Overview
The LM397MFX/NOPB is a single general-purpose voltage comparator produced by Texas Instruments. This device is designed to operate from a single 5-V to 30-V power supply or a split power supply, making it versatile for various applications. The LM397 features an open-collector output stage, which allows for the connection of an external pull-up resistor, enabling it to interface directly with TTL, CMOS, and other logic levels. It is available in a space-saving 5-Pin SOT-23 package and is pin-compatible with TI’s TL331, a single differential comparator.
Key Specifications
| Parameter | Value | Unit |
|---|---|---|
| Package Type | SOT-23-5 | |
| Pin Count | 5 | |
| Power Supply Type | Single or Dual | |
| Typical Single Supply Voltage | 5 V to 30 V | V |
| Supply Current | 300 µA | mA |
| Input Bias Current | ±1 nA | nA |
| Input Offset Voltage | ±2 mV | mV |
| Response Time | 440 ns (50-mV Overdrive) | ns |
| Input Common-Mode Voltage Range | 0 to VS – 1.5 V | V |
| Output Saturation Voltage | 180 mV to 400 mV (IO = -4 mA) | mV |
| Operating Temperature Range | -40°C to +85°C | °C |
Key Features
- Open-collector output stage allowing for external pull-up resistor connection
- Low supply current of 300 µA, virtually independent of supply voltage magnitude
- Low input bias current of ±1 nA and low input offset voltage of ±2 mV
- Fast response time of 440 ns with a 50-mV overdrive
- Input common-mode voltage range includes ground (0 to VS – 1.5 V)
- Compatible with TTL, CMOS, and other logic levels
- Space-saving 5-Pin SOT-23 package
- Pin-compatible with TI’s TL331, a single differential comparator
Applications
- A/D Converters
- Pulse and Square-Wave Generators
- Peak Detectors
- Industrial Applications
Q & A
- What is the typical supply voltage range for the LM397?
The LM397 can operate from a single 5-V to 30-V power supply or a split power supply.
- What is the package type of the LM397?
The LM397 is available in a 5-Pin SOT-23 package.
- What is the input common-mode voltage range for the LM397?
The input common-mode voltage range is from 0 to VS – 1.5 V.
- How does the open-collector output stage of the LM397 work?
The open-collector output stage requires an external pull-up resistor connected between the positive supply voltage and the output, allowing it to interface with TTL, CMOS, and other logic levels.
- What is the typical response time of the LM397?
The typical response time is 440 ns with a 50-mV overdrive.
- What are some common applications of the LM397?
Common applications include A/D converters, pulse and square-wave generators, peak detectors, and industrial applications.
- How does the LM397 handle hysteresis?
Hysteresis can be added to the LM397 to prevent oscillation or noisy output when the differential input is near the input offset voltage.
- What is the operating temperature range of the LM397?
The operating temperature range is -40°C to +85°C.
- Is the LM397 pin-compatible with other comparators?
Yes, the LM397 is pin-compatible with TI’s TL331, a single differential comparator.
- How should the LM397 be laid out on a PCB to maintain performance?
Proper grounding with a good, unbroken low-inductance ground plane, short lead lengths, and decoupling capacitors close to the supply voltage are recommended.
