Microchip Technology TC520ACOE

Overview

TC520ACOE from Microchip Technology is a serial interface adapter IC designed to manage phase control signals (A, B, CMPTR) for TC500/TC500A/TC510/TC514 dual-slope integrating A/D converters. It supports programmable conversion rate and resolution up to 17-bit accuracy plus polarity bit, operates from a single 5V supply, and delivers low power consumption (typically 0.8 mA). It enables polled or interrupt-mode host communication via a 3-wire serial port in portable data acquisition systems.

For engineers reviewing the TC520ACOE datasheet, TC520ACOE pinout, TC520ACOE application, or TC520ACOE equivalent, this device serves as a dedicated logic controller for precision dual-slope ADC interfacing-requiring attention to LOAD VALUE initialization, SYSCLK timing constraints (≤6 MHz external clock), DV interrupt synchronization, and CE-controlled conversion suspension.

Technical Context

The TC520ACOE integrates an 18-bit shift register, 16-bit counter, and state machine that sequences TC5XX A/D converter phases (Auto Zero, Integrate, De-integrate, Integrator Zero) using programmable LOAD VALUE. Its internal SYSCLK is derived by dividing OSCIN/OSCOUT input frequency by 4, supporting crystal (1–4 MHz) or external clock (up to 6 MHz).

Communication occurs over a 3-wire serial interface (DIN/DOUT/DCLK) with READ-activated data output and CE-gated conversion control. DV output signals data readiness at Auto Zero phase start, enabling either polling or IRQ-driven read cycles without requiring precise timing alignment to conversion completion.

Key Specifications

Pinout & Package

TC520ACOE is housed in a 16-pin SOIC (Wide) package with 0.300-inch body width and standard 0.050-inch lead pitch. Pin 1 is marked by a notch or dot; pins are numbered counterclockwise from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar serial A/D interface applications.

Compared with TC520ACPD, TC520ACOE offers surface-mount reliability and smaller footprint; compared with MAX132, it preserves design flexibility for optimizing integration time and noise rejection in specialized sensor front-ends.

Availability

TC520ACOE is available at Aetrix Electronics and suitable for portable instruments, industrial sensor interfaces, and medical instrumentation requiring stable component supply and long-term obsolescence management.

Supply support for TC520ACOE 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 Inc. is a U.S.-based semiconductor company specializing in microcontrollers, analog devices, and interface ICs for embedded control applications.

The TC520A product line was developed specifically to simplify integration of Microchip's TC500-family dual-slope A/D converters by handling timing-critical phase sequencing and serial data formatting in hardware.

FAQ

What is the primary function of the TC520ACOE in a data acquisition system?

The TC520ACOE acts as a dedicated serial interface adapter that manages phase control signals (A, B, CMPTR) for TC500/TC500A/TC510/TC514 dual-slope A/D converters. It relieves the host processor from real-time timing control, handles programmable integration time via LOAD VALUE, and formats conversion results into an 18-bit serial stream. This makes TC520ACOE essential for achieving high-precision, noise-immune DC measurements without burdening the main MCU.

How does the TC520ACOE achieve up to 17-bit resolution?

The TC520ACOE itself does not perform analog-to-digital conversion but enables up to 17-bit effective resolution (16 data bits + polarity + overrange) by precisely controlling the TC5XX A/D converter's integration and de-integration phases. Resolution is determined by the programmable LOAD VALUE, which sets the number of SYSCLK counts allocated to Auto Zero and Integrate phases-higher counts yield greater resolution at the cost of longer conversion time. The TC520ACOE shifts out the full 18-bit result (OVR/POL/data) serially upon READ activation.

Can the TC520ACOE operate without an external crystal?

Yes, the TC520ACOE can operate without an external crystal by using an external clock source applied to the OSCIN pin (with OSCOUT left floating). The device accepts a pulse train up to 6 MHz with ≥30% duty cycle, ≤15 ns rise/fall times, and 0–VIH amplitude. This option provides layout flexibility and avoids crystal-related EMI or startup delay issues, though crystal operation (1–4 MHz) offers better frequency stability for precision metrology applications.

What is the role of the DV pin on the TC520ACOE?

The DV (Data Valid) pin on the TC520ACOE is an active-low output that goes low at the start of each Auto Zero phase-indicating that the previous conversion's 18-bit result is fully loaded into the internal shift register and ready for serial readout. It serves as a hardware handshake signal, enabling either polling (checking DV before READ) or interrupt-driven operation (connecting DV to MCU IRQ). This eliminates guesswork about conversion completion timing and ensures deterministic data capture.

How is the LOAD VALUE initialized and updated on the TC520ACOE?

The LOAD VALUE is an 8-bit configuration byte that sets the upper byte of the TC520ACOE's 16-bit timebase counter, determining integration and auto-zero durations. It is initialized at power-up by shifting the byte MSB-first into DIN while LOAD is held low, then releasing LOAD high to latch it. The value can be reloaded dynamically during operation-e.g., during DV = low-to adapt integration time for different input ranges or noise environments. TC520ACOE does not retain LOAD VALUE across power cycles; reinitialization is mandatory after reset.