LT3571 - 75V DC/DC Converter for APD Bias
Features
- High Output Voltage: Up to 75V
- Integrated Schottky Diode
- 75V, 350mA Internal Switch
- High Side Fixed Voltage Drop APD Current Monitor
- Adjustable Frequency: 250kHz to 2MHz
- Frequency Synchronization
- Wide VIN Range: 2.7V to 20V
- Constant-Voltage and Constant-Current Regulation
- Programmable Current Limit Protection
- Surface Mount Components
- Low Shutdown Current <1μA
- Internal Soft-Start
- Internal Compensation
- CTRL Pin Allows Output Adjustment with No Polarity Inversion
- 3mm × 3mm 16-Lead QFN Package
AEC-Q100 data available for specific packages
Typical Application
Description
The LT3571 is a current mode step-up DC/DC converter designed to bias avalanche photodiodes (APDs) in optical receivers with an output voltage up to 75V. The LT3571 features a high side fixed voltage drop APD current monitor with better than 10% relative accuracy over the entire temperature range. The integrated power switch, Schottky diode and APD current monitor allow a small solution footprint and low solution cost. It combines a traditional voltage loop and a unique current loop to operate as a constant-current source or constant-voltage source. The inductor-based topology ensures an input free from switching noise. The integrated high side current monitor produces a current proportional to the APD current with better than 10% relative accuracy over four decades of dynamic range in the input range of 250nA to 2.5mA. This current can be used as a reference to provide a digitally programmed output voltage via the CTRL pin. The LT3571 is available in the tiny footprint (3mm × 3mm) 16-lead QFN package.Packaging
CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.
For complete and up to date package information and drawings, please refer to our packaging page
| Part Number | Package | Code | Temp | Package Drawing |
RoHS |
|---|---|---|---|---|---|
| LT3571EUD#PBF | 3x3 QFN-16 | UD | E | 05-08-1691 | Yes |
| LT3571EUD#TRPBF | 3x3 QFN-16 | UD | E | 05-08-1691 | Yes |
| LT3571IUD#PBF | 3x3 QFN-16 | UD | I | 05-08-1691 | Yes |
| LT3571IUD#TRPBF | 3x3 QFN-16 | UD | I | 05-08-1691 | Yes |
Order Info
- Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
- Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
- Please refer to our general ordering information or the product datasheet for more details
Package Variations and Pricing
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT3571EUD#PBF | 3x3 QFN-16 | E | $3.50 | $2.45 | Yes | |
| LT3571EUD#TRPBF | 3x3 QFN-16 | E | $2.51 | Yes | ||
| LT3571IUD#PBF | 3x3 QFN-16 | I | $3.89 | $2.72 | Yes | |
| LT3571IUD#TRPBF | 3x3 QFN-16 | I | $2.78 | Yes | ||
| Buy Now • Request Samples | ||||||
Demo Boards
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 |
|---|---|---|---|
| DC1423A | LT3571EUD Demo Board | 75V DC/DC Converter for APD Bias | $125.00 | |
| Buy Now | |||
Designed for Automotive and Transportation Applications
AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT3571IUD#PBF | 3x3 QFN-16 | I | $3.89 | $2.72 | Yes | |
| LT3571IUD#TRPBF | 3x3 QFN-16 | I | $2.78 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- APD Bias
- PIN Diode Bias
- Optical Receivers and Modules
- Fiber Optic Network Equipment
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Design Tools
LTspice
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LT3571
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
