LM339AMX/NOPB - 4-Comparator 36V IC | Texas Instruments
MPN: LM339AMX/NOPB ✓ ActiveLM339AMX/NOPB Overview
A voltage comparator is an analog semiconductor that compares two input voltages and changes its output state when the differential input crosses a defined threshold. The LM339 family belongs to the comparator hierarchy within analog and mixed-signal integrated circuits. Each of its four channels can operate independently, while common power and ground connections simplify implementation across multiple sensing or control functions.
The principal features of the LM339AMX/NOPB include four precision comparators, open-collector outputs, single-supply or dual-supply operation, and low power consumption. Its input offset voltage can be as low as 2 mV maximum for all four comparators. The open-collector architecture allows output transistors to be pulled up to a chosen logic voltage, enables wired-AND behavior, and permits use with CMOS, MOS, TTL, DTL, and ECL interfacing when suitable external pull-up circuitry is used.
The LM339 architecture is designed for a broad supply range of 2 V to 36 V, or approximately ±1 V to ±18 V in dual-supply operation. A typical response time of 1.3 µs provides adequate speed for threshold detection, overvoltage monitoring, and simple control loops. Because each comparator is electrically independent, unused channels should be configured according to the manufacturer's input and output recommendations to prevent unstable behavior.
Typical applications include industrial sensor interfaces, battery and power-supply monitoring, window and level comparators, control-system threshold detection, and low-level sensing. The wide supply range supports both compact low-voltage systems and higher-voltage industrial environments, while the 14-pin SOIC package supports conventional through-hole assembly and automated board assembly.
A key design consideration is the open-collector output: every channel requires an external pull-up resistor unless the output is intentionally connected to a wired bus. Select the pull-up voltage to match the receiving logic family, and account for its contribution to supply current and switching speed.
This page combines manufacturer specifications, package information, pin assignments, application guidance, and engineering-oriented comparisons to support component selection and PCB implementation.
Drop-in alternatives for LM339AMX/NOPB — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with LM339AMX/NOPB (same form factor and footprint) — differing in Logic Compatibility, Package, Comparator Type, Output Type, Comparator Count.
LM339AM/NOPB
✅ Drop-InContact for price
View Datasheet →LM339DE4
✅ Drop-InContact for price
View Datasheet →LM339DT
✅ Drop-InContact for price
View Datasheet →LM339ADR2
✅ Drop-InContact for price
View Datasheet →LM339DG
✅ Drop-InContact for price
View Datasheet →LM339AMX/NOPB Maximum Ratings & Electrical Characteristics
| Comparator Count | 4 comparators |
| Comparator Type | Precision, general-purpose |
| Supply Voltage Range | 2 V to 36 V |
| Dual-Supply Operating Range | Approximately ±1 V to ±18 V |
| Output Type | Open-collector |
| Response Time | 1.3 µs |
| Input Offset Voltage | As low as 2 mV maximum for all four comparators |
| Supply Current | 800 µA typical |
| Logic Compatibility | CMOS, MOS, TTL, DTL, and ECL |
| Package | 14-SOIC (D), 3.90 mm width |
| Pin Count | 14 pins |
| Mounting Type | Surface mount |
| Operating Temperature | 0°C to 70°C |
| Single-Supply Operation | Supported |
| Dual-Supply Operation | Supported |
| Wired-Logic Capability | Supported through open-collector outputs |
LM339AMX/NOPB Pin Configuration
| Pin 1 | OUT 1 — Comparator 1 open-collector output |
| Pin 2 | IN 1- — Comparator 1 inverting input |
| Pin 3 | IN 1+ — Comparator 1 noninverting input |
| Pin 4 | GND — Ground connection |
| Pin 5 | IN 2+ — Comparator 2 noninverting input |
| Pin 6 | IN 2- — Comparator 2 inverting input |
| Pin 7 | OUT 3 — Comparator 3 open-collector output |
| Pin 8 | OUT 4 — Comparator 4 open-collector output |
| Pin 9 | IN 4- — Comparator 4 inverting input |
| Pin 10 | IN 4+ — Comparator 4 noninverting input |
| Pin 11 | GND — Ground connection |
| Pin 12 | IN 3+ — Comparator 3 noninverting input |
| Pin 13 | IN 3- — Comparator 3 inverting input |
| Pin 14 | OUT 2 — Comparator 2 open-collector output |
Typical Applications
LM339AMX/NOPB is suitable for 6 applications: Industrial Sensor Threshold Detection, Power-Supply Overvoltage Monitoring, Battery Voltage Protection, Control-System Limit Switch, Low-Level Sensing and Signal Conditioning, Memory and Logic-Level Detection.
Industrial Sensor Threshold Detection
The LM339AMX/NOPB is well suited to comparing a sensor signal against a reference voltage when a compact, four-channel threshold detector is required. Its low input offset voltage, specified as low as 2 mV maximum for all four comparators, reduces the gap that must be covered near the switching point. The 1.3 µs typical response time also supports relatively prompt detection of level changes. Use one channel for each sensor or reference, configure the unused inputs according to the manufacturer guidance, and fit an external pull-up resistor at every open-collector output so the logic polarity matches the downstream controller.
Recommended
Power-Supply Overvoltage Monitoring
The LM339AMX/NOPB can monitor several power rails against independent reference thresholds using its four open-collector comparator channels. Its 2 V to 36 V supply capability is useful for industrial rails, while the low offset voltage supports fine threshold placement. A pulled-up output can signal an MCU input, optocoupler, or discrete driver when a rail exceeds its allowed range. During design, verify the comparator input common-mode limits for each monitored voltage and select the pull-up voltage so the fault signal cannot exceed the receiver’s absolute maximum rating.
Recommended
Battery Voltage Protection
The LM339AMX/NOPB can implement low-side or high-side battery protection thresholds by comparing a scaled battery voltage with a precision reference. Its wide supply range permits operation from industrial battery systems, while the low offset voltage helps narrow the switching band around the protection threshold. The 1.3 µs typical response time provides fast decision-making, but protection-loop delay, input filtering, and the chosen reference must be evaluated for the complete battery system. Each output needs a pull-up, and unused channels require stable input configurations.
Recommended
Control-System Limit Switch
The LM339AMX/NOPB can implement independent upper and lower limit switches for temperature, pressure, or position-feedback systems. Four channels provide a useful balance between sensing density and package size, and the open-collector outputs permit wired-AND fault signaling or direct interfaces to discrete logic. The 14-SOIC package supports conventional PCB assembly, while the 0°C to 70°C rating fits many commercial and industrial ambient installations. Validate sensor tolerances and hysteresis externally when the required switching accuracy is tighter than the comparator’s offset specification.
Recommended
Low-Level Sensing and Signal Conditioning
The LM339AMX/NOPB is appropriate for detecting small analog changes where a 2 mV maximum offset is valuable. Each channel can compare a conditioned sensor output with a local reference and provide a digital fault or event indication. Its typical 1.3 µs response time supports reasonably fast events, although source impedance and input filtering must be chosen to control offset error and noise. Because the output is open collector, the logic threshold is established by the external pull-up voltage rather than by the comparator itself, enabling flexible interface design.
Recommended
Memory and Logic-Level Detection
The LM339AMX/NOPB can support memory-voltage comparison and general logic-level detection because it provides four independent channels with open-collector outputs. The wide supply range allows the comparator itself to operate beside circuits using several voltage domains, although every input and pull-up rail must remain within its specified limits. A 1.3 µs typical response time is useful for ordinary threshold events rather than high-speed timing. Confirm input common-mode range, output sink current, pull-up value, and system timing before using the device in a new memory interface.
Recommended
Recommended Products Summary
Engineering reference data for LM339AMX/NOPB — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM339AM/NOPB | LM339DE4 | LM339DT | LM339ADR |
|---|---|---|---|---|---|
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | ROHM Semiconductor | International Rectifier |
| Package | 14-SOIC (D) | 14-SOIC (D) | 14-SOIC (D) | 14-SOIC (D) | 14-SOIC (D) |
| Comparator Count | 4 | 4 | 4 | 4 | 4 |
| Output Type | 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 |
Key Differentiators
- Lower specified offset for fine threshold placement (vs LM339DT)
- Same 14-SOIC quad-comparator architecture (vs LM339AM/NOPB)
- Matching response time with a 36 V maximum supply (vs LM339ADR)
Design Notes
Do not treat an open-collector output as a push-pull logic output. Each used channel needs a pull-up resistor connected to a suitable logic rail, and that rail must remain within the output pin's voltage limits. The resistor value sets the rise time and sink current: a smaller value produces a faster rising edge but increases current when the transistor asserts the fault. Confirm that the downstream device recognizes the resulting high level and that the pull-up rail remains valid during power-down.
Place the comparator close to the sensed node and reference source to minimize input trace pickup and resistive offset. Keep the two inputs of each channel away from switching nodes, and route the ground return directly to the device ground pin rather than through a noisy motor or relay return. If the input source has high impedance, add a nearby low-noise bias resistor and account for its thermal noise and leakage. The unused channel inputs should follow the manufacturer's recommended stable configuration.
Verify the input common-mode range at every actual rail and signal voltage, including tolerance and transient excursions. The 2 V to 36 V supply capability does not imply that every input can swing across the full supply range. Similarly, check the 1.3 µs response time against the required system timing and add external filtering or hysteresis when chatter around the threshold is unacceptable. These checks are especially important when the monitored signal crosses the reference frequently.
Compliance Information
The NOPB ordering suffix denotes a lead-free finish, but specific RoHS, REACH, halogen-free, and conflict-minerals declarations were not identified. AEC-Q100 qualification is not indicated for this 0°C to 70°C commercial-temperature device.
