Quad archives - DataSheetCafe.com

This is Quad Differential Comparator.

Part Number: LM339

Function: Low Power Low Offset Voltage Quad Comparator

Package: DIP 16 Pin type

Manufacturer: National Semiconductor (Texas Instruments)

National Semiconductor was acquired by Texas Instruments (TI) on September 23, 2011.

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Description

The LM339 series consists of four independent precision voltage comparators with an offset voltage specification as low as 2 mV max for all four comparators. These were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the power supply
voltage. These comparators also have a unique characteristic in that the input common-mode voltage range includes ground, even though operated from a single power supply voltage.

What is quad comparator?

A quad comparator is an integrated circuit (IC) that contains four independent voltage comparators in a single package. Each comparator has two inputs, the non-inverting input (V+) and the inverting input (V-), and a single output. The output is typically an open collector transistor that can sink current when the output is in a low state.

Quad comparators are commonly used in applications that require multiple voltage level detections, such as monitoring multiple sensors, controlling multiple circuits, or driving multiple LED displays. They can also be used in applications where a single comparator does not provide enough functionality or when space is limited.

Quad comparators have several advantages over using multiple single comparators, including reduced circuit complexity, lower power consumption, and reduced board space requirements.

Pinouts:

Features

1. Wide supply voltage range
2. Very low supply current drain (0.8 mA) — independent of supply voltage
3. Low input biasing current: 25 nA
4. Low input offset current: ±5 nA
5. Offset voltage: ±3 mV
6. Input common-mode voltage range includes GND
7. Differential input voltage range equal to the power supply voltage

Advantages:

1. Low power consumption
2. Wide operating voltage range
3. Four comparators in a single package
4. Open collector output stage allows easy interface with other circuits
5. Low input bias current and offset voltage
6. Wide temperature range

Disdvantages:

1. Slow response time compared to other high-speed comparators
2. Output stage is not suitable for driving capacitive loads
3. Limited output current capability

FAQs:

1. What is the difference between the LM339 and LM393 comparators?

The LM339 is a quad comparator, meaning it contains four independent comparators in a single package, while the LM393 is a dual comparator with two independent comparators. The LM339 has a wider range of operating voltages and a higher output sink current compared to the LM393.

2. Can the LM339 be used to drive a relay?

Yes, the open collector output stage of the LM339 can be used to drive a relay through a transistor and a diode. The diode is used to protect the transistor from voltage spikes generated by the relay coil when it is turned off.

3. What is the function of the hysteresis pin in the LM339?

The hysteresis pin (pin 5) in the LM339 is used to add positive feedback to the comparator, which can improve the stability and noise immunity of the comparator. When hysteresis is applied, the output of the comparator changes state at different input voltage levels depending on the direction of the input voltage change. This prevents the output from oscillating rapidly when the input voltage is close to the switching threshold.