Onsemi LM239DR2G Quad Differential Comparator: Datasheet, Pinout, and Application Circuits
The LM239DR2G from Onsemi is a highly reliable, quad independent precision voltage comparator designed to operate from a single power supply over a wide range of voltages. It is part of a family of comparators that have become industry standards for analog signal processing and decision-making circuits. Housed in a SOIC-14 package, this device is optimized for applications requiring low input bias current, low offset voltage, and a fast response time.
A primary strength of the LM239DR2G is its wide single-supply voltage range from 2V to 36V (or dual supplies of ±1V to ±18V). This flexibility makes it suitable for a vast array of applications, from battery-operated portable electronics to robust industrial control systems. Its low supply current drain of approximately 0.8mA per comparator is virtually independent of the supply voltage, enhancing its efficiency.
Key Datasheet Specifications
Supply Voltage Range: 2V to 36V
Input Offset Voltage: Typically 2mV
Input Bias Current: Typically 25nA
Response Time: Typically 1.3μs
Output Saturation Voltage: Typically 400mV at 4mA
Operating Temperature Range: -25°C to +85°C
Package: SOIC-14
Pinout Configuration (SOIC-14)
The pinout for the LM239DR2G is standardized for quad comparators:
Pins 1, 7, 8, 14: Outputs for Comparators 4, 3, 2, and 1, respectively.
Pins 2, 4, 6, 9: Inverting Inputs (-) for Comparators 4, 3, 2, and 1.
Pins 3, 5, 10, 12: Non-Inverting Inputs (+) for Comparators 4, 3, 2, and 1.
Pin 11: VCC+ (Positive Supply Voltage)
Pin 13: GND (Ground)
Application Circuits
1. Basic Voltage Comparator: The most fundamental circuit. The output switches from low to high when the voltage at the non-inverting (+) input exceeds the voltage at the inverting (-) input. A reference voltage is applied to one input, while the signal to be compared is applied to the other.
2. Schmitt Trigger (Debounced Comparator): To prevent output oscillation when a slowly changing input signal is near the trigger point, positive feedback is added via a resistor from the output back to the non-inverting input. This creates two distinct threshold voltages for rising and falling input signals, providing noise immunity and clean output transitions.
3. Zero-Crossing Detector: A specific application of the basic comparator circuit where the inverting input is grounded (0V reference). The output changes state whenever the AC input signal crosses the zero-voltage point, useful for timing circuits and phase control.
4. Window Comparator: This circuit uses two of the device's four comparators to detect when a signal is within or outside a specific voltage "window." It provides a distinct output logic state if the input voltage is between two predefined reference levels.
ICGOODFIND: The Onsemi LM239DR2G stands out as an exceptionally versatile and robust quad comparator. Its wide supply voltage range, low power consumption, and open-collector outputs (which allow for easy output level shifting and wired-OR configurations) make it an ideal choice for design engineers. It is perfectly suited for a broad spectrum of tasks, including threshold detection, analog-to-digital conversion, oscillator circuits, and voltage monitoring in automotive, industrial, and consumer applications.
Keywords: Voltage Comparator, Wide Supply Range, SOIC-14, Schmitt Trigger, Open Collector.
