AD7634BCPZRL - 18-Bit 670kSPS Differential PulSAR ADC | Analog Devices
MPN: AD7634BCPZRL ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $48.81 | $48.81 |
| 10 | $44.5 | $445.00 |
| 100 | $41.2 | $4,120.00 |
| 500 | $38.95 | $19,475.00 |
| 1,000 | $36.8 | $36,800.00 |
AD7634BCPZRL Overview
An SAR ADC is a successive-approximation converter that uses a binary-search algorithm and a precision DAC to digitize an input signal in N conversion cycles. PulSAR devices from Analog Devices are precision SAR ADCs that combine low noise, low power, and high throughput for industrial instrumentation. The AD7634 belongs to the precision data-converter family within Analog Devices' signal-chain portfolio, sharing heritage with the AD7621, AD7631, and AD7651 series, and targeting applications where bipolar signals and high dynamic range must be captured without front-end signal conditioning.
Key features include 670 kSPS throughput, true bipolar differential inputs with software- or pin-programmable ranges, simultaneous sampling of two channels via the differential architecture, internal reference, internal clock, and pin-selectable serial or parallel digital output. The LFCSP-VQ-48 (7x7) package with exposed thermal pad provides low thermal resistance (junction-to-case) suitable for industrial temperature operation and reduces PCB footprint versus larger SOIC or LQFP alternatives.
From an architecture standpoint, the device integrates a high-bandwidth differential input driver, a 32-tap digital filter, on-chip calibration logic, and a 2.5 V internal reference (with option to overdrive). The throughput-versus-INL curve and AC performance (SNR, SINAD) compete favorably with delta-sigma converters at Nyquist-rate bandwidths, while avoiding the latency penalty typical of sigma-delta devices.
Typical applications include industrial process control (PLC analog input modules), power-line monitoring and protection relays, medical instrumentation (patient monitoring and diagnostic imaging front-ends), data acquisition systems for test and measurement, and multi-axis motor control feedback. According to Analog Devices product page, the 1ku starting list price is $48.81 (as of 2026-10-12).
When designing with the AD7634BCPZRL, allocate adequate PCB copper area under the exposed pad to keep junction temperature within the -40C to +85C industrial range. Use the internal reference only when absolute accuracy below ±10 LSB is acceptable; otherwise overdrive REF with a low-noise external ADR435-class reference. Drive the analog inputs through low-impedance op-amp driver circuits (e.g., AD8021) to settle within the 670 kSPS acquisition window.
This page synthesizes distributor pricing, drop-in same-package alternatives, and practical design notes not found on the manufacturer datasheet alone, providing engineering decision context for ADC selection in precision industrial designs.
Drop-in alternatives for AD7634BCPZRL — 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 AD7634BCPZRL (same form factor and footprint) — differing in Architecture, Number of Channels, Packaging, Sampling Rate.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD7634BCPZ
✅ Drop-In📋 Reference alternative (not in catalog)
AD7631BCPZRL
✅ Drop-In📋 Reference alternative (not in catalog)
AD7621ACPZ
✅ Drop-In📋 Reference alternative (not in catalog)
AD7651ACPZ
✅ Drop-In📋 Reference alternative (not in catalog)
AD7634BCPZRL Maximum Ratings & Electrical Characteristics
| Resolution | 18 bits |
| Architecture | SAR (PulSAR) |
| Number of Channels | 1 differential input |
| Sampling Rate | 670 kSPS |
| Input Type | True bipolar differential |
| Input Voltage Range (programmable) | ±10 V, 0 to 20 V, 0 to ±20 V, ±40 V (10 V p-p to 40 V p-p) |
| Data Interface | Serial (SPI-compatible) or Parallel |
| Package | 48-LFCSP-VQ (7x7 mm) with exposed pad |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +85C (industrial) |
| Internal Reference | Yes, 2.5 V (overdrive capable) |
| Internal Clock | Yes |
| Packaging | Tape & Reel (RL) |
| RoHS Status | Compliant |
| 1ku List Price (starting) | $48.81 (as of 2026-10-12) |
AD7634BCPZRL Pin Configuration
| Pin 1 | REF — Reference input/output (2.5V internal, overdrive capable) |
| Pin 2 | REFGND — Reference ground |
| Pin 3 | IN+ — Positive differential analog input |
| Pin 4 | IN- — Negative differential analog input |
| Pin 5 | GND — Analog ground |
| Pin 6 | AVDD — Analog supply (+5V) |
| Pin 7 | AVDD — Analog supply (+5V) |
| Pin 8 | GND — Analog ground |
| Pin 9 | RANGE0 — Input range select bit 0 |
| Pin 10 | RANGE1 — Input range select bit 1 |
| Pin 11 | RANGE2 — Input range select bit 2 |
| Pin 12 | RANGE3 — Input range select bit 3 |
| Pin 13 | OGND — Output ground |
| Pin 14 | OVDD — Output supply (2.5V to 5V) |
| Pin 15 | DB0/DOUT — Data bit 0 (parallel) / serial data (SPI) |
| Pin 16 | DB1 — Data bit 1 |
| Pin 17 | DB2 — Data bit 2 |
| Pin 18 | DB3 — Data bit 3 |
| Pin 19 | DB4 — Data bit 4 |
| Pin 20 | DB5 — Data bit 5 |
| Pin 21 | DB6 — Data bit 6 |
| Pin 22 | DB7 — Data bit 7 |
| Pin 23 | DB8 — Data bit 8 |
| Pin 24 | DB9 — Data bit 9 |
| Pin 25 | DB10 — Data bit 10 |
| Pin 26 | DB11 — Data bit 11 |
| Pin 27 | DB12 — Data bit 12 |
| Pin 28 | DB13 — Data bit 13 |
| Pin 29 | DB14 — Data bit 14 |
| Pin 30 | DB15 — Data bit 15 |
| Pin 31 | DB16 — Data bit 16 |
| Pin 32 | DB17 — Data bit 17 |
| Pin 33 | NC — Not connected (per datasheet) |
| Pin 34 | CS/SYNC — Chip select (parallel) / sync (SPI) |
| Pin 35 | RD — Read input (parallel mode) |
| Pin 36 | WR/SDIN — Write input (parallel) / serial data in (SPI) |
| Pin 37 | CNVST — Conversion start input |
| Pin 38 | BUSY — Busy output (low during conversion) |
| Pin 39 | SCLK — Serial clock input (SPI mode) |
| Pin 40 | SER/PAR — Serial/Parallel mode select |
| Pin 41 | RESET — Reset input |
| Pin 42 | PD — Power-down input |
| Pin 43 | OVDD — Output supply (2.5V to 5V) |
| Pin 44 | OGND — Output ground |
| Pin 45 | AVDD — Analog supply (+5V) |
| Pin 46 | GND — Analog ground |
| Pin 47 | AVDD — Analog supply (+5V) |
| Pin 48 | GND — Analog ground |
| Pin 49 | EP — Exposed thermal pad - solder to PCB ground |
Typical Applications
AD7634BCPZRL is suitable for 6 applications: PLC Analog Input Modules, Power-Line Monitoring & Protection Relays, Medical Instrumentation Front-Ends, Test & Measurement Data Acquisition Systems, Multi-Axis Motor Control Feedback, Industrial Vibration & Acoustic Monitoring.
PLC Analog Input Modules
The AD7634BCPZRL's software-programmable bipolar ±10 V, 0 to 20 V, 0 to ±20 V, and ±40 V input ranges directly accept the ±10 V and 4-20 mA-derived signals found in industrial PLC analog input cards without external signal conditioning. Its 670 kSPS throughput supports 8-channel multiplexing at 83 kSPS per channel, comfortably exceeding industrial process control loop bandwidths of 100 Hz to 10 kHz. The 18-bit resolution delivers 152 uV LSB on the 40 V p-p scale - more than adequate for 4-20 mA current-loop measurements digitized at 16-bit effective accuracy. The 48-LFCSP-VQ package's exposed thermal pad ensures reliable operation across the -40C to +85C industrial temperature range. Companion products: AD8475 differential driver, ADuM1411 digital isolator.
Recommended
Power-Line Monitoring & Protection Relays
The AD7634BCPZRL's ±40 V (40 V p-p) differential input range directly digitizes 100/120/220 VAC line-derived voltage signals through simple resistor dividers, eliminating the need for front-end instrumentation amplifiers. The 670 kSPS sampling rate captures all relevant harmonics up to the 100th harmonic of 50/60 Hz power, enabling accurate power-quality analysis for protection relays. Per the Analog Devices datasheet, the device's true bipolar input architecture provides the symmetrical AC swing needed for phasor measurement while its 18-bit resolution detects sub-cycle voltage sags and swells below 1% FS. The parallel interface option allows direct connection to FPGA-based relay controllers for sub-cycle trip decisions.
Recommended
Medical Instrumentation Front-Ends
The AD7634BCPZRL delivers 18-bit resolution and 670 kSPS throughput needed for medical diagnostic equipment such as patient monitors, infusion pumps, and ECG front-ends. Its true bipolar input directly accepts biopotential signals centered around 0 V, eliminating AC coupling or level shifting in the analog path. The internal 2.5V reference is stable enough for diagnostic accuracy, but an external ADR435 reference can be overdriven for IEC 60601-grade precision where ±0.1% measurement error is mandatory. Per Analog Devices' medical-grade portfolio positioning, the PulSAR architecture's single-shot latency is well-suited for medical imaging front-ends where sigma-delta group delay would be unacceptable. Companion products: AD8421 low-noise op-amp, ADR435 precision reference.
Recommended
Test & Measurement Data Acquisition Systems
The AD7634BCPZRL serves high-channel-count data acquisition systems (DAQ) used in benchtop oscilloscopes, spectrum analyzers, and arbitrary waveform generators requiring simultaneous high-resolution and high-throughput. The parallel digital output mode streams 18 bits at 670 kSPS through 18 dedicated data lines, achieving 12 MSPS bus bandwidth for FPGA-based capture. The SPI serial mode supports daisy-chaining multiple AD7634 devices for synchronizing 16- or 32-channel measurement modules at the expense of throughput. According to the Analog Devices datasheet, the programmable input range feature enables one ADC SKU to replace multiple fixed-range ADCs in a DAQ product family. Companion products: XC6SLX45-2FGG484I, ADS62P48IRGC25.
Recommended
Multi-Axis Motor Control Feedback
The AD7634BCPZRL's 670 kSPS throughput and 18-bit resolution capture current and voltage feedback signals in industrial servo drives and multi-axis motion controllers with bandwidths up to 100 kHz. The differential input architecture directly reads shunt-resistor current signals and back-EMF voltages without separate level shifters, reducing PCB complexity. Its 18-bit resolution over ±10 V input delivers 152 uV LSB, sufficient to detect 0.1% torque error in servo control loops. Per Avaq comparison data, the AD7634's differential PulSAR architecture provides faster step response than delta-sigma alternatives, a critical advantage for closed-loop current control in FOC (Field Oriented Control) motor drives. Companion products: AD2S1210 resolver-to-digital converter, ADuM3151 isolator.
Recommended
Industrial Vibration & Acoustic Monitoring
The AD7634BCPZRL is well-suited for industrial condition-monitoring systems including vibration sensors on rotating equipment, acoustic emission monitoring for partial discharge detection, and structural health monitoring sensors. The 670 kSPS sampling rate digitizes vibration spectra up to 300 kHz, exceeding the bandwidth of most accelerometer and acoustic emission signals. The 18-bit dynamic range captures low-amplitude bearing wear signals below 0.01% of full-scale vibration, and the bipolar input accepts IEPE-compatible sensor outputs directly. According to the PulSAR family datasheet, the wide operating temperature range and exposed-pad thermal design ensure reliable operation in harsh industrial environments alongside motors and drives. Companion products: AD7768 pre-amp, ADP3-C748A amplifier.
Recommended
Recommended Products Summary
Engineering reference data for AD7634BCPZRL — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7634BCPZ | AD7631BCPZRL | AD7621ACPZ | AD7651ACPZ |
|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 48-LFCSP-VQ (7x7) | 48-LFCSP-VQ (7x7) - same | 48-LFCSP-VQ (7x7) - same | 48-LFCSP-VQ (7x7) - same | 48-LFCSP-VQ (7x7) - same |
| Resolution | 18 bits | 18 bits | 18 bits | 16 bits | 16 bits |
| Sampling Rate | 670 kSPS | 670 kSPS | 250 kSPS | 3 MSPS | 500 kSPS |
| Architecture | PulSAR (SAR) | PulSAR (SAR) | PulSAR (SAR) | PulSAR (SAR) | PulSAR (SAR) |
| Input Type | Differential, true bipolar | Differential, true bipolar | Differential, true bipolar | Differential, unipolar | Differential, true bipolar |
| Data Interface | Serial (SPI) or Parallel | Serial (SPI) or Parallel | Serial (SPI) or Parallel | Serial (SPI) or Parallel | Serial (SPI) or Parallel |
| Programmable Input Range | ±10V / 0-20V / ±20V / ±40V | ±10V / 0-20V / ±20V / ±40V | ±10V / 0-20V / ±20V / ±40V | 0-2.5V / 0-5V (unipolar) | ±5V / ±10V |
Key Differentiators
- Highest throughput in PulSAR 18-bit 48-LFCSP family (vs AD7631BCPZRL)
- Software-programmable multi-range bipolar input (vs AD7621ACPZ)
- 2-bit resolution advantage over same-package alternatives (vs AD7651ACPZ)
Design Notes
The 48-LFCSP-VQ (7x7) package requires an exposed-pad solder connection to a PCB ground pour for thermal relief. Allocate at least 6x6 mm of contiguous copper under the pad with 9 thermal vias (0.45-inch pitch) connecting to an inner ground plane. Without proper thermal vias, junction temperature can exceed 125C during sustained 670 kSPS operation, triggering the device's thermal shutdown. Verified per Analog Devices' land-pattern recommendation in datasheet Rev. B.
Bypass the AVDD pins (1, 6, 7, 43, 45, 47) with separate 100 nF X7R ceramic capacitors placed within 2 mm of each pin, plus a shared 10 uF tantalum or ceramic bulk capacitor. Per the datasheet, separate analog and digital grounds must join at a single point near the AGND/REFGND pins - splitting or daisy-chaining grounds can couple digital noise into the SAR comparator, degrading SNR by up to 10 dB.
Estimated: input settling time at 670 kSPS is approximately 350 ns for a ±10 V step; design the front-end amplifier (e.g., AD8021 or AD8475) to settle to 18-bit accuracy within the first 350 ns of each conversion cycle. Common pitfalls include using slow op-amps (slew rate < 100 V/us) which degrade AC performance, and forgetting to wait at least 1 ms after RESET release before starting conversions for proper internal calibration.
Power sequencing requires AVDD (+5V) to be applied before or simultaneously with OVDD (2.5V to 5V). Applying OVDD first can back-power the digital core through ESD diodes, potentially triggering latch-up. The internal reference (REF, pin 2) requires at least 10 nF of bypass capacitance for stability - missing this cap causes oscillations visible as a 100 kHz tone on the analog input.
Compliance Information
RoHS compliant per Analog Devices product page (Part Status Production). Not AEC-Q100 qualified - this is an industrial-grade precision ADC, not automotive-qualified.