MAX136CMH - 3½-Digit LCD ADC with Hold | Analog Devices
料号： MAX136CMH ✓ 量产中MAX136CMH 概述
An analog-to-digital converter, or ADC, converts an analog input voltage into a numeric representation for measurement, display, or further processing. The MAX136 belongs to the family of low-power, high-resolution integrating converters used in digital panel meters, laboratory instruments, weighing systems, and temperature-measurement equipment. Its 3½-digit architecture provides 1999-count resolution, while the high input impedance minimizes loading of the sensing circuit.
The MAX136's most distinctive feature is a Hold pin that can freeze or retain a conversion result. Unlike the Maxim ICL7136, the MAX136 includes this function, allowing a reading to remain stable while it is inspected or transferred. The device also directly drives nonmultiplexed LCD outputs, eliminating separate LCD driver hardware when the selected display uses the compatible segment arrangement.
Because the MAX136 uses a dual-slope integration technique, its performance depends on accurate reference and integration components. The manufacturer's datasheet describes the MAX136 as pin compatible with the Maxim ICL7136 after minor external component changes. That compatibility involves reviewing the Hold implementation and associated passive components rather than assuming an unconditional, board-for-board substitution.
Typical uses include digital laboratory meters, industrial panel indicators, environmental monitors, laboratory scales, process readouts, and portable instruments. In each application, the high-input-impedance measurement stage can be paired with a resistive divider or sensor bridge without loading the source significantly. The LCD output reduces system complexity in designs centered on a local numeric display.
For a new design, follow the reference, integration, analog-input, and display connections in the manufacturer datasheet. Pay particular attention to bypass capacitors, input filtering, PCB cleanliness, and the Hold timing. When replacing an ICL7136-based assembly, review the changed external components and verify the LCD segment mapping rather than relying on package similarity alone.
This page combines the MAX136CMH device identity, package information, application guidance, design cautions, and available drop-in candidates into an engineering-focused guide. It also distinguishes confirmed family variants from a replacement that requires external circuit changes, helping designers make a controlled compatibility decision before committing a PCB revision.
直接替换替代料： MAX136CMH ——相同封装，引脚兼容。需要 PCB 改动的不同封装料号已排除。
MAX136CMH+D
✅ 直接替换📋 参考替代料（不在目录中）
MAX136CMH+TD
✅ 直接替换📋 参考替代料（不在目录中）
MAX136CMH+
✅ 直接替换 ⚠️ 规格未核验📋 参考替代料（不在目录中）
MAX136CMH 最大额定值与电气特性
| ADC Type | Monolithic dual-slope analog-to-digital converter |
| 分辨率 | 3½ digits, 1999 counts |
| Input Type | Single-ended analog voltage input |
| Display Output | Direct nonmultiplexed LCD drive |
| Hold Function | Yes |
| 封装 | 44-pin MQFP, 10 mm x 10 mm |
| Terminal Count | 44 terminals |
| Terminal Form | Gull-wing leads |
| Package Shape | Square |
| 安装类型 | Surface mount |
| Production Status | Production |
MAX136CMH square 引脚配置指南
MAX136CMH（square 封装）的引脚配置。 该模拟元件具有输入、输出和电源引脚。请参阅制造商数据手册以了解失调调零、补偿和使能引脚配置。适用于信号调理和放大器电路。
暂无详细引脚数据： MAX136CMH.
请参阅 数据手册 以查看完整引脚配置。
典型应用
MAX136CMH 适用于 6 应用s: Digital Laboratory Panel Meter, Environmental Monitoring Instrument, Portable Weighing Scale Readout, Process Monitoring Readout, Portable Temperature Indicator, Handheld Test and Measurement Meter.
Digital Laboratory Panel Meter
The MAX136CMH fits a standalone laboratory meter because it combines a 3½-digit, 1999-count conversion system with direct nonmultiplexed LCD drive. The high-impedance measurement input helps preserve the signal from a resistive divider or sensor interface, while the Hold function can stabilize the reading during adjustment or observation. Place the reference and bypass components close to the device and follow the manufacturer's application circuit for display-drive and analog filtering details.
推荐
Environmental Monitoring Instrument
The MAX136CMH is suitable for a local environmental readout that measures a scaled sensor voltage and displays the result on a nonmultiplexed LCD. Its 3½-digit format provides 1999-count resolution without requiring a separate display-driver IC. The high-impedance input reduces errors in resistive probes, while Hold allows the displayed value to remain fixed during sample checks. Verify the input range, reference network, segment mapping, and calibration procedure in the manufacturer datasheet.
推荐
Portable Weighing Scale Readout
The MAX136CMH can provide the local numeric readout for a compact weighing-scale front panel. A load-cell signal can be conditioned into a voltage compatible with the converter, and the 3½-digit display can communicate a 1999-count measurement directly. The Hold pin is useful when a value must remain stable during inspection. The design must follow the recommended input filter and reference layout to prevent noise or drift from appearing as measurement variation.
推荐
Process Monitoring Readout
The MAX136CMH is useful in industrial process-monitoring equipment that converts a conditioned sensor signal into a local 3½-digit LCD indication. The integrated display drive simplifies instrument construction, and the high-impedance input helps avoid loading the measuring circuit. The Hold function supports temporary freezing of a reading during adjustment. For reliable operation, isolate the analog input from switching nodes, maintain the recommended bypass arrangement, and confirm the display's nonmultiplexed segment configuration.
推荐
Portable Temperature Indicator
The MAX136CMH can serve as the display and conversion engine in a portable temperature indicator driven by a resistive or ratiometric sensor. Its 3½-digit readout provides useful resolution for panel-style instruments, while the high-impedance input helps maintain sensor accuracy. Because the converter drives a nonmultiplexed LCD directly, the display interface remains compact. Review the input common-mode range, reference stability, and calibration method before selecting component values around the MAX136CMH.
推荐
Handheld Test and Measurement Meter
The MAX136CMH suits a handheld meter where low component count and a direct LCD readout are priorities. Its low-power 3½-digit architecture integrates measurement conversion and display drive in one 44-pin MQFP, while the Hold input lets an operator retain a measurement. The converter can be paired with resistive dividers or buffered sensor inputs, provided the electrical limits and reference requirements are followed. Layout work should emphasize short analog traces, stable grounding, and correct LCD segment assignment.
推荐
推荐产品汇总
工程参考数据： MAX136CMH ——对比、设计指导和合规信息。
选型指南
与替代料对比
| 参数 | 本产品 | MAX136CMH+D | MAX136CMH+TD | MAX136CMH+ |
|---|---|---|---|---|
| Package | 44-MQFP (10 mm x 10 mm) | 44-MQFP (10 mm x 10 mm) | 44-MQFP (10 mm x 10 mm) | 44-MQFP (10 mm x 10 mm) |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Converter Type | Monolithic dual-slope ADC | MAX136 family dual-slope ADC | MAX136 family dual-slope ADC | MAX136 family dual-slope ADC |
| Resolution | 3½ digits, 1999 counts | 3½ digits | 3½ digits | 3½ digits |
| Hold Function | Yes | Yes | Yes | Yes |
| LCD Drive | Direct nonmultiplexed LCD drive | Direct nonmultiplexed LCD drive | Direct nonmultiplexed LCD drive | Direct nonmultiplexed LCD drive |
| Pin Compatibility | MAX136 family, 44-pin MQFP | Same MAX136 family footprint | Same MAX136 family footprint | Same MAX136 family footprint |
关键差异点
- Adds a dedicated Hold function to the compatible MAX136 family （对比 ICL7136CMH)
- Integrates nonmultiplexed LCD drive with 3½-digit conversion （对比 ICL7136CMH)
- Direct 44-MQFP family sourcing within the MAX136 line （对比 ICL7136CMH)
设计说明
Route the analog input and reference paths as short, quiet traces, with the associated external components placed close to the MAX136CMH pins. Keep LCD output routing separated from the measurement input where practical, and avoid sharing high-current return paths directly beneath the converter. Start from the manufacturer's application circuit and preserve the recommended grounding topology.
Do not treat ICL7136CMH as a board-for-board replacement without reviewing the external-component changes associated with the MAX136 Hold function. Confirm the LCD segment mapping, Hold timing, reference network, and bypass connections. A matching 44-pin package establishes physical compatibility, but it does not by itself prove identical system behavior.
The high-impedance measurement input can pick up leakage and noise if the surrounding PCB is not clean. Use the recommended input filtering, guard or shield techniques where appropriate, and keep moisture or contamination away from the analog section. Check the reference potential and input common-mode limits against the operating range before finalizing the sensor interface.
Follow the manufacturer guidance for supply bypassing and clock-generation components rather than selecting values solely from generic dual-slope ADC examples. Decoupling capacitors should be placed at the relevant supply pins with short ground returns. Verify the actual supply range, clock amplitude, and reference voltage before committing the power subsystem.
合规信息
The MAX136 family is listed as production, but no explicit RoHS, REACH, lead-free, halogen-free, or conflict-minerals declarations were identified for the exact MAX136CMH ordering code.
