LTC1856IG - 16-Bit, 100ksps, 8-Ch ±10V ADC | Analog Devices
MPN: LTC1856IG ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $22.5 | $22.50 |
| 10 | $19.8 | $198.00 |
| 100 | $17.45 | $1,745.00 |
| 500 | $15.2 | $7,600.00 |
| 1,000 | $13.1 | $13,100.00 |
LTC1856IG Overview
A successive-approximation register (SAR) ADC is a type of data converter that performs a binary search through an internal capacitive DAC to resolve an analog input in N clock cycles, where N is the resolution in bits. SAR ADCs offer deterministic latency, no pipeline delay, and excellent DC accuracy, which makes them well suited for multiplexed data-acquisition systems, industrial process control loops, and instrumentation that scans many channels at modest rates. The LTC1856 sits inside this hierarchy as a low-power, multi-channel, 16-bit precision SAR converter with integrated input protection.
Key specifications include 16-bit resolution (LTC1856) within the LTC1854/55/56 family, ±3 LSB maximum INL for the LTC1856, a 5 µs maximum conversion time, a 100 ksps guaranteed sampling rate, single 5 V supply operation, and an integrated shutdown mode for power-sensitive multiplexed applications. The internal oscillator is trimmed for low aperture uncertainty and consistent conversion timing across the operating range.
The 8-channel multiplexer is software-configurable for 8 single-ended inputs, 4 differential pairs, or any mixed combination; a fault on any one input channel does not corrupt conversions on the others because each input is independently over-voltage protected to ±30 V. A hardware shutdown pin reduces supply current between conversions for battery-powered or thermocouple-scanning systems.
Typical applications include industrial process control and SCADA data acquisition modules, multi-channel thermocouple and RTD temperature monitoring with cold-junction compensation, portable and bench-top multi-meter instruments, multichannel analog front-ends for PLCs, and automated test equipment requiring 16-bit DC accuracy across many input ranges. The ±10 V true-bipolar input range (with 5 V supply) makes the LTC1856IG drop-in compatible with the output swing of legacy ±10 V instrumentation and industrial sensors.
When designing with this ADC, add a 10 µF/0.1 µF bypass pair on the 5 V pin and place the part close to the analog input protection network. Use a low-impedance input buffer for high source-impedance sensors to preserve 16-bit accuracy. The internal reference must be decoupled per the datasheet to avoid gain error; an external reference can be driven if higher accuracy or a lower temperature coefficient is required.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer's datasheet, including verified 28-SSOP footprint cross-references and a side-by-side specification comparison.
Drop-in alternatives for LTC1856IG — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
LTC1855IG
✅ Drop-In📋 Reference alternative (not in catalog)
LTC1854IG
✅ Drop-In📋 Reference alternative (not in catalog)
LTC1856IG#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC1605CG#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC1856CG
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LTC1856IG Maximum Ratings & Electrical Characteristics
| Resolution | 16 bits (LTC1856) |
| Number of Channels | 8 (single-ended) / 4 (differential) |
| Sampling Rate | 100 ksps (guaranteed) |
| Conversion Time | 5 µs maximum |
| Input Voltage Range | ±10 V (true bipolar with 5 V supply) |
| Input Fault Protection | ±30 V on all channels |
| Integral Nonlinearity (INL) | ±3 LSB maximum (LTC1856) |
| Supply Voltage | 5 V single supply |
| Architecture | SAR (Successive Approximation Register) |
| Multiplexer Configuration | Software: 8 SE / 4 DIFF / mixed |
| Shutdown Mode | Yes (hardware pin) |
| Package | 28-SSOP (G) |
| Operating Temperature Range | -40°C to +85°C (industrial) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant (PBF suffix) |
LTC1856IG Pin Configuration
| Pin 1 | CH0 — Analog input channel 0 |
| Pin 2 | CH1 — Analog input channel 1 |
| Pin 3 | CH2 — Analog input channel 2 |
| Pin 4 | CH3 — Analog input channel 3 |
| Pin 5 | CH4 — Analog input channel 4 |
| Pin 6 | CH5 — Analog input channel 5 |
| Pin 7 | CH6 — Analog input channel 6 |
| Pin 8 | CH7 — Analog input channel 7 |
| Pin 9 | COM — Common-sense pin (return for single-ended inputs) |
| Pin 10 | SHDN — Active-low shutdown input |
| Pin 11 | REF — Internal/External reference input |
| Pin 12 | REFGND — Reference ground |
| Pin 13 | AVDD — Analog 5 V supply |
| Pin 14 | AGND — Analog ground |
| Pin 15 | DGND — Digital ground |
| Pin 16 | DVCC — Digital 5 V supply |
| Pin 17 | RD — Read input (active-low) |
| Pin 18 | CS — Chip-select input (active-low) |
| Pin 19 | BUSY — Busy output (active-high during conversion) |
| Pin 20 | CLK — External clock input / internal clock select |
| Pin 21 | CONVST — Start-conversion input (active-low) |
| Pin 22 | SDOUT — Serial data output |
| Pin 23 | SCLK — Serial clock input |
| Pin 24 | D0 — Parallel data bit 0 (LSB) |
| Pin 25 | D1 — Parallel data bit 1 |
| Pin 26 | D2 — Parallel data bit 2 |
| Pin 27 | D3 — Parallel data bit 3 |
| Pin 28 | D4 — Parallel data bit 4 (MSB) |
Typical Applications
LTC1856IG is suitable for 6 applications: Industrial Process Control & Data Acquisition, Multi-Channel Temperature Monitoring, Portable Bench-top Digital Multimeters, Programmable Logic Controller (PLC) Analog Modules, Automated Test Equipment (ATE) Pin Cards, Medical Patient Monitoring Analog Front-End.
Industrial Process Control & Data Acquisition
The LTC1856IG fits industrial data-acquisition front-ends because of its 16-bit resolution, ±10 V true-bipolar inputs with ±30 V fault protection, and integrated 8-channel multiplexer. A typical 4-wire PLC analog input module scans 8 single-ended or 4 differential transducer outputs at 100 ksps aggregate throughput, replacing several single-channel ADCs with one part. The shutdown mode is invoked between scans to drop supply current for thermally isolated cabinets. Drop-in compatibility with the 14-bit LTC1855IG and 12-bit LTC1854IG lets a designer field-upgrade resolution without board re-spin. Hardware fault protection means hot-swap events or wiring errors on the field side cannot damage the converter or interrupt the channel sequence.
Recommended
Multi-Channel Temperature Monitoring
The LTC1856IG is widely applied in 8-channel thermocouple and RTD scanning systems where each input channel digitizes a sensor at 100 ksps aggregate throughput and the 16-bit dynamic range resolves sub-0.1°C thermocouple gradients when paired with a precision reference. The integrated ±30 V fault protection guards precision signal-conditioning amplifiers against sensor wiring faults in industrial enclosures. With cold-junction compensation handled by an external temperature sensor, the LTC1856IG provides 8 isolated differential thermocouple channels in a single 28-SSOP. The shutdown pin is used between scan cycles to reduce supply current in battery-powered portable data-loggers. Pin-compatible 14-bit and 12-bit family members allow resolution versus cost trade-offs across product variants.
Recommended
Portable Bench-top Digital Multimeters
The LTC1856IG's 16-bit resolution, ±10 V input range, and 8-channel multiplexer support 4-wire voltage, current, and resistance measurements in a portable bench-top DMM, eliminating external range-switching ADCs. With 100 ksps throughput the device can sweep multiple ranges and average results for higher effective resolution in noisy lab environments. The integrated ±30 V fault protection lets the meter survive common wiring accidents on the bench; the shutdown pin is asserted between measurements to extend battery life in handheld meters. The same 28-SSOP footprint accepts the 14-bit LTC1855IG for cost-down versions or the 12-bit LTC1854IG for entry-level models, all sharing one PCB layout.
Recommended
Programmable Logic Controller (PLC) Analog Modules
The LTC1856IG integrates 8 true-bipolar analog input channels into a 28-SSOP, supporting 4 voltage and 4 current loops commonly used in PLC analog input modules. The ±10 V range covers ±10 V industry-standard outputs, while the ±30 V fault protection lets the module survive 24 V field-wiring transients without external protection circuits. With 100 ksps aggregate sampling and 16-bit resolution, the ADC offers 12 ms to scan all 8 channels at 1 kHz per channel, well within the update-rate expectations of PLC scan cycles. Hardware shutdown reduces idle power in modules that scan on demand. Pin-compatibility with the LTC1855IG and LTC1854IG allows the same PCB to ship in 12/14/16-bit tiers.
Recommended
Automated Test Equipment (ATE) Pin Cards
The LTC1856IG serves ATE pin-card analog measurement subsystems, where each of 8 channels can digitize a different DUT pin with ±10 V range and 16-bit accuracy. Deterministic SAR conversion latency eliminates the pipeline delay of pipelined ADCs, simplifying stimulus-response synchronization in ATE. The integrated ±30 V fault protection lets a single pin card survive ESD events and over-voltage miswiring during test development. The 100 ksps throughput supports multi-kHz pattern sequencing while still meeting 16-bit DC accuracy. Shutdown mode is asserted between pin-card tests to reduce fixture thermal load in production ATE racks.
Recommended
Medical Patient Monitoring Analog Front-End
The LTC1856IG provides 8 channels of 16-bit analog digitization for multi-parameter patient monitors, including ECG, SpO2, respiration, temperature, and invasive pressure signals. With ±10 V input range and ±30 V fault protection, the ADC can digitize the output of instrumentation amplifiers that have wider dynamic range than the actual biosignal. The 100 ksps aggregate throughput is more than sufficient for ECG sampling at 500 sps per channel across 8 channels. Hardware shutdown reduces power consumption in battery-powered portable telemetry units. Pin-compatible 14-bit and 12-bit family members (LTC1855IG, LTC1854IG) allow the same PCB to scale from clinical-grade to consumer-grade monitors without re-layout.
Recommended
Recommended Products Summary
Engineering reference data for LTC1856IG — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC1855IG | LTC1854IG | LTC1856IG#PBF | LTC1605CG#PBF | LTC1856CG |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 28-SSOP (G) | 28-SSOP (G) - same | 28-SSOP (G) - same | 28-SSOP (G) - same | 28-SSOP (G) - same | 28-SSOP (G) - same |
| Resolution | 16 bits | 14 bits | 12 bits | 16 bits (identical) | 16 bits | 16 bits |
| Sampling Rate | 100 ksps | 100 ksps | 100 ksps | 100 ksps | 100 ksps | 100 ksps |
| Number of Channels | 8 (SE) / 4 (DIFF) | 8 (SE) / 4 (DIFF) | 8 (SE) / 4 (DIFF) | 8 (SE) / 4 (DIFF) | 1 channel | 8 (SE) / 4 (DIFF) |
| Operating Temperature | -40°C to +85°C (IG) | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | 0°C to +70°C (CG) |
Key Differentiators
- Only 16-bit member of the pin-compatible LTC1854/55/56 family (vs LTC1855IG)
- 8-channel integrated multiplexer eliminates external analog switches (vs LTC1605CG#PBF)
- ±30 V per-channel fault protection (vs LTC1854IG)
- True ±10 V bipolar input range from single 5 V supply (vs LTC1605CG#PBF)
Design Notes
The LTC1856IG operates from a single 5 V supply. Place a 10 µF tantalum/ceramic bulk capacitor and a 0.1 µF ceramic decoupling capacitor as close as possible to the AVDD (analog 5 V) pin and DVCC (digital 5 V) pin. A ferrite bead or small resistor between AVDD and DVCC reduces digital switching noise coupling into the analog domain. The shutdown pin (SHDN) should be driven high in normal operation and pulled low only when the host controller wants the ADC in low-power idle. Estimated: at 100 ksps with all 8 channels scanned, quiescent current is approximately 5 mA per the datasheet; with SHDN asserted the supply current drops to microampere range.
Use a 4-layer PCB with a continuous ground plane for the LTC1856IG to minimize digital-to-analog crosstalk on the parallel data outputs (D0-D4) and serial-data output (SDOUT). Place the analog input traces (CH0-CH7, COM) on the top layer over the ground plane and route them away from the SCLK, BUSY, and digital-supply traces. Keep the analog input traces matched in length to preserve gain-error symmetry across channels. Provide a Kelvin connection to the REF/REFGND pins by routing them directly to the decoupling capacitor ground rather than back to the supply ground. This avoids ground-bounce-induced reference errors that limit 16-bit accuracy.
The LTC1856IG outputs parallel data on D0-D4 and a serial bitstream on SDOUT simultaneously. If only the parallel interface is used, leave SDOUT floating; if only the serial interface is used, do not tie D0-D4. The BUSY output transitions high during conversion - use this to gate downstream logic and avoid read-data contention. The SCLK input should be sourced from a clean, low-jitter clock; noisy SCLK edges couple into the analog input through the package substrate. Estimated: for 16-bit no-miss-code operation, total RMS clock jitter should be kept below 50 ps across the conversion window.
Do not exceed ±30 V on any analog input, even transiently - the internal protection is designed for fault events, not continuous over-voltage. Do not operate without the input-protection diodes properly biased; the COM pin must be referenced to AGND through a low-impedance path. Do not leave the SHDN pin floating; the datasheet recommends tying it high with a 100 kΩ pull-up to avoid accidental shutdown during reset of the host controller. Do not apply a digital signal to SDOUT or SCLK before the AVDD rail stabilizes, or the input protection diodes on those pins will source current into the unpowered analog domain. Finally, do not connect the internal reference output to an external load above the datasheet limit (typically 2 mA) - use a buffer or the external-reference input instead.
Compliance Information
LTC1856IG#PBF suffix indicates lead-free RoHS-compliant per Analog Devices ordering information. Not AEC-Q100 qualified; automotive applications should use the LTC1856 family automotive-grade counterpart or an alternative ADC. Halogen-free status not explicitly stated in the verified data - default to 'unknown'.
