LM211DT - 200 ns Voltage Comparator | STMicroelectronics
Référence : LM211DT ✓ ActifLM211DT Présentation
A voltage comparator is an analog integrated circuit that compares two input voltages and changes its output state when the differential input crosses a selected threshold. In the broader semiconductor hierarchy, the LM211DT belongs to the comparator class, analog IC category, and power-management and signal-conditioning application ecosystem. Unlike an operational amplifier, the device is optimized for fast switching behavior and logic-compatible output drive rather than linear amplification.
The principal features of the LM211DT include low input current, a 200 ns propagation delay, and an output compatible with TTL, DTL, RTL, MOS, and open-collector or open-emitter logic. Its open-collector output can sink logic-level current while the output transistor remains off, making pull-up placement and system-level bus design important. The wide supply-voltage range supports both traditional analog rails and modern single-supply logic systems.
Internally, the comparator provides adjustable sensitivity because the output transition can be affected by the voltage difference between its non-inverting and inverting inputs. The STMicroelectronics datasheet also identifies a strobe control, allowing the designer to inhibit or enable output transitions according to system timing. Low input current is particularly useful when the comparator monitors high-impedance sensors, divider networks, or analog front ends where input bias current could shift the comparison threshold.
Typical applications include industrial sensor threshold detection, overvoltage and undervoltage supervision, relay or solenoid drive, window-comparator circuits, level translation, and conditioning slow sensor signals into fast logic events. The open-collector output is useful in systems that require wired logic, pull-up-controlled buses, or a fail-safe output state when the device is unpowered.
The primary design consideration is output topology. Place the required pull-up resistor from OUT to the positive logic rail, account for the maximum sink current, and use the STROBE pin according to the required timing. Check input common-mode range, supply polarity, output pull-up voltage, and propagation-delay requirements across the complete temperature range before treating a nominal 200 ns figure as sufficient for the application.
This page combines the LM211DT electrical characteristics, package information, comparison options, and application guidance into an engineering-focused reference. It also highlights practical distinctions between the comparator's low-current inputs, wide supply range, strobe function, and open-collector output so that selection is based on circuit behavior rather than part number alone.
Alternatives de remplacement direct pour LM211DT — même boîtier, compatible broche à broche. Les références à boîtier différent nécessitant une retouche du PCB sont exclues.
LM311DT
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LM311DG
✅ Remplacement direct📋 Alternative de référence (hors catalogue)
LM211DT Valeurs maximales et caractéristiques électriques
| Comparator Type | Single general-purpose voltage comparator |
| Number of Comparators | 1 |
| Propagation Delay | 200 ns |
| Supply Voltage Range | 5 V to ±15 V |
| Single-Supply Operation | 5 V minimum |
| Dual-Supply Operation | ±15 V maximum |
| Input Current | Low input current |
| Type de sortie | Open-collector |
| Logic Compatibility | TTL, DTL, RTL, MOS, open-collector, and open-emitter compatible |
| Strobe Control | Yes |
| Boîtier | 8-pin SOIC |
| Type de montage | Surface mount |
| Température de fonctionnement | -40 °C to +105 °C |
Configuration des broches de LM211DT
| Broche 1 | GND — Ground reference |
| Broche 2 | IN+ — Non-inverting input |
| Broche 3 | IN- — Inverting input |
| Broche 4 | V- — Negative supply connection |
| Broche 5 | STROBE — Output strobe control |
| Broche 6 | OUT — Open-collector comparator output |
| Broche 7 | V+ — Positive supply connection |
| Broche 8 | NC — Not connected |
Applications typiques
LM211DT convient pour 6 applications: Industrial Sensor Threshold Detection, Overvoltage and Undervoltage Supervision, Relay and Solenoid Interface, Level Translation and Logic Interface, Power Converter Feedback and Limit Detection, Precision Window Comparator.
Industrial Sensor Threshold Detection
The LM211DT fits industrial sensor threshold detection because its low input current reduces loading on high-impedance dividers and sensing networks, while its 200 ns response time converts slow analog transitions into timely logic events. Place the comparator across a scaled sensor signal and add hysteresis when noise could cause repeated output transitions. The open-collector OUT pin can feed a PLC input or another logic family through a suitable pull-up. Its 5 V to ±15 V operating range supports both field-level logic and dual-rail analog systems.
Recommandé
Overvoltage and Undervoltage Supervision
For supply supervision, the LM211DT compares a divided supply voltage against a reference and changes the open-collector output when the monitored rail crosses the selected limit. The 200 ns response time supports fast fault signaling, while operation from single 5 V through dual ±15 V covers a broad range of monitored systems. Add input filtering and controlled hysteresis to prevent repeated switching from ripple. Confirm the pull-up voltage remains within the output and downstream-device limits during normal operation.
Recommandé
Relay and Solenoid Interface
The LM211DT can provide the decision stage that drives a relay, solenoid, or other inductive load when the control system operates at a voltage or current outside the LM211 output stage's capability. Its open-collector output can sink the input current of an appropriate driver rather than directly powering a large load. The 200 ns propagation delay helps minimize switching delay, and the STROBE control can support coordinated system timing. Use a flyback path and a driver rated for the load instead of connecting an inductive load directly to OUT.
Recommandé
Level Translation and Logic Interface
The LM211DT is useful for level translation when a sensor or analog front end must produce a logic-compatible event for TTL, DTL, RTL, or MOS circuitry. Its output is compatible with several logic families, and the open-collector configuration allows the pull-up rail to be selected for the receiving system. Low input current is valuable when the source impedance is high. Verify input common-mode voltage, output sink current, and pull-up rise time at the intended clock or event rate before finalizing the interface.
Recommandé
Power Converter Feedback and Limit Detection
In power-converter control and protection, the LM211DT can compare a scaled output or feedback node with a reference to detect an out-of-range condition. Its 200 ns response reduces delay between crossing the threshold and issuing a system event, while the wide supply range permits use in both single-rail and split-rail environments. The open-collector output can pull down a status or shutdown node with a pull-up. Keep switching-node transients away from the input pins and use a stable reference to avoid nuisance trips.
Recommandé
Precision Window Comparator
The LM211DT can implement a precision window comparator when one device compares the monitored voltage with an upper threshold and another section or channel handles the lower threshold. Its single-comparator architecture makes it straightforward to combine several devices around a reference and switching network. Low input current limits the error introduced by high-value resistors, and the 200 ns response supports rapid state transitions. Use positive feedback for hysteresis and carefully account for the open-collector pull-up network when defining both trip points.
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Récapitulatif des produits recommandés
Données de référence d'ingénierie pour LM211DT — comparaison, recommandations de conception et informations de conformité.
Guide de sélection
Comparaison avec les alternatives
| Paramètre | Ce produit | LM311DT | LM311DG |
|---|---|---|---|
| Package | 8-pin SOIC | 8-pin SOIC | 8-pin SOIC |
| Brand | STMicroelectronics | Texas Instruments | Texas Instruments |
| Comparator Type | Single general-purpose voltage comparator | Single general-purpose voltage comparator | Single general-purpose voltage comparator |
| Supply Voltage Range | 5 V to ±15 V | 5 V to ±15 V | 5 V to ±15 V |
| Output Type | Open-collector | Open-collector | Open-collector |
| Input Current | Low input current | Low input current | Low input current |
| Strobe Control | Yes | Yes | Yes |
| Logic Compatibility | TTL, DTL, RTL, MOS, open-collector, and open-emitter compatible | TTL, DTL, RTL, MOS, open-collector, and open-emitter compatible | TTL, DTL, RTL, MOS, open-collector, and open-emitter compatible |
Principaux différenciateurs
- STMicroelectronics-specified LM211-family behavior (vs LM311DT)
- Low-current sensing interface (vs LM311DG)
- Broad logic-system interoperability (vs LM311DT)
Notes de conception
Treat OUT as an open-collector node rather than a push-pull logic output. Install the required pull-up resistor to the positive logic rail, and verify that its voltage, resistance, and resulting rise time satisfy both the LM211DT sink-current rating and the receiving circuit's timing requirements. Failure to install the pull-up or using a pull-up outside the output-voltage limits can prevent a valid high state or cause excess output current.
Keep the comparator input traces short and away from switching nodes, relay-coil wiring, and high-current supply paths. Connect the ground reference directly to the device ground and use a compact, stable reference network for the threshold circuit. If the inputs monitor a high-impedance source, minimize leakage from board contamination and neighboring signals. These layout practices reduce threshold shifts and false transitions that can otherwise appear as unreliable sensor behavior.
Use positive feedback or a controlled hysteresis network when the compared signals can cross the threshold slowly or contain noise. Hysteresis prevents repeated open-collector transitions near the switching point, while the 200 ns propagation delay remains relevant for fast edge cases. Calculate the hysteresis from the resistor network and account for input offset because excessively narrow hysteresis can still be overwhelmed by comparator error or supply variation.
For single 5 V operation, connect V− to ground and place bypass capacitance close to the supply pins. For dual ±15 V operation, route both rails with low-impedance connections and check input common-mode limits throughout the transition between power states. The open-collector output can remain in a defined state only when its pull-up supply and the device's supply sequencing are designed correctly, so verify the system state during power-up and power-down.
Informations de conformité
The STMicroelectronics datasheet states that the devices are offered in different grades of ECOPACK packages depending on environmental compliance, but no specific compliance status is stated for LM211DT in the available product information.