Analog Devices Inc. DC2196A-A

Overview

LTC2666 from Analog Devices (formerly Linear Technology) is an octal 16-bit/12-bit ±10V SoftSpan DAC with integrated 2.5V reference, rail-to-rail output buffers, independently programmable output ranges (0V–5V, 0V–10V, ±2.5V, ±5V, ±10V), and SPI/Microwire-compatible 3-wire serial interface operating up to 50MHz. It delivers ±4LSB max INL at 16 bits and drives ±10mA per channel - used in precision instrumentation and automated test equipment requiring multi-range analog control.

For engineers reviewing the LTC2666 datasheet, LTC2666 pinout, LTC2666 application, or LTC2666 equivalent, key selection criteria include guaranteed monotonicity over temperature, A/B toggle capability (hardware or software), 32-lead QFN package with exposed V– pad, internal/external reference flexibility, and ±10V rail-to-rail output swing under load.

Technical Context

The LTC2666 implements eight independent DAC channels sharing a single 2.5V buffered reference, each configurable via SPI register writes or hardware MSPAN pins for fixed or dynamic range selection. Its SoftSpan architecture enables per-channel span programming without external components.

It features dual input registers (A/B) with asynchronous toggle via dedicated TGP pin or SPI command, LDAC-controlled synchronous update, and hardware CLR for reset to power-on code/range. The integrated analog multiplexer routes any DAC output, REF, V+/V–, or temperature monitor to MUXOUT for diagnostics.

Key Specifications

Pinout & Package

32-lead (5mm × 5mm) QFN package with exposed pad connected to V–; requires soldering exposed pad to PCB ground plane for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar DAC applications.

Compared with AD5689R and DAC8568, the LTC2666 uniquely combines per-channel SoftSpan range selection, hardware A/B toggle, integrated analog multiplexer, and thermal interrupt in a single 32-lead QFN - reducing system-level complexity for high-integration test and control applications.

Availability

LTC2666 is available at Aetrix Electronics and suitable for optical networking, instrumentation, data acquisition, automatic test equipment, and process control applications requiring stable component supply, long-term lifecycle support, and guaranteed parametric performance across industrial temperature grades.

Supply support for LTC2666 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 LTC2666 belongs to ADI's precision DAC product line, designed specifically for applications demanding multi-channel, multi-range analog output with integrated diagnostics, robust thermal management, and deterministic timing behavior in harsh environments.

FAQ

What output voltage ranges does the LTC2666 support?

The LTC2666 supports five independent output ranges per channel: 0V to 5V, 0V to 10V, ±2.5V, ±5V, and ±10V. Each channel's range is programmable via SPI or fixed at power-up using MSP0–MSP2 pins. The LTC2666 achieves full 16-bit or 12-bit resolution across all ranges without interpolation, and its rail-to-rail output buffers maintain specified accuracy under ±10mA load conditions.

How does the LTC2666 handle reference voltage selection?

The LTC2666 integrates a 2.5V precision reference with ±10ppm/°C max temperature coefficient, routed by default to the REF pin. It can be disabled via SPI or REFCOMP pin configuration to allow external reference injection (0.5V to VCC–1.75V). When using the internal reference, CREF and CREFCOMP must each be bypassed with 0.1µF capacitors to GND for optimal noise and stability. The LTC2666 maintains specified INL and gain error only when reference loading remains within datasheet limits.

What is the purpose of the MUXOUT pin on the LTC2666?

The MUXOUT pin on the LTC2666 is a diagnostic analog multiplexer output that can route any of eight DAC outputs (VOUT0–VOUT7), REF, V+, V–, or the internal temperature monitor signal. This enables real-time verification of DAC outputs, supply rail monitoring, or thermal sensing without additional external probes or circuitry. Selection is controlled via SPI register writes, and the MUXOUT pin enters high-impedance state when disabled - making it ideal for embedded self-test and calibration routines in the LTC2666-based system.

Does the LTC2666 support hardware-based A/B register toggling?

Yes, the LTC2666 supports hardware-based A/B register toggling via the TGP (Toggle Pin) input. A falling edge on TGP updates selected DAC channels from Input Register A; a rising edge updates them from Input Register B - provided their respective toggle select bits (Tx) are set. This allows deterministic, low-latency switching between two preloaded output states without host processor involvement. If unused, TGP must be tied to IOVCC; tying it to GND disables hardware toggle functionality entirely in the LTC2666.

What thermal protection features does the LTC2666 include?

The LTC2666 includes an on-die thermal monitor with open-drain OVRTMP pin that asserts low when junction temperature exceeds 160°C. This signal remains active until the next CS/LD rising edge, allowing the host to initiate graceful shutdown or reduce load before permanent damage occurs. The exposed pad (connected to V–) must be soldered to the PCB for effective heat dissipation. Thermal shutdown is independent of supply voltages and operates across the full specified temperature range - a critical safety feature for the LTC2666 in enclosed or high-power-density applications.