LM393N - Dual Comparator 2-36V Open-Collector | 8-PDIP
MPN: LM393N ✓ Hoạt độngLM393N Tóm tắt
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.
Bộ thay thế dễ dàng lắp đặt cho LM393N — cùng gói, chân-to-chân tương thích. Các bộ phận yêu cầu hàn PCB bị loại trừ.
Các biến thể trong loạt này
Các mẫu cùng loạt có thể lắp đặt dễ dàng tương thích với LM393N (cùng hình factor và footprint) — khác nhau ở Package, Comparator Type, Output Type, RoHS Status, Supply Voltage Range.
LM2903N
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LM393N/NOPB
✅ Drop-In📋 Tham chiếu thay thế (không có trong danh mục)
LM293N
✅ Drop-In ⚠️ Thông số chưa được xác minhLiên hệ để biết giá
Xem tài liệu →LM393NG
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LM393P
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LM393D
✅ Drop-InLiên hệ để biết giá
Xem tài liệu →LM393N Tỷ lệ tối đa & tính chất điện
| Comparator Type | Dual General-Purpose Comparator |
| Number of Comparators | 2 (dual) |
| Kiểu đầu ra | 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) |
| Khoảng nhiệt độ hoạt động | 0 C to +70 C (LM393N) / -40 C to +85 C (LM2903N) |
| Hộp | 8-PDIP (DIP-8, through-hole) |
| Kiểu lắp đặt | Through-Hole |
| Trạng thái RoHS | Non-RoHS (LM393N); RoHS on LM393N/NOPB variant |
Cấu hình chân LM393N
| Chân 1 | 1OUT — Comparator A open-collector output (requires external pull-up) |
| Chân 2 | 1IN- — Comparator A inverting input |
| Chân 3 | 1IN+ — Comparator A non-inverting input |
| Chân 4 | GND — Ground / negative supply |
| Chân 5 | 2IN+ — Comparator B non-inverting input |
| Chân 6 | 2IN- — Comparator B inverting input |
| Chân 7 | 2OUT — Comparator B open-collector output (requires external pull-up) |
| Chân 8 | VCC — Positive supply voltage (2 V to 36 V) |
Ứng dụng tiêu biểu
LM393N phù hợp cho 6 Áp dụngs: 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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
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.
Được đề xuất
Tóm tắt các sản phẩm được đề xuất
Dữ liệu tham khảo kỹ thuật cho LM393N — so sánh, hướng dẫn thiết kế và thông tin tuân thủ.
Hướng dẫn chọn lựa
So sánh với các sản phẩm thay thế
| Tham số | Sản phẩm này | 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 |
Bảo phân biệt quan trọng
- Wide supply range 2V-36V with ground-sensing input (vsLM393LV (CMOS upgrade))
- Through-hole DIP-8 for hand prototyping and legacy designs (vsLM393D (SOIC-8 surface-mount version))
- Multi-sourced commodity with cross-brand drop-in equivalents (vsSpecialized precision comparator (e.g., LT1010))
Ghi chú thiết kế
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.
Thông tin tuân thủ
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.
