LM2903N - Dual Voltage Comparator, Open-Collector, 8-DIP | TI/STMicro/onsemi
MPN: LM2903N ✓ فعالLM2903N جائزہ
A voltage comparator is an analog building block that compares two input voltages and produces a binary digital output; when the non-inverting input exceeds the inverting input, the output switches state. The LM2903N belongs to the LM393/LM2903 family - a long-standing industry standard introduced for low-power single-supply sensing, and it sits in the hierarchy: comparator -> analog comparator -> signal conditioning IC -> integrated circuit. Its open-collector architecture requires an external pull-up resistor (typically 10 kohm to VCC), which lets multiple comparators be wire-ORed together and lets the output pull to a different rail than the supply voltage.
Key specifications include a 1.3 us typical response time at 5 V/2 mA, a 2.5 mV maximum input offset voltage (LM2903 grade), an input bias current of 25 nA typical, and ESD clamps on the inputs that tolerate human-body-model discharge. The device operates across the automotive-industrial -40 C to +125 C range (LM2903N suffix N designates the PDIP-8 package, not the temp grade).
The LM2903's architecture uses a PNP input stage that gives the inputs an exceptionally wide common-mode range that includes the negative rail (ground), which is why single-supply ground-referenced sensing is its dominant application. The open-collector NPN output stage isolates the comparator logic from the load voltage; only the pull-up rail sets the high-level output.
Typical applications include battery monitoring in 12 V/24 V automotive and industrial systems (window detectors, under-voltage cutoff), zero-crossing detectors for mains interfaces when paired with an optocoupler, line-receiver / level-shift interfaces between high-voltage analog and low-voltage logic, threshold alarms and signal-conditioning front-ends, and oscillator / relaxation-oscillator circuits.
When designing with the LM2903N, observe one trade-off: open-collector outputs use a pull-up resistor that adds RC delay to the rising edge - at 10 kohm with 100 pF of trace capacitance, rise time is about 1 us. For high-speed logic interfaces downstream, size the pull-up conservatively or use a discrete or integrated push-pull comparator when sub-microsecond edge rates are needed.
کے لیے ڈراپ اِن متبادل LM2903N — یکساں پیکیج، پن سے پن مطابقت پذیر۔ مختلف پیکیج والے پرزے جن کے لیے PCB دوبارہ کام درکار ہو، شامل نہیں ہیں۔
اس سیریز میں مختلف ورژن
اسی سیریز کے ماڈلز جو ڈراپ اِن مطابقت رکھتے ہیں LM2903N (یکساں فارم فیکٹر اور فٹ پرنٹ) — میں مختلف Package, RoHS Status, Comparator Type, Operating Temperature Range, Output Type.
LM2903N/NOPB
✅ ڈراپ-اِن📋 حوالہ جاتی متبادل (کیٹلاگ میں نہیں)
LM393N
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LM293N
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LM2903N
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LM2903N
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LM2903N
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LM2903N
✅ ڈراپ-اِنقیمت کے لیے رابطہ کریں
ڈیٹا شیٹ دیکھیں →LM2903N زیادہ سے زیادہ ریٹنگز اور برقی خصوصیات
| Comparator Type | Low Offset Voltage, Dual Differential |
| Number of Comparators | 2 (dual independent) |
| آؤٹ پٹ کی قسم | Open-Collector / Open-Drain |
| Supply Voltage (Single Supply) | 2 V to 36 V |
| Supply Voltage (Dual Supply) | ±1 V to ±18 V |
| Input Offset Voltage (Max) | 2.5 mV (LM2903 grade) |
| Input Bias Current (Typ) | 25 nA |
| Input Common-Mode Range | Includes ground (negative rail) |
| Output Sink Current (Typ) | 16 mA typical, 6 mA min |
| Response Time (Typ) | 1.3 us at 5 V / 2 mA |
| Differential Input Voltage (Max) | 36 V |
| آپریٹنگ درجہ حرارت رینج | -40 C to +125 C |
| پیکیج | 8-Pin PDIP (DIP-8, N suffix) |
| ماؤنٹنگ ٹائپ | Through-Hole |
| RoHS اسٹیٹس | Compliant (NOPB suffix); non-compliant original |
| Lead-Free / NOPB Option | Yes (LM2903N/NOPB) |
| Manufacturer Source Bases | TI, STMicroelectronics, onsemi, NXP |
LM2903N پن کنفیگریشن
| پن 1 | OUT1 — Open-collector output of comparator 1 |
| پن 2 | IN1- — Inverting input of comparator 1 |
| پن 3 | IN1+ — Non-inverting input of comparator 1 |
| پن 4 | V- / GND — Negative supply (or ground for single-supply operation) |
| پن 5 | IN2+ — Non-inverting input of comparator 2 |
| پن 6 | IN2- — Inverting input of comparator 2 |
| پن 7 | OUT2 — Open-collector output of comparator 2 |
| پن 8 | V+ — Positive supply (2 V to 36 V) |
عام استعمالات
LM2903N کے لیے موزوں ہے 6 ایپلیکیشنs: 12 V / 24 V Battery Voltage Monitor, Zero-Crossing Detector for Mains Interface, Window Comparator (Dual-Threshold Detector), Line-Receiver / Logic Level Shifter, Relaxation Oscillator / Square-Wave Generator, Automotive Threshold Alarm and Sensor Interface.
12 V / 24 V Battery Voltage Monitor
The LM2903N is widely used as the comparator core in 12 V and 24 V battery-monitoring modules because its 2 V-36 V supply range accepts automotive and industrial battery rails directly without pre-regulation, and its open-collector output can drive an LED or alarm transistor directly. Wire a resistor divider from the battery plus a stable reference (such as a TL431 or LM4040) into the inverting input; the divided battery voltage goes into the non-inverting input; when the battery sags below the threshold, the output goes low. The LM2903N operates across -40 C to +125 C, covering under-hood and outdoor-cabinet environments, and the 2.5 mV max offset contributes only ~0.04 percent threshold error for a 6 V trip point.
تجویز کردہ
Zero-Crossing Detector for Mains Interface
Use the LM2903N at the front end of an optocoupled mains interface: attenuate the 230 V/115 V mains with a high-impedance resistor divider and use a small filter capacitor to limit dV/dt, then feed the attenuated sinewave into one LM2903N input with a low-voltage reference on the other. The open-collector output drives an optocoupler LED through a current-limit resistor, providing galvanic isolation for a downstream timer, MCU, or triac-control logic. The LM2903N's ground-sensing input allows a single low-voltage supply rail (for example 5 V) to power the comparator, even though the input network is referenced near ground; this avoids needing a negative rail just to bias the comparator inputs.
تجویز کردہ
Window Comparator (Dual-Threshold Detector)
Two cascaded LM2903N comparators (one IC, since the part contains two) build a window comparator for detecting whether an analog signal lies inside or outside a programmable voltage window. Set the upper and lower thresholds with external resistor dividers and reference; wire the inputs so that OUT goes low when Vsig falls below the lower threshold or rises above the upper threshold. Typical use is supervising a 4-20 mA loop signal or a sensor supply rail; the LM2903N's 1.3 us response time is more than adequate for fault detection bandwidths in the kHz range. Wire-OR the two open-collector outputs together for a single 'out-of-range' flag.
تجویز کردہ
Line-Receiver / Logic Level Shifter
The LM2903N is the classic solution for shifting a higher-voltage analog or digital signal down to a lower-voltage logic domain: feed the signal into one input and connect a divided reference to the other, then use the open-collector output with a pull-up to the lower-voltage rail so the output logic-high follows the downstream logic supply rather than the comparator's VCC. This approach is robust for interfaces between a ±15 V op-amp world and a 3.3 V microcontroller, between 24 V industrial sensors and 5 V logic, or between unregulated mains-synchronous signals and a low-voltage counter.
تجویز کردہ
Relaxation Oscillator / Square-Wave Generator
A single LM2903N comparator plus an RC timing network and two resistors forms a textbook relaxation oscillator (also called an astable multivibrator) that generates square waves from a few Hz to ~50 kHz depending on RC values. The LM2903N's wide supply range (2-36 V) makes the oscillator amplitude programmable from a few volts up to about 33 V p-p, while the open-collector output with a pull-up resistor to any desired rail provides flexibility in output level. This topology is common in test-and-measurement fixtures, low-cost clock generators, PWM modulators, and tone generators; typical 10 kHz designs use 10 kohm + 0.01 uF for approximately 7 kHz output frequency.
تجویز کردہ
Automotive Threshold Alarm and Sensor Interface
Inside an automotive ECU, the LM2903N acts as a rugged threshold detector for low-speed analog sensor signals (temperature sensors via NTC/PTC thermistor dividers, fluid-level sensors, switch-bounce debouncing, and generic over-temperature alarms). Its -40 C to +125 C operating range, ESD-robust inputs, and tolerance of supply transients (within the 36 V abs-max envelope) are well-matched to 12 V automotive electrical environments. For AEC-Q100-qualified alternatives, TI recommends the TLV1702-Q1 or LM2903-Q1 in SOIC-8; the through-hole PDIP-8 LM2903N remains popular for development kits, hobby automotive projects, and industrial-grade (not automotive-qualified) designs.
تجویز کردہ
تجویز کردہ پروڈکٹس کا خلاصہ
کے لیے انجینئرنگ ریفرنس ڈیٹا LM2903N — موازنہ، ڈیزائن رہنمائی، اور تعمیل کی معلومات۔
انتخاب کی گائیڈ
متبادلات کے ساتھ موازنہ
| پیرامیٹر | یہ پروڈکٹ | LM2903N/NOPB | LM393N | LM293N | LM2903N (STMicro) | LM2903N (onsemi) |
|---|---|---|---|---|---|---|
| Package | 8-Pin PDIP (DIP-8, N suffix) | 8-Pin PDIP (DIP-8) - same | 8-Pin PDIP (DIP-8) - same | 8-Pin PDIP (DIP-8) - same | 8-DIP - same | 8-DIP - same |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | STMicroelectronics | onsemi |
| 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 (Single) | 2 V - 36 V | 2 V - 36 V | 2 V - 36 V | 2 V - 36 V | 2 V - 36 V | 2 V - 36 V |
| Operating Temperature | -40 C to +125 C | -40 C to +125 C | 0 C to +70 C | -40 C to +85 C | -40 C to +125 C | -40 C to +125 C |
| RoHS Compliant | Yes (NOPB suffix) | Yes | Yes (NOPB) | Yes (NOPB) | Yes | Yes |
اہم امتیازی خصوصیات
- Quad-source legacy dual comparator with 36 V supply range (بمقابلہLM393N (TI 0-70C version))
- Tighter input offset at the same price point (بمقابلہLM393N)
- Pin-to-pin second-source availability across multiple manufacturers (بمقابلہProprietary comparator pinouts (e.g. TLV3202 in SOIC-8))
- Through-hole PDIP-8 package (DIP-8) for prototyping and breadboards (بمقابلہSurface-mount-only comparators (LM2903DR SOIC-8))
ڈیزائن نوٹس
The LM2903N open-collector output requires an external pull-up resistor to any desired voltage rail up to 36 V, even when running the comparator itself on a separate supply. Choose pull-up values from 1 kohm to 100 kohm based on speed vs current trade-off: at 1 kohm the rise time is fast but quiescent current when low is 5 mA; at 100 kohm, rise time is ~10 us and on-current is 50 uA. Bypass V+ (pin 8) with a 0.1 uF ceramic capacitor placed physically close to the IC, since the comparator draws sharp switching transients from the rail during output transitions.
The LM2903N input common-mode range is specified from V- up to roughly (V+ - 1.5 V), so at a 5 V supply the inputs are only linear to ~3.5 V - do not present input voltages near the positive rail. Differential input voltage must not exceed 36 V, even if both inputs are within the common-mode range; clamping with back-to-back diodes or series resistors is advised if transients are expected. Note that the LM2903N suffix 'N' designates the PDIP-8 package, not the temperature grade - identical electrical behavior applies to other packages (SOIC-8, DSBGA) of the same die.
Layout tips for the LM2903N: keep input traces short and parallel to avoid injecting switching noise into the high-impedance comparator inputs; route output traces away from input traces to prevent feedback. For through-hole PDIP-8 designs use a single-point ground star at the LM2903N GND pin (pin 4) to avoid ground-loop-induced input offset. If the system uses high-impedance (>100 kohm) input dividers, add 10 pF to 100 pF bypass capacitors across the inputs to suppress RF rectification and stray switching noise pickup.
The LM2903N's open-collector topology is an excellent noise-margin asset, but it interacts with capacitive loads - the rise time is governed by R_pullup x C_load. A scope measurement on the OUT pin will show a slow ramp rather than a clean edge when driving >50 pF. For best signal integrity into downstream CMOS, size R_pullup for rise times below 1 us; for driving relays or LEDs directly, a slow ramp is acceptable. Add a 100 pF speed-up capacitor in parallel with R_pullup if you need sub-microsecond rising edges without sacrificing the pull-up's DC bias current.
تعمیل کی معلومات
LM2903N/NOPB (TI lead-free version) is fully RoHS compliant. The non-NOPB LM2903N uses lead terminations and is not RoHS compliant - choose NOPB for new designs. AEC-Q100 qualification not available in PDIP-8 form factor; the AEC-Q100 option for LM2903 family is the LM2903-Q1 in SOIC-8.
