_CKT
VOUT
OUT
V
V
MODE Threshold Rising
MODE(H)
MODE(L)
MODE
MODE Threshold Falling
V
I
MODE Pin Internal Pull-Down Current
EN Threshold Rising
= MODE = 32V
= EN = 32V
µA
V
IN
IN
l
l
V
V
2
EN(H)
EN(L)
EN Threshold Falling
0.4
V
I
EN Pin Internal Pull-Down Current
µA
EN
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
the maximum ambient temperature consistent with these specifications
is determined by specific operating conditions in conjunction with board
layout, the rated package thermal impedance and other environmental
factors.
Note 2: The LTC3261 is tested under pulsed load conditions such that
The junction temperature (T , in °C) is calculated from the ambient
temperature (T , in °C) and power dissipation (P , in Watts) according to
A D
J
T ≈ T . The LTC3261E is guaranteed to meet specifications from
J
A
0°C to 85°C junction temperature. Specifications over the –40°C to
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LTC3261I is guaranteed over the –40°C to 125°C operating junction
temperature range, the LTC3261H is guaranteed over the –40°C to 150°C
operating junction temperature range and the LTC3261MP is tested and
guaranteed over the full –55°C to 150°C operating junction temperature
range. High junction temperatures degrade operating lifetimes; operating
lifetime is derated for junction temperatures greater than 125°C. Note that
the formula:
T = T + (P • θ ),
J
A
D
JA
where θ = 40°C/W is the package thermal impedance.
JA
Note 3: This IC includes overtemperature protection that is intended
to protect the device during momentary overload conditions. Junction
temperatures will exceed 150°C when overtemperature protection is
active. Continuous operation above the specified maximum operating
junction temperature may result in device degradation or failure.
3261fb
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For more information www.linear.com/3261
LTC3261
Typical perForMance characTerisTics
(TA = 25°C, CFLY = 1µF, CIN = COUT = 10µF unless otherwise noted)
Oscillator Frequency
vs Supply Voltage
Oscillator Frequency vs RT
Shutdown Current vs Temperature
600
500
400
300
200
100
0
600
500
400
300
200
100
0
25
20
15
10
5
V
V
V
= 32V
= 12V
= 5V
IN
IN
IN
RT = GND
RT = 200kΩ
0
0
5
10
15
20
25
30
35
1
10
100
RT (kΩ)
1000
10000
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
3261 G01
3261 G02
3261 G03
Quiescent Current
vs Supply Voltage
(Constant Frequency Mode)
Quiescent Current vs Temperature
(Burst Mode Operation)
Quiescent Current vs Temperature
(Constant Frequency Mode)
140
120
100
80
14
12
10
8
9
8
7
6
5
4
3
2
1
0
f
f
f
= 500kHz
= 200kHz
= 50kHz
V
= 12V
RT = GND
OSC
OSC
OSC
IN
f
f
f
= 500kHz
= 200kHz
= 50kHz
OSC
OSC
OSC
V
= 32V
= 12V
= 5V
IN
V
IN
60
6
V
IN
40
4
20
2
0
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
0
5
10
15
20
25
30
35
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
3261 G04
3261 G05
3261 G06
Effective Open-Loop Resistance
vs Temperature
V
OUT Short-Circuit Current
VOUT Short Circuit Current
vs Temperature
vs Supply Voltage
60
55
50
45
40
35
30
25
20
250
200
150
100
50
200
180
160
140
120
100
V
V
V
= 32V
= 25V
= 12V
f
= 500kHz
V
= 12V
IN
IN
IN
IN
OSC
RT = GND
f
= 500kHz
= 200kHz
20
OSC
f
OSC
0
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
0
5
10
15
25
30
35
–50 –25
0
25
50
75 100 125
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
3261 G07
3261 G08
3261 G8b
3261fb
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For more information www.linear.com/3261
LTC3261
Typical perForMance characTerisTics
(TA = 25°C, CFLY = 1µF, CIN = COUT = 10µF unless otherwise noted)
Voltage Loss (VIN – |VOUT|)
Effective Open-Loop Resistance
vs Supply Voltage
VOUT Load Transient Burst Mode
Operation (MODE = H)
vs Output Current
(Constant Frequency Mode)
90
80
70
60
50
40
30
20
10
0
3.0
2.5
2.0
1.5
1.0
0.5
0.0
f
f
f
= 50kHz
= 200kHz
= 500kHz
V
= 12V
IN
OSC
OSC
OSC
V
OUT
f
f
= 200kHz
= 500kHz
OSC
OSC
500mV/DIV
AC-COUPLED
–5mA
I
OUT
–50mA
3261 G11
V
OSC
= 12V
2ms/DIV
IN
f
= 500kHz
0
5
10
15
20
25
30
35
0.1
1
10
100
SUPPLY VOLTAGE (V)
OUTPUT CURRENT (mA)
3261 G10
3261 G09
VOUT Transient
(MODE = Low to High)
Average Input Current
vs Output Current
V
OUT Ripple
100
10
1
V
OUT
V
OUT
MODE = L
500mV/DIV
10mV/DIV
AC-COUPLED
AC-COUPLED
MODE = L
V
MODE = H
OUT
200mV/DIV
MODE
MODE = H
AC-COUPLED
3261 G12
3261 G14
V
= 12V
= 500kHz
= –5mA
2ms/DIV
IN
100µs/DIV
V
f
= 12V
OSC
IN
f
I
OSC
OUT
= 500kHz
V
= 15V
IN
0.1
f
I
= 500kHz
= 5mA
OSC
OUT
0.1
1
10
100
OUTPUT CURRENT (mA)
3261 G13
3261fb
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For more information www.linear.com/3261
LTC3261
pin FuncTions
NC (Pins 1, 3, 6, 7,12): No Connect Pins. These pins are
not connected to the LTC3261 die. These pins should be
left floating or connected to ground. Pins 6 and 7 can also
be shorted to adjacent pins.
V (Pin9):InputVoltagefortheChargePump. V should
IN IN
be bypassed with a low impedance ceramic capacitor.
EN (Pin 10): Logic Input. A logic “high” on the EN pin
enables the inverting charge pump.
RT(Pin2):InputConnectionforProgrammingtheSwitch-
ing Frequency. The RT pin servos to a fixed 1.2V when
the EN pin is driven to a logic “high”. A resistor from RT
to GND sets the charge pump switching frequency. If the
RT pin is tied to GND, the switching frequency defaults
to a fixed 500kHz.
MODE (Pin 11): Logic Input. The MODE pin deter-
mines the charge pump operating mode. A logic “high”
on the MODE pin forces the charge pump into Burst
Mode operation regulating V
to approximately
OUT
–0.94 • V with hysteretic control. A logic “low” on the
IN
MODE pin forces the charge pump to operate as an open-
loop inverter with a constant switching frequency. The
switching frequency in both modes is determined by an
external resistor from the RT pin to GND. In Burst Mode,
this represents the frequency of the burst cycles before
the part enters the low quiescent current sleep state.
V
(Pin 4): Charge Pump Output Voltage. In constant
OUT
frequency mode (MODE = low) this pin is driven to –V .
IN
InBurstModeoperation, (MODE=high)thispinvoltageis
regulatedto–0.94•V usinganinternalburstcomparator
IN
with hysteretic control.
–
C (Pin 5): Flying Capacitor Negative Connection.
GND (Exposed Pad Pin 13): Ground. The exposed pack-
age pad is ground and must be soldered to the PC board
groundplaneforproperfunctionalityandforratedthermal
performance.
+
C (Pin 8): Flying Capacitor Positive Connection.
block DiagraM
8
5
+
–
C
C
S1
S4
V
V
OUT
IN
9
4
S3
S2
EN
CHARGE
PUMP
AND
INPUT
LOGIC
10
11
50kHz
TO
500kHz
OSC
RT
2
MODE
GND
13
3261 BD
3261fb
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For more information www.linear.com/3261
LTC3261
operaTion (Refer to the Block Diagram)
The LTC3261 is a high voltage inverting charge pump. It
supportsawideinputpowersupplyrangefrom4.5Vto32V.
Thefrequencyofchargingcyclesissetbytheexternalresistor
on the RT pin. The charge pump has a lower R at higher
OL
frequencies.ForBurstModeoperationitisrecommendedthat
Shutdown Mode
the RT pin be tied to GND. This minimizes the charge pump
R , quickly charges the output up to the burst threshold
OL
In shutdown mode, all circuitry except the internal bias is
turnedoff. TheLTC3261isinshutdownwhenalogiclowis
applied to the enable input (EN). The LTC3261 only draws
and optimizes the duration of the low current sleep state.
600
2µA (typical) from the V supply in shutdown.
IN
500
400
300
200
100
0
Constant Frequency Operation
The LTC3261 provides low noise constant frequency opera-
tion when a logic low is applied to the MODE pin. The charge
pump and oscillator circuit are enabled using the EN pin. At
thebeginningofaclockcycle,switchesS1andS2areclosed.
+
–
The external flying capacitor across the C and C pins is
charged to the V supply. In the second phase of the clock
IN
1
10
100
1000
10000
cycle, switches S1 and S2 are opened, while switches S3
RT (kΩ)
+
and S4 are closed. In this configuration the C side of the
3261 F01
flying capacitor is grounded and charge is delivered through
Figure 1. Oscillator Frequency vs RT
–
the C pin to V . In steady state the V
pin regulates at
OUT
OUT
–V less any voltage drop due to the load current on V
.
IN
OUT
Soft-Start
The charge transfer frequency can be adjusted between
50kHz and 500kHz using an external resistor on the RT
pin. At slower frequencies the effective open-loop output
The LTC3261 has built in soft-start circuitry to prevent
excessive current flow during start-up. The soft-start is
achievedbyinternalcircuitrythatslowlyrampstheamount
of current available at the output storage capacitor. The
soft-start circuitry is reset in the event of a commanded
shutdown or thermal shutdown.
resistance (R ) of the charge pump is larger and it is able
OL
to provide smaller average output current. Figure 1 can
be used to determine a suitable value of RT to achieve a
required oscillator frequency. If the RT pin is grounded,
the part operates at a constant frequency of 500kHz.
Short-Circuit/Thermal Protection
Burst Mode Operation
The LTC3261 has built-in short-circuit current limit as
well as overtemperature protection. During a short-circuit
condition, the part automatically limits its output current
to approximately 160mA. If the junction temperature ex-
ceedsapproximately175°Cthethermalshutdowncircuitry
disables current delivery to the output. Once the junction
temperature drops back to approximately 165°C current
deliverytotheoutputisresumed.Whenthermalprotection
is active the junction temperature is beyond the specified
operating range. Thermal protection is intended for mo-
mentary overload conditions outside normal operation.
Continuous operation above the specified maximum op-
erating junction temperature may impair device reliability.
The LTC3261 provides low power Burst Mode operation
when a logic high is applied to the MODE pin. In Burst
Mode operation, the charge pump charges the V
pin to
OUT
–0.94 • V (typical). The part then shuts down the internal
IN
oscillator to reduce switching losses and goes into a low
current state. This state is referred to as the sleep state in
which the IC consumes only about 60µA. When the output
voltage droops enough to overcome the burst comparator
hysteresis,thepartwakesupandcommenceschargepump
cycles until output voltage exceeds –0.94 • V (typical).
IN
This mode provides lower operating current at the cost of
higher output ripple and is ideal for light load operation.
3261fb
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For more information www.linear.com/3261
LTC3261
applicaTions inForMaTion
Effective Open-Loop Output Resistance
IOUT
COUT
1
f
OSC
VRIPPLE(P-P)
where f
≈
•
– t
ON
Theeffectiveopen-loopoutputresistance(R )ofacharge
OL
pump is a very important parameter which determines the
strength of the charge pump. The value of this parameter
depends on many factors such as the oscillator frequency
(f ), value of the flying capacitor (C ), the nonoverlap
is the oscillator frequency t is the on-time
of the oscillator (1µs) typical and C
output capacitor.
OSC
ON
is the value of the
OUT
OSC
FLY
time, the internal switch resistances (R ) and the ESR of
S
Just as the value of C
controls the amount of output
OUT
the external capacitors.
ripple,thevalueofC controlstheamountofripplepresent
IN
Typical R values as a function of temperature are shown
at the input (V ) pin. The amount of bypass capacitance
OL
IN
in Figure 2
required at the input depends on the source impedance
driving V . For best results it is recommended that V
IN
IN
60
V
V
V
= 32V
= 25V
= 12V
f
= 500kHz
IN
IN
IN
OSC
be bypassed with at least 2µF of low ESR capacitance. A
high ESR capacitor such as tantalum or aluminum will
have higher input noise than a low ESR ceramic capacitor.
Therefore, a ceramic capacitor is recommended as the
main bypass capacitance with a tantalum or aluminum
capacitor used in parallel if desired.
55
50
45
40
35
30
25
20
Flying Capacitor Selection
The flying capacitor controls the strength of the charge
pump. A 1µF or greater ceramic capacitor is suggested
for the flying capacitor for applications requiring the full
rated output current of the charge pump.
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
3261 F02
Figure 2. Typical ROL vs Temperature
For very light load applications, the flying capacitor may
be reduced to save space or cost. For example, a 0.2µF
capacitormightbesufficientforloadcurrentsupto20mA.
A smaller flying capacitor leads to a larger effective open-
loop resistance (R ) and thus limits the maximum load
current that can be delivered by the charge pump.
Input/Output Capacitor Selection
The style and value of capacitors used with the LTC3261
determineseveralimportantparameterssuchasregulator
control loop stability, output ripple, charge pump strength
andminimumturn-ontime.Toreducenoiseandripple,itis
recommendedthatlowESRceramiccapacitorsbeusedfor
thechargepumpoutput.Thechargepumpoutputcapacitor
should retain at least 2µF of capacitance over operating
temperature and bias voltage. Tantalum and aluminum
capacitors can be used in parallel with a ceramic capacitor
to increase the total capacitance but should not be used
alone because of their high ESR. In constant frequency
OL
Ceramic Capacitors
Ceramic capacitors of different materials lose their capaci-
tancewithhighertemperatureandvoltageatdifferentrates.
For example, a capacitor made of X5R or X7R material will
retainmostofitscapacitancefrom–40°Cto85°Cwhereasa
Z5UorY5Vstylecapacitorwillloseconsiderablecapacitance
over that range. Z5U and Y5V capacitors may also have a
poorvoltagecoefficientcausingthemtolose60%ormoreof
theircapacitancewhentheratedvoltageisapplied.Therefore
when comparing different capacitors, it is often more ap-
propriate to compare the amount of achievable capacitance
for a given case size rather than discussing the specified
mode, the value of C
directly controls the amount of
OUT
outputrippleforagivenloadcurrent.Increasingthesizeof
will reduce the output ripple at the expense of higher
C
OUT
minimum turn-on time. The peak-to-peak output ripple at
the V
pin is approximately given by the expression:
OUT
capacitance value. The capacitor manufacture’s data sheet
3261fb
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For more information www.linear.com/3261
LTC3261
applicaTions inForMaTion
should be consulted to ensure the desired capacitance at
all temperatures and voltages. Table 1 is a list of ceramic
capacitor manufacturers and their websites.
The power dissipated in the LTC3261 is:
P = (V – |V |) • (I
)
D
IN
OUT
OUT
where I
denotes output current at the V
pin.
OUT
OUT
Table 1
The derating curve in Figure 4 assumes a maximum ther-
AVX
Kemet
www.avxcorp.com
www.kemet.com
mal resistance, θ , of 40°C/W for the package. This can
JA
be achieved with a four layer PCB that includes 2oz Cu
traces and six vias from the exposed pad of the LTC3261
to the ground plane.
Murata
Taiyo Yuden
Vishay
www.murata.com
www.t-yuden.com
www.vishay.com
It is recommended that the LTC3261 be operated in the re-
TDK
www.component.tdk.com
gioncorrespondingtoT ≤150°Cforcontinuousoperation
J
Layout Considerations
as shown in Figure 4. Operation beyond 150°C should be
avoided as it may degrade part performance and liftetime.
At high temperatures, typically around 175°C, the part is
placed in thermal shutdown and the output is disabled.
When the part cools back down to a low enough tempera-
ture, typically around 165°C, the output is re-enabled and
the part resumes normal operation.
Duetohighswitchingfrequencyandhightransientcurrents
produced by LTC3261, careful board layout is necessary
for optimum performance. A true ground plane and short
connections to all the external capacitors will improve
performanceandensureproperregulationunderallcondi-
tions. Figure 3 shows an example layout for the LTC3261.
+
–
The flying capacitor nodes C and C switch large currents
at a high frequency. These nodes should not be routed
close to sensitive pins such as the RT pin .
GND
C
FLY
Thermal Management
V
V
OUT
IN
At high input voltages and maximum output current, there
can be substantial power dissipation in the LTC3261. If
the junction temperature increases above approximately
175°C, the thermal shutdown circuitry will automatically
deactivate the output. To reduce the maximum junction
temperature, a good thermal connection to the PC board
groundplaneisrecommended.Connectingtheexposedpad
of the package to a ground plane under the device on two
layers of the PC board can reduce the thermal resistance
of the package and PC board considerably.
EN
MODE
R
T
GND
3261 F03
Figure 3. Recommended Layout
6
5
4
3
2
1
0
θ
= 40°C/W
JA
Derating Power at High Temperatures
To prevent an overtemperature condition in high power
applications, Figure 4 should be used to determine the
maximumcombinationofambienttemperatureandpower
dissipation.
RECOMMENDED
OPERATION
T = 150°C
J
–50 –25
0
25 50 75 100 125 150 175
The power dissipated in the LTC3261 should always fall
under the line shown for a given ambient temperature.
AMBIENT TEMPERATURE (°C)
3261 F04
Figure 4. Maximum Power Dissipation vs Ambient Temperature
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For more information www.linear.com/3261
LTC3261
Typical applicaTions
High Input Divide by 2 Voltage Divider
C2
1µF
50V
+
–
C
C
9V TO 32V
V
IN
V
OUT
C1
4.7µF
50V
EN
LTC3261
MODE
RT
GND
3261 TA04
NOTE: MINIMUM LOAD OF
120µA IS REQUIRED TO
ASSURE START-UP
V
/2
IN
C3
4.7µF
25V
Inverting Charge Pump with Bipolar Doubler
D1
1N4148
D2
1N4148
~ 2V
IN
C2
1µF
50V
C5
4.7µF
100V
4.5V TO 32V
+
C
V
IN
C3
1µF
50V
C1
4.7µF
50V
–
EN
C
LTC3261
C4
D4
1N4148
1µF
50V
~ –2V
IN
IN
C6
D3
1N4148
MODE
RT
4.7µF
100V
–V
V
OUT
GND
C7
4.7µF
50V
3261 TA06
NOTE: I
• 2 + I
• 2 + I
< = 100mA
2VIN
–2VIN
OUT
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For more information www.linear.com/3261
LTC3261
Typical applicaTions
High Voltage to Inverted Low Voltage Charge Pump
4.5V TO 32V
C1
4.7µF
50V
V
V –V – |IOUT | •ROL
IN f
OUT
VOUT –
–V
f
V
V
IN
OUT
2
C4
4.7µF
50V
EN
+
C
C2
1µF
50V
D1
MBR0540
LTC3261
D2
MBR0540
C3
1µF
50V
D3
MBR0540
–
C
RT
MODE
GND
3261 TA07
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11
For more information www.linear.com/3261
LTC3261
package DescripTion
Please refer to http://www.linear.com/designtools/packaging/ for the most recent package drawings.
MSE Package
12-Lead Plastic MSOP, Exposed Die Pad
(Reference LTC DWG # 05-08-1666 Rev F)
BOTTOM VIEW OF
EXPOSED PAD OPTION
2.845 0.102
(.112 .004)
2.845 0.102
(.112 .004)
0.889 0.127
(.035 .005)
1
6
0.35
REF
1.651 0.102
(.065 .004)
5.23
(.206)
MIN
1.651 0.102
(.065 .004)
3.20 – 3.45
(.126 – .136)
0.12 REF
DETAIL “B”
CORNER TAIL IS PART OF
THE LEADFRAME FEATURE.
FOR REFERENCE ONLY
NO MEASUREMENT PURPOSE
DETAIL “B”
12
4.039 0.102
7
0.65
(.0256)
BSC
0.42 0.038
(.0165 .0015)
TYP
(.159 .004)
(NOTE 3)
0.406 0.076
RECOMMENDED SOLDER PAD LAYOUT
(.016 .003)
12 11 10 9 8 7
REF
DETAIL “A”
0.254
(.010)
3.00 0.102
(.118 .004)
(NOTE 4)
0° – 6° TYP
4.90 0.152
(.193 .006)
GAUGE PLANE
0.53 0.152
(.021 .006)
1
2 3 4 5 6
DETAIL “A”
0.86
(.034)
REF
1.10
(.043)
MAX
0.18
(.007)
SEATING
PLANE
0.22 – 0.38
(.009 – .015)
TYP
0.1016 0.0508
(.004 .002)
0.650
(.0256)
BSC
MSOP (MSE12) 0911 REV F
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
6. EXPOSED PAD DIMENSION DOES INCLUDE MOLD FLASH. MOLD FLASH ON E-PAD SHALL
NOT EXCEED 0.254mm (.010") PER SIDE.
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For more information www.linear.com/3261
LTC3261
revision hisTory
REV
DATE
DESCRIPTION
PAGE NUMBER
A
9/12
Changed the Operating Junction Temperature to –55°C to 150°C in the Absolute Maximum section
Added LTC3261HMSE and LTC3261MPMSE to Order Information table
Added the word junction to the heading for Electric Characteristics
Added LTC3261H and LTC3261MP guarantees into Note 2 following LTC3261I sentence
Deleted Thermal Shutdown curve from Figure 4
2
2
3
3
9
Changed two paragraphs with respect to operation at 150°C and thermal shutdown
Updated Related Parts list
9
14
6
B
1/13
Corrected pin number on MODE pin in Pin Functions page
3261fb
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 representa-
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
13
LTC3261
Typical applicaTion
24V to –24V Inverter
C2
1µF
8
5
+
–
C
C
9
4
2
–24V
24V
V
V
IN
OUT
C3
10µF
C1
10µF
LTC3261
10
11
EN
MODE
RT
GND
13
3261 TA03
relaTeD parTs
PART NUMBER
DESCRIPTION
COMMENTS
LT1054/LT1054L
Switched-Capacitor Voltage Converters with Regulator
V : 3.5V to 15V/7V, I
= 100mA/125mA, N8, S08,
OUT
IN
SO16 Packages
LTC1144
Switched-Capacitor Wide Input Range Voltage Converter Wide Input Voltage Range: 2V to 18V, I < 8µA,
SD
with Shutdown
SO8 Package
LTC1514/LTC1515
LT®1611
Step-Up/Step-Down Switched-Capacitor DC/DC
Converters
V : 2V to 10V, V : 3.3V to 5V, I = 60µA, SO8 Package
IN
OUT
Q
150mA Output, 1.4MHz Micropower Inverting Switching V : 0.9V to 10V, V
Regulator
=
OUT
34V, ThinSOT™ Package
IN
LT1614
250mA Output, 600kHz Micropower Inverting Switching V : 0.9V to 6V, V
= 30V, I = 1mA, MS8, SO8 Packages
OUT Q
IN
Regulator
LTC1911
250mA, 1.5MHz Inductorless Step-Down DC/DC
Converter
V : 2.7V to 5.5V, V
= 1.5V/1.8V, I = 180µA,
Q
IN
OUT
OUT
MS8 Package
LTC3250/LTC3250-1.2/ Inductorless Step-Down DC/DC Converters
LTC3250-1.5
V : 3.1V to 5.5V, V
= 1.2V, 1.5V, I = 35µA,
Q
IN
ThinSOT Package
LTC3251
LTC3252
LTC3260
500mA Spread Spectrum Inductorless Step-Down DC/DC V : 2.7V to 5.5V, V : 0.9V to 1.6V, 1.2V, 1.5V, I = 9µA, MS10E
IN
OUT
Q
Converter
Package
Dual 250mA, Spread Spectrum Inductorless Step-Down V : 2.7V to 5.5V, V : 0.9V to 1.6V, I = 50µA,
IN
OUT
Q
DC/DC Converter
DFN12 Package
Low Noise Dual Supply Inverting Charge Pump
V : 4.5V to 32V, V
= –V , I
= 100mA, F
= 50kHz to
IN
OUT
IN OUT
OSC
+
+
–
500kHz, V
= 1.2V to 32V, I
= 50mA, V = –1.2V to –32V,
LDO
LDO
LDO
–
I
= 50mA, DE14 and MSE16 Packages
LDO
3261fb
LT 0113 REV B • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
14
●
●
(408)432-1900 FAX: (408) 434-0507 www.linear.com/3261
LINEAR TECHNOLOGY CORPORATION 2012
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