LINEAR TECHNOLOGY LTC1879 User's Manual
Summary
The LTC1879 is a high-efficiency synchronous buck regulator designed for sophisticated power management in portable electronics. This detailed manual provides engineers with comprehensive specifications and application guidance for the device, which delivers up to 95% efficiency while maintaining an ultra-low quiescent current (15mA). Ideal for designers of cellular phones, wireless modems, and battery-powered systems requiring stable voltage regulation across a wide input range (2.65V–10V). Learn about its constant frequency operation, advanced modes like Burst Mode, and robust protection features to ensure optimal battery life and performance in demanding applications.
Page 1 Text Content
LTC1879
1.2A Synchronous
Step-Down Regulator with 15µA Quiescent Current
FEATURES DESCRIPTIO High Efficiency: Up to 95% The LTC®1879 is a high efficiency monolithic synchro- Low Quiescent Current: Only 15µA with No Load nous buck regulator using a constant frequency, current 550k Hz Constant Frequency Operation mode architecture. Operating supply current is only 15µA
2.65V to 10V Input Voltage Range with no load and drops to <1µA in shutdown. The input VOUT from 0.8V to VIN, IOUT to 1.2A supply voltage range of 2.65V to 10V makes the LTC1879 True PLL Frequency Locking from 350k Hz to 750k Hz ideally suited for both single and dual Li-Ion battery-pow- Power Good Output Voltage Monitor ered applications. 100% duty cycle provides low dropout Low Dropout Operation: 100% Duty Cycle operation, extending battery life in portable systems.
Burst Mode® or Pulse Skipping Operation
The switching frequency is internally set to 550k Hz, allow-
Current Mode Operation for Excellent Line and Load
ing the use of small surface mount inductors and capaci-
Transient Response
tors. For noise sensitive applications, the LTC1879 can be
Shutdown Mode Draws <1µA Supply Current
externally synchronized from 350k Hz to 750k Hz. Burst
±2% Output Voltage Accuracy
Mode operation is inhibited during synchronization or
Overcurrent and Overtemperature Protected
when the SYNC/MODE pin is pulled low.
Available in 16-Lead SSOP Package EF FI CI EN CY
The internal synchronous rectifier switch increases effi- ciency and eliminates the need for an external Schottky
APPLICATIO S diode. Low output voltages are easily supported with a
0.8V feedback reference voltage. The LTC1879 is available
Cellular Telephones
in a 16-lead SSOP package.
Portable Computers
, LTC and LT are registered trademarks of Linear Technology Corporation.
Wireless Modems
Burst Mode is a registered trademark of Linear Technology Corporation.
TYPICAL APPLICATIO
High Efficiency Step-Down Converter Efficiency vs Output Load Current VIN
2.65V TO 10V
CIN VIN = 3.6V
10µF SVIN
RUN/SS PVIN
VIN = 7.2V
SYNC/MODE SWP 6.2µH
VOUT* VIN = 10V
LTC1879
PGOOD SWN
150k COUT
ITH PGND 47µF
Burst Mode OPERATION
VFB VOUT = 3.1V SGND 80.6k L = 6.2µH
1879 TA01a OUPUT CURRENT (m A)
CIN: TAIYO YUDEN CERAMIC LMK325BJ106MN 1879 TA01b
COUT: TDK CERAMIC C4532X5ROJ476M L1: TOKO A921CY6R2M *VOUT CONNECTED TO VIN (MINUS SWITCH AND L1 VOLTAGE DROP) FOR 2.65V < VIN < 3.1V
Page Summary Contents For LINEAR TECHNOLOGY LTC1879 User's Manual
Manual Details
| Brand | Linear |
|---|---|
| Pages | 20 |
| File Size | 256.26 KB |
| Published | May 30, 2026 |
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Frequently Asked Questions
What is the input voltage range for the LTC1879?
The IC operates with an input voltage range of 2.65V to 10V.
How low can the device draw power when idle?
It drops to less than 1mA in shutdown mode.
What cycle frequency is best for battery applications?
The internal synchronous rectifier switch increases efficiency, eliminating the need for external Schottky diodes.
Can this converter support multiple voltage outputs?
Yes, it supports a 'Power Good Output Voltage Monitor' and can monitor voltage drops while operating in bursts.