LTC2321HUFD-16 - 16-Bit Dual SAR ADC, 2Msps, 28-QFN | ADI
MPN: LTC2321HUFD-16 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $14.95 | $14.95 |
| 10 | $13.45 | $134.50 |
| 100 | $11.85 | $1,185.00 |
| 500 | $10.45 | $5,225.00 |
| 1,000 | $9.2 | $9,200.00 |
LTC2321HUFD-16 Overview
What is a SAR ADC? A successive approximation register analog-to-digital converter is a type of ADC that performs a binary search through successive bit trials to digitize an analog input. SAR ADCs sit in the ADC hierarchy as: SAR ADC -> Nyquist-rate ADC -> data converter -> mixed-signal IC -> semiconductor. They are prized for excellent DC accuracy, low latency, deterministic latency, and very low power consumption relative to their throughput, which is why SAR ADCs dominate multi-channel precision data-acquisition front ends.
Key features of the LTC2321HUFD-16 include a wide 8 V_P-P differential input range, ±4 LSB typical INL with no missing codes at 16 bits, 81 dB SNR, and a low-drift (20 ppm/°C max) on-board reference that is pin-selectable between 2.048 V and 4.096 V. The serial LVDS-compatible interface reduces digital noise coupling on the board while enabling fast data transfer to an FPGA or DSP. The H-grade version operates over the extended industrial temperature range and supports an automotive temperature grade, simplifying qualification for harsh-environment designs.
Architecturally, the LTC2321HUFD-16 uses a capacitive charge-redistribution DAC for the SAR conversion and integrates the reference, reference buffer, and input drivers on-die. This reduces external BOM count and minimizes the analog front-end complexity. Each ADC channel has its own dedicated sampling network, allowing true simultaneous sampling at multi-phase, which is critical for phase-coherent measurements such as quadrature demodulation in software-defined radio.
Typical applications include industrial process control and data acquisition, software-defined radio baseband I/Q digitization, motor control feedback loops, automotive sensor signal chains, medical instrumentation, and multichannel precision test equipment. The wide common-mode range makes it suitable for directly digitizing signals from bridge sensors, current shunts, and photodiode front-ends without additional level shifting.
When designing with this device, route analog and digital grounds separately, place the bypass capacitors as close to the supply pins as possible, and treat the LVDS interface traces as a 100-ohm differential pair with controlled impedance. Always consult the ADI datasheet for the recommended layout and the reference decoupling network.
This page synthesizes distributor pricing, drop-in alternative analysis, and practical design guidance not found in the manufacturer datasheet, providing an engineering-focused reference for selecting, sourcing, and implementing the LTC2321HUFD-16 in production designs.
Drop-in alternatives for LTC2321HUFD-16 — 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:
LTC2321IUFD-16#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2321CUFD-16#PBF
✅ Drop-In📋 Reference alternative (not in catalog)
LTC2321HUFD-16 Maximum Ratings & Electrical Characteristics
| Resolution | 16 bit |
| Architecture | SAR (Successive Approximation Register) |
| Number of Channels | 2 (simultaneous sampling) |
| Sampling Rate | 2 Msps per channel |
| Input Type | Differential, wide common-mode range |
| Differential Input Range | 8 V_P-P |
| Supply Voltage | 3.3 V or 5 V single supply |
| INL (typical) | ±4 LSB |
| No Missing Codes | 16 bits |
| SNR | 81 dB |
| On-board Reference | 2.048 V or 4.096 V selectable, 20 ppm/°C max drift |
| Digital Interface | Serial LVDS-compatible |
| Package | 28-Pin QFN (4x5 mm) with EP |
| Operating Temperature Grade | H (extended, automotive capable) |
| RoHS Status | Compliant (PBF suffix) |
LTC2321HUFD-16 Pin Configuration
| Pin 1 | GND — Analog ground |
| Pin 2 | REFSELECT — Reference voltage select (2.048 V or 4.096 V) |
| Pin 3 | REFCAP — Reference bypass capacitor |
| Pin 4 | GND — Analog ground |
| Pin 5 | AIN1+ — Channel 1 positive analog input |
| Pin 6 | AIN1- — Channel 1 negative analog input |
| Pin 7 | GND — Analog ground |
| Pin 8 | AIN2+ — Channel 2 positive analog input |
| Pin 9 | AIN2- — Channel 2 negative analog input |
| Pin 10 | GND — Analog ground |
| Pin 11 | VDD — Analog supply (3.3 V or 5 V) |
| Pin 12 | GND — Analog ground |
| Pin 13 | OVDD — Digital output supply |
| Pin 14 | GND — Digital ground |
| Pin 15 | SCK+ — LVDS serial clock positive |
| Pin 16 | SCK- — LVDS serial clock negative |
| Pin 17 | SDO1+ — LVDS data output 1 positive |
| Pin 18 | SDO1- — LVDS data output 1 negative |
| Pin 19 | SDO2+ — LVDS data output 2 positive |
| Pin 20 | SDO2- — LVDS data output 2 negative |
| Pin 21 | CNV — Conversion input / chip enable |
| Pin 22 | BUSY — Conversion busy indicator |
| Pin 23 | GND — Digital ground |
| Pin 24 | RESET — Reset input |
| Pin 25 | PD — Power-down input |
| Pin 26 | GND — Digital ground |
| Pin 27 | VDD — Analog supply |
| Pin 28 | EP — Exposed pad - thermal/ground connection |
Typical Applications
LTC2321HUFD-16 is suitable for 6 applications: Industrial Process Control & Data Acquisition, Software-Defined Radio (SDR) Baseband I/Q Digitization, Motor Control Current Sensing, Automotive Sensor Signal Chains, Medical Instrumentation, Multichannel Precision Test & Measurement.
Industrial Process Control & Data Acquisition
The LTC2321HUFD-16 is a strong fit for industrial multi-channel data-acquisition front ends because its 2 Msps per-channel simultaneous sampling captures phase-coherent signals from bridge sensors, RTDs, and current shunts without skew. The 81 dB SNR and ±4 LSB INL preserve accuracy across the 8 V_P-P differential input range, while the on-board 2.048 V or 4.096 V reference with 20 ppm/°C max drift removes an external reference and its associated long-term drift. H-grade operating range plus automotive-capable temperature grade supports factory-floor and outdoor cabinet installations. Place the ADC adjacent to sensors with separate analog and digital ground planes; route the LVDS interface as 100-ohm differential pairs to the FPGA.
Recommended
Software-Defined Radio (SDR) Baseband I/Q Digitization
For SDR baseband chains, the LTC2321HUFD-16 digitizes the I and quadrature I channels simultaneously at 2 Msps, eliminating inter-channel phase skew that would otherwise corrupt demodulation. Its 81 dB SNR provides sufficient dynamic range for narrow-band demodulation of moderate-SNR signals, and the LVDS-compatible serial interface minimizes digital coupling into the RF front end. The 8 V_P_P differential input range accommodates direct connection to common baseband amplifier outputs without additional level shifting. Use controlled-impedance routing for the LVDS lines and keep the analog and digital grounds separated under the QFN exposed pad.
Recommended
Motor Control Current Sensing
Field-oriented control of three-phase motors requires simultaneous sampling of at least two phase currents to perform the Clarke and Park transformations; the LTC2321HUFD-16's dual-channel simultaneous sampling at 2 msps handles this directly. The 16-bit resolution and 81 dB SNR enable precise current measurement across the full dynamic range of PWM switching, while the wide 8 V_P_P input range accommodates shunt signals without front-end gain stages. The H-grade temperature rating suits under-hood and industrial drive environments. Use Kelvin routing from the shunt resistor to the AIN+/AIN- pins to avoid IR-drop errors.
Recommended
Automotive Sensor Signal Chains
The H-grade and automotive temperature capability of the LTC2321HUFD-16 supports AEC-Q100-style qualification paths when used in body, chassis, or ADAS sensor interfaces. The differential inputs and wide common-mode range simplify connection to bridge-type pressure sensors, strain gauges, and battery-current shunts common in EV powertrains. The integrated 2.048 V or 4.096 V reference removes a discrete component and its associated drift. Implement ISO 7637-2 transient immunity on the supply rails and use shielded twisted pairs for sensor wiring.
Recommended
Medical Instrumentation
The LTC2321HUFD-16's 81 dB SNR and no-missing-codes-at-16-bits performance support medical front-end equipment such as patient-monitoring modules, ECG front ends, and bench-top diagnostic analyzers. The simultaneous dual-channel sampling enables direct digitization of differential bioelectric potentials, while the on-board low-drift reference maintains calibration across varying clinical environments. The wide differential input range tolerates the large DC offsets common in electrophysiology. Follow IEC 60601-1 isolation and creepage/clearance requirements and add patient-protection networks upstream of the ADC inputs.
Recommended
Multichannel Precision Test & Measurement
For automatic test equipment, bench-top instruments, and modular data-acquisition cards, the LTC2321HUFD-16 provides 16-bit and 2 Msps per-channel sampling in a compact 28-QFN footprint that scales to many channels per board. The LVDS serial interface allows high-channel-count designs without excessive FPGA pin consumption. The integrated reference and small package simplify dense board layouts. Use matched-length LVDS routing across channels and a quiet analog ground island around each ADC.
Recommended
Recommended Products Summary
Engineering reference data for LTC2321HUFD-16 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LTC2321IUFD-16#PBF | LTC2321CUFD-16#PBF |
|---|---|---|---|
| Package | 28-QFN (4x5) | 28-QFN (4x5) - same | 28-QFN (4x5) - same |
| Brand | Analog Devices | Analog Devices - same | Analog Devices - same |
| Resolution | 16 bit | 16 bit | 16 bit |
| Channels | 2 simultaneous | 2 simultaneous | 2 simultaneous |
| Sampling Rate | 2 Msps | 2 Msps | 2 Msps |
| SNR | 81 dB | 81 dB | 81 dB |
| Input Range | 8 V_P-P differential | 8 V_P-P differential | 8 V_P-P differential |
| Temperature Grade | H (extended/automotive) | I (industrial) | C (commercial 0-70C) |
Key Differentiators
- H-grade operating range with automotive capability (vs LTC2321IUFD-16#PBF)
- True simultaneous dual-channel sampling at 2 Msps (vs LTC2321CUFD-16#PBF)
- On-board low-drift reference (20 ppm/°C max) (vs Generic dual SAR ADCs without internal reference)
Design Notes
Per the ADI datasheet, keep analog and digital grounds separate and connect them at a single point near the ADC. Place the REFCAP and supply bypass capacitors as close as possible to the corresponding pins. The QFN exposed pad must be soldered to a thermal/ground pad for proper heat dissipation and mechanical reliability.
Route the LVDS clock and data pairs as 100-ohm differential traces with matched length. Maintain 100-ohm differential impedance over a continuous reference plane; avoid stubs and keep the LVDS traces away from noisy switching signals. Source-terminate near the ADC if the LVDS pair length is long.
Use low-noise LDO regulators to feed the analog VDD rail from a switching pre-regulator; the SAR ADC's 81 dB SNR is sensitive to supply noise. Decouple OVDD close to the ADC pin and add a ferrite bead between analog and digital supplies if they share a source.
Do not exceed the absolute maximum analog input voltage; use a front-end protection network when digitizing signals from bridge sensors or current shunts subject to fault transients. Confirm REFSELECT logic level before power-up, since selecting the wrong reference voltage can saturate the input range.
Compliance Information
PBF suffix indicates Pb-free and RoHS-compliant per ADI ordering information. H-grade temperature rating supports automotive-grade qualification paths.
