Features and Benefits
- Maintains Constant Frequency at Low Output Currents
- Dual N-Channel MOSFET Synchronous Drive
- Programmable Fixed Frequency (PLL Lockable)
- Wide VIN Range: 3.5V to 36V Operation
- Ultrahigh Efficiency
- Very Low Dropout Operation: 99% Duty Cycle
- Low Dropout, 0.5A Linear Regulator for VPP
- Generation or Low Noise Audio Supply
- Built-In Power-On Reset Timer
- Programmable Soft Start
- Low-Battery Detector
- Remote Output Voltage Sense
- Foldback Current Limiting (Optional)
- Pin Selectable Output Voltage
- Logic-Controlled Micropower Shutdown: IQ < 30µA
- Output Voltages from 1.19V to 9V
- Available in 28- and 36-Lead SSOP Packages
The LTC1438/LTC1439 are dual, synchronous stepdown switching regulator controllers which drive external N-channel power MOSFETs in a phase-lockable fixed frequency architecture. The Adaptive Power™ output stage selectively drives two N-channel MOSFETs at frequencies up to 400kHz while reducing switching losses to maintain high efficiencies at low output currents.
An auxiliary 0.5A linear regulator using an external PNP pass device provides a low noise, low dropout voltage source. A secondary winding feedback control pin (SFB1) guarantees regulation regardless of load on the main output by forcing continuous operation.
An additional comparator is available for use as a low battery detector. A power-on reset timer (POR) is included which generates a signal delayed by 65536/fCLK (typ 300ms) after the output is within 5% of the regulated output voltage. Internal resistive dividers provide pin selectable output voltages with remote sense capability on one of the two outputs.
The operating current levels are user-programmable via external current sense resistors. Wide input supply range allows operation from 3.5V to 30V (36V maximum).
- Notebook and Palmtop Computers, PDAs
- Portable Instruments
- Battery-Operated Devices
- DC Power Distribution Systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Documentation & Resources
R393 Reliability Data3/22/201820 K
AN84 - Linear Technology Magazine Circuit Collection, Volume IV8/20/20072M
DC106B - Demo Manual9/24/2009242K
LTC1438/LTC1439 - SPECIFICATION NOTICE11/5/2004110K
A Third Generation Dual, Opposing-Phase Switching Regulator Controller6/1/1999 LT Journal
VID Voltage Programmer for Intel Mobile Processors8/1/1998 LT Journal
Tools & Simulations
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|Part Number||Material Declaration||Reliability Data||Pin/Package Drawing||CAD Symbols, Footprints & 3D Models|
|LTC1439CG#PBF||Material Declaration||Reliability Data||36-Lead SSOP|
|LTC1439CG#TRPBF||Material Declaration||Reliability Data||36-Lead SSOP|
|LTC1439CGW#PBF||Material Declaration||Reliability Data||36-Lead SSOP (Wide 0.3 Inch)|
|LTC1439CGW#TRPBF||Material Declaration||Reliability Data||36-Lead SSOP (Wide 0.3 Inch)|
|LTC1439EG#PBF||Material Declaration||Reliability Data||36-Lead SSOP|
|LTC1439EG#TRPBF||Material Declaration||Reliability Data||36-Lead SSOP|
|LTC1439IG#PBF||Material Declaration||Reliability Data||36-Lead SSOP|
|LTC1439IG#TRPBF||Material Declaration||Reliability Data||36-Lead SSOP|
|LTC1439IGW#PBF||Material Declaration||Reliability Data||36-Lead SSOP (Wide 0.3 Inch)|
|LTC1439IGW#TRPBF||Material Declaration||Reliability Data||36-Lead SSOP (Wide 0.3 Inch)|
|Wafer Fabrication Data||R393 Reliability Data|
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