LT1737 - High Power Isolated Flyback Controller
Features
- Drives External Power MOSFET
- Supply Voltage Range: 4.5V to 20V
- Flyback Voltage Limited Only by External Components
- Senses Output Voltage Directly from Primary Side Winding—No Optoisolator Required
- Moderate Accuracy Regulation Without User Trims
- Regulation Maintained Well into Discontinuous Mode
- Switching Frequency from 50kHz to 250kHz with External Capacitor
- Available in 16-Pin GN and SO Packages
- Optional Load Compensation
- Optional Undervoltage Lockout
- External ISENSE Resistor
- Shutdown Feature Reduces IQ to 50µA Typ
AEC-Q100 data available for specific packages
Typical Application
Description
The LT1737 is a monolithic switching regulator controller specifically designed for the isolated flyback topology. It drives the gate of an external MOSFET and is generally powered from a DC supply voltage. Output voltage feedback information may be supplied by a variety of methods including a third transformer winding, the primary winding or even direct DC feedback (see Applications Information). Its gate drive capability coupled with a suitable external MOSFET and other power path components can deliver load power up to tens of Watts.
The LT1737 has a number of features not found on other isolated flyback controller ICs presently available. By utilizing current mode switching techniques, it provides excellent AC and DC line regulation. Its unique control circuitry can maintain regulation well into discontinuous mode in most applications. Optional load compensation circuitry allows for improved load regulation. An optional undervoltage lockout pin halts operation when the application input voltage is too low. An optional external capacitor implements a soft-start function.
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 |
|---|---|---|---|---|---|
| LT1737CGN#PBF | SSOP-16 | GN | C | 05-08-1641 (GN16) | Yes |
| LT1737CGN#TRPBF | SSOP-16 | GN | C | 05-08-1641 (GN16) | Yes |
| LT1737CS#PBF | SO-16 | S | C | 05-08-1610 (S16) | Yes |
| LT1737CS#TRPBF | SO-16 | S | C | 05-08-1610 (S16) | Yes |
| LT1737IGN#PBF | SSOP-16 | GN | I | 05-08-1641 (GN16) | Yes |
| LT1737IGN#TRPBF | SSOP-16 | GN | I | 05-08-1641 (GN16) | Yes |
| LT1737IS#PBF | SO-16 | S | I | 05-08-1610 (S16) | Yes |
| LT1737IS#TRPBF | SO-16 | S | I | 05-08-1610 (S16) | 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 | |
|---|---|---|---|---|---|---|
| LT1737CGN#PBF | SSOP-16 | C | $3.55 | $3.00 | Yes | |
| LT1737CGN#TRPBF | SSOP-16 | C | $3.06 | Yes | ||
| LT1737CS#PBF | SO-16 | C | $3.43 | $2.90 | Yes | |
| LT1737CS#TRPBF | SO-16 | C | $2.96 | Yes | ||
| LT1737IGN#PBF | SSOP-16 | I | $4.14 | $3.50 | Yes | |
| LT1737IGN#TRPBF | SSOP-16 | I | $3.56 | Yes | ||
| LT1737IS#PBF | SO-16 | I | $4.03 | $3.40 | Yes | |
| LT1737IS#TRPBF | SO-16 | I | $3.46 | 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 |
|---|---|---|---|
| DC418A | LT1737CS | Isolated, Triple Output Power Supply, Vin=8V to 36V, Vout=+15V @ 100mA, -15V @ 100mA, +5V @ 200mA | $150.00 | |
| 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 | |
|---|---|---|---|---|---|---|
| LT1737IGN#PBF | SSOP-16 | I | $4.14 | $3.50 | Yes | |
| LT1737IGN#TRPBF | SSOP-16 | I | $3.56 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- Isolated Flyback Switching Regulators
- Medical Instruments
- Instrumentation Power Supplies
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Design Tools
LTspice
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Models for the following parts are available in LTspice:
LT1737
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.
