Analog Devices Inc. LTC1609ISW#PBF

Overview

LTC1609ISW#PBF from Analog Devices (formerly Linear Technology) is a 16-bit, 200ksps serial analog-to-digital converter with integrated sample-and-hold, precision 2.5V reference, and internal clock. It operates from a single 5V supply, delivers ±2LSB INL and guaranteed no missing codes over temperature, and supports bipolar (±10V, ±5V, ±3.3V) and unipolar (0V–10V, 0V–5V, 0V–4V) input ranges. It is used in high-speed industrial data acquisition systems requiring stable DC accuracy and low power.

For engineers reviewing the LTC1609ISW#PBF datasheet, LTC1609ISW#PBF pinout, LTC1609ISW#PBF application, or LTC1609ISW#PBF equivalent, key selection criteria include its 200ksps throughput, ±10V input capability, 87dB SNR, 20-pin SO package, and support for both internal/external reference operation - critical for precision sensor interfacing and multiplexed DAQ designs.

Technical Context

The LTC1609ISW#PBF implements a switched-capacitor successive approximation architecture with auto-zeroing comparator and 16-bit capacitive DAC. Its conversion cycle comprises a 2µs acquisition phase followed by a 3µs conversion phase, achieving 5µs total throughput time. The device uses separate analog (AGND1/AGND2) and digital (DGND) ground pins to minimize noise coupling between signal and logic domains.

It features dual serial interface modes: internal clock mode (DATACLK outputting 16 pulses per conversion) or external clock mode (DATACLK as input synchronized to EXT/INT pin). Data format (straight binary or two's complement) is selected via SB/BTC pin, and TAG pin enables daisy-chaining of multiple converters in external clock mode.

Key Specifications

Pinout & Package

Package: 20-lead plastic SO (SW package), 0.300" wide, RoHS-compliant, moisture sensitivity level 1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit serial ADC applications.

Compared with ADS7809UB and AD977AARZ, the LTC1609ISW#PBF provides 2× higher throughput, superior DC linearity, and full integration of reference and clock - reducing component count and improving system-level SNR in space-constrained industrial DAQ designs.

Availability

LTC1609ISW#PBF is available at Aetrix Electronics and suitable for industrial process control, multiplexed data acquisition systems, and high-speed PC-based DAQ requiring stable component supply, long-term lifecycle support, and guaranteed RoHS compliance.

Supply support for LTC1609ISW#PBF 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

Analog Devices, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing technologies, serving industrial, automotive, communications, and healthcare markets.

The LTC1609ISW#PBF belongs to Linear Technology's precision data acquisition product line, designed specifically for high-resolution, medium-speed industrial sensing and control applications demanding low power, small footprint, and robust DC/AC performance.

FAQ

What input voltage ranges does the LTC1609ISW#PBF support?

The LTC1609ISW#PBF supports six factory-specified input ranges: bipolar ±10V, ±5V, ±3.3V and unipolar 0V–10V, 0V–5V, 0V–4V. These are configured using external resistor networks connected to R1IN, R2IN, and R3IN pins as defined in Tables 1a and 1b of the datasheet. Each range has a specified nominal input impedance (e.g., 22.9kΩ for ±10V), and all inputs are overvoltage protected to ±25V.

How does the LTC1609ISW#PBF handle reference voltage selection?

The LTC1609ISW#PBF includes an internal 2.5V ±5ppm/°C reference, accessible at the REF pin and buffered at CAP. It also accepts external references from 2.3V to 2.7V applied to REF, enabling higher accuracy when paired with precision external sources. The internal reference remains active unless overdriven; external reference operation requires disabling the internal source via proper biasing per datasheet Figure 7.

Can the LTC1609ISW#PBF operate in power-down mode without losing conversion data?

Yes. When PWRD is driven high, the LTC1609ISW#PBF enters power-down mode drawing only 50µW, but retains the most recent conversion result in its internal 16-bit shift register. Data remains accessible via serial interface as long as it has not been clocked out prior to shutdown - enabling low-power sleep/wake cycles in portable DAQ systems.

What is the purpose of the TAG pin on the LTC1609ISW#PBF?

The TAG pin on the LTC1609ISW#PBF serves as a daisy-chain identifier in external clock mode (EXT/INT = high). At the start of conversion, the logic level present on TAG is latched and shifted out on the DATA line after the 16-bit conversion result. This allows multiple LTC1609ISW#PBF devices to share a single DATACLK and DATA bus, with each device's output tagged for downstream demultiplexing.

Does the LTC1609ISW#PBF require separate analog and digital ground planes?

Yes. The LTC1609ISW#PBF has three distinct ground connections: AGND1 (for analog inputs), AGND2 (for REF/CAP), and DGND (for digital I/O). These must be tied together at a single point - typically the analog ground plane - to prevent digital noise from modulating the reference or analog input paths. Separating AGND1 and AGND2 minimizes buffer-induced noise coupling into the reference node.