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UC3901

ACTIVE

Isolated feedback generator, 0C to 70C

Product details

Features 1% reference, Isolated feedback generator, Synchronizable Operating temperature range (°C) 0 to 70 Vin (max) (V) 40 Device type Isolated feedback generator Rating Catalog
Features 1% reference, Isolated feedback generator, Synchronizable Operating temperature range (°C) 0 to 70 Vin (max) (V) 40 Device type Isolated feedback generator Rating Catalog
PDIP (N) 14 181.42 mm² 19.3 x 9.4 SOIC (D) 14 51.9 mm² 8.65 x 6 SOIC (DW) 16 106.09 mm² 10.3 x 10.3
  • 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
  • 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

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.

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.

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Technical documentation

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Type Title Date
* Data sheet Isolated Feedback Generator datasheet (Rev. A) 13 Jan 2010
Application note DN-19 A Simple Isolation Amplifier Using the UC1901 05 Sep 1999
Application note DN-33 Optocoupler Feedback Drive Techniques Using the UC3901 and UC3903 05 Sep 1999
Application note The UC1901 Simplifies the Problem of Isolated Feedback in Switching Regulators 05 Sep 1999

Design & development

For additional terms or required resources, click any title below to view the detail page where available.

Simulation model

UCx901 Family PSpice Average Model

SLUM063.ZIP (88 KB) - PSpice Model
Simulation model

UCx901 Family PSpice Transient Model

SLUM066.ZIP (42 KB) - PSpice Model
Simulation model

UCx901 Family TINA-TI Average Reference Design

SLUM058.TSC (1026 KB) - TINA-TI Reference Design
Simulation model

UCx901 Family TINA-TI Average Spice Model

SLUM059.ZIP (7 KB) - TINA-TI Spice Model
Simulation model

UCx901 Family TINA-TI Transient Reference Design

SLUM064.TSC (828 KB) - TINA-TI Reference Design
Simulation model

UCx901 Family TINA-TI Transient Spice Model

SLUM065.ZIP (9 KB) - TINA-TI Spice Model
Package Pins Download
PDIP (N) 14 View options
SOIC (D) 14 View options
SOIC (DW) 16 View options

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