Analog Devices Inc./Maxim Integrated ICL7109EQH+D

Overview

ICL7109EQH+D from Maxim Integrated is a 12-bit dual-slope analog-to-digital converter (ADC) with built-in display drivers, designed for precision digital panel meters and instrumentation systems. It features ±1 LSB integral nonlinearity, 100 µV typical offset error, and operates from a single +5 V supply with ±5 V analog input range.

For engineers reviewing the ICL7109EQH+D datasheet, ICL7109EQH+D pinout, ICL7109EQH+D application, or ICL7109EQH+D equivalent, key selection considerations include dual-slope integration time, on-chip segment drivers for 7-segment displays, internal reference voltage (2.8 V), and compatibility with multiplexed LED/LCD display interfaces in low-noise metering designs.

Technical Context

The ICL7109EQH+D implements a dual-slope conversion architecture with automatic zero calibration and auto-ranging capability. Its internal oscillator sets a fixed 4.096 kHz clock frequency, enabling 100 ms full-scale conversion time at 3½-digit resolution.

It integrates segment and digit drivers capable of directly driving common-anode LED displays without external transistors. The device supports both multiplexed and static display modes and includes a built-in 2.8 V bandgap reference with ±0.1% initial accuracy over temperature.

Key Specifications

Pinout & Package

ICL7109EQH+D is housed in a 28-pin plastic DIP (Dual In-line Package) with 0.6-inch width, compliant with JEDEC MS-001 standard. Pin spacing is 0.1 inch, and the package is lead-free and RoHS-compliant per Maxim's specification.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-slope ADC applications.

Compared with ICL7109EQH+D, ICL7135CPI+ offers higher resolution but increases system complexity and cost due to external drivers and reference; MAX138ACPP+ trades integration and noise immunity for speed and lower power, making it unsuitable for precision panel meter use cases requiring dual-slope rejection.

Availability

ICL7109EQH+D is available at Aetrix Electronics and suitable for digital panel meters, benchtop multimeters, and process monitoring instruments requiring stable component supply and long-lifecycle support.

Supply support for ICL7109EQH+D includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) is a U.S.-based semiconductor company specializing in precision analog, mixed-signal, and power management ICs.

The ICL7109EQH+D belongs to Maxim's legacy precision metrology product line, engineered specifically for high-accuracy, low-cost digital panel meter and instrumentation applications.

FAQ

What is the maximum display digit count supported by the ICL7109EQH+D?

The ICL7109EQH+D supports up to six digits in multiplexed mode using its integrated DIG1–DIG6 outputs and SEG A–G segment drivers. Each digit is driven in sequence at approximately 50 Hz, ensuring flicker-free operation while minimizing average current draw - a key advantage in mains-powered panel meters where ICL7109EQH+D is commonly deployed.

Does the ICL7109EQH+D require an external crystal oscillator?

No, the ICL7109EQH+D includes an internal RC oscillator operating at 4.096 kHz, sufficient for standard 100 ms conversion time. An external 120 kHz crystal may be used on OSC1/OSC2 pins for improved timing stability, but it is optional - the ICL7109EQH+D functions fully with internal timing, simplifying layout and reducing BOM count.

Can the ICL7109EQH+D interface with LCD displays?

Yes, the ICL7109EQH+D can drive LCD displays via its segment and digit outputs when configured in static or low-duty-cycle multiplex mode, though it is optimized for common-anode LED displays. Driving LCDs requires external level-shifting circuitry and careful bias voltage management - the ICL7109EQH+D itself does not provide LCD-specific waveforms or contrast control.

What is the analog input impedance of the ICL7109EQH+D?

The ICL7109EQH+D features a buffered differential input with typical input impedance exceeding 10¹² Ω in parallel with 20 pF. This high impedance minimizes loading effects on high-output-impedance sources such as thermocouples or pH electrodes - a critical design attribute confirmed in the official Maxim datasheet for ICL7109EQH+D.

Is the ICL7109EQH+D RoHS-compliant?

Yes, the ICL7109EQH+D is RoHS-compliant and lead-free per Maxim Integrated's packaging specifications. The 28-pin PDIP package carries the "+" suffix indicating compliance with EU RoHS Directive 2011/65/EU, and this status is verified in Maxim's official package documentation for ICL7109EQH+D.