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LINEAR TECHNOLOGY LT1949 User's Manual

Summary

This detailed technical manual covers the LT1949, a fixed-frequency PWM DC/DC Converter designed for generating stable bias voltages. Key features include high voltage switching up to 30V, low quiescent current operation, and an integrated low-battery detector for robust portable electronics. It is ideal for designers creating complex systems such as large screen LCD panels, diagnostic medical instruments, or specialized data logging equipment requiring reliable, efficient power solutions in miniature packages.

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LT1949

600k Hz, 1A Switch PWM DC/DC Converter

FEATURES DESCRIPTIO 1A, 0.5Ω, 30V Internal Switch The LT®1949 is a fixed frequency step-up DC/DC con- Operates with VIN as Low as 1.5V verter with a 1A, 0.5Ω internal switch. Capable of gener- 600k Hz Fixed Frequency Operation ating 10V at 175m A from a 3.3V input, the LT1949 is ideal

Low-Battery Detector Stays Active in Shutdown for generating bias voltages for large screen LCD panels. Low VCESAT Switch: 410m V at 800m A Constant frequency 600k Hz operation results in a low Pin-for-Pin Compatible with the LT1317B noise output that is easy to filter and the 30V switch rating Small 8-Lead MSOP and SO Packages allows output voltage up to 28V using a single inductor. An external compensation pin gives the user flexibility in optimizing loop compensation, allowing small low ESR

APPLICATIO S

ceramic capacitors to be used at the output. The 8-lead LCD Bias Supplies MSOP and SO packages ensure a low profile overall GPS Receivers solution.

Battery Backup

EF FI CI EN CY The LT1949 includes a low-battery detector that stays

Portable Electronic Equipment

alive when the device goes into shutdown. Quiescent

Diagnostic Medical Instrumentation

current in shutdown is 25µA, while operating current is 4.5m A. , LTC and LT are registered trademarks of Linear Technology Corporation.

TYPICAL APPLICATIO VIN 3.3V L1

D1 VOUT = 10V

10µH C1 VIN SW

4.2VIN 3VIN3.6VIN

LT1949

1M VOUT SHDNSHUTDOWN FB 10V 175m A

VC GND

CERAMIC

C1: AVX TAJA226M006R 1949 F01

C2: TAIYO YUDEN LMK325BJ106MN

D1: MBRM120LT3 LOAD CURRENT (m A)

L1: SUMIDA CDRH62B-100 1949 F02

Figure 1. 3.3V to 10V/175m A DC/DC Converter Figure 2. 3.3V to 10V Converter Efficiency

Page Summary Contents For LINEAR TECHNOLOGY LT1949 User's Manual

Page 1 LT1949 600k Hz, 1A Switch PWM DC/DC Converter FEATURES DESCRIPTIO 1A, 0.5Ω, 30V Internal Switch The LT®1949 is a fixed frequency step-up DC/DC con- Operates with VIN as Low as 1.5V verter with a 1A, 0...
Page 2 LT1949 ABSOLUTE AXI U RATI GS (Note 1) VIN, LBO Voltage 12V Junction Temperature 125°C SW Voltage –0.4V to 30V Operating Temperature Range (Note 2) FB Voltage VIN + 0.3V LT1949EMS8.......................
Page 3 SW IT CH OL TA GE (V OS CI LL AT OR RE QU EN CY (k Hz LT1949 ELECTRICAL CHARACTERISTICS The ● denotes specifications which apply over the full operating temperature range, otherwise specifications are...
Page 4 QU IE SC EN CU RR EN (µ A) LT1949 TYPICAL PERFOR A CE CHARACTERISTICS Quiescent Current, SHDN = 0V FB Pin Bias Current SHDN Pin Current FB IN IA CU RR EN (n A) –50 –25 –50 –25 TEMPERATURE (°C) TEMPERA...
Page 5 LT1949 BLOCK DIAGRA REFERENCE VC LBO ERROR 200m V AMPLIFIER ENABLE SHUTDOWN R1 A1 (EXTERNAL) COMPARATOR FB SW (EXTERNAL) FF RAMP DRIVER GENERATOR Q3Q A2 COMPARATOR 600k Hz OSCILLATOR GND 1949 BD Figur...
Page 6 LT1949 OPERATIO LBOLBI GROUND PLANE LT1949 L1 SHUTDOWN MULTIPLE VIAs Figure 4. Recommended Component Placement for Boost UU WU Converter. Note Direct High Current Paths Using Wide PC Traces. Minimize ...
Page 7 LT1949 TYPICAL APPLICATIO 4 Cell to 5V SEPIC Converter 10µH VOUT 4V TO 9V VIN SW L2 1M LT1949 C1 C3 4.7µF SHDN FB 10µF 16V 6.3V VC GND 1M 33k C1, C2: TAIYO YUDEN EMK316BJ475ML C3: TAIYO YUDEN JMK316BJ...
Page 8 LT1949 TYPICAL APPLICATIO Low Profile Triple Output LCD Bias Generator VIN 8V 3.3V 200m A VIN SW SHDNSHUTDOWN 1% LBI LT1949 C1 FB C2 C4 VC GND C1: AVX TAJB226M010 C5 C2: TAIYO YUDEN TMK432BJ106MN X7R ...

Manual Details

Brand Linear
Pages 8
File Size 161.50 KB
Published June 16, 2026
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Frequently Asked Questions

What is the operating temperature range for this device?

The LT1949ES8/LT1949IS8 models have an operating range of -40°C to 85°C.

Is the LT1949 compatible with other versions?

Yes, it is pin-for-pin compatible with the LT1317B and supports a 30V switch rating.

Does the converter have battery backup features?

The LT1949 includes a low-battery detector that remains active in shutdown to keep portable equipment running.

What is the typical input voltage for operation?

Typical application examples show operation from 3.3V or 3.6V, but the general input range can accommodate voltages up to 12V.