How to Use ST662: Examples, Pinouts, and Specs

The ST662 is a dual voltage regulator designed to provide stable and reliable output voltages. It is commonly used in power supply circuits to ensure consistent voltage levels for electronic devices. This component is particularly useful in applications requiring both positive and negative voltage outputs, such as operational amplifiers, analog circuits, and other precision electronic systems.

• Power supply circuits for analog and digital devices
• Operational amplifier circuits
• Portable electronic devices
• Battery-powered systems
• Mixed-signal systems requiring dual voltage rails

• Input Voltage Range: 4.5V to 9V
• Output Voltage: +5V and -5V (fixed)
• Output Current: Up to 30mA (positive output), up to 20mA (negative output)
• Quiescent Current: 1.5mA (typical)
• Operating Temperature Range: -40°C to +85°C
• Package Type: SO-8 (Surface Mount) or DIP-8 (Through-Hole)

The ST662 is an 8-pin IC. Below is the pinout and description:

1. Power Supply Input: Connect a DC voltage source (4.5V to 9V) to the VIN pin. Ensure the input voltage is within the specified range to avoid damage to the IC.
2. Output Capacitors: Connect appropriate capacitors to stabilize the output voltages:
   • A 10µF capacitor between VOUT+ and GND.
   • A 10µF capacitor between VOUT- and GND.
3. Charge Pump Capacitors: Connect a 10µF capacitor between CAP+ and CAP- to enable the internal charge pump circuit.
4. Shutdown Control: If you want to enable the regulator, connect the SHDN pin to VIN or leave it floating. To disable the regulator, pull the SHDN pin to GND.
5. Load Connection: Connect your load to the VOUT+ and VOUT- pins. Ensure the load current does not exceed the maximum ratings (30mA for VOUT+ and 20mA for VOUT-).

• Use low-ESR capacitors for better performance and stability.
• Avoid exceeding the maximum input voltage (9V) to prevent damage.
• Ensure proper heat dissipation if the IC operates near its maximum current ratings.
• Keep the layout compact and minimize trace lengths for the capacitors to reduce noise.

The ST662 can be used to provide dual voltage rails for circuits interfaced with an Arduino UNO. Below is an example of how to connect the ST662 to an Arduino-powered circuit:

/* Example: Using ST662 to power an op-amp circuit with Arduino UNO
   This code demonstrates how to read an analog signal from an op-amp
   powered by the ST662 and display the result on the serial monitor. */

const int analogPin = A0; // Analog pin connected to op-amp output

void setup() {
  Serial.begin(9600); // Initialize serial communication at 9600 baud
}

void loop() {
  int sensorValue = analogRead(analogPin); // Read the analog value
  float voltage = sensorValue * (5.0 / 1023.0); // Convert to voltage
  Serial.print("Voltage: ");
  Serial.print(voltage);
  Serial.println(" V");
  delay(500); // Wait for 500ms before the next reading
}

Note: Ensure the ST662 is properly connected to provide +5V and -5V to the op-amp circuit. The Arduino UNO itself can supply the input voltage (5V) to the ST662.

1. No Output Voltage:

   • Check if the input voltage is within the specified range (4.5V to 9V).
   • Verify that the SHDN pin is not pulled low (shutdown mode).
   • Ensure all capacitors are correctly connected and have the proper values.

2. Output Voltage is Unstable:

   • Use low-ESR capacitors for the output and charge pump.
   • Check for loose connections or long traces in the PCB layout.

3. Excessive Heat:

   • Ensure the load current does not exceed the maximum ratings.
   • Verify that the input voltage is not too high.

4. Negative Output Voltage Missing:

   • Check the capacitor between CAP+ and CAP-. Ensure it is properly connected and has the correct value (10µF).

Q1: Can I use the ST662 with a 3.3V input?
A1: No, the minimum input voltage for the ST662 is 4.5V. Using a lower voltage may result in improper operation or no output.

Q2: What happens if I exceed the maximum output current?
A2: Exceeding the maximum output current can cause the output voltage to drop or the IC to overheat. Always stay within the specified current limits.

Q3: Can I leave the SHDN pin floating?
A3: Yes, the SHDN pin can be left floating, as it has an internal pull-up resistor. However, for better control, it is recommended to connect it to VIN or GND as needed.

Q4: What type of capacitors should I use?
A4: Use low-ESR electrolytic or ceramic capacitors for optimal performance and stability.

By following these guidelines and best practices, the ST662 can be effectively used in a variety of power supply applications.