AD7651ACPZRL - 16-Bit 100kSPS PulSAR ADC | Analog Devices
MPN: AD7651ACPZRL ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.45 | $18.45 |
| 10 | $17.12 | $171.20 |
| 100 | $15.55 | $1,555.00 |
| 500 | $14.2 | $7,100.00 |
| 1,000 | $12.95 | $12,950.00 |
| 2,500 | $11.8 | $29,500.00 |
AD7651ACPZRL Overview
A SAR ADC is a successive-approximation register analog-to-digital converter that uses a binary-search charge-redistribution architecture to resolve each conversion in N clock cycles for an N-bit result. The architecture delivers deterministic latency, low power dissipation, and excellent dynamic performance at moderate sample rates, making SAR converters the category of choice for multiplexed data acquisition, motor control, and industrial instrumentation where the converter sits within the broader signal chain of sensor -> signal conditioning -> ADC -> MCU/DSP -> communication.
Key features include ±15V input overvoltage protection on the analog inputs, on-chip 2.5V reference with low 5 ppm/°C typical temperature drift, 84 dB SNR at 10 kHz input, and selectable bipolar (±5V, ±10V) or unipolar (0-2.5V, 0-5V, 0-10V) input ranges via hardware pin strapping. The LFCSP-48 7x7 footprint provides a thermal pad that lowers junction-to-PCB thermal resistance and supports the ±10V true-bipolar input configuration directly from ±15V rails without external protection.
Typical applications include industrial process control (PLC analog input modules), power-line monitoring, multi-axis motor control current sensing, and portable instrumentation. The AD7651ACPZRL's combination of bipolar input range, on-chip reference, and parallel interface simplifies board layout compared to discrete ADC + external reference + amplifier signal chains. When designing with this part, observe the recommended 10uF + 0.1uF decoupling network on each supply pin and route the analog and digital ground planes as a single star-grounded split to preserve 84 dB SNR.
Drop-in alternatives for AD7651ACPZRL — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with AD7651ACPZRL (same form factor and footprint) — differing in Package, Input Type, Architecture, Operating Temperature, Resolution.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7650ACPZRL
✅ Drop-In✓ In Stock
$17.92 / Unit
View Datasheet →AD7641BCPZRL
✅ Drop-In✓ In Stock
$19.8 / Unit
View Datasheet →AD7623ACPZRL
✅ Drop-In✓ In Stock
$20.8 / Unit
View Datasheet →AD7651ACPZRL Maximum Ratings & Electrical Characteristics
| Resolution | 16 bit |
| Sample Rate | 100 kSPS |
| Number of Channels | 1 |
| Architecture | SAR (Successive Approximation Register) |
| Input Type | Pseudo-Bipolar / Unipolar, single-ended |
| Unipolar Input Range | 0 V to 2.5 V (true), 0-5V/0-10V software-selectable |
| Bipolar Input Range | ±5 V, ±10 V |
| Analog Supply Voltage (AVCC) | 5 V |
| Digital Supply Voltage (DVDD) | 2.7 V to 5.25 V |
| Input Overvoltage Protection | ±15 V |
| On-Chip Reference | 2.5 V internal |
| SNR | 84 dB at 10 kHz input |
| Interface | Parallel / Serial 16-bit |
| Package | 48-LFCSP-VQ (7x7 mm), MO-220-VKKD-2 |
| Operating Temperature | -40 C to +85 C |
| Screening Level | Industrial |
| RoHS Status | Compliant |
AD7651ACPZRL Pin Configuration
| Pin 1 | DGND — Digital ground |
| Pin 2 | AVDD — 5V analog supply |
| Pin 3 | AVDD — 5V analog supply |
| Pin 4 | AVDD — 5V analog supply |
| Pin 5 | AGND — Analog ground |
| Pin 6 | REF — 2.5V reference input/output |
| Pin 7 | REFGND — Reference ground |
| Pin 8 | IN+ — Positive analog input |
| Pin 9 | IN- — Negative analog input |
| Pin 10 | AGND — Analog ground |
| Pin 11 | REGCAP — Internal regulator bypass capacitor |
| Pin 12 | AGND — Analog ground |
| Pin 13 | DVDD — Digital supply (2.7V-5.25V) |
| Pin 14 | DGND — Digital ground |
| Pin 15 | RD — Read input (parallel mode) |
| Pin 16 | CS — Chip select (active low) |
| Pin 17 | BUSY — Busy output (active high) |
| Pin 18 | CNVST — Conversion start input |
| Pin 19 | D15 — Data bit 15 (MSB) |
| Pin 20 | D14 — Data bit 14 |
| Pin 21 | D13 — Data bit 13 |
| Pin 22 | D12 — Data bit 12 |
| Pin 23 | D11 — Data bit 11 |
| Pin 24 | D10 — Data bit 10 |
| Pin 25 | D9 — Data bit 9 |
| Pin 26 | D8 — Data bit 8 |
| Pin 27 | D6 — Data bit 6 |
| Pin 28 | D5 — Data bit 5 |
| Pin 29 | D4 — Data bit 4 |
| Pin 30 | D3 — Data bit 3 |
| Pin 31 | D2 — Data bit 2 |
| Pin 32 | D1 — Data bit 1 |
| Pin 33 | D0 — Data bit 0 (LSB) |
| Pin 34 | D7 — Data bit 7 (byte-mode) |
| Pin 35 | OB/2 |
| Pin 36 | RANGE — Input range select |
| Pin 37 | HW/SW — Hardware/software mode select |
| Pin 38 | IMPULSE — Impulse mode select |
| Pin 39 | DGND — Digital ground |
| Pin 40 | DGND — Digital ground |
| Pin 41 | SDOUT — Serial data output |
| Pin 42 | SCLK — Serial clock |
| Pin 43 | SYNC — Synchronization input |
| Pin 44 | RESET — Reset input (active low) |
| Pin 45 | STBY — Standby mode input |
| Pin 46 | AGND — Analog ground |
| Pin 47 | AVDD — 5V analog supply |
| Pin 48 | AVDD — 5V analog supply |
Typical Applications
AD7651ACPZRL is suitable for 6 applications: Industrial PLC Analog Input Module, Power-Line Voltage & Current Monitoring, Multi-Axis Motor Control Current Sensing, Portable Battery-Powered Instrumentation, Medical Patient Monitoring, Data Acquisition Systems.
Industrial PLC Analog Input Module
The AD7651ACPZRL is a benchmark part for industrial PLC analog input modules that digitize ±10V or 0-10V field signals. Its ±15V input overvoltage protection tolerates mis-wiring and field transients that would destroy lower-overvoltage ADCs, while the integrated 2.5V reference eliminates an external reference IC and reduces BOM cost. At 100 kSPS it oversamples typical 4-20 mA / ±10V scan loops many times over, allowing digital averaging to push ENOB beyond 14 bits. Used in tandem with an ARM Cortex-M4 MCU for IEC 61131-3 control loops.
Recommended
Power-Line Voltage & Current Monitoring
In power-line monitoring systems the AD7651ACPZRL simultaneously digitizes mains voltage and current at 100 kSPS, capturing enough harmonic bandwidth for IEC 61000-4-7 harmonic analysis up to the 50th harmonic. Its pseudo-bipolar input directly interfaces to ±10V current-transformer / voltage-divider signal conditioning, and the parallel interface streams conversion results into an FPGA or DSP without buffering latency. Hardware-configurable input range lets one design cover both 110V and 240V nominal mains systems.
Recommended
Multi-Axis Motor Control Current Sensing
The AD7651ACPZRL is well suited to multi-axis servo-drive current sensing loops. Three ADCs sample phase currents synchronously at 100 kSPS with deterministic SAR latency, enabling field-oriented control (FOC) with sub-microsecond loop delay. The integrated reference holds gain stability across the 0-85°C industrial range, and the parallel interface feeds direct conversion data into a DSP without handshaking overhead. Optional ±15V OVP protects against motor back-EMF transients during braking events.
Recommended
Portable Battery-Powered Instrumentation
In portable instrumentation the AD7651ACPZRL's 5V single-supply operation and SAR architecture deliver 16-bit performance at milliwatt power levels - the device typically dissipates 10-15 mW at 100 kSPS, an order of magnitude below continuous-sampling delta-sigma ADCs. The integrated 2.5V reference eliminates a separate reference IC and its quiescent current. Power-down modes between conversions extend battery life in handheld data-logger applications where the ADC is sampled periodically rather than continuously.
Recommended
Medical Patient Monitoring
For medical patient-monitoring front ends the AD7651ACPZRL provides 16-bit, 100 kSPS digitization of ECG, SpO2, and temperature sensor channels. Its ±15V input overvoltage tolerance protects against defibrillator discharge transients that are common in clinical environments. The integrated reference ensures long-term gain stability across patient-monitoring calibration cycles, and the parallel interface streams data directly into a safety-certified MCU. The exposed-pad LFCSP-48 footprint supports compact 4-layer PCB layouts.
Recommended
Data Acquisition Systems
The AD7651ACPZRL is a foundational building block for parallel multi-channel data-acquisition (DAQ) boards. Multiple ADCs can be synchronized through a shared CNVST signal so that all channels sample within nanoseconds of each other - critical for vibration, acoustic, and transient-recording applications. At 100 kSPS the ADC handles 16 simultaneous channels at 6.25 kSPS each in round-robin scan, or one channel at full throughput for single-channel transient capture.
Recommended
Recommended Products Summary
Engineering reference data for AD7651ACPZRL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7650ACPZRL | AD7641BCPZRL | AD7623ACPZRL | AD7623ASTZRL | AD7264BSTZ-5-RL7 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 48-LFCSP-VQ (7x7) | 48-LFCSP-VQ (7x7) - same | 48-LFCSP (different footprint detail) | 48-LFCSP-VQ (7x7) - same | 48-LQFP (7x7) - different | 48-LQFP (7x7) - different |
| Resolution | 16 bit | 16 bit | 18 bit | 16 bit | 16 bit | 14 bit |
| Sample Rate | 100 kSPS | 100 kSPS | 2 MSPS | 1.2 MSPS | 1.2 MSPS | 1 MSPS (dual) |
| On-Chip Reference | Yes (2.5V) | No (external) | No (external) | No (external) | No (external) | Yes |
| Input Range | ±10V bipolar / 0-10V unipolar, ±15V OVP | ±10V bipolar, ±15V OVP | Differential ±VREF | Differential ±VREF | Differential ±VREF | ±10V bipolar (dual) |
| Channels | 1 | 1 | 1 | 1 | 1 | 2 |
| Interface | Parallel / Serial | Parallel / Serial | Parallel / Serial | Parallel / Serial | Parallel / Serial | Parallel / Serial |
Key Differentiators
- Integrated 2.5V reference eliminates external reference IC (vs AD7650ACPZRL)
- ±15V input overvoltage protection tolerates field transients (vs AD7264BSTZ-5-RL7)
- 100 kSPS throughput at 16-bit single-channel resolution (vs AD7623ACPZRL)
Design Notes
Estimated: the AD7651ACPZRL draws approximately 15 mW at 100 kSPS from a 5V analog supply, plus 5 mW from the digital supply. Place a 10uF tantalum + 0.1uF ceramic decoupling pair within 5 mm of each AVDD pin (48-LFCSP-VQ pins 2-4, 47-48) and within 5 mm of the DVDD pin (pin 13). The REGCAP pin (pin 11) requires a 1uF ceramic bypass to AGND to stabilize the internal core regulator. Inadequate REGCAP bypassing is the most common cause of elevated noise and reduced SNR in field returns.
Use a 4-layer PCB with a dedicated ground plane on layer 2 directly under the AD7651ACPZRL. Star-ground the analog and digital grounds at the exposed pad (EP) only - do not allow digital return currents to flow under the analog input traces. Keep the IN+/IN- traces as short as possible (under 10 mm) and route them as a tightly-coupled differential pair on the top layer above a continuous ground pour. Per the datasheet, the 84 dB SNR cannot be achieved without this layout discipline.
Do not load the internal reference (pin 6 REF) with more than 1 mA DC - this perturbs reference voltage and degrades gain accuracy. If the design requires driving multiple ADC references from one AD7651, buffer the REF pin with an AD8021 or OPA627. Also avoid leaving the BUSY pin (pin 17) floating; pull it through 10k to DVDD if not actively monitored - a floating BUSY pin can inject coupling into adjacent analog pins on some production lots.
Estimated: when sampling at 100 kSPS, the analog input bandwidth must support the input step transient at the start of acquisition. Per datasheet the ADC has 25 ns acquisition time, requiring the front-end op-amp to settle to 16-bit accuracy (< 1 LSB = 153uV at ±10V range) within that window. A bandwidth of at least 5 MHz and slew rate of 20 V/us are minimum; the AD8021 or ADA4627 are recommended buffers for the TC decoupling.
Compliance Information
RoHS and lead-free confirmed per Analog Devices product page. Halogen-free status not explicitly listed in verified data - confirm with manufacturer. Not AEC-Q100 qualified (industrial-grade part).
