Datasheet LTC3901 (Analog Devices)

LTC3901 Secondary Side Synchronous Driver for Push-Pull and Full-Bridge Converters
U FEATURES DESCRIPTIO
■
N-Channel Synchronous MOSFET Driver
The LTC®3901 is a secondary side synchronous rectifier ■
Programmable Timeout
driver designed to be used in isolated push-pull and full- ■
Reverse Inductor Current Sense
bridge converter power supplies. The chip drives two ■ Gate Drive Transformer Synchronization external N-channel MOSFETs and accepts a transformer- Sequence Monitor generated bipolar input to maintain sychronization with ■ Wide VCC Supply Range: 4.5V to 11V the primary side controller. ■ 15ns Rise/Fall Times at VCC = 5V, CL = 4700pF The LTC3901 provides a full range of protection features ■ Undervoltage Lockout for the external MOSFETs. A programmable timeout func- ■ Small 16-Lead SSOP Package tion is included that disables both drivers when the syn-
U
chronization signal is missing or incorrect. Additionally,
APPLICATIO S
the chip senses the output inductor current through the ■ 48V Input Isolated DC/DC Converters drain-source resistance of the two MOSFETs, turning off ■ Isolated Telecom Power Supplies the MOSFETs if the inductor current reverses. The LTC3901 ■ Distributed Power Step-Down Converters also shuts off the drivers if the supply is low or if the ■ Industrial Control System Power Supplies synchronization sequence is incorrect. ■ Automotive and Heavy Equipment , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners.
U TYPICAL APPLICATIO
L1 ISOLATION VOUT + BARRIER 12V COUT T1 VIN 36V TO 72V CSE+ VCC MA MB ME ME CSE– GND LTC3901 DRVA DRVB CSF+ PV LTC3723 CC PUSH-PULL MF MF CONTROLLER CSF– COMP V PGND FB SDRA SDRB SYNC TIMER T2 OUT FB LT4430 OR LT1431 OPTOCOUPLER DRIVER COMP 3901 F01
Figure 1. Simplified Isolated Push-Pull Converter
3901f 1