Texas Instruments ADS7835E/2K5G4

Overview

ADS7835E/2K5G4 from Texas Instruments (formerly Burr-Brown) is a 12-bit, 500kHz throughput SAR analog-to-digital converter with integrated sample-and-hold, internal 2.5V reference, and synchronous serial interface. It operates from a single +5V supply, delivers ±2.5V bipolar input range, and achieves 72dB SNR at 10kHz - ideal for portable spectrum analyzers and multi-channel battery-powered data loggers.

For engineers reviewing the ADS7835E/2K5G4 datasheet, ADS7835E/2K5G4 pinout, ADS7835E/2K5G4 application, or ADS7835E/2K5G4 equivalent, key selection considerations include guaranteed no-missing-codes performance, power-down mode reducing dissipation to 2.5mW, MSOP-8 package compatibility, and binary two's complement serial output timing synchronized to CONV and CLK.

Technical Context

The ADS7835E/2K5G4 implements a capacitive redistribution SAR architecture fabricated in 0.6µm CMOS, enabling inherent sample-and-hold functionality without external components. Its analog input stage uses a 2kΩ–2kΩ voltage divider referenced to the internal 2.5V bandgap, supporting true bipolar operation from a single supply.

Digital control is fully asynchronous between CONV and CLK: conversion start and hold-mode transition are triggered on CONV edges independent of clock phase, while serial data transmission (MSB-first by default) is synchronized to CLK rising edges. Power-down entry occurs automatically when CONV remains low through the 13th clock cycle.

Key Specifications

Pinout & Package

ADS7835E/2K5G4 is housed in an MSOP-8 package (Package Drawing 337), measuring 3.0mm × 3.0mm × 1.0mm, with exposed pad for thermal enhancement and RoHS-compliant lead finish.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit SAR ADC applications.

Compared with ADS7835EB/2K5, the ADS7835E/2K5 trades 1 LSB linearity for lower cost and identical integration; versus ADS8320ID, it delivers 5× higher speed and built-in reference at the expense of resolution - making ADS7835E/2K5 the optimal choice for battery-powered, medium-speed, space-constrained acquisition.

Availability

ADS7835E/2K5G4 is available at Aetrix Electronics and suitable for portable instrumentation, wireless baseband receivers, multi-channel data loggers, and DSP-based signal processing systems requiring stable component supply across extended production lifecycles.

Supply support for ADS7835E/2K5G4 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 acquired Burr-Brown in 2000 and maintains full technical and manufacturing continuity for legacy precision analog products including the ADS7835 family.

The ADS7835 product line was designed specifically for portable, low-power, high-speed data acquisition - emphasizing integrated references, compact packaging, and flexible serial interfacing to reduce system-level design complexity.

FAQ

What is the guaranteed operating temperature range for the ADS7835E/2K5G4?

The ADS7835E/2K5G4 is specified and tested over –40°C to +85°C ambient temperature. All key parameters-including INL, DNL, SNR, and power consumption-are guaranteed across this range. The device uses a 0.6µm CMOS process optimized for stability in industrial environments, and its MSOP-8 package includes thermal enhancements to sustain performance at upper temperature limits. This makes ADS7835E/2K5G4 suitable for deployment in outdoor sensors and automotive cabin electronics.

Does the ADS7835E/2K5G4 require external components for stable operation?

Yes, the ADS7835E/2K5G4 requires specific external passive components: a 0.1µF ceramic capacitor and 2.2µF tantalum capacitor on VREF; a 0.1µF ceramic and 10µF tantalum capacitor on +VCC; and an external buffer amplifier for AIN when driving from high-impedance sources. These are not optional - omitting the VREF bypass capacitors causes reference noise spikes that degrade SFDR by >10dB, while insufficient +VCC decoupling increases power-supply rejection ratio errors beyond specification. The ADS7835E/2K5G4 datasheet provides exact placement guidelines.

Can the ADS7835E/2K5G4 interface directly with SPI peripherals?

Yes, the ADS7835E/2K5G4 supports SPI-like operation: CONV acts as chip select, CLK as serial clock, and DATA as MOSI/MISO (output-only). However, it lacks native SPI framing - data is always 12-bit two's complement with no frame sync, and timing must follow tCKCH/tCKCS constraints. To interface with standard SPI controllers, firmware must manage CONV timing manually (e.g., assert CONV before CLK, hold for ≥13 cycles for power-down). The ADS7835E/2K5G4 does not support daisy-chaining or multi-device sharing of CLK/DATA lines without external logic.

What is the purpose of the dual GND pins on the ADS7835E/2K5G4?

The ADS7835E/2K5G4 features separate analog (Pin 3) and digital (Pin 4) ground connections to minimize noise coupling between the sensitive analog front-end and switching digital interface. Internally, these grounds tie to distinct substrate regions. For optimal performance, both pins must be connected to a single low-impedance ground plane at one point near the device - never split into separate analog/digital ground planes. Routing traces from each GND pin directly to the same via or copper pour prevents ground bounce from corrupting the 12-bit conversion accuracy, especially during high-speed serial data transfer.

How does the power-down mode affect conversion latency in the ADS7835E/2K5G4?

In power-down mode (entered when CONV stays low through the 13th CLK cycle), the ADS7835E/2K5G4 disables internal bias currents and clock distribution, reducing supply current to 0.5mA. Upon CONV rising edge, full functionality resumes within tCVPU = 50ns - meaning the first conversion after wake-up is valid with no pipeline delay. There is no latency penalty: acquisition time remains 350ns, and conversion time stays 1.625µs. This allows microcontrollers to gate power between samples without sacrificing real-time responsiveness - critical for burst-mode acquisition in energy-harvesting systems.