Features Low Voltage Reference: 600mV
Low temperature coefficient reference: 25ppm accurate reference voltage to 600mV: +6mV at TJ=25°C
High PSRR: 45dB at 300kHz
High Line Rejection: 1 mV (from 2.2V to 18V VCC)
Low Supply Current: 300μA
Open Collector Output Direct Drive Optocoupler Compact 5-Pin SOT23 Package Industrial Temperature Range: -40°C to 85°C

Application switching power supply control loop low temperature coefficient voltage reference power management Zener diode to replace isolated DC-DC converter network, telecom and mobile base station power supply adjustable voltage reference

DESCRIPTION The CAT102 is a low voltage reference and amplifier. Designed for low voltage power supply control loop supplies, the reference voltage has been designed to be 600mV. The reference voltage is nominally 600mV at 8mV from -40°C to 105°C junction temperature. Also, the error amplifier output and supply voltage pins are separate pins. Power supply rejection is 45dB higher than that at 300kHz. The output, output, is capable of sinking 20mA at a maximum saturation voltage of 250mV. When combined with an optocoupler, the CAT102 can act as an error amplifier, feedback control switching power supplies in an isolated low output voltage loop.

Electrical Characteristics Electrical characteristics are guaranteed over the entire operating temperature from -40°C to +85°C, junction C from -40°C to +105°C unless otherwise specified. Ambient temperature must be derated based on power dissipation and package thermal characteristics.1 Unless otherwise stated, test conditions are VIN = 3V, FB = output, output current = 1mA.


Application Information The CAT102 adjustable shunt regulator isolates the input and output of a power supply, ideal for use with an optocoupler feedback path in isolated power supply applications. The CAT102 sinks 20mA of electrical signal and VOUT is at 0.3V. A wide input voltage range enables the device to operate from 2.2V to 18V. A relatively accurate FB input of the CAT102 is a 600mV reference. If the FB input is low, the OUT pin sinks no current. If FB rises above 600mV, sink 20mA to the OUT pin. Figure 1 shows the CAT102 regulator configured as a shunt. To generate an output voltage of 0.6V, the FB pin must be connected directly to the OUT pin. A 1.0µF capacitor to GND is recommended from OUT when the output voltage is 0.6V. A resistor divider connected from OUT to GND is used to generate a higher output voltage by the following equations: VOUT = (1 + R1/R2) x 0.6V The current limit can be adjusted by a resistor connected to R3 at IN and OUT pins. For example, a 3.3V supply VIN is associated with R3=135Ω, a 10V supply works best with R3=470Ω. The CAT102 shunt regulator is limited to low current in pin-to-pin applications and can sink up to 20mA maximum.


Precautions:
1. All dimensions are in mm.
2. Package Outline Dimensions which include metal burrs.
3. Package Outline Author Flash Exclusive. The burr shall not exceed 0.076MM.
4. All package surfaces are mirror finish.
5. The forming die faces up, faces down and forms with the die.
6. The length of the foot, measured at the "A" intercept point of the outer lead and datum.
7. LEADFINISH plating: 0.00762MM-0.0254MM. Exclusive LEADFINISH plating on package outline.