AS589

The ALPHA Semiconductor AS589 is a 2-terminal band-gap precision voltage reference, which provides a stable fixed out voltage of 1.23 volts. ALPHA Semiconductor's design, process, and precise on chip trimming enable us to achieve a low temperature coefficient as low as 5 ppm/ and ±4% reference tolerance. The AS589 is an excellent choice for applications which are looking for low input current between 50uA to 5mA, low drift over temperature low noise, low power, and low cost. The AS589 is available in many versions. The AS589.T, M, L, K grades are specified for 0 to +70 operation, in (TO- 52/92) packages, and the AS589 U, T and S grades are rated for -55 to +125 in metal can packages(TO-52).

The AS589 possesses the features of low drift(5ppm/); low dynamic impedance 0.6 S) Typ.; operating current 50A to 5mA; low [ower 60W @ IIN=50A; low output tolerance ±0.4%; low noise 5V p-p Typ.; direct replacements for LM113, ICL8069, AD589, MP5010; low cost. While AS589 are applicated in A to D and D to A converters; constant current source; digital voltmeter; power supply monitor; precision regulators.

The AS589 acts as a two terminal shunt-type regulator. This device provides a constant output current at a wide range of input current of 50uA to 50mA. The below figure is a simplified connection of output voltage of 1.2 or less. The minimum capacitor of 1000pF is required for additional filtering to provide lower noise. The AS589 low power operation makes it suitable for battery operated equipment. This device is ideal for use with a CMOS analog-to-digital converter as a reference. The below figure shows this device used with two common integrating type CMOS A/D converters. The AS589 can be used as a building block to generate other values of reference voltage. The below figure shows the circuit design that produces a buffered 10V output. Total supply current is approx. 2mA. The A589 is also suitable to use with CMOS digital-to-analog converter. This figure shows the requirement of DAC in negative reference voltage in order to provide a positive output range. The below circuit shows AS589 supplying the -l.OV reference to multiplying DAC.