LM393 - Dual Open-Collector Comparator | Texas Instruments
MPN： LM393 ✓ 啟用中LM393 概覽
A voltage comparator is an analog semiconductor that compares two input voltages and produces a digital output indicating their relative relationship. The LM393 belongs to the comparator hierarchy within analog ICs and broader signal-conditioning and power-management systems. Unlike an operational amplifier, its output is intended to switch actively and can operate from a single supply while accepting an input common-mode range down to ground.
Key features include two independent comparator channels, differential input voltage capability up to ±38 V, and compatibility with TTL, MOS, and CMOS logic. The open-collector output allows a designer to set the output logic voltage through an external pull-up resistor. This architecture is useful when driving multiple wired-open outputs, connecting to a bus, or interfacing with a supply domain different from the comparator output pull-up.
The LM393 can operate from a single supply or split supply, while the common-mode input range reaches ground for many sensing conditions. Its differential input limit equals the maximum-rated supply voltage, but the absolute maximum rating should not be interpreted as a normal operating range. Input protection, supply sequencing, and output pull-up selection remain important design constraints.
Typical uses include window detection in power supplies, battery monitoring, sensor threshold conditioning, industrial control interfaces, automotive electronics, and consumer equipment. In each case, the LM393 provides a simple high-or-low decision without the output stage normally associated with a push-pull logic device.
For reliable designs, select the correct package ordering code, verify the temperature grade, place decoupling close to the supply pins, and use a pull-up resistor sized for the intended logic family and output-current limit. Check input transients against the absolute maximum ratings rather than relying on nominal common-mode limits.
This product page combines the LM393 device description with functional guidance, drop-in replacement considerations, application patterns, and engineering-oriented comparisons. It helps buyers distinguish the open-collector dual comparator from op-amp alternatives while supporting package, temperature, and lifecycle decisions before requesting a quote.
直接替換替代品，適用於 LM393 — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： LM393 （相同外形與佔位） — 差異在於 Comparator Type, Operating Temperature Range, Package, Output Type, Input Bias Current.
LM393B
✅ 直接替換📋 參考替代品（不在目錄中）
LM2936BMX-3.3/NOPB
✅ 直接替換聯絡詢價
查看資料表 →LM2903BIDR
✅ 直接替換聯絡詢價
查看資料表 →LM2903BIDR
✅ 直接替換聯絡詢價
查看資料表 →LM393 最大額定值與電氣特性
| Comparator Type | Dual independent precision voltage comparator |
| Number of Channels | 2 channels |
| Supply Voltage Range | 2 V to 30 V |
| Supply Configuration | Single or split supply |
| Common-Mode Input Range | Includes ground |
| Differential Input Voltage Range | ±38 V |
| 輸出類型 | Open-collector |
| Logic Compatibility | TTL, MOS, and CMOS compatible |
| 工作溫度範圍 | 0 C to 70 C for LM393 grade |
| Package Options | 8-pin SOIC and other manufacturer order codes |
| 安裝類型 | Surface mount |
| Output Pull-Up | External resistor required |
| B-Version Compatibility | Drop-in replacement for LM293, LM393, and LM2903 |
LM393 8-pin soic and other manufacturer order codes 腳位配置指南
LM393（8-pin soic and other manufacturer order codes 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： LM393.
請參閱 資料表 以查看完整腳位配置。
典型應用
LM393 適用於 6 應用s: Power-Supply Window Detection, Battery Voltage Threshold Monitoring, Industrial Sensor Interfacing, Automotive Fault Detection, Consumer Equipment Limit Switching, LED Constant-Current and Overvoltage Control.
Power-Supply Window Detection
The LM393 fits power-supply window detection because it provides two independent comparator channels, operates from a 2 V to 30 V supply range, and can compare a feedback signal with upper and lower references. Each open-collector output can sink current and use a pull-up to establish the logic-high voltage. Configuring one channel for an overvoltage condition and the other for an undervoltage condition simplifies fault signaling, although the output states must be interpreted according to the selected input polarity. The designer should account for input offset near the threshold, add filtering where the monitored rail is noisy, and keep the feedback divider within the common-mode input range. The LM393 does not actively drive the high state, so the pull-up voltage, resistor value, and sink-current capability must be selected together.
推薦
Battery Voltage Threshold Monitoring
The LM393 is useful for battery threshold monitoring because its common-mode input range includes ground and its two channels can independently compare a divided battery voltage with reference levels. A resistive divider can scale the battery signal into the input range, while the open-collector outputs can pull down an alarm or status line through an external pull-up. This arrangement works well for low-voltage systems where the comparator must operate from a single supply. Engineering checks include the maximum differential input under charging transients, reference accuracy, input offset, and the behavior of the pull-up during a disconnected battery. For cells that can exceed the selected ordering code's supply limit, add a dedicated clamp or protection network rather than relying on absolute-maximum ratings.
推薦
Industrial Sensor Interfacing
The LM393 can convert a slowly changing sensor signal into a switching decision for industrial control equipment. Its two independent channels support duplicate limit checks or the comparison of a sensor signal with a reference. The common-mode range extending to ground permits operation from a single supply in many 3.3 V or 5 V sensing systems, while the differential input capability of ±38 V accommodates signal transitions when operating limits are respected. A pull-up resistor defines the digital output state, and optional positive feedback can add hysteresis so noise near the threshold does not cause repeated transitions. The input network should limit transient energy, and the selected package and temperature grade must match the enclosure conditions.
推薦
Automotive Fault Detection
The LM393's open-collector outputs and dual-channel architecture are suitable for simple automotive fault-detection functions when the selected ordering code has the required automotive qualification. The comparator can evaluate a divided sensor or supply-rail signal against a reference and pull a wired fault line low when a limit is exceeded. The 2 V to 30 V supply range supports many 12 V and 24 V system rails, subject to transient suppression and the exact device ratings. Because the base LM393 grade is associated with a 0 C to 70 C range, an automotive design should normally select an appropriately qualified orderable code. Reverse-battery pulses, load-dump events, and ESD can exceed routine operating limits, so external protection is essential.
推薦
Consumer Equipment Limit Switching
The LM393 can implement compact limit-switching functions in consumer equipment where two threshold decisions are needed without a large microcontroller footprint. Its open-collector outputs can drive an LED, relay-driver input, or logic status line using an external pull-up. A single-supply configuration simplifies low-cost designs because the common-mode input range includes ground, while split supplies provide additional headroom for bipolar sensing when required. The design should account for output saturation, pull-up rise time, and any tolerance in the reference divider. If the target product requires a narrower operating-temperature range, a broader environment grade, or a push-pull output, choose a more suitable ordering code rather than modifying the footprint after manufacture.
推薦
LED Constant-Current and Overvoltage Control
The LM393 can be used as a discrete supervisory element in LED or other constant-current systems. One channel may compare the voltage across a current-sense resistor with a reference, while the other monitors a supply or load condition. The open-collector output can pull down an oscillator, disable a driver, or assert a fault signal through a pull-up. The comparator's ground-referenced common-mode capability is valuable in low-side sensing arrangements, and the differential input rating allows a degree of transient margin when normal operating limits are respected. Layout should keep the sense path short and away from switching nodes. The selected ordering code must also satisfy the ambient temperature, output-current, and supply requirements of the complete lamp or load-control circuit.
推薦
推薦產品摘要
工程參考資料，適用於 LM393 — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LM393B | LM293 | LM2903 | LM2903B | TS393 |
|---|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | ROHM Semiconductor |
| Package | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 |
| Comparator Channels | 2 channels | 2 channels | 2 channels | 2 channels | 2 channels | 2 channels |
| Output Type | Open-collector | Open-collector | Open-collector | Open-collector | Open-collector | Open-collector |
| External Output Pull-Up | Required | Required | Required | Required | Required | Required |
主要差異化特點
- Two independent threshold channels in one 8-pin package (對比LM339PWR)
- Broader specified operating-temperature range (對比LM393)
- Improved B-version electrical specifications (對比LM393)
設計說明
Place the supply-decoupling capacitor close to the comparator's supply and ground pins, and keep the input traces short to reduce noise pickup and propagation-delay variation. Route the two channels separately when one input is a precision reference and the other is a switching signal. The open-collector output needs a pull-up resistor; place that resistor near the receiving logic or driver input when long traces would otherwise add capacitance and slow the rising edge.
Do not use the ±38 V differential-input rating as a normal operating range. Keep normal input voltages inside the recommended common-mode interval, especially with single-supply operation, where the useful input range may not extend above the positive supply rail. Use resistor dividers or clamping networks for signals that can overshoot. This prevents comparator saturation, input damage, and long recovery times when an input leaves its valid common-mode region.
Add hysteresis when the sensed signal crosses the threshold slowly or contains noise, because a small offset error can otherwise cause repeated output transitions. Positive feedback from the output to the non-inverting input creates a controlled switching gap. Also verify that the pull-up voltage is acceptable for the output pin, that its resistor does not exceed the channel's sink-current capability, and that the selected package suffix matches the PCB footprint.
合規資訊
The base LM393 ordering code does not uniquely establish package, temperature grade, or organization-specific compliance status. Confirm these attributes against the exact orderable MPN and manufacturer declarations.
