LINEAR TECHNOLOGY LTC1622 Low Input Voltage Current Mode Step-Down DC DC Controller Data Sheet User Manual

Summary

The LTC1622 is a highly efficient constant frequency DC/DC controller designed for low input voltage applications (2V to 10V). This manual provides comprehensive technical specifications detailing its core features, including high efficiency, excellent line and load regulation, and advanced operational modes like Burst Mode and Shutdown. It enables designers of battery-powered equipment, portable computers, and cellular devices to create energy-optimized power systems by allowing for low quiescent current draw and configurable synchronization frequencies up to 750kHz.

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LTC1622

Low Input Voltage Current Mode Step-Down DC/DC Controller

FEATURES DESCRIPTIO High Efficiency The LTC®1622 is a constant frequency current mode step- Constant Frequency 550k Hz Operation down DC/DC controller providing excellent AC and DC load VIN Range: 2V to 10V and line regulation. The device incorporates an accurate

Multiampere Output Currents undervoltage feature that shuts the LTC1622 down when OPTI-LOOPTM Compensation Minimizes COUT the input voltage falls below 2V.

Selectable, Burst Mode Operation

The LTC1622 boasts a ±1.9% output voltage accuracy and

Low Dropout Operation: 100% Duty Cycle

consumes only 350µA of quiescent current. For applica-

Synchronizable up to 750k Hz

tions where efficiency is a prime consideration and the

Current Mode Operation for Excellent Line and Load

load current varies from light to heavy, the LTC1622 can

Transient Response

be configured for Burst Mode TM operation. Burst Mode

Low Quiescent Current: 350µA

operation enhances low current efficiency and extends

Shutdown Mode Draws Only 15µA Supply Current

battery run time. Burst Mode operation is inhibited during

±1.9% Reference Accuracy

synchronization or when the SYNC/MODE pin is pulled low

Available in 8-Lead MSOP EF FI CI EN CY

to reduce noise and possible RF interference. APPLICATIO S High constant operating frequency of 550k Hz allows the use of a small inductor. The device can also be synchro-

1- or 2-Cell Li-Ion Powered Applications

nized up to 750k Hz for special applications. The high

Cellular Telephones frequency operation and the available 8-lead MSOP pack- Wireless Modems

age create a high performance solution in an extremely

Portable Computers

small amount of PCB area.

Distributed 3.3V, 2.5V or 1.8V Power Systems

To further maximize the life of the battery source, the

Scanners

P-channel MOSFET is turned on continuously in dropout

Battery-Powered Equipment

(100% duty cycle). In shutdown, the device draws a mere

, LTC and LT are registered trademarks of Linear Technology Corporation.

Burst Mode and OPTI-LOOP are a trademarks of Linear Technology Corporation. 15µA.

TYPICAL APPLICATIO

Efficiency vs Load Current with VIN Burst Mode Operation Enabled

2.5V TO 8.5V

VIN = 4.2V

VIN 10µF

0.03Ω VIN = 3.3V

ITH SENSE–

10k PDRV Si3443DV

L1 VIN = 6V

C3 LTC1622 4.7µH

220p F VIN = 8.4V

SYNC/MODE 2.5V

IR10BQ015 159k

RUN/SS GND

470p F VFB R4

VOUT = 2.5V RSENSE = 0.03Ω

C1: TAIYO YUDEN CERAMIC EMK325BJ106MNT L1: MURATA LQN6C-4R7 1622 F01a C2: SANYO POSCAP 6TPA47M R2: DALE WSL-1206 0-03Ω D1: INTERNATIONAL RECTIFIER IR10BQ015

LOAD CURRENT (m A)

Figure 1. High Efficiency Step-Down Converter

Page Summary Contents For LINEAR TECHNOLOGY LTC1622 Low Input Voltage Current Mode Step-Down DC DC Controller Data Sheet User Manual

Page 1 LTC1622 Low Input Voltage Current Mode Step-Down DC/DC Controller FEATURES DESCRIPTIO High Efficiency The LTC®1622 is a constant frequency current mode step- Constant Frequency 550k Hz Operation down ...

Page 2 LTC1622 ABSOLUTE MAXIMUM RATINGS (Note 1) Input Supply Voltage (VIN).........................–0.3V to 10V Operating Temperature Range RUN/SS Voltage .......................................–0.3V to 2.4...

Page 3 NO RM AL IZ ED RE QU EN CY SH UT DO CU RR EN (µ A) LTC1622 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are a...

Page 4 EF FI CI EN CY LTC1622 TYPICAL PERFORMANCE CHARACTERISTICS Efficiency vs Load Current for Figure 1 with Burst Mode Load Step Transient Response Load Step Transient Response Operation Defeated Burst En...

Page 5 LTC1622 FUNCTIONAL DIAGRA VIN VCC Y = “0” ONLY WHEN X IS A CONSTANT “1” BURST DEFEAT OTHERWISE Y = “1” SLOPE COMP 5SYNC/ MODE VFB SENSE– VIN FREQ SHIFT SLEEP VIN VREF EA 0.12V ICOMP BURST 2.5µA gm = 0...

Page 6 LTC1622 OPERATIO (Refer to Functional Diagram) the ITH pin will drop. When the ITH voltage goes below Short-Circuit Protection 0.12V, the sleep signal goes high, turning off the external When the outp...

Page 7 LTC1622 APPLICATIONS INFORMATION The basic LTC1622 application circuit is shown in Figure VOUT. The inductor’s peak-to-peak ripple current is given 1. External component selection is driven by the loa...

Page 8 LTC1622 APPLICATIONS INFORMATION preferred at high switching frequencies, so design goals In applications where the maximum duty cycle is less than can concentrate on copper loss and preventing satura...

Page 9 LTC1622 APPLICATIONS INFORMATION The allowable forward voltage drop in the diode is calcu- lated from the maximum short-circuit current as: ∆V ESR OUT RIPPLE  f C  OUT where f is the operating fre...

Page 10 LTC1622 NO RM AL IZ ED OL TA GE APPLICATIONS INFORMATION is limiting the efficiency and which change would produce the most improvement. Efficiency can be expressed as: Efficiency = 100% – (η1 + η2 + ...

Page 11 LTC1622 APPLICATIONS INFORMATION Transition Loss = 3(VIN)2IO(MAX)CRSS(f) VOUTLTC1622 Other losses including CIN and COUT ESR dissipative R2 VFBITH losses, and inductor core losses, generally account f...

Page 12 LTC1622 APPLICATIONS INFORMATION down to 2.7V. Let’s assume that the MOSFET dissipation layout diagram in Figure 6. Check the following in your is to be limited to PP = 250m W and its thermal resistan...

Page 13 LTC1622 TYPICAL APPLICATIONS LTC1622 1.8V/1.5A Regulator with Burst Mode Operation Disabled 2.5V TO SENSE– VIN L1 3.3µH VOUT ITH PDRV 1.8V LTC1622 VFB GND C2 RUN/ SYNC/ R4 SS MODE 75k C4 1622 TA01 560...

Page 14 LTC1622 TYPICAL APPLICATIONS LTC1622 2.5V/3A Regulator with External Frequency Synchronization VIN 3.3V TO SENSE– VIN 16V ITH PDRV LTC1622 D1 4.7µH VOUT R1 VFB GND 2.5V RUN/ SYNC/ C2 158k SS MODE 100µ...

Page 15 LTC1622 Dimensions in inches (millimeters) unless otherwise noted.PACKAGE DESCRIPTION MS8 Package 8-Lead Plastic MSOP (LTC DWG # 05-08-1660) 0° – 6° TYP SEATING PLANE REF MSOP (MS8) 1098 (0.65) BSC DI...

Page 16 LTC1622 TYPICAL APPLICATION Small Footprint 3.3V/1A Regulator Efficiency vs Load Current VIN 3.3V TO VIN = 3.5V SENSE– VIN CERAMIC ITH PDRV M1 L1 VIN = 4.2V LTC1622 2.2µH VIN = 6V VFB GND 3.3V 10k SYN...

Manual Details

Brand	Current
Pages	16
File Size	187.62 KB
Published	May 28, 2026

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Frequently Asked Questions

How can I improve efficiency with fluctuating loads?

Utilize Burst Mode operation which enhances low current efficiency and extends battery run time.

What defines the minimum working input voltage?

The LTC1622 is rated to operate with an input voltage range from 2V up to 10V.

How much power does the unit consume when deactivated?

In shutdown mode, the device draws a very low amount of current: approximately 15mA.

What protection mechanism guards against low input voltage?

The incorporated undervoltage feature automatically shuts the LTC1622 down if the input falls below 2V.