ICL7137CMH - 3.5-Digit LED ADC | Maxim Integrated
MPN： ICL7137CMH ✓ 啟用中ICL7137CMH 概覽
An integrated 3.5-digit LED display ADC is a specialized data-converter and display-control component. It combines analog measurement, digital counting, and display drive functions in one monolithic device. The dual-slope conversion technique used by the ICL7137 integrates the input voltage over a fixed interval, rejecting periodic noise and providing accurate results for slow-moving or repetitive measurements. This architecture fits the hierarchy ADC > data converter > integrated circuit > semiconductor.
The defining feature of the ICL7137 is direct LED-display support. Unlike a general-purpose ADC that outputs only a digital code, the device includes the active circuitry needed to illuminate a multiplexed seven-segment display. The 3.5-digit format supports readings from negative 999 through positive 999, subject to the detailed reference, input, and operating conditions in the manufacturer datasheet. Its low supply current makes it especially relevant to handheld meters, panel instruments, and portable measurement systems.
Dual-slope conversion offers useful advantages for panel meters because its accuracy does not depend on a high-frequency clock being multiplied into the measurement result in the same way as many successive-approximation converters. The averaging behavior helps attenuate periodic interference. The manufacturer describes versatility and accuracy as inherent features of the converter, while the integrated clock, reference, counter, and display-driver functions reduce the external component count required for a complete measurement instrument.
Typical implementations include digital multimeters, laboratory panel meters, temperature-measurement instruments, process-monitoring displays, laboratory equipment, and battery-powered meters. The direct LED interface is especially valuable when a readable numerical display is required at the point of measurement. Such systems can use the converter without adding a separate display decoder or segment driver, reducing board area and simplifying firmware requirements.
The main design considerations are reference stability, input-range implementation, display current, layout, and timing. The input and reference networks must be designed around the electrical limits specified by the manufacturer datasheet. Display resistors and LED current determine brightness and power consumption, while the under-200-uA supply-current figure explicitly excludes display current. PCB placement should keep analog input, reference, and clock paths away from display-return currents and switching nodes.
This page organizes the ICL7137CMH specifications, package information, sourcing path, practical use cases, and verified same-footprint alternatives. It also separates the low converter supply consumption from the additional power demanded by the LED display, helping engineers evaluate both instrument accuracy and battery-life requirements before selecting the ADC and display circuitry.
直接替換替代品，適用於 ICL7137CMH — 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。
ICL7137CMH+D
✅ 直接替換📋 參考替代品（不在目錄中）
ICL7137CMH-D
✅ 直接替換📋 參考替代品（不在目錄中）
ICL7137CMH 最大額定值與電氣特性
| Converter Type | Monolithic dual-slope ADC |
| 解析度 | 3.5 digits |
| Channel Count | 1 channel |
| Display Interface | Direct LED display interface |
| 供應電流 | Less than 200 uA, excluding LED display current |
| 封裝 | 44-pin MQFP |
| Package Dimensions | 10 x 10 mm |
| Terminal Count | 44 terminals |
| Package Shape | Square |
| Lead Form | Gull wing |
| Temperature Grade | Commercial |
| 工作溫度 | 0 C to 70 C |
| Input Voltage | 2.6 V to 3.2 V |
| Screening Level | Commercial |
| RoHS Compliance | Compliant |
| 安裝類型 | Surface mount |
| Integrated Functions | LED display driver, dual-slope ADC, and clock circuitry |
| Conversion Technique | Dual-slope |
ICL7137CMH square 腳位配置指南
ICL7137CMH（square 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： ICL7137CMH.
請參閱 資料表 以查看完整腳位配置。
典型應用
ICL7137CMH 適用於 6 應用s: Digital Multimeter Display, Battery-Powered Panel Meter, Laboratory Measurement Instrument, Process Monitoring Display, Temperature Measurement Instrument, Service and Field-Test Meter.
Digital Multimeter Display
The ICL7137CMH fits a digital multimeter because it combines a 3.5-digit dual-slope ADC with active circuitry for directly driving an LED display. The converter itself draws less than 200 uA when display current is excluded, allowing a portable meter to allocate most of its power budget to the measurement and display functions. The 44-pin MQFP package provides separate connections for the measurement system and display drive. Designers should calculate total display consumption separately, size the segment resistors for the intended brightness, and verify the converter’s reference and input network in the manufacturer datasheet.
Battery-Powered Panel Meter
A battery-powered panel meter benefits from the ICL7137CMH’s less-than-200-uA converter supply current, measured without the external LED display load. The monolithic 3.5-digit conversion and display-drive approach reduces the circuitry needed beside the display and simplifies instrument construction. Because the operating range is 0 C to 70 C for the commercial version, the enclosure and battery chemistry must remain within that range. Final battery-life estimates should include average LED segment current, conversion frequency, and any reference or input-network consumption.
Laboratory Measurement Instrument
The ICL7137CMH is suitable for a laboratory instrument that presents a direct numerical reading without a separate display processor. Its dual-slope conversion method supports stable measurement of slowly changing analog inputs, while the integrated LED drive simplifies the display subsystem. The 44-pin MQFP provides a compact surface-mount solution for a multi-function instrument. Reference layout, input filtering, clock source, and display-return current separation should be reviewed against the manufacturer application guidance before production release.
Process Monitoring Display
In process-monitoring equipment, the ICL7137CMH can convert a sensor or conditioned analog signal into a readable 3.5-digit LED display. Direct display drive is valuable where an operator needs a local measurement indication and a separate controller would add unnecessary complexity. The commercial 0 C to 70 C range fits controlled indoor equipment, while the input and reference circuitry should use the measurement range required by the process signal. LED brightness and filtering should be selected for the viewing environment.
Temperature Measurement Instrument
The ICL7137CMH can form the display front end of a temperature-measurement instrument when the sensor signal is conditioned into the converter’s supported input range. The 3.5-digit format suits practical thermometers, test equipment, and temperature controllers that display a bounded value. Its low converter supply current helps portable designs, and the integrated LED interface reduces the number of dedicated display-driver components. Calibration offsets, sensor linearity, reference accuracy, and display resolution should be evaluated together when choosing the required measurement range.
Service and Field-Test Meter
The ICL7137CMH is appropriate for a rugged field-test meter requiring an immediately readable LED indication. The dual-slope conversion system and 3.5-digit display combine measurement and presentation in one monolithic component, while the less-than-200-uA converter current supports battery-operated instruments. In field use, the display brightness may need to exceed laboratory brightness to remain readable, increasing total consumption above the converter-only figure. The commercial temperature range also requires attention where ambient conditions can fall outside 0 C to 70 C.
工程參考資料，適用於 ICL7137CMH — 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 | ICL7137CMH+D | ICL7137CMH-D |
|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Maxim Integrated |
| Package | 44-pin MQFP, 10 x 10 mm | 44-MQFP, 10 x 10 mm | QFP-44, 10 x 10 mm |
| Converter Type | Dual-slope ADC | Dual-slope ADC | Dual-slope ADC |
| Resolution | 3.5 digits | 3.5 digits | 3.5 digits |
| Display Interface | Direct LED display interface | Direct LED display interface | Direct LED display interface |
| Special Feature | Direct LED display drive | Display driver | Direct LED display drive |
主要差異化特點
- Integrated LED display drive (對比ICL7136CMH+D)
- Low converter supply consumption (對比General-purpose panel ADC without integrated display drive)
- Compact 3.5-digit measurement integration (對比ADC plus external display driver)
設計說明
Separate converter consumption from display consumption when sizing a battery. The documented converter supply current is less than 200 uA excluding LED display current, so add the calculated average LED segment current, current-limiting-network loss, and any other circuit load. Review the exact operating mode and conversion rate in the manufacturer datasheet before using the under-200-uA figure as a complete system budget.
Route the analog input, voltage reference, and clock-related connections away from LED display return paths and switching nodes. Place the input and reference network close to the associated converter pins, and keep the display current paths spatially separated from sensitive measurement traces. Because the device is a 44-pin MQFP, use a layout that accommodates its 0.5 mm-class lead pitch while observing the manufacturer’s land pattern and solder recommendations.
Do not select a nominal LED or LCD companion solely from the converter function. The ICL7137 targets an LED display, while the ICL7136 family targets a non-multiplexed LCD and is not a drop-in substitute. Confirm display polarity, digit count, multiplexing, segment current, reference configuration, input range, and every physical pin in the manufacturer datasheet before releasing the PCB.
合規資訊
The verified package listing identifies the ICL7137CMH-D family as RoHS compliant. No additional REACH, lead-free, halogen-free, conflict-minerals, or automotive-qualification declaration was established.
