GS432

Choose GS432 when your application requires a reference voltage below 2.5V or when operating from low supply voltages. The 1.25V output is ideal for 1.8V and 2.5V systems where a 2.5V reference would leave insufficient headroom. The lower minimum operating current (60μA vs 100μA) benefits ultra-low-power battery applications. The SC70-3 package option is smaller than GS431's SOT23-3, saving board space in compact designs. However, GS432 has slightly lower accuracy (1% vs 0.5%) and higher drift (30ppm vs 20ppm), so choose GS431 when precision is more important than voltage level. For ADC references, match the reference to your ADC's input range - if your signals are 0-1V, the 1.25V reference provides better utilization than 2.5V.

Choose GS432 for low-voltage systems and ultra-low-power designs. Choose GS431 when higher precision is required.

In a 1.8V system, the GS432's 1.25V output provides adequate headroom for proper operation. Connect the series resistor from the 1.8V supply to the GS432 cathode. Calculate resistor value: R = (1.8V - 1.25V) / Ioperating. For 200μA operation: R = 0.55V / 200μA = 2.75kΩ, use 2.7kΩ standard value. Verify minimum supply headroom: 1.8V - 1.25V = 0.55V, which is adequate for proper regulation. The GS432 will maintain 1.25V output as long as supply stays above approximately 1.4V. For battery-powered systems where voltage declines during discharge, verify operation at end-of-life voltage. The low 60μA minimum current allows operation even with large series resistors when current must be minimized.

GS432 works well in 1.8V systems with adequate headroom. Calculate series resistor for your current requirements.

The temperature coefficient (tempco) of 30ppm/°C means the reference voltage changes by 30 parts per million for each degree Celsius temperature change. For GS432's 1.25V output over 100°C range: Error = 1.25V × (30/1,000,000) × 100 = 3.75mV. This is 0.3% error from drift alone. Combined with 1% initial accuracy, total error could be ±1.3% over temperature. For better accuracy, you can calibrate at a known temperature or use software compensation if temperature is monitored. The 30ppm specification is maximum - typical devices perform better. For applications requiring highest accuracy over temperature, consider references with lower tempco (10-20ppm/°C) or implement temperature compensation in your system.

Calculate total error including initial accuracy and tempco over your temperature range. Consider calibration for highest accuracy.

The GS432 provides an excellent reference voltage for current sense amplifier circuits. In a typical application, a sense resistor (e.g., 0.1Ω) converts current to voltage, which is amplified by an op-amp (like GS8511) with gain set by feedback resistors. The GS432 provides a stable reference for the amplifier's offset or for setting comparison thresholds. For example, in a 1A overcurrent detection circuit: 1A × 0.1Ω = 100mV across sense resistor. Amplify by 12.5x to get 1.25V, which matches GS432 output for direct comparator connection. The 1% accuracy is adequate for most protection applications. The low tempco ensures consistent thresholds over temperature. For bidirectional current sensing, bias the amplifier output to mid-scale using the reference.

Use GS432 as stable reference for current sense circuits. Match reference voltage to your sense amplifier gain and threshold requirements.

The SC70-3 package is significantly smaller than SOT23-3, making it ideal for space-constrained designs. SC70-3 dimensions are approximately 2.0mm × 2.1mm vs SOT23-3's 2.9mm × 2.8mm - about 50% smaller footprint. The smaller package has slightly worse thermal resistance (higher θja), which may limit maximum operating current at high ambient temperatures. Power dissipation capability is reduced: SC70-3 can typically handle 200-250mW vs 300-400mW for SOT23-3. For most GS432 applications with modest currents (<10mA), thermal limitations are not significant. The SC70-3 pinout is compatible with SOT23-3, allowing interchangeability in many designs. PCB layout requires more attention with SC70-3 due to smaller pads and tighter clearances. Both packages have similar electrical performance and reliability characteristics.

Choose SC70-3 for space-constrained designs. Choose SOT23-3 for higher power dissipation or easier handling.

The GS432 output noise consists of broadband noise and 1/f (flicker) noise components. Typical wideband noise is in the 10-50μVrms range over 10Hz to 10kHz bandwidth. This noise can affect sensitive ADC measurements and comparator thresholds. To reduce noise, add a bypass capacitor (0.1μF to 10μF) from reference output to ground - larger capacitors filter lower frequencies. A series resistor (10-100Ω) with the capacitor creates an RC filter for additional noise reduction. For lowest noise, buffer the reference with a low-noise op-amp like GS8511 configured as a low-pass filter. Keep reference traces away from switching signals that could couple noise. The noise is relatively constant with operating current, so increasing current does not significantly reduce noise. For precision applications, measure noise in your specific circuit configuration.

Add bypass capacitors and RC filtering to reduce reference noise. Buffer with low-noise op-amp for most sensitive applications.