ICL7109CMH+T - 12-Bit Dual-Slope ADC, 44-MQFP | Maxim Integrated
MPN: ICL7109CMH+T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $14.35 | $1,435.00 |
| 500 | $12.8 | $6,400.00 |
| 1,000 | $11.45 | $11,450.00 |
ICL7109CMH+T Overview
What is a dual-slope integrating ADC? It is a type of analog-to-digital converter that uses a two-stage integration process: first it integrates the input voltage over a fixed time, then it integrates a reference voltage of opposite polarity until the integrator output returns to zero. The number of clock cycles required for the second integration is proportional to the input voltage. Dual-slope ADCs sit within the broader ADC taxonomy, which includes successive-approximation-register (SAR), sigma-delta, and flash converters. They are valued for excellent normal-mode noise rejection at integer multiples of the integration period, making them ideal for noisy industrial environments.
The ICL7109 family employs CMOS technology to achieve low power consumption while delivering true 12-bit performance with ±1 LSB total uncalibrated accuracy. The device integrates BCD/three-state binary output drivers, a precision bandgap reference, and a charge-balance converter. Differential input capability and high common-mode rejection enable direct connection to bridge sensors and thermocouples without front-end instrumentation amplifiers. Active-low RUN/HOLD and BUSY handshake lines allow direct connection to UARTs and parallel microprocessor busses.
Typical applications include digital panel meters, weigh scales, process control loops, thermometry with thermocouple/PT100 front ends, pH meters, blood analyzers, and battery-powered portable instrumentation. The wide supply range (typically ±5 V or single +5 V) and commercial temperature grade (0°C to +70°C) suit industrial and bench instruments. For systems requiring noise-immune A/D conversion with deterministic integration behavior, the ICL7109 remains a proven workhorse, and the ICL7109CMH+T variant comes in surface-mount 44-MQFP for automated assembly.
When designing with the ICL7109CMH+T, place the integrating and reference capacitors with low-leakage, low-dielectric-absorption types (typically polypropylene or polystyrene) directly at the chip pins. Use a guard ring around the integrator input to minimize leakage current from the PCB. The crystal oscillator reference capacitor and integrating RC networks should be sized for the chosen conversion rate: a 3.58 MHz crystal yields roughly 30 conversions/second. Do not exceed the absolute maximum analog input voltage of ±15 V relative to supply ground.
Drop-in alternatives for ICL7109CMH+T — 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+T (same form factor and footprint) — differing in Mounting Type, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ICL7109CMH+
✅ Drop-In✓ In Stock
$10.85 / Unit
View Datasheet →TC7109ACKW
✅ Drop-In📋 Reference alternative (not in catalog)
ICL7109CMH+T Maximum Ratings & Electrical Characteristics
| Resolution | 12 bits + sign + over-range |
| Architecture | Dual-slope integrating |
| Number of Channels | 1 differential input |
| Output Type | Three-state binary (with polarity and over-range) |
| Package | 44-MQFP (10x10 mm, Metric Quad Flat Pack) |
| Number of Pins | 44 |
| Terminal Form | GULL WING |
| Package Code | QFP |
| Package Shape | SQUARE |
| Temperature Grade | COMMERCIAL |
| Maximum Conversion Rate | 30 conversions/sec at 3.58 MHz crystal |
| Uncalibrated Accuracy | ±1 LSB (max) |
| Reference | Internal bandgap (external reference option) |
| Mounting Type | Surface Mount |
ICL7109CMH+T Pin Configuration
| Pin 1 | GND — Digital ground |
| Pin 2 | STATUS — Status output |
| Pin 3 | POL — Polarity output |
| Pin 4 | OR — Over-range output |
| Pin 5 | B12 — Bit 12 (MSB) three-state output |
| Pin 6 | B11 — Bit 11 three-state output |
| Pin 7 | B10 — Bit 10 three-state output |
| Pin 8 | B9 — Bit 9 three-state output |
| Pin 9 | B8 — Bit 8 three-state output |
| Pin 10 | B7 — Bit 7 three-state output |
| Pin 11 | B6 — Bit 6 three-state output |
| Pin 12 | B5 — Bit 5 three-state output |
| Pin 13 | B4 — Bit 4 three-state output |
| Pin 14 | B3 — Bit 3 three-state output |
| Pin 15 | B2 — Bit 2 three-state output |
| Pin 16 | B1 — Bit 1 (LSB) three-state output |
| Pin 17 | TEST — Test pin |
| Pin 18 | OSC1 — Oscillator input |
| Pin 19 | OSC3 — Oscillator output |
| Pin 20 | OSC2 — Oscillator |
| Pin 21 | REF HI — Reference voltage high |
| Pin 22 | REF LO — Reference voltage low |
| Pin 23 | REF CAP+ — Reference capacitor positive |
| Pin 24 | REF CAP- — Reference capacitor negative |
| Pin 25 | INT IN — Integrator input |
| Pin 26 | INT OUT — Integrator output |
| Pin 27 | BUFFER OUT — Buffer output |
| Pin 28 | C REF+ — Auto-zero capacitor positive |
| Pin 29 | C REF- — Auto-zero capacitor negative |
| Pin 30 | IN HI — Analog input high |
| Pin 31 | IN LO — Analog input low |
| Pin 32 | COMMON — Common (analog ground) |
| Pin 33 | V- — Negative supply |
| Pin 34 | RUN/HOLD — Run/Hold control input |
| Pin 35 | MODE — Mode select input |
| Pin 36 | SEND — Send input |
| Pin 37 | CE — Chip enable |
| Pin 38 | LBEN — Low-byte enable |
| Pin 39 | HBEN — High-byte enable |
| Pin 40 | V+ — Positive supply |
| Pin 41 | DGND — Digital ground |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
ICL7109CMH+T is suitable for 6 applications: Digital Panel Meter (DPM), Weigh Scale / Load Cell Instrumentation, Process Control Loop Monitoring, Thermometry with Thermocouple Front End, pH / Blood Analyzer Bench Instruments, Battery-Powered Portable Instrumentation.
Digital Panel Meter (DPM)
The ICL7109CMH+T's 12-bit resolution and dual-slope architecture make it ideal for digital panel meters reading ±2V full scale. Its 60Hz normal-mode noise rejection at 3.58MHz crystal cuts through industrial mains noise, while the differential input accepts low-level sensor signals directly. Use the three-state binary outputs plus sign/over-range flags for processor display multiplexing or direct LCD driver interfacing.
Recommended
Weigh Scale / Load Cell Instrumentation
Weigh scales rely on the ICL7109CMH+T's 12-bit resolution, differential input, and excellent line-frequency noise rejection to read strain-gauge bridge outputs accurately. With 3.58MHz crystal the integrator naturally rejects 60Hz pickup common in industrial environments, achieving better than 0.1% accuracy without calibration. Pair the ICL7109CMH+T with an instrumentation amp front end and force-sensor bridge for direct kilogram/pound readout.
Recommended
Process Control Loop Monitoring
Process control loops use the ICL7109CMH+T to digitize 4-20mA or 0-10V sensor signals with high noise immunity. The dual-slope integrator rejects switching-converter noise from nearby motor drives and solenoid valves. Three-state binary outputs interface directly to industrial PLC backplanes or UARTs, while the BUSY handshake line simplifies interrupt-driven sample acquisition in SCADA systems.
Recommended
Thermometry with Thermocouple Front End
The ICL7109CMH+T handles thermocouple millivolt signals through its differential input with high common-mode rejection. Combined with cold-junction compensation and an instrumentation amp, the ADC delivers 12-bit temperature readings suitable for industrial furnace and oven monitoring. Dual-slope integration filters thermocouple lead-wire 50/60Hz pickup, improving stability in long-cable installations.
Recommended
pH / Blood Analyzer Bench Instruments
Clinical chemistry analyzers benefit from the ICL7109CMH+T's high-resolution differential measurement of pH electrode and ion-selective probe outputs. The integrating architecture's normal-mode noise rejection delivers stable readings in electrically noisy laboratory environments. Its commercial temperature grade suits bench-top analyzers, while low power consumption keeps thermal load on precision analog front ends to a minimum.
Recommended
Battery-Powered Portable Instrumentation
Although the ICL7109CMH+T is not the lowest-power ADC, it remains popular in portable digital multimeters and field instruments where noise rejection and 12-bit accuracy outweigh conversion speed. CMOS technology keeps quiescent current modest for the conversion period, and the on-chip reference eliminates external regulator bulk. Surface-mount 44-MQFP packaging supports compact handheld enclosures used by field technicians.
Recommended
Recommended Products Summary
Engineering reference data for ICL7109CMH+T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ICL7109CMH+ | TC7109IJL | TC7109ACKW |
|---|---|---|---|---|
| Brand | Maxim Integrated | Maxim Integrated | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (10x10) | 44-MQFP (10x10) - same | 44-PLCC - different | 44-MQFP (10x10) - same |
| Resolution | 12-bit + sign + OR | 12-bit + sign + OR | 12-bit + sign + OR | 12-bit + sign + OR |
| Architecture | Dual-slope integrating | Dual-slope integrating | Dual-slope integrating | Dual-slope integrating |
| Conversion Rate | 30 conv/sec @ 3.58 MHz | 30 conv/sec @ 3.58 MHz | 30 conv/sec @ 3.58 MHz | 30 conv/sec @ 3.58 MHz |
| Uncalibrated Accuracy | ±1 LSB | ±1 LSB | ±1 LSB | ±1 LSB |
| VOH Source Current | Standard | Standard | Standard | Improved (TC7109A enhancement) |
| Pin-to-Pin on 44-MQFP Footprint | Yes (reference) | Yes | No (44-PLCC differs) | Yes |
Key Differentiators
- Tape-and-reel packaging for SMT production (vs ICL7109CMH+)
- Proven noise-rejection architecture for industrial environments (vs TC7109ACKW)
- Direct microprocessor/UART interface (vs ICL7107CM44)
Design Notes
Use a PCB guard ring tied to COMMON (pin 32) around the integrator input node (pin 25) and its capacitor/resistor to minimize leakage current from PCB contamination. Surface-mount boards with no-clean flux residue can introduce nanoampere-level leakage currents that degrade linearity at 12-bit resolution. Place the integrator capacitor (typically 0.22µF polypropylene) directly at pins 25-26 with the shortest possible trace length. Estimated: at room temperature with 10nA leakage, a 0.22µF integrator integrates approximately 4.5 LSBs of error per conversion over a 100ms integration window.
Bypass V+ (pin 40) and V- (pin 33) supplies with 10µF tantalum in parallel with 0.1µF ceramic capacitors placed within 5mm of the supply pins. The ICL7109CMH+T's charge-pump action during integrator reset can inject switching noise into the supply rails; insufficient decoupling causes 1-2 LSB noise coupling into the reference. Use separate analog and digital ground returns joined only at the ADC's GND/COMMON pins to prevent digital output driver currents from corrupting the analog integrator node.
Do not substitute generic ceramic (X7R/Y5V) capacitors for the integrator (INT, pin 25-26) and reference (REF CAP, pin 23-24) capacitors. These capacitor types exhibit high dielectric absorption (>2%) which directly degrades dual-slope linearity and causes conversion-to-conversion drift. Use polypropylene, polystyrene, or NPO/C0G ceramic types for these positions. Auto-zero capacitor (C REF, pins 28-29) can use a higher-grade ceramic but should still avoid high-DA types like Z5U. Per the Maxim datasheet, integrator capacitor tolerance should be ±5% or better.
Compliance Information
RoHS/REACH compliance status was not provided in the verified web data and should be confirmed via the manufacturer's latest declaration. The 'T' suffix denotes tape-and-reel packaging and the part is supplied lead-free per modern Maxim/Analog Devices manufacturing practice, but exact RoHS compliance should be verified through the manufacturer product folder before production use.
