Analog Devices Inc. LTC1861HMS#TRPBF

Overview

LTC1861HMS#TRPBF from Analog Devices (formerly Linear Technology) is a 12-bit, 250ksps, 2-channel software-selectable multiplexed successive approximation ADC in a 10-lead MSOP package, operating on a single 5V supply with 850µA typical supply current and auto-shutdown to 1nA between conversions. It features true differential input capability per channel, SPI/MICROWIRE-compatible serial I/O, and guaranteed operation from –40°C to 125°C - deployed in high-speed, low-power industrial data acquisition systems.

For engineers reviewing the LTC1861HMS#TRPBF datasheet, LTC1861HMS#TRPBF pinout, LTC1861HMS#TRPBF application, or LTC1861HMS#TRPBF equivalent, key selection criteria include its 2-channel MUX configuration flexibility, 12-bit resolution at 250ksps, H-grade temperature range, MSOP-10 thermal performance (θ_JA = 210°C/W), and compatibility with external reference voltages from 1V to V_CC.

Technical Context

The LTC1861HMS#TRPBF implements a switched-capacitor SAR architecture with integrated sample-and-hold, supporting both single-ended and differential analog input modes via a 2-bit software-configurable MUX. Its conversion timing is deterministic: t_CONV = 2.75–3.3 µs (H-grade), synchronized by CONV rising edge and serially read out on SDO using SCK falling edges.

It uses separate AGND and DGND pins for analog/digital domain isolation, requires external bypassing of V_CC and V_REF with ≥1µF tantalum capacitors, and draws only 1nA quiescent current when CONV remains high post-conversion - enabling ultra-low-power duty-cycled sensing in battery-operated instrumentation.

Key Specifications

Pinout & Package

Package: 10-lead plastic MSOP (MS package), 3.00mm × 3.00mm body, 0.50mm pitch, θ_JA = 210°C/W, rated for operation up to +125°C.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 12-bit, 2-channel SAR ADC applications.

Compared with LTC1865CMS#PBF and ADS7822U, the LTC1861HMS#TRPBF uniquely balances 2-channel software MUX agility, H-grade temperature robustness, and sub-1µA shutdown current - making it optimal for thermally demanding, multi-sensor, battery-sensitive systems where pin count and power are constrained.

Availability

LTC1861HMS#TRPBF is available at Aetrix Electronics and suitable for industrial motor control feedback, portable battery-powered DMMs, and isolated remote sensor nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for LTC1861HMS#TRPBF 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 acquired Linear Technology in 2017 and maintains its high-performance signal chain portfolio with rigorous automotive and industrial qualification standards.

The LTC1861 belongs to Linear's µPower SAR ADC family, designed specifically for compact, low-power, high-speed data acquisition in harsh thermal environments - emphasizing precision, integration, and reliability without external support components.

FAQ

What is the maximum clock frequency supported by LTC1861HMS#TRPBF for reliable serial communication?

The LTC1861HMS#TRPBF supports a maximum SCK frequency of 16.7MHz under H-grade conditions (–40°C to +125°C). This timing is validated across the full temperature range and ensures correct setup/hold margins for SDI and SDO operations. Exceeding this limit may cause data corruption or missed conversions, especially at temperature extremes. Always verify timing margins using the recommended operating conditions table in the official datasheet.

Does LTC1861HMS#TRPBF require an external reference voltage, or can it operate with VCC as reference?

The LTC1861HMS#TRPBF requires an external reference voltage applied to the VREF pin - unlike the SO-8 version, the MSOP-10 variant does not internally tie VREF to VCC. It accepts 1V to 5V references, enabling precise scaling for low-amplitude sensors. Using VCC directly as reference is not supported in this package; doing so risks violating the absolute input range and degrading INL performance.

How does the 2-channel MUX in LTC1861HMS#TRPBF configure differential versus single-ended modes?

The LTC1861HMS#TRPBF uses a 2-bit word shifted into SDI (on rising SCK edges after CONV goes low) to select among four configurations: single-ended CH0 or CH1 referenced to AGND, or differential CH0–CH1 or CH1–CH0. The MUX mapping is defined in Table 1 of the datasheet; no external hardware changes are needed - only the SDI command sequence determines input topology per conversion cycle.

What is the guaranteed minimum conversion time for LTC1861HMS#TRPBF across its full operating temperature range?

The guaranteed maximum conversion time for LTC1861HMS#TRPBF is 3.3µs at –40°C to +125°C (H-grade), with typical performance of 2.75µs. This value is production-tested and specified in the "Timing Characteristics" table. System timing budgets must allocate ≥3.3µs from CONV rising edge to SDO data validity to ensure robust operation across temperature and process variation.

Can LTC1861HMS#TRPBF interface directly with a microcontroller GPIO without level-shifting?

Yes - the LTC1861HMS#TRPBF is fully compatible with 5V-tolerant or 5V-output microcontrollers. Its digital inputs (CONV, SCK, SDI) accept VIH ≥2.4V and VIL ≤0.8V at VCC = 5V, and its SDO output drives VOH ≥4.5V (at 10µA) and VOL ≤0.4V (at 1.6mA), meeting standard 5V CMOS logic thresholds. No level-shifting is required when interfacing with 5V MCUs such as STM32F3/F4 or PIC18F series.