LM111-LM211 - High-Speed Differential Comparator | Texas Instruments
MPN: LM111-LM211 ✗ End of Life| Qty | Unit Price | Extended |
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| 1 | $0 | $0.00 |
| 10 | $0 | $0.00 |
| 100 | $0 | $0.00 |
| 500 | $0 | $0.00 |
| 1,000 | $0 | $0.00 |
LM111-LM211 Overview
A voltage comparator is an analog integrated circuit that compares two input voltages and produces a digital logic state indicating which input is higher. In the broader electronics hierarchy, a differential comparator belongs to comparator ICs, analog-to-digital decision interfaces, and signal-conditioning semiconductors. It is commonly used where a sensor, reference voltage, timing ramp, or control signal must be translated into a logic-level event.
The LM111, LM211, and LM311 devices are described by Texas Instruments as single high-speed voltage comparators. Their low input currents are useful when the driving source has high impedance or when input bias current could otherwise create measurement errors. The family supports conventional ±15 V supplies and +5 V logic-system operation, making it suitable for legacy analog, control, timing, and industrial interface circuits. Output levels are compatible with most TTL and MOS circuits, although the open-collector output requires an appropriate pull-up arrangement.
The LM111, LM211, and LM311 differ primarily in their specified operating-temperature families: TI identifies the LM111-N as specified from −55°C to +125°C, the LM211-N from −25°C to +85°C, and the LM311-N from 0°C to +70°C. The target string LM111-LM211 is therefore a family or ordering designation rather than one uniquely specified package-and-temperature variant. The exact commercial suffix, package, pin configuration, and current availability must be confirmed against the selected manufacturer orderable part.
Typical uses include precision voltage thresholding, zero-crossing detection, peak detection, window comparison, pulse timing, sensor interface conditioning, and control logic interfacing. The comparator is placed between a signal source and a downstream TTL or MOS input, with its output configured to drive the receiving device through a suitable pull-up or interface network. Engineers should verify supply polarity, input common-mode limits, output pull-up voltage, switching behavior, and input offset requirements in the manufacturer datasheet before layout release.
The key design consideration is that an open-collector comparator is not a push-pull logic driver. The output node floats when the device is off, so the external pull-up resistor, pull-up voltage, load capacitance, and required logic rise time must be selected together. Input filtering and grounding are also important when the comparator is used near precision thresholds or noisy switching nodes. This page distinguishes verified family-level facts from parameters that require a specific package and orderable suffix.
This page synthesizes the verified manufacturer and distributor references for the LM111-LM211 family, separates documented family-level capabilities from orderable-device requirements, and highlights the design decisions that determine whether an open-collector comparator is suitable in a given circuit. The alternatives listed here are limited to parts explicitly supported as same-family or comparator cross-reference candidates; exact replacement must be checked against the selected package and suffix.
Drop-in alternatives for LM111-LM211 — 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 LM111-LM211 (same form factor and footprint) — differing in Product Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LM311
✅ Drop-In📋 Reference alternative (not in catalog)
LM111-N
✅ Drop-In📋 Reference alternative (not in catalog)
LM211-N
✅ Drop-In📋 Reference alternative (not in catalog)
LT111A
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →NTE922
✅ Drop-In✓ In Stock
$10.136 / Unit
View Datasheet →LM111-LM211 Maximum Ratings & Electrical Characteristics
| Product Type | Single differential voltage comparator |
| Comparator Family | LM111, LM211, LM311 |
| Supply Compatibility | ±15 V and single +5 V supplies |
| Input Configuration | Differential |
| Input Current | Low input current; exact maximum value depends on selected variant |
| Output Type | Open-collector |
| Logic Compatibility | Compatible with most TTL and MOS circuits |
| LM111-N Operating Temperature | −55°C to +125°C |
| LM211-N Operating Temperature | −25°C to +85°C |
| LM311-N Operating Temperature | 0°C to +70°C |
| LM111-N Pin Configuration | Same as LM106 and LM710, according to TI product information |
| Typical Applications | Precision squaring and peak detection |
| Comparator Function | Compares two input voltages and provides a logic output |
| RoHS Status | unknown |
| REACH Status | unknown |
| AEC-Q100 Qualification | unknown |
LM111-LM211 standard Pin Configuration Guide
Pin configuration for LM111-LM211 (standard 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 LM111-LM211.
Refer to the datasheet for full pin configuration.
Typical Applications
LM111-LM211 is suitable for 6 applications: Precision Voltage Thresholding, Peak Detection, TTL and MOS Logic Interfacing, Zero-Crossing Detection, Sensor Signal Conditioning, Pulse and Timing Control.
Precision Voltage Thresholding
LM111-LM211 fits threshold detection when a low-input-current comparator can monitor a high-impedance reference or sensor node without excessive bias error. The verified TI family description supports differential comparison, while the listed precision-squaring and peak-detection use cases indicate suitability for accurate switching decisions. Place the reference on one input and the sensed signal on the other, then use the open-collector output with a pull-up for the following logic stage. Confirm the selected variant's input offset, common-mode range, and propagation delay before setting the threshold, because those values were not included in the supplied web data.
Recommended
Peak Detection
The LM111-LM211 can serve in peak-detection circuits where a varying waveform is compared against a stored or slowly changing reference level. Its low input current helps reduce loading when the source impedance is high, and its single differential input pair simplifies the decision function. The open-collector output can be pulled up and latched or processed by external logic. Validate the comparator's offset voltage, slew behavior, and recovery from overload for the particular waveform, because the supplied verified data confirms the function but not the complete dynamic-response limits.
Recommended
TTL and MOS Logic Interfacing
LM111-LM211 is appropriate for interfacing analog decisions to digital systems because TI explicitly states that the family output levels are compatible with most TTL and MOS circuits. The open-collector output requires an external pull-up, allowing the interface voltage to match the receiving logic rather than forcing one fixed output voltage. Select the pull-up supply and resistor based on sink-current, rise-time, and load-capacitance requirements. The verified family data does not provide the complete output-current table, so the selected suffix datasheet must be used for the final interface calculation.
Recommended
Zero-Crossing Detection
A LM111-LM211 comparator can detect the point at which a bipolar or offset signal crosses a reference, providing a digital transition for timing and control circuits. The differential inputs allow the signal and reference to be compared directly, while the open-collector output can trigger external logic through a pull-up. In practical designs, account for input noise, reference offset, propagation delay, and output rise time; these can determine the accuracy and repeatability of the crossing event. The verified TI material confirms the comparator function but does not quantify every timing parameter for every suffix.
Recommended
Sensor Signal Conditioning
LM111-LM211 can convert a sensor-derived voltage into a logic event when the sensor output requires thresholding rather than amplification. Its low input current is advantageous for high-impedance sensing networks, and the wide supply range supports both analog-style and logic-oriented rails. Place the sensor signal and precision reference on the differential inputs, add filtering appropriate to the sensor bandwidth, and use the open-collector output to drive a pull-up or latch. Verify input common-mode limits and offset for the exact LM111, LM211, or LM311 suffix before use.
Recommended
Pulse and Timing Control
The LM111-LM211 family can generate a clean timing event by comparing a ramp, oscillator, or pulse-derived voltage against a control reference. The resulting open-collector transition can feed a timer, flip-flop, or other logic circuit after adding the required pull-up. Designers should use hysteresis or positive feedback when the compared signal has noise or a slow crossing slope, otherwise output chatter can degrade timing accuracy. The comparator's response time and input offset must be checked in the selected datasheet before setting narrow pulse widths or high repetition rates.
Recommended
Recommended Products Summary
Engineering reference data for LM111-LM211 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LM311 | LM111-N | LM211-N | LT111A | NTE922 |
|---|---|---|---|---|---|---|
| Comparator Type | Single differential voltage comparator | Single differential voltage comparator | Single differential voltage comparator | Single differential voltage comparator | Improved general-purpose comparator | Comparator replacement candidate; detailed data not supplied |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices | NTE |
Key Differentiators
- Temperature-grade choice within the documented comparator family (vs LM311)
- Wide supply compatibility (vs LT111A)
- Low-input-current differential comparison (vs LT111A)
Design Notes
Do not treat LM111-LM211 as a fully specified single orderable part until the exact suffix and package are selected. The family includes LM111, LM211, and LM311 variants with different temperature specifications. Confirm the package drawing, pin configuration, supply limits, input ratings, and output-current limits before releasing a PCB layout. TI specifically identifies LM111-N as having the same pin configuration as LM106 and LM710, but that statement does not determine every package variant in the family.
Because the comparator uses an open-collector output, add an external pull-up resistor sized for the receiving logic's input current, voltage level, capacitance, and required rise time. Keep the pull-up connection short where possible to reduce output-node capacitance and ringing. Verify the comparator sink-current rating and the receiver's input thresholds in the selected suffix datasheet. The supplied verified data confirms TTL/MOS compatibility but does not provide a universal pull-up value.
Route the comparator inputs as short, guarded traces and keep them away from switching-node and high-current return paths. Use a stable reference node and provide local bypassing according to the selected device's recommended application circuit. If the input source has high impedance, minimize leakage from adjacent boards and connectors because even low specified input current can create a meaningful voltage error. Hysteresis can reduce repeated output transitions when the input crosses the threshold slowly or contains noise.
Use the supply arrangement required by the selected LM111, LM211, or LM311 suffix, including correct polarity and bypass placement. The family is documented for ±15 V and single +5 V operation, but those examples do not replace the complete minimum and maximum supply ratings. Check input common-mode voltage and output pull-up voltage independently; a valid supply rail does not guarantee that the input signal or pull-up node remains within the selected comparator's limits.
Do not select LM311 as a universal replacement for an LM211 design when the system must operate above +70°C. TI documents LM311-N at 0°C to +70°C and LM211-N at −25°C to +85°C. Likewise, LM111-N covers −55°C to +125°C, so it may be required for wider temperature environments. Validate temperature grade, electrical ratings, package, and availability independently rather than relying only on the family name.
Compliance Information
The supplied verified data does not state RoHS, REACH, AEC-Q100, lead-free, halogen-free, or conflict-minerals status for LM111-LM211. These values must be verified for the exact orderable suffix.
