Analog Devices Inc. LTC1859CG#TRPBF

Overview

LTC1859CG#TRPBF from Analog Devices (formerly Linear Technology) is a 16-bit, 8-channel, 100ksps software-programmable analog-to-digital converter with ±25V fault-protected inputs, single 5V supply operation, and ±3LSB integral nonlinearity. It supports unipolar (0V–5V/0V–10V) and bipolar (±5V/±10V) input spans via SoftSpan™ configuration and integrates internal 2.5V reference and 4.096V buffered reference output. It serves in industrial data acquisition systems requiring high channel density and robust input protection.

For engineers reviewing the LTC1859CG#TRPBF datasheet, LTC1859CG#TRPBF pinout, LTC1859CG#TRPBF application, or LTC1859CG#TRPBF equivalent, key selection criteria include its 16-bit resolution with ±3LSB INL over temperature, SPI/MICROWIRE™ serial interface timing (up to 20MHz SCK), 28-pin SSOP package footprint, and dual power shutdown modes (Nap/Sleep) enabling <27.5mW active power dissipation.

Technical Context

The LTC1859CG#TRPBF employs a successive approximation register (SAR) architecture with integrated sample-and-hold, factory-trimmed internal clock (5µs max conversion time), and programmable resistor-divider network preceding the 8-channel analog multiplexer. Its SoftSpan™ range selection occurs per-channel via 8-bit command word written to SDI before CONVST assertion.

It features three independent ground domains (AGND1/AGND2/AGND3), separate analog (AVDD), digital (DVDD), and output buffer (OVDD) supplies, and fault isolation that prevents ±25V overvoltage on unselected channels from corrupting the selected channel's conversion result.

Key Specifications

Pinout & Package

Package: 28-lead plastic SSOP (G package), 0°C to 70°C operating temperature range, lead-free finish.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LTC1859CG#TRPBF, AD7606BSTZ offers simultaneous sampling but lacks per-channel span flexibility and consumes >2.5× more power, while ADS8688IPWR adds PGA functionality at half the sampling rate-making LTC1859CG#TRPBF optimal for cost- and power-sensitive designs requiring adaptive input scaling.

Availability

LTC1859CG#TRPBF is available at Aetrix Electronics and suitable for industrial process control, PLC I/O modules, and PC-based data acquisition systems requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for LTC1859CG#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.

The LTC1859CG#TRPBF belongs to ADI's legacy Linear Technology precision data acquisition product line, engineered for high-channel-count, fault-tolerant industrial measurement systems where software-configurable input ranges reduce system design complexity.

FAQ

What is the maximum sampling rate supported by the LTC1859CG#TRPBF?

The LTC1859CG#TRPBF guarantees a maximum sampling rate of 100ksps when converting through any of the eight analog input channels (CH0–CH7). This is achieved with a typical conversion time of 4µs and acquisition time of 1µs. When using only the dedicated ADC+ and ADC– pins (bypassing the multiplexer), the rate increases to 166ksps, as confirmed in the Timing Characteristics table of the official datasheet.

Does the LTC1859CG#TRPBF require an external reference voltage?

No, the LTC1859CG#TRPBF operates fully autonomously with its internal 2.5V bandgap reference (VREF) and 4.096V buffered reference (REFCOMP), both factory-trimmed and temperature-compensated. However, VREF can be overdriven with an external precision reference if higher absolute accuracy is required-this is explicitly supported and documented in the Applications Information section.

How does the SoftSpan™ feature work on the LTC1859CG#TRPBF?

The SoftSpan™ feature on the LTC1859CG#TRPBF allows per-channel software programming of input voltage ranges (0V–5V, 0V–10V, ±5V, or ±10V) via an 8-bit command word sent to SDI before asserting CONVST. This command configures on-chip resistor dividers and offset networks *before* the multiplexer, eliminating errors from switch resistance and enabling true channel-by-channel range independence.

What is the purpose of the three AGND pins (AGND1, AGND2, AGND3) on the LTC1859CG#TRPBF?

The LTC1859CG#TRPBF uses AGND1 for the analog input multiplexer and reference circuitry, AGND2 for the ADC core and sample-and-hold, and AGND3 as the substrate connection. Separating these grounds minimizes noise coupling between sensitive analog blocks and improves PSRR and THD performance-especially critical for 16-bit accuracy. They must be tied together at a single low-impedance point near the device.

Can the LTC1859CG#TRPBF interface directly with a 3.3V microcontroller?

Yes, the LTC1859CG#TRPBF supports 3V-compatible digital I/O: its SDI, SCK, and RD inputs accept VIH ≥ 2.4V and VIL ≤ 0.8V at VDD = 4.75–5.25V, and OVDD can be supplied at 3V–5V to set SDO output swing. This allows direct connection to 3.3V logic without level shifters, provided OVDD is set to 3.3V and timing margins (e.g., t11 hold time ≥ 7ns) are met.