LM239AD - Quad Open-Collector Comparator | Texas Instruments
料号： LM239AD ✓ 量产中LM239AD 概述
A comparator is an analog integrated circuit that compares two input voltages and changes its output state when one input becomes higher than the other. Within the semiconductor hierarchy, the LM239AD belongs to the comparator, analog IC, and signal-conditioning categories. Unlike a digital logic gate, the comparator evaluates continuously varying analog voltages and is commonly placed at the boundary between sensors, transducers, reference circuits, and digital control systems.
The principal product attributes are four independent comparator channels, differential inputs, open-collector outputs, and a 14-pin SOIC package. Open-collector outputs require an external pull-up resistor to establish a usable high voltage. This arrangement allows the output to be pulled to an external supply, supports wired-AND behavior when multiple comparators share a node, and provides compatibility with TTL, CMOS, and MOS logic when the pull-up voltage and sink-current limits are selected correctly.
Each channel compares an inverting input with a non-inverting input. The open-collector transistor pulls the output low when the non-inverting input is below the inverting input and releases the output when that relationship reverses. Because the four sections are independent, they can evaluate different thresholds in one package, reducing component count in multilevel sensing, window-detection, and control systems. The open-collector architecture also prevents the comparator from driving a supply rail directly, which is useful in systems with multiple voltage domains.
Typical uses include industrial sensor interfaces, automotive battery and system monitoring, consumer threshold detection, memory-cell sensing, and logic-level translation. In a battery monitor, the comparators can establish several voltage thresholds against an external reference. In a memory system, they can detect charge or voltage levels with minimal external circuitry. Their independent channels also make the device suitable for four-limit or four-zone monitoring where separate comparator decisions are required.
Designers should verify the exact input common-mode range, supply-voltage limits, input-offset voltage, response time, output sink current, and electrical characteristics against the manufacturer datasheet before finalizing a design. Place the pull-up resistor close to the output node, maintain the device within its rated common-mode input range, and account for input bias current when using high source impedances. Decoupling and unused-channel handling should follow the device recommendations in the manufacturer documentation.
This page combines the LM239AD product identity, comparator operating principle, package information, sourcing guidance, drop-in alternatives, comparison points, and practical application guidance. It is intended to help engineers identify the correct channel count, output architecture, package, and operating limits before integrating the device into analog-control or sensing equipment.
直接替换替代料： LM239AD ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
LM239AD 最大额定值与电气特性
| Comparator Type | Quad differential comparator |
| Number of Channels | 4 channels |
| Channel Independence | 4 independent comparators |
| 输出类型 | Open-collector |
| Supply Configuration | Single or split supply |
| 封装 | 14-SOIC |
| 安装类型 | Surface mount |
| Differential Input Range | Up to ±38 V |
| Low Input Bias Current | 25 nA typical |
| Output Compatibility | TTL, CMOS, and MOS compatible |
LM239AD 14-soic 引脚配置指南
LM239AD（14-soic 封装）的引脚配置。 该模拟元件具有输入、输出和电源引脚。请参阅制造商数据手册以了解失调调零、补偿和使能引脚配置。适用于信号调理和放大器电路。
暂无详细引脚数据： LM239AD.
请参阅 数据手册 以查看完整引脚配置。
典型应用
LM239AD 适用于 6 应用s: Industrial Threshold Detection, Battery Monitoring, Automotive System Monitoring, Memory Level Sensing, Sensor Signal Conditioning, Consumer Logic Interfacing.
Industrial Threshold Detection
The LM239AD suits industrial threshold-detection boards because it provides four independent differential comparator channels in one 14-pin SOIC. Each channel can compare a sensed voltage with a reference and use an open-collector output to indicate the comparison result. The typical 25 nA input bias current helps preserve accuracy with moderate source impedances, while the external pull-up allows the logic-high level to match a selected system rail. Use the manufacturer's pin table to assign the four channels and confirm common-mode limits against the industrial input range.
推荐
Battery Monitoring
The LM239AD can implement multi-level battery monitoring with its four independent differential comparator channels. Resistor-divider sensing can feed one input, while a precision reference feeds the other, allowing separate signals for undervoltage, overvoltage, and intermediate conditions. The 14-pin SOIC package reduces the number of discrete comparator packages, and each open-collector output can drive a wired-AND alarm node. The design must keep divider and reference nodes within the rated common-mode input range and use an appropriate pull-up voltage.
推荐
Automotive System Monitoring
The LM239AD can support automotive-style system monitoring by comparing several divided system voltages against reference levels. Four independent channels make it possible to monitor different rails or conditions with one IC, while open-collector outputs provide flexible interface voltage selection. The manufacturer identifies automotive electronic applications among the LM239 family's intended uses. Before production use, verify the exact ordering suffix, temperature grade, AEC-Q100 status, electrical limits, and automotive qualification documentation for the selected manufacturer and distributor source.
推荐
Memory Level Sensing
The LM239AD is designed in part for memory applications, where analog voltage levels must be converted into digital threshold decisions. Four independent channels can monitor different cell or rail conditions and provide separate open-collector status outputs. The external pull-up resistor allows the interface to operate from a compatible logic supply, while the low 25 nA typical input bias current reduces loading from high-impedance sensing networks. Confirm input offset, common-mode range, response time, and output timing before using the device in a specific memory architecture.
推荐
Sensor Signal Conditioning
The LM239AD converts sensor-derived analog voltages into logic-compatible threshold events for downstream control. A sensor amplifier or resistive divider can produce a signal that is compared against a reference, with each open-collector output driving an alarm, enable, or status input. The 25 nA typical input bias current is useful when the sensing path has appreciable impedance, and the four channels reduce board area. Check the common-mode range, output sink current, pull-up voltage, and switching behavior in the manufacturer datasheet.
推荐
Consumer Logic Interfacing
The LM239AD can bridge a wide-range analog signal to CMOS, MOS, or TTL-compatible logic through its open-collector outputs. The pull-up resistor sets the high voltage independently of the comparator supply, which is useful when interfacing legacy sensing circuits to a newer logic domain. The 14-pin SOIC package integrates four channels for compact consumer appliances and control boards. Confirm output sink current and timing at the selected pull-up resistance, and account for the allowed input common-mode range in the original design.
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推荐产品汇总
工程参考数据： LM239AD ——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 | LM239AD |
|---|---|---|
| Brand | Texas Instruments | STMicroelectronics |
| Package | 14-SOIC | 14-SO |
| Comparator Type | Quad differential comparator | Standard general-purpose comparator |
| Number of Channels | 4 channels | 4 channels |
| Output Type | Open-collector | Open-collector |
| Output Compatibility | TTL, MOS, and CMOS compatible | TTL, CMOS, DTL, ECL, and MOS listed |
| Intended Applications | Level detection, low-level sensing, memory, consumer, automotive, and industrial electronics | General-purpose comparator applications |
关键差异点
- Four-channel integration reduces comparator package count （对比 STMicroelectronics LM239AD)
- Open-collector outputs support flexible logic-high sourcing （对比 STMicroelectronics LM239AD)
- Single- and split-supply operating capability （对比 STMicroelectronics LM239AD)
设计说明
Always connect an external pull-up resistor to each used open-collector output. Calculate the resistor using the required logic-high voltage, output sink-current limit, input leakage of the receiving device, and required rise time. Do not assume the output can source current. Check the selected pull-up voltage against the comparator supply and permitted output-voltage limits before layout release.
Place each pull-up resistor close to the corresponding output or shared wired-AND node to limit parasitic capacitance and switching noise. Keep the four comparator inputs away from high-current switching paths and provide a stable ground reference. The 14-pin SOIC footprint is compact, so pin assignments and exposed routing around adjacent inputs deserve review against the manufacturer pin-description table.
Account for input bias current when the comparison source has high impedance. Estimated: if the input source presents 1 MΩ, a 25 nA typical bias current can create approximately 25 mV of error; the actual impact depends on source topology and temperature. Use the maximum bias-current specification from the manufacturer datasheet for worst-case threshold design rather than relying only on the typical value.
合规信息
The retrieved product information does not provide explicit RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals declarations for the exact LM239AD ordering code.