LM393QT - Dual Open-Collector Comparator | STMicroelectronics
料号： LM393QT ✓ 量产中LM393QT 概述
A voltage comparator is an analog integrated circuit that compares two input voltages and produces a digital logic result indicating which input is higher. The comparator category belongs to the broader signal-conditioning and decision-making hierarchy, where its output can enable switching, threshold detection, protection, or system-control functions. The LM393QT uses open-collector outputs, allowing multiple comparator outputs to be wired together when a suitable pull-up is present.
Key features include two independent comparators, a 300 ns response time, low-power operation with an input-current rating of 25 nA, and a wide 2 V to 36 V supply range. Rail-to-rail input operation allows each input to approach the supply rails, while the open-collector architecture provides flexible output pull-up selection and wired logic capability.
The two channels share a common supply and ground but otherwise operate independently. The open-collector transistor can pull its output low while disabling the output driver during the high state, so an external pull-up resistor is required for normal logic-high operation. This architecture does not actively drive the output high, a key consideration when designing level-shifting or fault-detection circuits.
Typical uses include battery and power-supply monitoring, sensor threshold detection, overvoltage and undervoltage protection, window comparison, signal conditioning, and industrial control systems. Its 2 mm by 2 mm UFSON package also supports compact mixed-signal designs where board area is constrained.
When laying out the device, route the two comparator channels away from noisy switching nodes and connect input and output tracks to minimize coupling. Select pull-up resistors according to the required logic rise time, output current, and available supply voltage, while confirming that every downstream device can tolerate the open-collector output arrangement.
This page combines manufacturer specifications, practical pinout guidance, application analysis, and verified sourcing references. It also emphasizes the electrical and layout checks required to use the LM393QT reliably in threshold-detection, protection, and low-power signal-conditioning systems.
直接替换替代料： LM393QT ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
该产品暂无直接替换替代料。
请求替代料LM393QT 最大额定值与电气特性
| Comparator Type | General-purpose dual comparator |
| Number of Comparators | 2 |
| 输出类型 | Open-collector |
| Input Common-Mode Range | Rail-to-rail |
| Supply Voltage Range | 2 V to 36 V |
| Response Time | 300 ns |
| Input Current | 25 nA |
| Power Class | Low power |
| 封装 | 8-pin UFSON |
| Package Dimensions | 2 mm x 2 mm |
| Total Pin Count | 8 pins |
| 安装类型 | Surface mount |
| RoHS 状态 | Compliant |
LM393QT 引脚配置
| 引脚 1 | OUT 1 — Open-collector output for comparator channel 1 |
| 引脚 2 | IN1− — Inverting input for comparator channel 1 |
| 引脚 3 | IN1+ — Non-inverting input for comparator channel 1 |
| 引脚 4 | GND — Ground connection |
| 引脚 5 | IN2+ — Non-inverting input for comparator channel 2 |
| 引脚 6 | IN2− — Inverting input for comparator channel 2 |
| 引脚 7 | OUT 2 — Open-collector output for comparator channel 2 |
| 引脚 8 | VCC — Positive supply connection |
典型应用
LM393QT 适用于 6 应用s: Industrial Overvoltage Protection, Battery Threshold Monitoring, Sensor Signal Conditioning, Power-Supply Window Monitor, LED Drive and Discrete Control, Data Acquisition Front End.
Industrial Overvoltage Protection
The LM393QT is suitable for an industrial overvoltage protection circuit because its 2 V to 36 V supply range accommodates common control rails and its response time is 300 ns. One comparator channel can compare a divided feedback signal with a precision reference while the second channel monitors an undervoltage or fault condition. The open-collector outputs can directly pull down a system fault line or drive a suitable logic gate through a pull-up resistor. Design the divider to limit the input voltage at all operating conditions, and confirm that the monitored rail cannot exceed the comparator's absolute maximum rating.
推荐
Battery Threshold Monitoring
The LM393QT can supervise a battery pack with two independent threshold channels, one for an upper limit and another for a lower limit. Its rail-to-rail input characteristic supports sensing across much of the supply range, while the 25 nA input-current specification helps minimize loading of high-impedance battery dividers. The 300 ns response allows rapid fault signaling, although the external pull-up and filter components determine the practical behavior of the open-collector output. Account for cell imbalance, temperature drift, and input filtering when calculating divider values.
推荐
Sensor Signal Conditioning
The LM393QT is useful for converting a slowly changing sensor signal into a clean threshold event. A resistive divider and reference establish the switching point, while the comparator rejects small variations around the threshold according to its input characteristics. The dual-channel arrangement permits a second reference or hysteresis function. Because the output is open-collector, a pull-up resistor sets the logic-high voltage and influences the output rise time. Place the divider close to the input pins, keep sensitive traces away from switching nodes, and add filtering where the sensor produces noise near the decision threshold.
推荐
Power-Supply Window Monitor
The LM393QT can monitor whether a supply lies between a lower and an upper limit by assigning one channel to each threshold. Its dual open-collector outputs support active-low fault indication and can be combined through wired logic or routed to a controller input. The 2 V to 36 V operating range is useful for industrial and telecommunications rails, while the 300 ns response allows prompt fault detection. Select divider and reference components for the required accuracy, account for input bias effects, and verify that the pull-up voltage remains compatible with every receiver connected to the fault node.
推荐
LED Drive and Discrete Control
The LM393QT can control an LED or discrete switching stage by comparing a control voltage with a reference and sinking current from the open-collector output. This arrangement is useful for simple illumination indicators, relay-driver interfaces, and discrete power-control stages. The external pull-up determines the output voltage, while the comparator sinks current according to the selected network and device limits. Keep the output current within the datasheet's sink-current capability, provide adequate return paths, and avoid placing fast switching nodes beside the high-impedance input pins.
推荐
Data Acquisition Front End
The LM393QT can serve as a coarse range selector ahead of an ADC or data-conversion system. One comparator detects when an analog input crosses a programmed threshold, and the second provides another boundary for a dual-threshold decision. Its 300 ns response is suitable for low-frequency sensor monitoring and general control rather than precision waveform analysis. The open-collector output can be pulled up to the acquisition logic's supply voltage, but the resulting rise time and input capacitance should be checked. Use short traces, a stable reference, and careful return-path layout to prevent false switching.
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推荐产品汇总
工程参考数据： LM393QT ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 |
|---|---|
| Brand | STMicroelectronics |
| Package | 8-pin UFSON (2 mm x 2 mm) |
| Number of Comparators | 2 |
| Output Type | Open-collector |
| Input Common-Mode Range | Rail-to-rail |
| Supply Voltage Range | 2 V to 36 V |
| Response Time | 300 ns |
| Input Current | 25 nA |
| RoHS Status | Compliant |
关键差异点
- Compact dual-comparator package （对比 LM339AM)
- Wide supply operating range （对比 LM393LV)
- Open-collector wired-logic capability （对比 TLV2402ID)
设计说明
Do not treat an open-collector output as a push-pull logic output. The LM393QT can sink current but cannot actively source the logic-high state, so every output requires a pull-up resistor. Select the resistor using the required rise time, input capacitance, available supply voltage, and permissible supply current. When multiple open-collector outputs share a node, the node remains low whenever any attached output transistor is conducting.
Place the comparator inputs, reference divider, and any feedback components close to the corresponding pins to minimize susceptibility to injected noise. Route outputs away from the input and supply traces to reduce feedback through board capacitance. Keep the ground connection short and connect it to the quiet ground path of the analog section. The 2 mm by 2 mm UFSON package also requires careful land-pattern alignment and a controlled assembly process.
Keep the LM393QT supply within its 2 V to 36 V operating range and verify startup, transient, and fault conditions against the manufacturer's absolute maximum ratings. Decouple the supply pin near the package with the capacitance recommended in the manufacturer documentation. Input signals must also remain within the permitted common-mode range; rail-to-rail operation does not remove the need to verify absolute maximum input and differential voltage limits.
合规信息
RoHS compliance is identified in the LM393QT product information. No specific REACH, halogen-free, conflict-minerals, or automotive qualification claim is established.
