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Design Note
Reliability Data
Press Release
- 80V Synchronous Buck-Boost Controller Features -55°C to 150°C Operating Junction Temperature Range
- Convert Any Input Voltage from 2.8V to 80V into a Fixed Output Voltage or Output Current with Up to 98% Efficiency at 250W
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Features
- Single Inductor Allows VIN Above, Below, or Equal to Regulated VOUT
- VIN Range 2.8V (Need EXTVCC > 6.4V) to 80V
- VOUT Range: 1.3V to 80V
- Quad N-Channel MOSFET Gate Drivers
- Synchronous Rectification: Up to 98% Efficiency
- Input and Output Current Monitor Pins
- Synchronizable Fixed Frequency: 100kHz to 400kHz
- Integrated Input Current, Input Voltage, Output and Output Voltage Feedback Loops
- Clock Output Usable To Monitor Die Temperature
- Available in 38-Lead (5mm × 7mm) QFN and TSSOP Packages with the TSSOP Modified for Improve Voltage Operation
Typical Application
Description
The LT®8705 is a high performance buck-boost switching regulator controller that operates from input voltages above, below or equal to the output voltage. The part has integrated input current, input voltage, output current and output voltage feedback loops. With a wide 2.8V to 80V input and 1.3V to 80V output range, the LT8705 is compatible with most solar, automotive, telecom and battery-powered systems.
The LT8705 includes servo pins to indicate which feedback loops are active. The MODE pin selects among Burst Mode® operation, discontinuous or continuous conduction mode at light loads. Additional features include a 3.3V/12mA LDO, a synchronizable fixed operating frequency, onboard gate drivers, adjustable UVLO, along with input and output current monitoring with programmable maximum levels.
| LT8705 | |
| LT8705A | Improved, pin-to-pin compatible version of LT8705. Recommended for all new designs |
5x7 QFN-38,TSSOP-38
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LT8705EFE#PBF | TSSOP | 38 | E | $8.50 | $5.95 |
| LT8705EFE#TRPBF | TSSOP | 38 | E | $6.01 | |
| LT8705EUHF#PBF | QFN | 38 | E | $8.50 | $5.95 |
| LT8705EUHF#TRPBF | QFN | 38 | E | $6.01 | |
| LT8705HFE#PBF | TSSOP | 38 | H | $9.76 | $6.83 |
| LT8705HFE#TRPBF | TSSOP | 38 | H | $6.89 | |
| LT8705IFE#PBF | TSSOP | 38 | I | $9.40 | $6.58 |
| LT8705IFE#TRPBF | TSSOP | 38 | I | $6.64 | |
| LT8705IUHF#PBF | QFN | 38 | I | $9.40 | $6.58 |
| LT8705IUHF#TRPBF | QFN | 38 | I | $6.64 | |
| LT8705MPFE#PBF | TSSOP | 38 | MP | $25.37 | $17.76 |
| LT8705MPFE#TRPBF | TSSOP | 38 | MP | $17.82 | |
| LT8705AEUHF#TRPBF | QFN | 38 | E | $8.56 | $6.01 |
| LT8705AIUHF#TRPBF | QFN | 38 | I | $9.46 | $6.64 |
| LT8705AMPFE#TRPBF | TSSOP | 38 | MP | $25.43 | $17.82 |
| LT8705AEFE#TRPBF | TSSOP | 38 | E | $8.56 | $6.01 |
| LT8705AMPFE#PBF | TSSOP | 38 | MP | $25.37 | $17.76 |
| LT8705AIUHF#PBF | QFN | 38 | I | $9.40 | $6.58 |
| LT8705AIFE#TRPBF | TSSOP | 38 | I | $9.46 | $6.64 |
| LT8705AEFE#PBF | TSSOP | 38 | E | $8.50 | $5.95 |
| LT8705AHFE#TRPBF | TSSOP | 38 | H | $9.82 | $6.89 |
| LT8705AEUHF#PBF | QFN | 38 | E | $8.50 | $5.95 |
| LT8705AIFE#PBF | TSSOP | 38 | I | $9.40 | $6.58 |
| LT8705AHFE#PBF | TSSOP | 38 | H | $9.76 | $6.83 |
Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.
| Part Number | Description | Price | Documentation |
|---|---|---|---|
| DC1924A | LT8705EUHF Demo Board | 36V ≤ VIN ≤ 80V; Vout = 48V @ 5A | $250.00 |