LT111A - 250ns Voltage Comparator | Analog Devices
MPN： LT111A ✗ 停產LT111A 概覽
A voltage comparator is an integrated circuit that determines whether an input voltage is above or below a reference level, producing a logic output suitable for control, monitoring, or switching decisions. The LT111A belongs to the comparator family within analog integrated circuits and power-management control systems. Unlike an operational amplifier intended primarily for linear amplification, the comparator is optimized for fast, saturated output transitions and threshold decisions.
The LT111A improves on the LM111 general-purpose comparator according to the manufacturer datasheet. Its headline specifications include 1.0 mV maximum input offset voltage, 5.0 nA maximum input offset current, and 250 ns maximum response time. The input stage accepts differential input signals up to ±30 V, while the output can drive loads up to 50 mA referenced to ground or either supply, as stated in the datasheet search data.
The component includes offset balancing and strobe capability. A separate output ground pin allows the output reference to be selected independently of the circuit ground, which is useful when interfacing to systems with different output-return requirements. The output can also be combined for OR-style logic, although exact implementation depends on the surrounding circuit and output configuration.
Typical uses include precision threshold detection, sensor signal conditioning, window comparison, overvoltage indication, zero-crossing detection, and industrial control systems. The 250 ns response is suitable for systems that need faster decisions than general-purpose slow comparators while retaining wide input-voltage capability.
Designers must account for the obsolete lifecycle status, supply arrangement, input common-mode limits, output polarity, and thermal constraints. The verified manufacturer result identifies LT111A as obsolete and directs users to contact Analog Devices for a replacement product. New designs should therefore confirm availability, lifecycle status, and any recommended replacement before committing to production.
This page consolidates the verified manufacturer specifications, obsolete-status notice, package information, design guidance, and sourcing limitations for engineers comparing the LT111A with legacy comparator systems.
直接替換替代品，適用於 LT111A — 相同封裝，腳位對腳位相容。需重新設計 PCB 的不同封裝零件不列入。
此系列的變體
與下列產品可直接替換的同系列型號： LT111A （相同外形與佔位） — 差異在於 Product Type, AEC-Q100 Qualification, Comparator Family, Maximum Input Offset Current, Maximum Input Offset Voltage.
LT1011A
✅ 直接替換📋 參考替代品（不在目錄中）
LT111A 最大額定值與電氣特性
| Product Type | General-purpose voltage comparator |
| Maximum Input Offset Voltage | 1.0 mV |
| Maximum Input Offset Current | 5.0 nA |
| Maximum Response Time | 250 ns |
| Supply Configuration | Single 5 V to ±15 V |
| Differential Input Signal Range | ±30 V |
| Maximum Output Load Current | 50 mA referenced to ground or either supply |
| Output Ground | Separate output ground pin |
| Input Offset Balancing | Supported |
| Strobe Capability | Supported |
| Output OR Capability | Supported |
| Positive Input Voltage Limit | 30 V above negative supply |
| Negative Input Voltage Limit | Negative supply |
| Maximum Junction Temperature | 150 °C |
| 封裝 | TO-5 |
LT111A to-5 腳位配置指南
LT111A（to-5 封裝）的腳位配置。 此類比元件具有輸入、輸出與電源腳位。偏移歸零、補償與致能腳位配置請參閱製造商資料表。適用於訊號調理與放大器電路。
無詳細腳位定義資料： LT111A.
請參閱 資料表 以查看完整腳位配置。
典型應用
LT111A 適用於 7 應用s: Precision Threshold Detection, Sensor Signal Conditioning, Overvoltage and Fault Detection, Industrial Control Logic, Zero-Crossing Detection, Window and Limit Comparison, Legacy Test and Measurement.
Precision Threshold Detection
LT111A is suitable for threshold detection because the manufacturer specifies a maximum input offset voltage of 1.0 mV and a maximum response time of 250 ns. Place the sensed signal on one input and a reference voltage on the other, then use the output to trigger a control, alarm, or state transition. The comparison threshold can be affected by input offset, bias current, resistor tolerances, and supply variation, so the reference network should be evaluated rather than assumed ideal.
推薦
Sensor Signal Conditioning
LT111A can convert a sensor-derived voltage into a clean logic decision when the sensor output crosses a defined limit. Its 5.0 nA maximum input offset current and 1.0 mV maximum input offset voltage provide defined starting points for input-stage design, while the 250 ns maximum response supports relatively prompt threshold events. Protection, filtering, input common-mode range, and grounding should be added around the sensor interface before deployment.
推薦
Overvoltage and Fault Detection
The LT111A can monitor a power rail or control node and generate an overvoltage indication when the input exceeds a reference threshold. The separate output ground is useful when the comparator output must be referenced to a different return point, while the 250 ns maximum response can provide fast fault signaling. For safety-critical or high-energy systems, add independent filtering, appropriate resistor ratings, and a qualified replacement strategy because LT111A is obsolete.
推薦
Industrial Control Logic
LT111A is applicable to industrial control logic when a comparator is needed to translate an analog condition into a switching command. Its single 5 V through ±15 V supply capability supports different supply arrangements, and the output can drive up to 50 mA loads referenced to ground or either supply. The obsolete lifecycle status requires lifecycle confirmation and a manufacturer-approved alternative before new production equipment is released.
推薦
Zero-Crossing Detection
LT111A can be used to detect when an analog waveform crosses a reference level, with its 250 ns maximum response providing a defined propagation-time basis. The input stage accepts differential signals up to ±30 V according to the verified material, but external attenuation or protection may still be required. Check the selected supply, input voltage limits, output polarity, and external load before using the comparator in waveform or timing systems.
推薦
Window and Limit Comparison
By combining threshold comparisons and logic functions, LT111A can support upper-limit, lower-limit, or window decisions. Its offset-balancing capability can help reduce threshold mismatch when appropriately connected, while the separate output ground provides flexibility in mixed-signal return paths. The circuit must be evaluated for logic overlap, noise margin, propagation delay, and the input and output limits specified by the manufacturer datasheet.
推薦
Legacy Test and Measurement
LT111A is relevant to existing test and measurement equipment that uses a discrete general-purpose comparator for trigger, limit, or polarity decisions. The verified specifications provide useful references for repair and redesign: 1.0 mV maximum input offset voltage, 5.0 nA maximum input offset current, and 250 ns maximum response time. Because the product is obsolete, preserve the original datasheet and verify the exact replacement before changing calibrated equipment.
推薦
推薦產品摘要
工程參考資料，適用於 LT111A — 比較、設計指引及合規資訊。
選型指南
與替代品比較
| 參數 | 本產品 | LT1011A | LM111 |
|---|---|---|---|
| Product Type | General-purpose voltage comparator | General-purpose comparator | General-purpose comparator |
| Package | TO-5 | TO-5 - verify exact package suffix | TO-5 - verify exact package suffix |
| Brand | Analog Devices | Analog Devices | Texas Instruments |
主要差異化特點
- Improved LM111 comparator positioning (對比LM111)
- Wide differential input capability (對比LM111)
- Separate output-ground flexibility (對比LT1011A)
設計說明
Do not treat LT111A as a drop-in replacement solely because it is an LM111-family comparator. The verified material says LT111A is an improved version of the LM111, but it does not provide a complete pin and parameter equivalence table. Verify package suffix, pin functions, output architecture, input common-mode range, supply limits, propagation behavior, and output loading against the exact alternative datasheet before releasing a PCB or production order.
Keep comparator input traces short and away from high-current switching nodes because a 1.0 mV maximum input offset specification is only one contributor to real threshold accuracy. Place the threshold-setting components close to the input pins, use a low-value, low-noise reference path where appropriate, and provide a clean return for the separate output-ground pin. Ground-loop current can shift the decision point even when the comparator itself is operating correctly.
The LT111A supports single 5 V through ±15 V supplies according to the verified manufacturer data, but the external circuit must respect the positive and negative input limits. The positive input limit is 30 V above the negative supply, while the negative input limit is the negative supply. Confirm the complete operating condition, including output state and load, before applying external signals or connecting the output to another supply domain.
合規資訊
The supplied manufacturer material identifies LT111A as obsolete but does not provide RoHS, REACH, lead-free, halogen-free, conflict-minerals, or AEC-Q100 status. Values remain unknown rather than inferred.
