UCC3926 Datasheet | Unitrode

FEATURES - Integral Non-inductive Current Sense Element with Internal Kelvin Connections - 20A Current Rating - Bi-directional, High Side or Low Side Sensing - Internal Temperature Nulling Circuitry for Current Sense Element and Amplifier - Logic patible Current Direction Status Output - Low Offset, Chopper Stabilized Current Sense Amplifier - Unmitted Amplifier with User Programmable Gain - Overcurrent Indication with User Programmable Threshold DESCRIPTION The UCC3926 Current Sensor IC contains a wideband, transimpedance amplifier for converting the current through an internal, non-inductive 1.3mΩ shunt resistor into a proportional voltage. The sense element operates in both high-side (VDD referenced) and low-side (GND referenced) applications. The UCC3926 can measure currents up to ±20A. This transimpedance amplifier gain is precisely trimmed to 33.3mΩ to convert a 15A input into a 500m V output signal. It has a very low input offset voltage from chopper-stabilization. A cross-switching block rectifies the input signal by forcing the differential output, AOP positive with respect to the other differential output, AON. SIGN indicates the polarity of the current. The UCC3926 programmable amplifier provides three functions. It converts the differential transimpedance output signal into a single-ended signal. It has a user-controlled gain stage that sets the maximum current level to the desired voltage and it level shifts the zero current point to the desired level as well. A parator then pares the output of the instrumentation amplifier to a user-set reference voltage on OCREF, which provides an overcurrent status bit OC. The UCC3926 is available in the 16 pin SOIC package. BLOCK DIAGRAM SLUS266A - OCTOBER 1999 UDG-97139-1 ABSOLUTE MAXIMUM RATINGS Input Sense Current (IIN) - - - - - ± 20A Supply Voltage, VDD - - - - - . . . 14.5V Inrush Current, 50µs - - - ....