LM211DG - 200 ns Single Comparator | onsemi | SOIC-8
MPN: LM211DG ✓ ActiveLM211DG Overview
A voltage comparator is an analog integrated circuit that compares two input voltages and changes its output state when one input crosses the other. The LM211 belongs to the broader comparator, analog IC, and semiconductor hierarchy. Its open-collector output can interface with TTL, MOS, DTL, and RTL logic, while its ability to accept split supplies makes it useful in systems that do not share a common signal ground.
Key features include one comparator channel, a 200 ns response time, and operation across a 5 V to 30 V single-supply range. The open-collector output provides a flexible way to drive compatible digital logic, lamps, or relays when an appropriate pull-up arrangement is used. The specified operating temperature range for LM211DG is -25°C to 85°C.
The LM211 architecture is designed for high-speed threshold detection rather than precision amplification. Its input stage can operate independently of system ground, which helps when comparing signals referenced to a different potential. The open-collector output remains in a high-impedance state unless pulled down, allowing the output transition speed to depend partly on the external pull-up resistor and associated capacitance.
Typical applications include industrial control interfaces, pulse-width and timing circuits, sensor threshold detection, relay or lamp drive, level translation between analog and digital systems, and general-purpose logic interfacing. The combination of a 200 ns response time and flexible supply options also suits pulse-width measurement and fast event detection circuits.
When designing around the LM211DG, account for the open-collector output when calculating rise time and fanout. Keep input and output paths short, use a pull-up resistor appropriate for the driven logic family, and check input common-mode limits for the selected supply configuration before finalizing the schematic.
This product summary combines the LM211DG electrical envelope, package information, sourcing context, pin-compatible alternatives, and practical interface guidance. It supports faster component selection by separating core operating characteristics from application-specific design considerations.
Drop-in alternatives for LM211DG — 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 LM211DG (same form factor and footprint) — differing in Number of Channels, Operating Temperature Range, Package.
LM211DG4
✅ Drop-In📋 Reference alternative (not in catalog)
LM211DRE4
✅ Drop-In📋 Reference alternative (not in catalog)
LM311DG
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
BTS3110NHUMA1
✅ Drop-InContact for price
View Datasheet →TS311A
✅ Drop-In📋 Reference alternative (not in catalog)
LM211DG Maximum Ratings & Electrical Characteristics
| Comparator Type | Single high-speed voltage comparator |
| Number of Channels | 1 channel |
| Response Time | 200 ns |
| Single-Supply Operating Voltage | 5 V to 30 V |
| Split-Supply Operation | ±15 V |
| Output Type | Open-collector |
| Logic Compatibility | DTL, MOS, RTL, and TTL |
| Input Isolation | Inputs can be isolated from system ground |
| Operating Temperature Range | -25°C to 85°C |
| Maximum Supply Voltage | 36 VDC |
| Package | 8-pin SOIC |
| Package Width | 3.90 mm |
| Package Body Length | 0.154 inch |
| Pin Count | 8 pins |
| Output Drive Capability | Capable of driving lamps or relays |
| Datasheet File Size | 121 KB |
| Datasheet Length | 10 pages |
LM211DG 0.154 inch Pin Configuration Guide
Pin configuration for LM211DG (0.154 inch 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 LM211DG.
Refer to the datasheet for full pin configuration.
Typical Applications
LM211DG is suitable for 6 applications: Industrial Threshold Detection, Pulse-Width and Timing Control, TTL and MOS Logic Interfacing, Relay and Lamp Drive Interface, Sensor Signal Conditioning, Power Supply and Regulation Monitoring.
Industrial Threshold Detection
The onsemi LM211DG fits industrial threshold-detection circuits because it combines a 200 ns response time with operation from 5 V to 30 V. Place the comparator across a sensor or divided reference signal so the output changes state when the two inputs cross. The open-collector output can feed a pull-up and a controller input, while the -25°C to 85°C specified range covers many industrial environments. Verify the sensor's voltage range, common-mode limits, noise immunity, and galvanic-isolation requirements before finalizing the interface.
Recommended
Pulse-Width and Timing Control
The LM211DG is appropriate for pulse-width, zero-cross, and event-timing measurements because its documented response time is 200 ns. Use one input for the incoming pulse and the other for a threshold reference, then use the open-collector output to drive a counter or capture input through an external pull-up. Account for pull-up resistance and wiring capacitance when estimating the output rise time, because the 200 ns comparator response does not include all externally generated propagation delay.
Recommended
TTL and MOS Logic Interfacing
Use the LM211DG when an analog signal must be converted into a logic-compatible transition. Its open-collector output supports DTL, MOS, RTL, and TTL interfacing, allowing the comparator to sink current while an external pull-up establishes the high state. This arrangement is useful for open-collector bus signaling and for isolating the logic pull-up voltage from the comparator supply when required. Select the pull-up resistor to balance fanout against rise time and confirm the output's absolute voltage and current limits.
Recommended
Relay and Lamp Drive Interface
The LM211DG can support relay and lamp drive applications because the manufacturer identifies these loads as compatible with the device's open-collector output. For a lamp, determine whether the output path and pull-up network can handle its operating current and provide appropriate protection. For a relay, use a suitable driver stage when coil current exceeds the comparator's direct load capability, and include a flyback path across the coil. The selected driver must preserve the polarity and timing behavior required by the control system.
Recommended
Sensor Signal Conditioning
The LM211DG can convert a sensor-derived analog level into a clean binary decision. Place the sensor output on one input and a selectable reference on the other, then route the open-collector result into a pull-up and downstream digital stage. The 5 V to 30 V supply range provides flexibility for industrial and embedded systems, while isolated input operation can help when the sensed voltage is referenced away from system ground. Validate common-mode range, input offset, noise, and switching behavior against the actual sensor and operating conditions.
Recommended
Power Supply and Regulation Monitoring
Use the LM211DG to monitor a power rail or divided auxiliary supply and generate an alert when the measured level crosses a reference. Its 200 ns response permits rapid detection of transients, while the 5 V to 30 V single-supply range can cover many industrial control rails. The open-collector output can trigger an alarm, disable another circuit, or feed a supervisor through a pull-up. Check input common-mode limits, output leakage, and system-level filtering to prevent false events.
Recommended
Recommended Products Summary
Engineering reference data for LM211DG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM211DG4 | LM211DRE4 | LM311DG | TS311 | TS311A |
|---|---|---|---|---|---|---|
| Brand | onsemi | onsemi | onsemi | onsemi | STMicroelectronics | STMicroelectronics |
| Package | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC |
| Comparator Type | Single high-speed voltage comparator | Single comparator | Single comparator | Single comparator | Single comparator | Single comparator |
Key Differentiators
- Documented high-speed response (vs LM311DG)
- Wide single-supply operating range (vs TS311)
- Direct interface with multiple logic families (vs TS311A)
- Input-ground isolation capability (vs LM211DG4)
Design Notes
Do not treat the 200 ns comparator response time as the complete output transition time. The open-collector output rises through an external pull-up resistor, so the observed edge also depends on pull-up resistance, input capacitance, wiring, and the load's threshold. Use the pull-up value required by the driven logic interface and confirm that the resulting rise time satisfies the receiving circuit.
Respect the listed 36 VDC maximum supply voltage, including supply tolerance, startup overshoot, and transient margin. The 5 V to 30 V operating interval applies to single-supply operation, while ±15 V is a supported split-supply arrangement. Confirm the absolute voltage presented to every supply pin under fault conditions and ensure the input common-mode range remains valid at the minimum supply voltage.
Keep the comparator inputs short and route them away from high-current switching paths to reduce coupled noise and false threshold transitions. Place the output pull-up close to the driven input when practical, and keep the return path continuous. When the inputs are isolated from system ground, define the input return carefully to prevent parasitic ground loops and unintended coupling between the comparator and driven circuit.
Use a relay driver or suitable switching stage when coil or lamp current exceeds the comparator's permitted output load. The LM211 can support lamp and relay interfacing, but the open-collector pin still has finite sink-current and voltage limits. Add the required flyback protection for an inductive coil and verify every load against the exact manufacturer limits before energizing it.
Compliance Information
No definitive RoHS, REACH, lead-free, halogen-free, or conflict-minerals status appears in the cited manufacturer or distributor records. AEC-Q100 qualification is not indicated.