Onsemi LM293DMR2G Dual Differential Comparator: Datasheet, Pinout, and Application Circuit Guide
The LM293DMR2G from onsemi is a highly versatile, dual differential comparator housed in a space-saving SOIC-8 package. Designed for a wide range of applications, this component is prized for its low power consumption, wide supply voltage range, and ability to operate from a single or dual power supply. This guide provides an essential overview of its datasheet specifications, pin configuration, and a practical application circuit.
Datasheet Overview and Key Specifications
The LM293DDR2G is engineered for reliable performance in harsh environments. Its key electrical characteristics, as outlined in the datasheet, make it suitable for industrial control systems, automotive electronics, and consumer appliances.
Wide Supply Voltage Range: It can operate from a single supply voltage ranging from 2V to 36V, or from dual supplies of ±1V to ±18V.
Low Supply Current: The device draws a very low quiescent current of 0.4 mA per comparator (typical), independent of the supply voltage, which is ideal for battery-powered devices.
Low Input Bias Current: The input bias current is typically 25 nA, minimizing the error in sensing applications.
Common-Mode Input Voltage Range: Includes ground (V-), allowing it to sense signals at the negative rail, which is crucial for single-supply operations.
Differential Input Voltage Range: Equal to the supply voltage, providing significant flexibility in input signal levels.
Open-Collector Outputs: The outputs can be pulled up to a voltage different from the supply voltage (up to 36V), enabling easy interface with various logic families (e.g., TTL, CMOS) or driving loads like relays and lamps.
Pinout Configuration
The LM293DMR2G is an 8-pin device with the following pinout:
Pin 1: Output 1
Pin 2: Inverting Input 1 (-IN1)
Pin 3: Non-Inverting Input 1 (+IN1)
Pin 4: Ground (V-)
Pin 5: Non-Inverting Input 2 (+IN2)
Pin 6: Inverting Input 2 (-IN2)
Pin 7: Output 2
Pin 8: Positive Supply (V+)
Application Circuit Guide: A Basic Dark-Activated Switch
A classic application for a comparator like the LM293DMR2G is a light-sensing circuit. Here’s how to configure one channel as a dark-activated switch.
Components Required:
LM293DMR2G Comparator (one channel used)
Photoresistor (LDR)
Potentiometer (e.g., 10kΩ)
Resistor (10kΩ pull-up at output)
LED (with current-limiting resistor)
Power Supply (e.g., 5V or 12V)
Circuit Operation:
1. Voltage Divider Reference: Connect the potentiometer between V+ and Ground. The wiper of the pot connects to the inverting input (-IN1, Pin 2). This sets a adjustable reference voltage.
2. Light-Sensing Divider: Connect the photoresistor (LDR) in series with a fixed resistor between V+ and Ground. The junction between the LDR and the resistor connects to the non-inverting input (+IN1, Pin 3). This creates a voltage that varies with light intensity.
3. Output Action: The open-collector output (Pin 1) is connected to V+ through a pull-up resistor and an LED circuit.
4. Adjustment: In bright light, the LDR's resistance is low, so the voltage at +IN1 is lower than the reference voltage at -IN1. The output is low, sinking current and keeping the LED off.
5. Triggering: As darkness falls, the LDR's resistance increases, raising the voltage at +IN1. When this voltage exceeds the reference voltage at -IN1, the output transistor turns off, and the output goes high (via the pull-up resistor), lighting up the LED.
This simple circuit demonstrates the core function of the comparator: comparing two analog voltages and providing a digital output based on which is larger.
The onsemi LM293DMR2G stands out as a robust and efficient solution for voltage comparison tasks. Its wide operating voltage range and low power consumption make it exceptionally adaptable for both industrial and consumer applications. The open-collector output offers unmatched flexibility for level-shifting and driving diverse loads. Whether used in a simple sensor circuit or a complex monitoring system, this comparator provides reliable performance and design simplicity, solidifying its status as a fundamental component in an electronics engineer's toolkit.
Keywords: Comparator, Open-Collector, Differential, SOIC-8, Low Power Consumption
