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LM2642

ACTIVE

4.5-V to 30-V, two-phase peak current mode synchronous buck controller

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TPS51397A ACTIVE 4.5-V to 24-V input, 10-A, synchronous step-down regulator Upgraded current rating with light-load efficiency and is soft start adjustable.

Product details

Vin (min) (V) 4.5 Vin (max) (V) 30 Vout (min) (V) 1.238 Vout (max) (V) 27 Iout (max) (A) 6 Iq (typ) (mA) 1 Switching frequency (min) (kHz) 300 Switching frequency (max) (kHz) 300 Features Adjustable current limit, Enable, Phase Interleaving, Power good, Synchronous Rectification Operating temperature range (°C) -40 to 125 Regulated outputs (#) 2 Number of phases 2 Rating Catalog Control mode current mode Type Controller
Vin (min) (V) 4.5 Vin (max) (V) 30 Vout (min) (V) 1.238 Vout (max) (V) 27 Iout (max) (A) 6 Iq (typ) (mA) 1 Switching frequency (min) (kHz) 300 Switching frequency (max) (kHz) 300 Features Adjustable current limit, Enable, Phase Interleaving, Power good, Synchronous Rectification Operating temperature range (°C) -40 to 125 Regulated outputs (#) 2 Number of phases 2 Rating Catalog Control mode current mode Type Controller
TSSOP (PW) 28 62.08 mm² 9.7 x 6.4
  • Two Synchronous Buck Regulators
  • 180° Out of Phase Operation
  • 4.5V to 30V Input Range
  • Power Good Function Monitors Ch.1
  • 37µA Shutdown Current
  • 0.04% (typical) Line and Load Regulation Error
  • Current Mode Control With or Without a Sense Resistor
  • Independent Enable/Soft-start Pins Allow Simple Sequential Startup Configuration.
  • Configurable for Single Output Parallel Operation.
  • Adjustable Cycle-by-Cycle Current Limit
  • Input Under-voltage Lockout
  • Output Over-voltage Latch Protection
  • Output Under-voltage Protection with Delay
  • Thermal Shutdown
  • Self Discharge of Output Capacitors When the Regulator is OFF
  • TSSOP package

All trademarks are the property of their respective owners.

  • Two Synchronous Buck Regulators
  • 180° Out of Phase Operation
  • 4.5V to 30V Input Range
  • Power Good Function Monitors Ch.1
  • 37µA Shutdown Current
  • 0.04% (typical) Line and Load Regulation Error
  • Current Mode Control With or Without a Sense Resistor
  • Independent Enable/Soft-start Pins Allow Simple Sequential Startup Configuration.
  • Configurable for Single Output Parallel Operation.
  • Adjustable Cycle-by-Cycle Current Limit
  • Input Under-voltage Lockout
  • Output Over-voltage Latch Protection
  • Output Under-voltage Protection with Delay
  • Thermal Shutdown
  • Self Discharge of Output Capacitors When the Regulator is OFF
  • TSSOP package

All trademarks are the property of their respective owners.

The LM2642 consists of two current mode synchronous buck regulator controllers with a switching frequency of 300kHz.

The two switching regulator controllers operate 180° out of phase. This feature reduces the input ripple RMS current, thereby significantly reducing the required input capacitance. The two switching regulator outputs can also be paralleled to operate as a dual-phase single output regulator.

The output of each channel can be independently adjusted from 1.3 to VIN• maximum duty cycle. An internal 5V rail is also available externally for driving bootstrap circuitry.

Current-mode feedback control assures excellent line and load regulation and a wide loop bandwidth for excellent response to fast load transients. Current is sensed across either the Vds of the top FET or across an external current-sense resistor connected in series with the drain of the top FET. Current limit is independently adjustable for each channel.

The LM2642 features analog soft-start circuitry that is independent of the output load and output capacitance. This makes the soft-start behavior more predictable and controllable than traditional soft-start circuits.

A PGOOD1 pin is provided to monitor the dc output of channel 1. Over-voltage protection is available for both outputs. A UV-Delay pin is also available to allow delayed shut off time for the IC during an output under-voltage event.

The LM2642 consists of two current mode synchronous buck regulator controllers with a switching frequency of 300kHz.

The two switching regulator controllers operate 180° out of phase. This feature reduces the input ripple RMS current, thereby significantly reducing the required input capacitance. The two switching regulator outputs can also be paralleled to operate as a dual-phase single output regulator.

The output of each channel can be independently adjusted from 1.3 to VIN• maximum duty cycle. An internal 5V rail is also available externally for driving bootstrap circuitry.

Current-mode feedback control assures excellent line and load regulation and a wide loop bandwidth for excellent response to fast load transients. Current is sensed across either the Vds of the top FET or across an external current-sense resistor connected in series with the drain of the top FET. Current limit is independently adjustable for each channel.

The LM2642 features analog soft-start circuitry that is independent of the output load and output capacitance. This makes the soft-start behavior more predictable and controllable than traditional soft-start circuits.

A PGOOD1 pin is provided to monitor the dc output of channel 1. Over-voltage protection is available for both outputs. A UV-Delay pin is also available to allow delayed shut off time for the IC during an output under-voltage event.

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Technical documentation

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Type Title Date
* Data sheet LM2642 Two-Phase Synchronous Step-Down Switching Controller datasheet (Rev. I) 03 Apr 2013
User guide LM2642 Buck Controller Evaluation Module User's Guide (Rev. I) PDF | HTML 25 Jan 2022
Selection guide Power Management Guide 2018 (Rev. R) 25 Jun 2018
Analog Design Journal Reduce buck-converter EMI and voltage stress by minimizing inductive parasitics 21 Jul 2016
Analog Design Journal Controlling switch-node ringing in synchronous buck converters 26 Apr 2012

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