The document introduces the features of the TC7135. It is a 4-1/2-digit A/D converter with a 50ppm (1/20000) resolution and a maximum nonlinearity error of 1 count. An automatic zero cycle reduces zero error to 10µV and zero drift to 0.5µV/°C. A maximum input current of 10pA minimizes source impedance errors. Rollover error is limited to ±1 count. Microprocessor-based measurement systems are supported by BUSY, STROBE, and RUN/HOLD control signals. Remote data acquisition systems (with data transfer via UARTs) are also possible. The additional control pins and multiplexed BCD outputs make the TC7135 the ideal converter for display or microprocessor-based measurement systems.
The TC7135 is a 4‑1/2 digit (50 ppm) analog‑to‑digital converter designed for precision sensor interfaces and high‑accuracy DC measurements. It features low rollover error (+1 count), low nonlinearity (+1 count), 1 pA input leakage and a 2 µV/°C zero‑drift.
The device is offered in 28‑pin PDIP, 28‑pin PLCC and 64‑pin PQFP packages. Detailed pin descriptions, electrical specifications, and functional block diagrams are provided, along with guidance on dual‑slope conversion operation and analog section behavior.
| Resolution | 4‑1/2 digit (50 ppm) |
|---|---|
| Nonlinearity Error | +1 Count Max |
| Input Leakage Current | 1 pA (typ 10 pA) |
| Low Input Current | 1 pA |
| Zero‑Drift | 2 µV/°C |
| Positive Supply Voltage (V+) | 4 V – 6 V |
| Clock Frequency | up to 1.2 MHz |
| Power Dissipation | up to 30 mW |
| Full Scale Voltage | 2 V |
It provides a 4‑1/2 digit resolution, equivalent to 50 ppm (1 part in 20,000).
The input leakage current is as low as 1 pA (typical 10 pA).