Texas Instruments ADS7864Y/250

Overview

ADS7864Y/250 from Texas Instruments is a dual 12-bit, 500kHz simultaneous-sampling analog-to-digital converter with six fully differential input channels (A0/A1, B0/B1, C0/C1), 2µs per-channel throughput, ±0.75 LSB integral linearity, and internal 2.5V reference - designed for real-time motor phase current acquisition in three-phase inverters.

For engineers reviewing the ADS7864Y/250 datasheet, ADS7864Y/250 pinout, ADS7864Y/250 application, or ADS7864Y/250 equivalent, key selection factors include simultaneous sampling capability across three channel pairs, parallel 16-bit interface timing, bipolar input support via external level shift, and TQFP-48 package compatibility with industrial motor control PCB layouts.

Technical Context

The ADS7864Y/250 integrates two independent SAR ADC cores sharing a common 8MHz clock domain, each driving three differential sample-and-hold amplifiers with matched aperture delay (≤100ps) and 40MHz small-signal bandwidth. Its dual-converter architecture enables true simultaneous capture of paired channels (e.g., A0/A1) without inter-channel skew.

Control logic uses three dedicated HOLD inputs (HOLDA/HOLDB/HOLDC) to initiate conversion on specific channel groups, while BUSY, RD, and CS coordinate parallel data readout in 16-bit words containing 12-bit two's complement data plus 3-bit channel address and DB15 data-valid flag.

Key Specifications

Pinout & Package

TQFP-48 (PFB) package with exposed thermal pad; 0.5mm lead pitch; RoHS-compliant; specified for –40°C to +85°C operation.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar simultaneous-sampling ADC applications.

Compared with ADS7864Y/250, ADS8588SIPM trades speed for resolution and serial simplicity, while AD7656ASTZ offers higher voltage range but requires external timing coordination for true simultaneity - making ADS7864Y/250 optimal for cost-sensitive, space-constrained motor control designs demanding deterministic 500kHz sampling.

Availability

ADS7864Y/250 is available at Aetrix Electronics and suitable for motor control, multi-axis positioning systems, and 3-phase power control requiring stable component supply across extended industrial temperature ranges.

Supply support for ADS7864Y/250 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

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with over 50 years of innovation in precision data converters and motor control solutions.

The ADS7864Y/250 belongs to TI's high-speed simultaneous-sampling ADC product line, engineered specifically for real-time current/voltage acquisition in industrial motor drives and power electronics where phase coherence and timing determinism are critical.

FAQ

What is the maximum clock frequency supported by the ADS7864Y/250?

The ADS7864Y/250 supports an external CLOCK input up to 8MHz, which corresponds to its rated 500kHz per-channel sampling rate. At 8MHz, the minimum clock period is 125ns with ≥40ns high/low times. Exceeding 8MHz violates timing specifications and may cause conversion errors or BUSY signal instability in the ADS7864Y/250.

Does the ADS7864Y/250 require an external reference voltage?

No, the ADS7864Y/250 includes an internal 2.5V reference with ±0.025V initial accuracy and 10ppm/°C drift, accessible via REFOUT and usable directly at REFIN. An external reference (1.2V–2.6V) is optional for applications needing different full-scale ranges, but the ADS7864Y/250 operates fully functional with its internal reference enabled by default.

How does the ADS7864Y/250 achieve simultaneous sampling across all six channels?

The ADS7864Y/250 achieves true simultaneous sampling using three independent HOLD inputs (HOLDA, HOLDB, HOLDC) that control separate sample-and-hold amplifiers for each channel pair. When all three HOLD signals are asserted low simultaneously, all six differential inputs enter hold mode at the same instant, preserving phase relationships - a capability confirmed in the ADS7864Y/250 datasheet Figure 26 timing diagram.

What is the purpose of the BYTE pin on the ADS7864Y/250?

The BYTE pin (Pin 28) on the ADS7864Y/250 enables 8-bit bus compatibility: when driven high, it splits the 16-bit output word into two 8-bit reads - DB7–DB0 on the first RD pulse and DB15–DB8 on the second. This reduces PCB trace count in resource-constrained designs without sacrificing resolution, and is fully supported in the ADS7864Y/250's parallel interface timing specification.

Can the ADS7864Y/250 interface directly with ±10V industrial sensors?

Yes, the ADS7864Y/250 can interface with ±10V sensors using the bipolar input level-shift circuit shown in Figure 25 of its datasheet: an OPA340 op-amp with four resistors scales ±10V to ±2.5V differential input range compatible with the ADS7864Y/250's internal 2.5V reference - no additional ADC or level-shifter IC is required for this configuration.