LM2903XK - Dual Open-Drain Comparator | Runic Technology
MPN: LM2903XK ✓ ActiveLM2903XK Overview
A voltage comparator is a semiconductor that evaluates the relationship between two voltages and changes its output state when one input crosses the other. The comparator category belongs to the broader signal-conditioning and interface-IC hierarchy, where an analog voltage decision is converted into a logic-compatible event. The LM2903XK open-drain output can support wired logic, system monitoring, threshold detection, and control functions when paired with an appropriate pull-up resistor.
The LM2903XK provides two comparator channels, open-drain output structures, and an 8-SOIC package identified as SOIC-8 with a 0.154-inch, 3.90 mm width. PartGenie classifies the device for industrial-control and consumer-electronics applications. Its listed environmental-handling classification is MSL 3 for 168 hours, while its compliance records identify RoHS3 compliance and no REACH impact.
Because the output is open drain, each channel can pull its output node to a defined logic-low state but cannot actively drive a logic-high state. A pull-up resistor or compatible pull-up network is therefore required. This arrangement provides useful flexibility because the output can be referenced to a supply selected by the system designer, while multiple open-drain outputs can share a bus when the electrical conditions and device limits permit.
Typical uses include monitoring a power rail against a reference, detecting sensor thresholds, generating reset or fault signals, comparing two analog signals, and implementing simple control loops. The dual-channel format is especially useful when a system requires two related decisions, such as an upper-limit detector and a lower-limit detector, without using separate single-channel packages.
The primary PCB considerations are pin orientation, input common-mode limits, output pull-up values, and the voltage and current ratings of the open-drain nodes. Designers should use the manufacturer datasheet pin-description table and electrical characteristics before finalizing input ranges, output sink-current limits, supply limits, and decoupling requirements. A local ground-reference arrangement is important for stable comparator behavior.
This product page consolidates the LM2903XK function, package information, compliance records, verified source links, and application guidance. It also identifies confirmed package-related alternatives and clearly separates them from unverified or differently packaged options so that engineers can assess PCB compatibility before making a replacement decision.
Drop-in alternatives for LM2903XK — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
LM2903XK-Q1
✅ Drop-In📋 Reference alternative (not in catalog)
LM2903XK-04#
✅ Drop-In📋 Reference alternative (not in catalog)
LM2903XK Maximum Ratings & Electrical Characteristics
| Comparator Type | Dual general-purpose voltage comparator |
| Number of Channels | 2 channels |
| Output Type | Open-drain |
| Package | 8-SOIC |
| Package Width | 0.154 in (3.90 mm) |
| Mounting Type | Surface mount |
| Moisture Sensitivity Level | MSL 3 (168 hours) |
| RoHS Compliance | RoHS3 compliant |
| REACH Compliance | Unaffected |
| Primary Applications | Industrial control and consumer electronics |
LM2903XK 0.154 in (3.90 mm) Pin Configuration Guide
Pin configuration for LM2903XK (0.154 in (3.90 mm) package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for LM2903XK.
Refer to the datasheet for full pin configuration.
Typical Applications
LM2903XK is suitable for 6 applications: Industrial Power-Rail Monitoring, Sensor Threshold Detection, Consumer-Electronics Fault Detection, Window Limit Comparator, Industrial Control Logic Interface, Battery and Charger Status Detection.
Industrial Power-Rail Monitoring
The LM2903XK is suitable for monitoring an industrial power rail against a reference because it provides two general-purpose comparator channels with open-drain outputs. Two channels can independently indicate excessive and insufficient voltage conditions, reducing the number of packages required for window supervision. Each output can pull a shared or separate pull-up node toward ground when its comparison condition is met. The designer must confirm the target's supply range, common-mode input range, output sink-current capability, and operating-temperature limits in the manufacturer datasheet before choosing resistor values or fault thresholds.
Recommended
Sensor Threshold Detection
The two LM2903XK channels can compare sensor-derived voltages with reference thresholds and produce open-drain events for alarms, control logic, or data acquisition. This arrangement is useful when a sensor output crosses defined operating limits and the downstream system expects a low-active digital indication. Because open-drain outputs require pull-up resistors, the designer can select the logic voltage independently of the comparator supply where electrical conditions permit. Verify input common-mode limits, offset voltage, propagation delay, and output behavior against the actual sensor range before setting thresholds.
Recommended
Consumer-Electronics Fault Detection
In consumer electronics, the LM2903XK can implement compact fault detection for supply, display, audio, or interface signals where two threshold decisions are needed. The open-drain outputs can drive a system fault line, an enable signal, or a microcontroller interrupt input after the required pull-up network is fitted. The dual-channel arrangement reduces board area compared with two separate comparator packages. Board-level design should maintain a stable reference ground, account for comparator offset and propagation delay, and confirm that the selected operating range covers the product's intended ambient conditions.
Recommended
Window Limit Comparator
The LM2903XK is well suited to an upper-and-lower window limit circuit because its two channels can independently compare a measured voltage against high and low references. One open-drain output can indicate an over-limit condition while the other indicates an under-limit condition, allowing a controller to recognize valid operating states. This approach is applicable to battery packs, regulated rails, and industrial signal ranges. The component's exact offset voltage, input range, supply limits, and response time must be taken from the datasheet so that guard bands around each threshold prevent marginal or oscillating decisions.
Recommended
Industrial Control Logic Interface
The LM2903XK can convert two analog decision points into open-drain logic signals for industrial controllers, PLC inputs, or discrete interface circuits. A pull-up establishes the inactive-high state, while the comparator actively pulls the node low when its channel changes state. This configuration can support wired fault signals without requiring a totem-pole output driver. When the comparator sits near a switching controller or motor circuit, route its ground reference carefully, keep sensitive input traces away from high-current paths, and verify the output-node voltage and current limits against the interface load.
Recommended
Battery and Charger Status Detection
The dual channels of the LM2903XK can monitor two battery-related thresholds, such as pack undervoltage and overvoltage, and provide open-drain fault indications to a charger or protection controller. The pull-up can be connected to the relevant control logic rail, while each comparator channel handles one threshold direction. This topology reduces component count in compact battery systems. Designers should confirm whether the battery voltage can exceed the comparator's permitted input and supply limits, and must add appropriate protection and scaling so that all pins remain within their absolute-maximum ratings.
Recommended
Recommended Products Summary
Engineering reference data for LM2903XK — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM2903XK-Q1 | LM2903XK-04# |
|---|---|---|---|
| Brand | Runic Technology | Runic Technology | LEXUS Semiconductor |
| Package | 8-SOIC | 8-SOIC | SOP8 |
| Comparator Configuration | Dual channel | Dual channel | 2 channels |
| Output Type | Open-drain | Open-drain | Open-drain |
Key Differentiators
- Two independent general-purpose comparator channels in one package (vs LM2903XK-04#)
- Automotive-oriented same-family alternative available for qualification review (vs LM2903XK-Q1)
- Open-drain output architecture supports flexible logic-level interfacing (vs LM2903XK-04#)
Design Notes
Place each open-drain output pull-up resistor close to the associated LM2903XK output node and the receiving logic input. This minimizes trace exposure to capacitive loading and switching noise. Keep the pull-up value high enough to remain within the comparator's sink-current limit at the selected logic voltage, but low enough to achieve the required rise time. Confirm the package orientation and pin assignments from the manufacturer pin-description table before routing the board.
Route both comparator inputs away from switching nodes, motor windings, power inductors, and high-current return paths. A comparator can interpret small changes on its reference or signal input as a meaningful state transition, so input traces should be short and referenced to the same quiet ground used by the threshold source. If the inputs cross unrelated analog or digital regions, inspect the assembled board for ground-potential differences that could shift the comparison threshold.
Do not connect an open-drain output to a voltage that exceeds its permitted output rating, and do not omit the external pull-up. Before applying power, verify that both input voltages, the supply voltage, and every pulled-up output node remain inside the absolute-maximum limits. Also account for input offset and propagation delay when defining alarm margins. The manufacturer datasheet is the controlling source for these electrical limits.
Keep the pull-up loop small and avoid routing the two comparator inputs as a long parallel pair through electrically noisy regions. Place any input filtering or clamping components close to the corresponding pin, and use a stable reference source if the threshold must remain predictable. Changes in pull-up voltage, input source impedance, or nearby switching activity can affect decision timing, so validate the complete analog path rather than only the IC output.
Compliance Information
PartGenie identifies the LM2903XK as RoHS3 compliant, REACH unaffected, and MSL 3 for 168 hours. AEC-Q100 status and lead-free or halogen-free status are not established for the target.
