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LINEAR LTC3252 Data Sheet Manual

Summary

Harnessing low noise and high efficiency, this dual, inductorless step-down DC/DC converter provides two adjustable regulated outputs from a range of 2.7V to 5.5V. Ideal for battery-powered and space-constrained applications such as handheld devices, cellular phones, and DSP power supplies. This technical manual offers comprehensive details on electrical characteristics, spread spectrum operation, low quiescent current modes, and robust protection features, guiding system designers through optimal integration planning.

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查询LTC3252供应商

LTC3252

Dual, Low Noise, Inductorless Step-Down DC/DC Converter

FEATURES DESCRIPTIO 2.7V to 5.5V Input Voltage Range The LTC®3252 is a switched capacitor step-down DC/DC No Inductors converter that produces two adjustable regulated outputs Typical Efficiency 50% Higher than LDOs from a single 2.7V to 5.5V input. The part uses switched

Spread Spectrum Operation capacitor fractional conversion to achieve a typical effi- Low Input and Output Noise ciency increase of 50% over that of a linear regulator. No Shutdown Disconnects Load from VIN inductors are required.

Dual Adjustable Independent Outputs

A unique constant frequency, spread spectrum architec-

(Range: 0.9V to 1.6V)

ture provides a very low noise regulated output as well as

Output Current: 250m A Each Output

low noise at the input. The part also has Burst Mode®

Low Operating Current: IIN = 60µA Typ

operation to provide high efficiency at low output currents,

(35µA with One Output Enabled)

as well as ultralow current shutdown.

Low Shutdown Current: IIN = 0.01µA Typ

Soft-Start Limits Inrush Current at Turn On Low operating currents (60µA with both outputs enabled, Short Circuit and Over Temperature Protected 35µA with one output enabled) and low external parts Available in 4mm × 3mm 12-Pin DFN Package count make the LTC3252 ideally suited for space-con-

EF FI CI EN CY strained battery-powered applications. The part is short-

APPLICATIO S circuit and overtemperature protected and is available in a tiny 4mm × 3mm 12-pin DFN package.

Handheld Electronic Devices

, LTC and LT are registered trademarks of Linear Technology Corporation. Cellular Phones Burst Mode is a registered trademark of Linear Technology Corporation.

Low Voltage Logic Supplies DSP Power Supplies 3.3V to 1.5V Conversion

TYPICAL APPLICATIO 1.5V and 1.2V Output Voltages with Shutdown 1.5V/1.2V Efficiency vs Input Voltage

IOUT (1.5V) = 100m A

VOUT = 1.5V

OFF ON EN1 OUT1 IOUT (1.2V) = 100m A

IOUT ≤ 250m A

ON EN2OFF 470k

LTC3252-1.5V

1-CELL VIN FB1 4.7µF Li-ION

4.7µF LTC3252-1.2V

OR 3-CELL C1+ 510k

LTC3252

Ni MH 1µF

LDO-1.5V

VOUT = 1.2V

C2+ OUT2

IOUT ≤ 250m A

LDO-1.2V

GND FB2 4.7µF

3252 TA01 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5

VIN (V)

3252 TA01a

Page Summary Contents For LINEAR LTC3252 Data Sheet Manual

Page 1 查询LTC3252供应商 LTC3252 Dual, Low Noise, Inductorless Step-Down DC/DC Converter FEATURES DESCRIPTIO 2.7V to 5.5V Input Voltage Range The LTC®3252 is a switched capacitor step-down DC/DC No Inductors conv...
Page 2 LTC3252 ABSOLUTE AXI RATI GS PACKAGE/ORDER I FOR ATIO (Notes 1, 6) TOP VIEW ORDER PART VIN to GND ................................................–0.3V to 6.0V NUMBER EN1, EN2, FB1, FB2 to GND –0.3V t...
Page 3 (V IN (µ A) LTC3252 ELECTRICAL CHARACTERISTICS Note 1: Absolute Maximum Ratings are those values beyond which the life Note 4: Minimum operating voltage required for regulation is: of a device may be ...
Page 4 FR EQ UE NC (M Hz LTC3252 TYPICAL PERFOR A CE CHARACTERISTICS Oscillator Max/Min Frequency vs 1.2V Output Voltage vs Supply Supply Voltage Voltage 1.2V Efficiency vs Load Current 2.0 1.30 TA = 25°C 1....
Page 5 LTC3252 PI FU CTIO C2– (Pin 8): Flying Capacitor 2 Negative Terminal (C2). EN2 (Pin 11): Input Enable Pin 2. When EN2 is high, OUT2 is enabled. When EN2 is low OUT2 is shut down. OUT2 (Pin 9): Regulat...
Page 6 LTC3252 OPERATIO (Refer to Simplified Block Diagram) The LTC3252 has two switched capacitor charge pumps to Short-Circuit/Thermal Protection step down VIN to two regulated output voltages. The two The...
Page 7 LTC3252 OPERATIO (Refer to Simplified Block Diagram) Unlike conventional buck converters, the LTC3252’s inter- threshold (30m A typ). When this occurs, the part shuts nal oscillator is designed to pro...
Page 8 LTC3252 OPERATIO UT (µ F) (Refer to Simplified Block Diagram) Output Capacitor Selection tance required for good transient response (see the Ce- ramic Capacitor Selection Guidelines section). The styl...
Page 9 LTC3252 OPERATIO (Refer to Simplified Block Diagram) Further input noise reduction can be achieved by filtering discussing the specified capacitance value. For example, the input through a very small ...
Page 10 LTC3252 OPERATIO (Refer to Simplified Block Diagram) Thermal Management IOUT1 = 150m A and OUT1 regulating at 1.5V the measured efficiency is 80.6% which is in close agreement with the To reduce the m...
Page 11 LTC3252 TYPICAL APPLICATIO Li-Ion to 1.5V/1.2V Outputs VIN EN2 OFF ON OUT2 ON EN1 OUT2OFF 1.5V OUT1 250m A 1.2V OUT1 C2+ 470k 250m A LTC3252 1µF C1– FB2 FB1 GND 510k Li-ION 4.7µF 510k 3252 TA02 PACKAG...
Page 12 LTC3252 TYPICAL APPLICATIO Fixed 3.3VIN to 1.5VOUT at 300m A 3-Cell Ni MH with Digitally Selectable 1.2V/1.5V Output OFF ON VIN EN2 EN2 3.3V VIN EN2 OUT IOUT EN1EN1 OUT2 EN1 OUT2 1.5V 300m A OUT1 C2+ ...

Manual Details

Brand Linear
Pages 12
File Size 281.50 KB
Published June 06, 2026
35 views

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Frequently Asked Questions

What is the minimum input voltage for the LTC3252?

The operating range starts at 2.7V.

How does the LTC3252 achieve low noise output?

It uses a unique constant frequency, spread spectrum architecture.

What is the typical efficiency of this converter?

It offers a high typical efficiency through capacitor fractional conversion.

Is the product protected against overtemperature or short circuits?

Yes, it features inherent short circuit and overtemperature protection.