Microchip Technology TC7109ACKW

Overview

TC7109ACKW from Microchip Technology is a 12-bit plus sign CMOS dual-slope integrating analog-to-digital converter (ADC) with true differential input and reference, 15 µV_P-P typical input noise, 1 pA typical input bias current, and zero integrator cycle for fast overload recovery. It operates with ±5 V supplies and supports both parallel Direct mode and UART Handshake mode for remote data logging in precision measurement systems.

For engineers reviewing the TC7109ACKW datasheet, TC7109ACKW pinout, TC7109ACKW application, or TC7109ACKW equivalent, key selection considerations include its differential bridge transducer interface capability, auto-zero architecture eliminating manual calibration, integrated reference output (–2.8 V), and 44-pin PQFP package optimized for industrial instrumentation requiring high CMRR and low drift.

Technical Context

The TC7109ACKW implements a four-phase dual-slope conversion cycle-Auto-Zero (AZ), Signal Integrate (INT), Reference De-integrate (DE), and Zero Integrator (ZI)-with fixed 2048-clock INT phase and variable DE phase proportional to input voltage. Its internal auto-zero loop compensates buffer, integrator, and comparator offsets, achieving <10 µV input-referred offset and <1 µV/°C zero drift.

Digital interface flexibility is provided via MODE-selectable operation: Direct mode uses CE/LOAD, HBEN, and LBEN as active-low parallel bus controls; Handshake mode repurposes those pins as TTL-compatible outputs synchronized to UART TBRE/TBRL signals, enabling drop-in serial interfacing without external logic.

Key Specifications

Pinout & Package

TC7109ACKW is housed in a 44-pin Plastic Quad Flat Package (PQFP) with 0.8 mm lead pitch, RoHS-compliant, and rated for 0°C to +70°C operation. Pin numbering follows standard PQFP convention with Pin 1 at top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar integrating ADC applications.

Compared with MAX134ACPP and ICL7109CPLZ, the TC7109ACKW uniquely balances 12-bit precision, robust overload recovery, and UART-ready digital interface in a surface-mount PQFP package - making it optimal for cost-sensitive, noise-immune industrial data loggers where reliability trumps raw resolution.

Availability

TC7109ACKW is available at Aetrix Electronics and suitable for industrial instrumentation, portable test equipment, and bridge-based sensor interfaces requiring stable component supply, long-lifecycle support, and consistent parametric performance across production batches.

Supply support for TC7109ACKW 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

Microchip Technology is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and interface ICs for industrial, automotive, and consumer applications.

The TC7109ACKW belongs to Microchip's legacy precision analog converter product line, designed specifically for high-accuracy, low-drift DC measurement systems where dual-slope architecture delivers inherent noise rejection and stability without complex calibration.

FAQ

What is the maximum recommended clock frequency for stable operation of the TC7109ACKW?

The TC7109ACKW is designed for an 8192-clock conversion cycle. With a typical crystal oscillator frequency of 3.58 MHz, the effective conversion rate is ~437 Hz. Operating above 4.0 MHz may degrade integrator settling and increase nonlinearity; Microchip specifies 3.58 MHz as the validated frequency for full 12-bit accuracy across temperature.

Does the TC7109ACKW require external passive components to function as a complete ADC system?

Yes, the TC7109ACKW requires eight passive components and a crystal to form a complete dual-slope ADC: two precision resistors (R_INT, R_REF), three capacitors (C_INT, C_REF, C_AZ), two bypass capacitors, and one 3.58 MHz crystal. These set integration time, reference scaling, and auto-zero stability - values are specified in DS21456D Section 4.0.

How does the TC7109ACKW handle input overrange conditions, and what design impact does this have?

The TC7109ACKW executes a dedicated Zero Integrator (ZI) phase after overrange detection, actively driving the integrator output to 0 V to remove residual charge. This prevents carryover error into subsequent conversions - a critical feature in multiplexed systems where one channel's overrange would otherwise corrupt the next channel's reading, as confirmed in DS21456D Section 3.1.4.

Can the TC7109ACKW operate with a single +5 V supply instead of ±5 V?

No, the TC7109ACKW requires dual supplies: V+ = +5 V and V− = −5 V (absolute max ratings: +6.2 V and −9 V). Its analog section relies on symmetric rails to achieve ±4 V integrator swing and proper common-mode range for differential inputs. Single-supply operation is not supported and will result in saturation or undefined behavior.

What is the purpose of the BUFF OSC OUT pin (Pin 25) on the TC7109ACKW, and how is it used?

The BUFF OSC OUT pin provides a buffered, low-impedance copy of the internal oscillator signal - either crystal-derived (when OSC SEL = LOW) or RC-derived (when OSC SEL = HIGH). It can drive external circuitry (e.g., RUN/HOLD timing control or secondary clock domains) without loading the oscillator core, preserving frequency stability and startup reliability per DS21456D Section 2.0.