UC3901N

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UC3901N

Isolated Feedback Generator

Packaging

Package | PIN: N | 14
Temp: C (0 to 70)
Carrier: Partial Tube
Qty Price
1-9 $5.91
10-24 $5.32
25-99 $4.97
100-249 $4.46
250-499 $4.16
500-749 $3.62
750-999 $3.13
1000+ $3.07

Features

  • An Amplitude-Modulation System for Transformer Coupling an Isolated Feedback Error Signal
  • Low-Cost Alternative to Optical Couplers
  • Internal 1% Reference and Error Amplifier
  • Internal Carrier Oscillator Usable to 5MHz
  • Modulator Synchronizable to an External Clock
  • Loop Status Monitor

Texas Instruments  UC3901N

The UC1901 family is designed to solve many of the problems associated with closing a feedback control loop across a voltage isolation boundary. As a stable and reliable alternative to an optical coupler, these devices feature an amplitude modulation system which allows a loop error signal to be coupled with a small RF transformer or capacitor.

The programmable, high-frequency oscillator within the UC1901 series permits the use of smaller, less expensive transformers which can readily be built to meet the isolation requirements of today's line-operated power systems. As an alternative to RF operation, the external clock input to these devices allows synchronization to a system clock or to the switching frequency of a SMPS.

An additional feature is a status monitoring circuit which provides an active-low output when the sensed error voltage is within ±10% of the reference. The DRIVERA output, DRIVERB output, and STATUS output are disabled until the input supply has reached a sufficient level to allow proper operation of the device.

Since these devices can also be used as a DC driver for optical couplers, the benefits of 4.5 to 40V supply operation, a 1% accurate reference, and a high gain general purpose amplifier offer advantages even though an AC system may not be desired.