DocumentationDatasheet
Design Note
- DN261 - Chip Set Offers Low Cost Alternative to 48V Telecom Modules
- DN299 - Multiple Output Isolated Power Supply Achieves High Efficiency with Secondary Side Synchronous Post Regulator
Reliability Data
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Features
- High Efficiency Over Wide Load Current Range
- ±0.8% Output Voltage Accuracy
- Dual N-Channel MOSFET Synchronous Drivers
- Pulse Transformer Synchronization
- Optocoupler Feedback Driver
- Programmable Current Limit Protection
- ±5% Margin Output Voltage Adjustment
- Adjustable Overvoltage Fault Protection
- Power Good Flag
- Auxiliary 3.3V Logic Supply
- Available in 16-Lead SSOP and SO Packages
Typical Application
Description
The LTC1698 is a precision secondary-side forward converter controller that synchronously drives external N-channel MOSFETs. It is designed for use with the LT3781 primary-side synchronous forward converter controller to create a completely isolated power supply. The LT3781 synchronizes the LTC1698 through a small pulse transformer and the LTC1698 drives a feedback optocoupler to close the feedback loop. Output accuracy of ±0.8% and high efficiency over a wide range of load currents are obtained.
The LTC1698 provides accurate secondary-side current limit using an external current sense resistor. The input voltage at the MARGIN pin provides ±5% output voltage adjustment. A power good flag and overvoltage input are provided to ensure proper power supply conditions. An auxiliary 3.3V logic supply is included that supplies up to 10mA of output current.
SO-16,SSOP-16
Package Variations and Pricing
| Part Number | Package | Pins | Temp | Price (1-99) |
Price (1k)* |
|---|---|---|---|---|---|
| LTC1698EGN#PBF | SSOP | 16 | E | $6.27 | $5.30 |
| LTC1698EGN#TRPBF | SSOP | 16 | E | $5.36 | |
| LTC1698ES#PBF | SO | 16 | E | $6.33 | $5.35 |
| LTC1698ES#TRPBF | SO | 16 | E | $5.41 | |
| LTC1698IGN#PBF | SSOP | 16 | I | $6.92 | $5.85 |
| LTC1698IGN#TRPBF | SSOP | 16 | I | $5.91 | |
| LTC1698IS#PBF | SO | 16 | I | $6.98 | $5.90 |
| LTC1698IS#TRPBF | SO | 16 | I | $5.96 | |
| LTC1698EGN | SSOP | 16 | E | $12.54 | $10.60 |
| LTC1698EGN#TR | SSOP | 16 | E | $10.72 | |
| LTC1698ES | SO | 16 | E | $12.66 | $10.70 |
| LTC1698ES#TR | SO | 16 | E | $10.82 | |
| LTC1698IGN | SSOP | 16 | I | $13.84 | $11.70 |
| LTC1698IGN#TR | SSOP | 16 | I | $11.82 | |
| LTC1698IS | SO | 16 | I | $13.96 | $11.80 |
| LTC1698IS#TR | SO | 16 | I | $11.92 |
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 |
|---|---|---|---|
| DC479A | LT3781EG, LTC1698EGN, LT1783CS5 | Isolated Synchronous, Forward Converter, Vin=36V-72V, Vout=3.3V @ 15A | $75.00 | |
| DC617A | LT3781EG LTC1698EGN LT1783CS5 | Isolated Synchronous Forward Converter, +Vin = 36V - 72V, +Vout = 2.5V @ 20A, Quarter Brick footprint | $75.00 | |
| DC759A | LT1952EGN, LTC1698EGN | 48Vin to 5V at 20A Converter, +Vin = 36V - 72V, +Vout = +5V at 20A | $175.00 |