LT1940
PRODUCTIONDual Monolithic 1.4A, 1.1MHz Step-Down Switching Regulator
- Part Models
- 4
- 1ku List Price
- Starting From $4.62
Overview
- Wide Input Voltage Range:
- LT1940: 3.6V to 25V
- LT1940L: 3.6V to 7V
- Two 1.4A Output Switching Regulators with Internal Power Switches
- Constant 1.1MHz Switching Frequency
- Anti-Phase Switching Reduces Ripple
- Independent Shutdown/Soft-Start Pins
- Independent Power Good Indicators Ease Supply Sequencing
- Uses Small Inductors and Ceramic Capacitors
- Small 16-Lead Thermally Enhanced TSSOP Surface Mount Package
The LT1940 is a dual current mode PWM step-down DC/DC converter with internal 2A power switches. Both converters are synchronized to a single 1.1MHz oscillator and run with opposite phases, reducing input ripple current. The output voltages are set with external resistor dividers, and each regulator has independent shutdown and soft-start circuits. Each regulator generates a power-good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.
The LT1940’s 1.1MHz switching frequency allows the use of tiny inductors and capacitors, resulting in a very small dual 1.4A output solution. Constant frequency and ceramic capacitors combine to produce low, predictable output ripple voltage. With its wide input range of 3.6V to 25V, the LT1940 regulates a wide variety of power sources, from 4-cell batteries and 5V logic rails to unregulated wall transformers, lead acid batteries and distributed-power supplies. The LT1940L is intended to operate from regulated 5V supplies. A current mode PWM architecture provides fast transient response with simple compensation components and cycle-by-cycle current limiting. Frequency foldback and thermal shutdown provide additional protection.
Applications
- Disk Drives
- DSP Power Supplies
- Wall Transformer Regulation
- Distributed Power Regulation
- DSL Modems
- Cable Modems
Documentation
Data Sheet 1
User Guide 1
Application Note 1
Design Note 1
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal. View our quality and reliability program and certifications for more information.
| Part Model | Pin/Package Drawing | Documentation | CAD Symbols, Footprints, and 3D Models |
|---|---|---|---|
| LT1940EFE#PBF | 16-Lead TSSOP w/ EP | ||
| LT1940EFE#TRPBF | 16-Lead TSSOP w/ EP | ||
| LT1940LEFE#PBF | 16-Lead TSSOP w/ EP | ||
| LT1940LEFE#TRPBF | 16-Lead TSSOP w/ EP |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
May 18, 2026 - 26_0072 Epoxy Change for Select TSSOP Products |
||
| LT1940EFE#PBF | PRODUCTION | |
| LT1940EFE#TRPBF | PRODUCTION | |
| LT1940LEFE#PBF | PRODUCTION | |
| LT1940LEFE#TRPBF | PRODUCTION | |
|
Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL |
||
| LT1940EFE#PBF | PRODUCTION | |
| LT1940EFE#TRPBF | PRODUCTION | |
| LT1940LEFE#PBF | PRODUCTION | |
| LT1940LEFE#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
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Request a Driver/SoftwareHardware Ecosystem
| Parts | Product Life Cycle | Description |
|---|---|---|
| Circuit Monitors 1 | ||
| LTC2960 | RECOMMENDED FOR NEW DESIGNS | 36V Nano-Current Two-Input Voltage Monitor |
| Hot Swap Controllers 1 | ||
| LT4363 | RECOMMENDED FOR NEW DESIGNS | High Voltage Surge Stopper with Current Limit |
| Power System Management (PSM) & Sequencers 1 | ||
| LTC2974 | RECOMMENDED FOR NEW DESIGNS | 4-Channel PMBus Power System Manager Featuring Accurate Output Current Measurement |
| Switching Regulators & Controllers 1 | ||
| LTC3880 | RECOMMENDED FOR NEW DESIGNS | Dual Output PolyPhase Step-Down DC/DC Controller with Digital Power System Management |
Tools & Simulations
LTspice
Models for the following parts are available in LTspice:
- LT1940
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
Evaluation Kits
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