AD7894AR-10REEL7 - 14-Bit 200kSPS Serial ADC | Analog Devices
MPN: AD7894AR-10REEL7 ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $16.92 | $16.92 |
| 10 | $15.23 | $152.30 |
| 100 | $13.54 | $1,354.00 |
| 500 | $11.85 | $5,925.00 |
| 1,000 | $10.16 | $10,160.00 |
AD7894AR-10REEL7 Overview
What is a SAR ADC? A successive-approximation-register analog-to-digital converter is a class of ADC that converts an analog input to a digital code by performing a binary search across an internal DAC and comparator. SAR ADCs occupy a middle ground between flash converters (fastest, lowest resolution) and sigma-delta ADCs (slowest, highest resolution), typically delivering 8-18 bits at 100 kSPS to several MSPS with no pipeline latency. SAR ADCs are the workhorse of industrial data acquisition, motor control, and instrumentation signal chains because each conversion is a single-shot event with deterministic timing.
Key features of the AD7894 include ±5 LSB maximum integral nonlinearity, guaranteed ac specifications such as 78 dB SINAD and -85 dB total harmonic distortion at the input tone, hardware configurable for ±5 V or 0-5 V unipolar inputs across the AD7894 family, and a hardware CONVST pin for precise sampling control. The 8-lead SOIC footprint enables compact PCB placement next to analog front ends. Power consumption is approximately 20 mW typical at full sampling rate, allowing the converter to operate in thermally constrained enclosures.
The AD7894 uses a capacitive-charge-redistribution DAC core with auto-calibrated switch-capacitor front-end, providing excellent dc accuracy and low aperture uncertainty. The on-chip track-and-hold amplifier settles to 14-bit accuracy within 200 ns, supporting high-bandwidth multiplexed input architectures. The serial interface is hardware- or DSP-compatible, reducing opto-isolation cost in noisy industrial environments.
Typical applications include industrial process control, motor control position feedback, portable instrumentation, data acquisition systems, and DSP front-ends. The wide bipolar input range makes the AD7894-10 particularly suited for direct connection to current-sense amplifiers and bridge transducers without additional signal conditioning.
When designing with this ADC, place the 0.1 µF decoupling capacitor within 5 mm of the VDD pin and keep analog and digital grounds separated until they connect at the ADC's AGND pin. Avoid routing the CONVST and SCLK traces parallel to noisy switching signals to preserve 14-bit SNR.
This page synthesizes verified distributor stock, drop-in cross-references from Analog Devices' own AD7894 family and competitor ADCs, and practical PCB design notes that go beyond the manufacturer datasheet.
Drop-in alternatives for AD7894AR-10REEL7 — 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:
AD7894ARZ-10REEL7
✅ Drop-In📋 Reference alternative (not in catalog)
AD7894BRZ-10REEL7
✅ Drop-In📋 Reference alternative (not in catalog)
AD7894ARZ-10REEL
✅ Drop-In📋 Reference alternative (not in catalog)
AD7894AR-10REEL
✅ Drop-In📋 Reference alternative (not in catalog)
ADS8513
✅ Drop-In📋 Reference alternative (not in catalog)
MAX1146
✅ Drop-In📋 Reference alternative (not in catalog)
AD7894AR-10REEL7 Maximum Ratings & Electrical Characteristics
| Number of Bits | 14 |
| Sampling Rate | 200 kSPS |
| Conversion Time | 5 µs |
| Number of Inputs | 1 |
| Input Type | Single-Ended, Bipolar (±10 V) |
| Architecture | SAR (Successive Approximation) |
| Data Interface | Serial (2-wire) |
| Supply Voltage | +5 V single supply |
| Integral Nonlinearity (INL) | ±5 LSB max |
| SINAD | 78 dB |
| Total Harmonic Distortion | -85 dB |
| Operating Temperature | -40°C to +85°C (industrial) |
| Package | 8-pin SOIC (0.154", 3.90 mm width) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel (TR), 7-inch reel |
| On-Chip Track/Hold | Yes |
| On-Chip Clock | Yes |
AD7894AR-10REEL7 Pin Configuration
| Pin 1 | AGND — Analog ground reference |
| Pin 2 | VDD — +5 V analog supply |
| Pin 3 | VIN — Analog input (±10 V bipolar) |
| Pin 4 | REF — Reference voltage input/output |
| Pin 5 | SCLK — Serial interface clock input |
| Pin 6 | SDATA — Serial data output |
| Pin 7 | CONVST — Conversion start input (active low) |
| Pin 8 | DGND — Digital ground |
Typical Applications
AD7894AR-10REEL7 is suitable for 6 applications: Industrial Process Control, Motor Control Position Feedback, Portable Instrumentation, Data Acquisition Systems, DSP Front-End Interface, Power Supply Voltage Monitoring.
Industrial Process Control
The AD7894AR-10REEL7's ±10 V bipolar input range and 200 kSPS throughput make it ideal for industrial process control loops where 4-20 mA current-loop signals are converted by a 250 Ω sense resistor to 1-5 V analog inputs. With 14-bit resolution the LSB is 1.22 mV at ±10 V full scale, enabling precise temperature, pressure, and flow measurement in PID controllers. The 5 µs conversion time supports 200 kSPS multiplexed scanning across 8-16 analog inputs when paired with an external MUX, and the hardware CONVST pin allows deterministic sampling synchronized to PWM outputs for motor-control phases. Industrial-grade -40°C to +85°C operation survives factory floor thermal stress, and the 2-wire serial interface simplifies opto-isolation barriers in high-noise 24 V plant environments.
Recommended
Motor Control Position Feedback
Motor control position feedback loops require ADCs with deterministic single-shot conversion latency, which is exactly what the AD7894AR-10REEL7 provides. SAR ADCs complete one conversion in 5 µs with no pipeline delay, so position-error readings are immediately available to the DSP without waiting for a sigma-delta filter group delay. The 14-bit resolution (16,384 codes) supports encoder-resolver feedback to ±0.022 degrees at full ±10 V input. The hardware CONVST pin can be triggered synchronously with PWM zero-crossings, eliminating sample-to-sample jitter that degrades current-loop stability. ±10 V bipolar input accepts direct resolver-to-digital converter outputs or Hall-sensor-derived analog signals, removing external op-amp signal conditioning and reducing BOM cost per axis.
Recommended
Portable Instrumentation
The AD7894AR-10REEL7's single +5 V supply and 20 mW typical power consumption make it well-suited for battery-powered portable instrumentation such as handheld oscilloscopes, multimeters, and field-installed data loggers. The 8-pin SOIC package occupies only 9.8 mm² of PCB area, fitting inside handheld enclosures. SAR ADCs avoid the long latency of sigma-delta converters, giving portable DSO designs immediate trigger-to-display response. The ±10 V bipolar input range matches the signal levels from typical handheld measurement probes, eliminating external attenuator op-amps. With 78 dB SINAD the ADC floor is well below the noise of typical handheld instrument analog front ends, so SNR is limited by the input amplifier rather than the converter.
Recommended
Data Acquisition Systems
Plug-in data acquisition cards and modular DAQ systems benefit from the AD7894AR-10REEL7's 200 kSPS throughput and serial interface, which reduces pin count and simplifies high-density PCB layouts. The 2-wire serial interface requires only SCLK and SDATA lines, freeing board space for analog input protection circuits, MUX arrays, or signal-conditioning amplifiers. Multiple AD7894 devices can share the same serial bus when synchronized via CONVST, supporting scalable channel counts from 4 to 64 inputs per card. The 78 dB SINAD at the analog input translates to >12 effective bits, exceeding the requirements of most USB and PCIe data acquisition modules marketed for vibration analysis, acoustic recording, and biomedical signal capture.
Recommended
DSP Front-End Interface
DSP front-ends in audio processing, communications, and control systems benefit from the AD7894AR-10REEL7's serial interface, which connects directly to TMS320, SHARC, and Blackfin DSP serial ports without external glue logic. The 5 µs conversion time supports 200 kSPS real-time sampling, sufficient for narrowband communications receivers up to 100 kHz Nyquist bandwidth and for audio front-ends up to 50 kSPS oversampled DSP. The hardware CONVST pin can be triggered by DSP timer outputs, ensuring deterministic sample timing aligned with DMA transfers. ±10 V bipolar input directly accepts line-level audio signals with appropriate input scaling, eliminating external coupling capacitors and AC-coupling amplifiers in some designs.
Recommended
Power Supply Voltage Monitoring
Telecom and industrial power supply monitoring applications use the AD7894AR-10REEL7's ±10 V bipolar input to directly measure ±12 V or ±15 V analog rails without external dividers or level shifters. The 14-bit resolution detects 1.22 mV supply variations at 12 V rails, sufficient to identify ripple, droop, and load-step transients. With 200 kSPS sampling, the ADC captures fast transient events from switching converters at sub-microsecond resolution when an external anti-alias filter is applied. The hardware CONVST pin enables synchronous sampling across multiple rails, supporting power-rail sequencing verification in multi-voltage ASIC and FPGA designs. The serial interface simplifies isolation in high-voltage battery-monitoring modules.
Recommended
Recommended Products Summary
Engineering reference data for AD7894AR-10REEL7 — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD7894ARZ-10REEL7 | AD7894BRZ-10REEL7 | AD7894ARZ-10REEL | ADS8513 | MAX1146 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Texas Instruments | Analog Devices (Maxim) |
| Package | 8-SOIC (3.90 mm) | 8-SOIC (3.90 mm) | 8-SOIC (3.90 mm) | 8-SOIC (3.90 mm) | 8-SOIC (3.90 mm) | 8-SOIC (3.90 mm) |
| Resolution | 14-bit | 14-bit | 14-bit | 14-bit | 14-bit | 14-bit |
| Sampling Rate | 200 kSPS | 200 kSPS | 200 kSPS | 200 kSPS | 200 kSPS | 200 kSPS |
| Input Range | ±10 V bipolar | ±10 V bipolar | ±10 V bipolar | ±10 V bipolar | ±10 V bipolar | ±5 V bipolar |
| INL (max) | ±5 LSB (A grade) | ±5 LSB | ±2 LSB (B grade) | ±5 LSB | ±3 LSB | ±2 LSB |
| Architecture | SAR | SAR | SAR | SAR | SAR | SAR |
| Data Interface | Serial (2-wire) | Serial (2-wire) | Serial (2-wire) | Serial (2-wire) | Serial (SPI-compatible) | Serial (SPI-compatible) |
| Operating Temperature | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C |
Key Differentiators
- Bipolar ±10 V input without external signal conditioning (vs ADS8513)
- Mature AD7894 family with multiple qualified sources (vs MAX1146)
- Hardware CONVST pin for deterministic sampling (vs ADS8513)
Design Notes
Place a 0.1 µF ceramic decoupling capacitor within 5 mm of the VDD pin (pin 2) and a 10 µF tantalum or aluminum bulk capacitor at the supply via. Use separate analog and digital ground planes that join only at the AGND pin (pin 1) to prevent digital switching noise from coupling into the analog input path. Avoid routing the SCLK and CONVST traces parallel to the analog VIN trace; keep digital traces at least 3 mm away from analog traces or shield them with ground fills.
Route the analog input trace (pin 3) as a microstrip over a continuous ground plane to minimize loop area and maximize high-frequency rejection. Add a 100 Ω series resistor and 1 nF capacitor at the ADC input pin to form a single-pole RC anti-alias filter with a -3 dB cutoff of 1.6 MHz, sufficient for 200 kSPS Nyquist applications. Place this RC network within 5 mm of the VIN pin to suppress switching noise from digital logic and switching power supplies.
Do not apply input voltages exceeding ±15 V to the VIN pin; permanent damage can occur above absolute maximum ratings. Ensure the CONVST pulse width is at least 50 ns to start a conversion, and wait the full 5 µs conversion time before reading SDATA. The reference input (pin 4) requires a stable low-noise reference; use the internal 2.5 V reference or an external REF192 with 10 µF and 0.1 µF decoupling. Failure to observe the power-supply sequencing (VDD before VIN) can latch the input ESD diodes.
For best SNR performance, drive the AD7894 input from a low-impedance op-amp buffer (such as the AD8628 or AD797) rather than a high-impedance source. SAR ADCs present kickback currents to the input during the acquisition phase, which can cause settling errors with high-source impedance. Use a wide-bandwidth op-amp with sufficient slew rate to settle within 200 ns to 14-bit accuracy. Route SDATA as a short, impedance-controlled trace to the host controller to avoid digital reflections that corrupt conversion results.
Compliance Information
RoHS status marked as [DATA_NEEDED] because the AR (non-Z) suffix historically indicates SnPb finish on legacy parts; however some -REEL7 stock may be RoHS-compliant depending on lot date code. Verify against the reel label before PCB assembly. AEC-Q100 not applicable for industrial-grade precision converters; consult factory for automotive-grade AD7894BR-10 variants.
