LM393N - Dual Comparator 2-36V Open-Collector | 8-PDIP
料号： LM393N ✓ 量产中| 数量 | 单价 | 小计 |
|---|---|---|
| 1 | $0.42 | $0.42 |
| 10 | $0.36 | $3.60 |
| 100 | $0.28 | $28.00 |
| 500 | $0.22 | $110.00 |
| 1,000 | $0.18 | $180.00 |
LM393N 概述
A comparator is an analog decision element that compares two input voltages and produces a logic-level output indicating which input is larger. The LM393N fits within a hierarchy of: comparator -> analog comparator -> signal-conditioning IC -> semiconductor. Within the broad comparator category, the LM393N belongs to the low-power, low-offset, open-collector-output class (synonym: voltage comparator), distinct from the LM339 quad family and the more modern CMOS comparators such as the LMV393 and LM393LV.
Key specifications of the LM393N include: input offset voltage as low as 2 mV maximum (LM193/LM193A series; typical LM393 spec is ±5 mV), input bias current of 25 nA typical, common-mode input range that includes ground, and a propagation delay of approximately 1.3-1.5 microseconds. The open-collector output stage requires a pull-up resistor (typically 2-10 kohm from output to the positive logic rail). The device operates across a -40 C to +85 C ambient temperature range and is widely used in battery-powered systems thanks to its low quiescent current draw (typically 0.4 mA per comparator).
Typical applications of the LM393N include zero-crossing detectors for AC line signals, battery voltage monitors and low-battery cutoff circuits, window comparators, over-voltage and over-current protection circuits, square-wave/relaxation oscillators, voltage level shifters (e.g., 5 V CMOS to 12 V relay logic), and analog sensor threshold detectors for photodiodes, thermistors, and Hall-effect sensors. The wide supply range and ground-sensing input make it especially useful in single-rail automotive and industrial 12 V/24 V systems.
When designing with this device, remember that the open-collector output cannot actively source current - you must provide a pull-up resistor on each output. Also, the input common-mode range is limited to 0 V to VCC-1.5 V; inputs that approach the upper rail may saturate the input stage. For low-voltage (<5 V) battery applications where lower quiescent current is critical, consider the LMV393 (CMOS) or LM393LV as direct upgrades.
直接替换替代料： LM393N ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
本系列中的变体
可与以下型号直接替换的同系列型号： LM393N （相同外形与封装尺寸） ——差异在于 Package, Output Type, RoHS Status, Comparator Type, Operating Temperature Range.
快速对比工具——选择替代料号进行并排对比：
LM2903N
✅ 直接替换✓ 有现货
$0.27 / 个
查看数据手册 →LM393N/NOPB
✅ 直接替换📋 参考替代料（不在目录中）
LM293N
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
LM393NG
✅ 直接替换📋 参考替代料（不在目录中）
LM393N 最大额定值与电气特性
| Comparator Type | Dual General-Purpose Comparator |
| Number of Comparators | 2 (dual) |
| 输出类型 | Open-Collector / Open-Drain (single-ended) |
| Input Offset Voltage (max) | 5 mV (LM393N); 2 mV (LM193/LM393A grade) |
| Input Bias Current (typ) | 25 nA |
| Supply Voltage Range (single supply) | 2 V to 36 V |
| Supply Voltage Range (dual supply) | ±1 V to ±18 V |
| Output Sink Current (max) | 16 mA |
| Propagation Delay (typ) | 1.3 us (300 mV overdrive) |
| Common-Mode Input Range | 0 V to VCC - 1.5 V (ground sensing) |
| Quiescent Current (typ) | 0.4 mA per comparator (0.8 mA total) |
| 工作温度范围 | 0 C to +70 C (LM393N) / -40 C to +85 C (LM2903N) |
| 封装 | 8-PDIP (DIP-8, through-hole) |
| 安装类型 | Through-Hole |
| RoHS 状态 | Non-RoHS (LM393N); RoHS on LM393N/NOPB variant |
LM393N 引脚配置
| 引脚 1 | 1OUT — Comparator A open-collector output (requires external pull-up) |
| 引脚 2 | 1IN- — Comparator A inverting input |
| 引脚 3 | 1IN+ — Comparator A non-inverting input |
| 引脚 4 | GND — Ground / negative supply |
| 引脚 5 | 2IN+ — Comparator B non-inverting input |
| 引脚 6 | 2IN- — Comparator B inverting input |
| 引脚 7 | 2OUT — Comparator B open-collector output (requires external pull-up) |
| 引脚 8 | VCC — Positive supply voltage (2 V to 36 V) |
典型应用
LM393N 适用于 6 应用s: Battery Voltage Monitor & Low-Battery Cutoff, Zero-Crossing Detector for AC Line Signals, Window Comparator / Over-Voltage Protection, Square-Wave / Relaxation Oscillator, Voltage Level Shifter (3.3V to 12V/24V), Analog Sensor Threshold Detector (Photodiode, Thermistor, Hall).
Battery Voltage Monitor & Low-Battery Cutoff
The LM393N's wide 2-36 V supply range and ground-sensing input make it ideal for battery monitoring in single-cell Li-ion or multi-cell lead-acid packs. Comparator A's inverting input is tied to a resistor-divider reference (e.g., 2.5 V TL431 or 1.25 V internal Vbe), while the non-inverting input senses scaled battery voltage through a high-impedance divider. When the battery drops below threshold, the open-collector output pulls low to drive a P-FET gate that disconnects the load. Typical threshold accuracy is ±50 mV with 1% external resistors. The 25 nA input bias current prevents battery drain when the system is idle, an advantage over BJT-based comparator circuits.
推荐
Zero-Crossing Detector for AC Line Signals
The LM393N is a classic building block for mains-frequency zero-crossing detectors used in triac/SCR phase-control dimmers and TRIAC trigger timing circuits. A resistor-divider scales the 120/230 VAC line to less than 36 V peak (within the LM393N's supply rating); comparator A then drives its open-collector output low each time the AC line crosses zero. The 1.3 us propagation delay is fast enough for 50/60 Hz zero crossings and keeps phase-control error under 0.05 degrees. The same topology works for opto-isolator-based feedback paths in isolated AC-DC converters, where the LM393N's open-collector output drives an optocoupler LED directly without additional driver transistors.
推荐
Window Comparator / Over-Voltage Protection
The LM393N's two independent comparators in a single package are ideally suited for window comparator circuits that detect under-voltage, over-voltage, or both. Comparator A flags under-voltage below the lower threshold while comparator B flags over-voltage above the upper threshold. Their open-collector outputs are tied together (wired-OR) to a single alarm line that goes low whenever either condition is detected. With 1% external resistor dividers, typical threshold accuracy is ±2%; with 0.1% resistors, ±0.5%. The 36 V supply tolerance handles 12 V and 24 V automotive/industrial rails directly without additional regulation, and the 16 mA output sink drives relay coils, opto-isolators, or logic-level signals.
推荐
Square-Wave / Relaxation Oscillator
The LM393N forms a classic relaxation oscillator with just three external components: a resistor R from output to non-inverting input, a resistor R' from non-inverting input to VCC, and a timing capacitor C from non-inverting input to ground (or inverting input cross-coupled). The oscillation frequency is approximately f = 1 / (2 * R * C * ln((VCC - V_low) / (VCC - V_high))). With R = 10 kohm and C = 100 nF, the LM393N yields around 700 Hz on a 5 V supply - useful for audible-tone generation, test-signal injection, or simple clocking for microcontroller-free designs. The 1.3 us propagation delay caps the usable frequency around 100 kHz before distortion becomes significant.
推荐
Voltage Level Shifter (3.3V to 12V/24V)
The LM393N's open-collector output is a textbook level shifter between incompatible logic rails. Power the LM393N from the source rail (e.g., 3.3 V or 5 V) but pull its open-collector output up to the target rail (e.g., 12 V, 24 V, or even 36 V) through a 4.7 kohm to 10 kohm pull-up resistor. When the comparator output transistor is OFF, the line sits at the target rail; when ON, the line pulls to ground. This same-circuit shifter works in both directions and even translates between negative and positive domains. With propagation delay of 1.3 us, the LM393N supports UART (115 kbaud clean) and slower SPI/I2C buses; for high-speed buses use the TI SN74LVC8T245PW.
推荐
Analog Sensor Threshold Detector (Photodiode, Thermistor, Hall)
The LM393N shines in analog sensor interfaces where a binary decision is needed. For photodiode-input light detectors, the photodiode connects to the inverting input; the non-inverting input is biased by a fixed reference; the open-collector output drives an LED indicator or logic-level signal. For thermistor-based temperature switches, a voltage divider with the thermistor feeds one input; the other sees a fixed threshold set by a stable reference; the output toggles when temperature crosses the trip point. The 25 nA input bias current keeps loading on high-impedance sensors negligible - critical when the sensor output is in the tens of microamps range. The 8-PDIP package remains the dominant form factor for hand-built sensor modules.
推荐
推荐产品汇总
工程参考数据： LM393N ——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 | LM2903N | LM393N/NOPB | LM293N | LM393NG | LM393P |
|---|---|---|---|---|---|---|
| Package | 8-PDIP (DIP-8) | 8-PDIP (DIP-8) - identical through-hole | 8-PDIP (DIP-8) - identical through-hole | 8-PDIP (DIP-8) - identical through-hole | 8-PDIP (DIP-8) - identical through-hole (onsemi) | 8-PDIP (DIP-8) - identical through-hole (NXP) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | onsemi | NXP Semiconductors |
| Number of Comparators | 2 | 2 | 2 | 2 | 2 | 2 |
| Output Type | Open-Collector | Open-Collector | Open-Collector | Open-Collector | Open-Collector | Open-Collector |
| Supply Voltage Range | 2 V to 36 V | 2 V to 36 V | 2 V to 36 V | 2 V to 36 V | 2 V to 36 V | 2 V to 36 V |
| Operating Temperature | 0 C to +70 C | -40 C to +85 C (automotive) | 0 C to +70 C | -25 C to +85 C (industrial) | 0 C to +70 C | 0 C to +70 C |
| Input Offset Voltage (max) | 5 mV | 5 mV | 5 mV | 5 mV | 5 mV | 5 mV |
| RoHS Status | Non-RoHS (legacy LM393N) | Non-RoHS (LM2903); RoHS on -NOPB suffix | RoHS-compliant | Non-RoHS (legacy) | RoHS-compliant | RoHS-compliant |
关键差异点
- Wide supply range 2V-36V with ground-sensing input （对比 LM393LV (CMOS upgrade))
- Through-hole DIP-8 for hand prototyping and legacy designs （对比 LM393D (SOIC-8 surface-mount version))
- Multi-sourced commodity with cross-brand drop-in equivalents （对比 Specialized precision comparator (e.g., LT1010))
设计说明
Estimated: in DIP-8 through-hole layouts, place the pull-up resistor (typically 4.7 kohm to VCC) as physically close to pin 1 and pin 7 (the open-collector outputs) as possible to minimize trace-induced ringing. Keep comparator input traces short and away from switching-converter or relay-driving traces. The 8-PDIP package pairs naturally with through-hole 100 nF bypass capacitor from VCC (pin 8) directly to GND (pin 4); a short trace on this bypass is critical because the LM393N can sink up to 16 mA and pull 100 mA peak through VCC during output transitions.
Estimated: three classic LM393N design pitfalls. (1) Forgetting the pull-up resistor - the output will float high-impedance and the downstream circuit will see undefined logic. (2) Driving the input above VCC or below ground - the absolute-maximum differential input voltage is 36 V and exceeding this destroys the input stage; clamp with external diodes if the source may exceed the rails. (3) Exceeding 16 mA output sink current at 100% duty cycle will overheat the output transistor; if driving a relay or LED directly, check worst-case continuous sink current rather than average.
Estimated: the LM393N has a typical propagation delay of 1.3 us with 5 mV overdrive, but slower edges (<2 us) are realistic with small overdrive (<5 mV). For high-precision zero-crossing detection use a 5 mV to 50 mV input overdrive to ensure clean sub-microsecond transitions. If your timing budget is tighter than 500 ns, consider the TLV3201 (40 ns) or LMV331 (200 ns) as faster drop-in alternatives. For oscillation circuits, account for the propagation delay in your frequency calculation or the oscillation will run 5-10% slow at higher frequencies.
合规信息
Legacy LM393N is non-RoHS (contains lead). The LM393N/NOPB suffix variant is RoHS-compliant and lead-free. Choose NOPB suffix for new designs. AEC-Q100 not qualified - use LM2903N for automotive. Reach compliance confirmed per TI product information.
