LT8709
RECOMMENDED FOR NEW DESIGNSNegative Input Synchronous Multi-Topology DC/DC Controller
- Part Models
- 4
- 1ku List Price
- Starting From $5.54
Overview
- Wide Negative Input Range: –4.5V to –80V
- Rail-to-Rail Output Current Monitor and Control
- Input Voltage Regulation for High Impedance Inputs
- Power Good Indication Pin
- MODE Pin for Forced CCM (Continuous Conduction Mode) or Pulse-Skipping/DCM (Discontinuous Conduction Mode) Operation
- Switching Frequency Up to 750kHz
- Easily Configurable as a Buck, Boost, Buck-Boost, or
- Inverting Converter with a Single Feedback Pin
- Can be Synchronized to an External Clock
- High Gain EN/FBIN Pin Accepts Slowly Varying Input Signals
- 20-Lead TSSOP Package
The LT8709 is a synchronous PWM controller for negative-to-negative or negative-to-positive DC/DC conversion, with rail-to-rail output current monitor and control. The LT8709 is ideal for many local power supply designs. It can be easily configured in buck, boost, buck-boost, and inverting topologies with negative input voltages.
In addition, the LT8709’s rail-to-rail output current sense allows the part to be configured in current limited applications such as battery or capacitor charging. The PG pin is used for power good indication.
The LT8709’s switching frequency range can be set between 100kHz and 750kHz. The part may be clocked internally at a frequency set by the resistor from the RT pin to the –VIN pin, or it may be synchronized to an external clock.
The LT8709 also features innovative EN/FBIN pin circuitry that allows for slowly varying input signals and an adjustable undervoltage lockout function. The pin is also used as input voltage regulation to avoid collapsing a high impedance input supply. Additional features such as frequency foldback, thermal shutdown and soft-start are integrated. The LT8709 is available in a 20-lead TSSOP package.
Applications
- High Power Negative Input, Negative Output Power Supplies
- High Power Negative Input, Positive Output Power Supplies
- Telecom Equipment Power Supplies
- Cathodic Protection Power Supplies
Documentation
Data Sheet 1
User Guide 1
Video 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 |
|---|---|---|---|
| LT8709EFE#PBF | 20-Lead TSSOP w/ EP | ||
| LT8709EFE#TRPBF | 20-Lead TSSOP w/ EP | ||
| LT8709IFE#PBF | 20-Lead TSSOP w/ EP | ||
| LT8709IFE#TRPBF | 20-Lead TSSOP w/ EP |
| Part Models | Product Lifecycle | PCN |
|---|---|---|
|
Apr 6, 2022 - 22_0068 Laser Top Mark for ETSSOP and TSSOP Packages Assembled in ADPG [PNG] and UTL |
||
| LT8709EFE#PBF | PRODUCTION | |
| LT8709EFE#TRPBF | PRODUCTION | |
| LT8709IFE#PBF | PRODUCTION | |
| LT8709IFE#TRPBF | PRODUCTION | |
This is the most up-to-date revision of the Data Sheet.
Software Resources
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Tools & Simulations
LTspice 4
- LT8709 Demo Circuit - Negative Buck-Boost Regulator with Output Current Monitor & Power Good (-4.5V to -38Vin to -12Vout @ 5A)
- LT8709 Demo Circuit - Negative Buck Regulator with Output Current Monitor & Power Good (-16V to -30Vin to -12V @ 8.5A)
- LT8709 Demo Circuit - Negative Boost Regulator with Output Current Monitor & Power Good (-4.5V to -9Vin to -12V @ 4.5A)
- LT8709 Demo Circuit - Negative Inverting Regulator with Output Current Monitor & Power Good (-4.5V to -42Vin to 5V @ 4A)
Models for the following parts are available in LTspice:
- LT8709
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.
