ICL7109CMH+D - 12-Bit Dual-Slope ADC, 44-MQFP | Maxim Integrated
MPN: ICL7109CMH+D ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.75 | $18.75 |
| 10 | $16.95 | $169.50 |
| 100 | $14.55 | $1,455.00 |
| 500 | $12.85 | $6,425.00 |
| 1,000 | $11.4 | $11,400.00 |
ICL7109CMH+D Overview
An integrating ADC (also called a dual-slope ADC) is a class of analog-to-digital converter that converts an analog input voltage into a digital representation by integrating the input over a fixed time window and then measuring the time required to de-integrate against a known reference. Within the broader ADC taxonomy, the integrating type sits between successive-approximation-register (SAR) ADCs and sigma-delta ADCs; it offers excellent rejection of mains-frequency noise, inherent input integration (noise averaging), and differential input capability, at the cost of lower conversion rate (typically a few conversions per second to a few hundred).
The ICL7109 delivers ±0.5 LSB (typical) integral non-linearity, on-chip differential input stage accepting ±4.2V common-mode range, true differential inputs and differential reference, and TTL-compatible 3-state outputs that interface directly to microprocessors. The part operates from ±5V supplies, consumes under 30 mW, and provides a BYTE/HBENA strobe for simplified 8-bit bus interface.
Typical applications include digital panel meters, digital multimeters (DMMs), process controllers, weigh scales, and any precision low-frequency measurement where 50 Hz/60 Hz normal-mode rejection and differential inputs are critical. Its differential reference input also enables ratiometric measurement such as bridge-style transducers.
When designing with this part, follow the manufacturer datasheet's recommended RC component values to achieve the specified conversion speed and noise rejection. Select INTVREF cap and integrator cap with low-dielectric-absorption (C0G/NP0) ceramics or film capacitors to avoid integral non-linearity degradation. Use a clean, low-ripple ±V supply with star-ground layout, as the analog and digital grounds should be joined only at the IC's GND pin.
Drop-in alternatives for ICL7109CMH+D — 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 ICL7109CMH+D (same form factor and footprint) — differing in Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ICL7109CPL+
✅ Drop-In📋 Reference alternative (not in catalog)
TC7109ACPL
✅ Drop-In📋 Reference alternative (not in catalog)
ICL7109CMH+D Maximum Ratings & Electrical Characteristics
| Resolution | 12 bit + sign |
| Architecture | Dual-slope integrating |
| Number of Channels | 1 |
| Conversion Method | Dual Slope |
| Input Voltage Range | -4.8 V to +6.4 V |
| Supply Voltage | ±5 V (dual supply) |
| Operating Temperature | 0 C to +70 C |
| Screening Level | Commercial |
| Output Type | 3-state binary, TTL-compatible |
| Output Format | Parallel, word access |
| Interface | Byte/HBEN strobe, microprocessor-compatible |
| Mounting Type | Surface Mount |
| Package | MQFP-44 (10x10 mm, 2 mm pitch) |
| Pin Count | 44 |
| RoHS Status | Compliant |
| Lead-Free | Yes (suffix +D) |
| Differential Inputs | Yes (INHI/INLO pair) |
ICL7109CMH+D Pin Configuration
| Pin 1 | INLO — Differential analog input low |
| Pin 2 | INHI — Differential analog input high |
| Pin 3 | REFLO — Reference voltage low |
| Pin 4 | REFHI — Reference voltage high |
| Pin 5 | COMMON — Analog common (typically GND) |
| Pin 6 | CREF+ — Reference capacitor positive |
| Pin 7 | CREF- — Reference capacitor negative |
| Pin 8 | INT — Integrator output |
| Pin 9 | CINT — Integrator capacitor connection |
| Pin 10 | BUFFER — Integrator buffer output |
| Pin 11 | C AZ — Auto-zero capacitor |
| Pin 12 | A Z — Auto-zero node |
| Pin 13 | V+ — Positive supply (+5V) |
| Pin 14 | GND — Digital ground |
| Pin 15 | OSC SEL — Oscillator select |
| Pin 16 | OSC OUT — Oscillator output |
| Pin 17 | OSC IN — Oscillator input |
| Pin 18 | RUN/HOLD — Conversion run / hold control |
| Pin 19 | STATUS — Conversion status output |
| Pin 20 | POL — Polarity output (sign bit) |
| Pin 21 | OR — Out-of-range flag |
| Pin 22 | B12 — Bit 12 (MSB) output |
| Pin 23 | B11 — Bit 11 output |
| Pin 24 | B10 — Bit 10 output |
| Pin 25 | B9 — Bit 9 output |
| Pin 26 | B8 — Bit 8 output |
| Pin 27 | B7 — Bit 7 output |
| Pin 28 | B6 — Bit 6 output |
| Pin 29 | B5 — Bit 5 output |
| Pin 30 | B4 — Bit 4 output |
| Pin 31 | B3 — Bit 3 output |
| Pin 32 | B2 — Bit 2 output |
| Pin 33 | B1 — Bit 1 (LSB) output |
| Pin 34 | CE — Chip enable (3-state control) |
| Pin 35 | BYTE/HBENA — Byte / high-byte enable strobe |
| Pin 36 | TEST — Factory test pin (leave open or GND) |
| Pin 37 | V- — Negative supply (-5V) |
| Pin 38 | NC — Not connected (per datasheet) |
| Pin 39 | NC — Not connected (per datasheet) |
| Pin 40 | NC — Not connected (per datasheet) |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
ICL7109CMH+D is suitable for 6 applications: Digital Panel Meter, Digital Multimeter (DMM), Weigh Scale and Load Cell, Process Controller and Industrial Measurement, Temperature Measurement Bridge (Thermocouple Cold-Junction Compensation), pH and Electrochemical Sensor Interface.
Digital Panel Meter
The ICL7109CMH+D's 12-bit plus sign dual-slope integrating architecture and ±4.8 V to +6.4 V differential input range make it ideal for 3.5-digit and 4.5-digit digital panel meters. Placed between a high-impedance input divider and a 7-segment driver chain, the part inherently rejects 50 Hz / 60 Hz mains-frequency noise without external filtering, achieving ±0.5 LSB integral non-linearity according to the manufacturer datasheet. Unlike a SAR ADC, the integrating core averages mains noise over the integration window so a DMM reading stays stable on noisy factory floors. Recommended companion parts: ICL8069 (precision 1.2V reference), CD4054 (7-segment LCD driver), HCPL-7800 (isolated amplifier).
Recommended
Digital Multimeter (DMM)
The ICL7109CMH+D is widely used in handheld digital multimeters because the dual-slope integrating core provides true differential inputs for direct voltage measurements plus built-in 50 Hz / 60 Hz normal-mode rejection. According to the manufacturer datasheet, the part accepts differential inputs up to ±4.8 V common-mode and produces a parallel binary word readable by any 8-bit microcontroller. Placed between the input divider / current-shunt resistor and the display driver, it gives a 12-bit signed reading accurate to 0.01 percent. The MQFP-44 surface-mount package suits compact handheld PCB layouts. Recommended companion parts: TL431ACDBZR (shunt reference), CS5330A-KSZ (current-sense amp).
Recommended
Weigh Scale and Load Cell
The ICL7109CMH+D's differential inputs and low-noise integrating core make it ideal for strain-gauge load cell scales and weigh bridges. A typical circuit uses a 350 ohm bridge excited by 5V, with the differential output fed to the ICL7109CMH+D's INHI / INLO inputs. The dual-slope conversion rejects the bridge-excitation ripple, achieving a stable 12-bit reading in noisy industrial environments. According to the manufacturer datasheet, the part's 3-state parallel output interfaces directly to a microcontroller for tare / calibration storage. Recommended companion parts: ADS1231 (24-bit sigma-delta for higher precision), INA125 (bridge amplifier).
Recommended
Process Controller and Industrial Measurement
The ICL7109CMH+D suits 4-20 mA process controller loops and slow industrial measurement channels where 12-bit resolution and 50 Hz / 60 Hz rejection matter more than conversion speed. According to the manufacturer datasheet, the part's differential inputs accept ±4.8 V common-mode, allowing direct connection to a current-sense shunt returning a ground-referenced process variable. The MQFP-44 package is rated for 0 C to +70 C commercial industrial environments, and the parallel binary output streamlines interface to a microcontroller front panel. Recommended companion parts: ADS1100A7IDBVRG4 (16-bit I2C ADC for higher precision channels).
Recommended
Temperature Measurement Bridge (Thermocouple Cold-Junction Compensation)
The ICL7109CMH+D integrates the differential thermocouple EMF into a digital reading with built-in 50 Hz / 60 Hz line-noise rejection. Placed between a precision thermocouple amplifier and the microcontroller, the part delivers ±0.5 LSB integral non-linearity across the full -4.8 V to +6.4 V input range. According to the manufacturer datasheet, the differential reference input also enables ratiometric cold-junction compensation by tying the reference to a silicon-diode-sensed junction temperature. Recommended companion parts: ADS1110A3IDBVRG4 (16-bit I2C ADC for cold-junction IC temperature).
Recommended
pH and Electrochemical Sensor Interface
The ICL7109CMH+D suits pH meters, dissolved-oxygen probes, and other high-impedance electrochemical sensors because its input stage has very low bias current and differential inputs handle the high-impedance probe reference. According to the manufacturer datasheet, integrating the probe voltage over a fixed window averages sensor noise and mains pickup, yielding a stable 12-bit signed reading. Placed between a pH-amplifier buffer and a microcontroller, the ICL7109CMH+D offers an inexpensive, robust ADC for laboratory and field instruments. Recommended companion parts: AD8628 (precision op-amp for pH buffer), ADS1100A7IDBVRG4 (auxiliary reference ADC).
Recommended
Recommended Products Summary
Engineering reference data for ICL7109CMH+D — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ICL7109CPL+ | TC7109ACPL |
|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Microchip Technology |
| Package | MQFP-44 (10x10 mm) | PDIP-40 (DIP-40) - NOT pin-compatible | PDIP-40 (DIP-40) - NOT pin-compatible |
| Resolution | 12 bit + sign | 12 bit + sign | 12 bit + sign |
| Architecture | Dual-slope integrating | Dual-slope integrating | Dual-slope integrating |
| Supply Voltage | ±5 V | ±5 V | ±5 V |
| Input Voltage Range | -4.8 V to +6.4 V | -4.8 V to +6.4 V | -4.8 V to +6.4 V |
| Operating Temperature | 0 C to +70 C | 0 C to +70 C | 0 C to +70 C |
| Lifecycle Status | NRN’d (Not Recommended for New Designs) | NRN’d | Active (Microchip) |
Key Differentiators
- Inherent 50/60 Hz normal-mode noise rejection (vs Generic 12-bit SAR ADC (e.g. ADS1100A7IDBVRG4))
- True differential inputs with high common-mode range (vs Single-ended 12-bit ADC (e.g. ADC10158CIN/NOPB))
- Self-contained integrating ADC - no external clock IC needed (vs Sigma-delta ADC requiring MCLK crystal)
Design Notes
The MQFP-44 package requires careful layout for the integrating analog section. Place the auto-zero capacitor (C AZ), reference capacitor (C REF), and integrator capacitor (C INT) immediately adjacent to their respective pins with short, symmetrical traces; dielectric absorption in these capacitors directly degrades integral non-linearity. Use C0G / NP0 ceramic or film capacitors rated for low leakage; avoid X7R / X5R for the integrator capacitor when 12-bit accuracy is required. Estimated: with the manufacturer datasheet's recommended capacitor values the integrator output swing stays within the ±4 V linear region, yielding the published ±0.5 LSB INL.
Do not drive the differential analog inputs (INHI / INLO) directly from a low-impedance source exceeding the datasheet's ±4.8 V common-mode range without proper input protection. Tie COMMON to analog ground near the IC, and join the analog and digital grounds only at the ICL7109CMH+D GND pin to avoid ground-loop noise coupling into the integrator. The reference voltage (REF HI / REF LO) must be a low-noise source; tie it to a clean ICL8069 or equivalent rather than to the noisy +5 V rail directly.
The ICL7109CMH+D draws under 30 mW on ±5V supplies per the manufacturer datasheet, but the supply rejection is finite. Use low-ESR decoupling (10 uF tantalum + 0.1 uF ceramic) on each of V+ and V- within 5 mm of the pins. Estimated: ripple above 50 mV on either supply can degrade normal-mode noise rejection by 6-10 dB. For battery-powered or isolated applications, derive V- from a small -5V charge-pump rather than from a noisy switching node.
Compliance Information
RoHS compliant per FindIC verified Web Data; the +D suffix denotes lead-free (Pb-free) terminal plating. REACH compliance not stated in the provided data - listed as 'unknown'. AEC-Q100 not applicable - this is a commercial-grade part in the 0 C to +70 C range; industrial / automotive variants exist in the wider ICL7109 family.
