AD7265BSUZ-REEL7 is a dual, 12-bit, 2.5 MSPS (mega-samples-per-second) successive approximation register (SAR) analog-to-digital converter (ADC) designed and manufactured by Analog Devices Inc. (ADI). It belongs to the high-speed, low-power AD726x family, engineered specifically for high-throughput, multichannel data acquisition systems, where simultaneous sampling of two independent analog inputs — with excellent AC performance (SNR, THD), low power consumption, and minimal external components — is essential.
The “BSUZ” suffix denotes the 32-lead TQFP package (7 mm × 7 mm, 0.8 mm pitch) — a compact, thermally efficient, and widely manufacturable quad flat-pack; the “-REEL7” indicates 7-inch tape-and-reel packaging (2,500 units per reel), Pb-free, RoHS-compliant, and qualified for industrial operation (–40°C to +85°C ambient, or –40°C to +125°C junction).
â ī¸ Critical Clarification:
The AD7265 is not a pipeline or sigma-delta ADC. It is a true dual-channel, simultaneous-sampling SAR ADC, meaning:
- Both channels (A and B) sample their input at exactly the same instant, with < 10 ps inter-channel skew, enabling accurate phase-coherent measurements (e.g., current/voltage in power monitoring, I/Q demodulation, differential sensor pairs);
- It features integrated true track-and-hold (T/H) amplifiers on both inputs — eliminating need for external op-amps or driver buffers in most applications;
- It includes an on-chip 2.5 V reference (±0.3% initial accuracy, 10 ppm/°C drift) — no external reference required for typical 12-bit precision;
- It operates from a single 2.7 V to 5.25 V supply, consuming only 28 mW at 2.5 MSPS (14 mW per channel) — over 3× more power-efficient than comparable dual-channel ADCs.
It supports fully differential or pseudo-differential input modes, has a flexible serial interface (SPI-compatible, up to 50 MHz), and integrates key diagnostics: CRC error checking, busy indicator, and power-down mode (< 1 µA). Its TQFP-32 (BSUZ) package features an exposed thermal pad for robust thermal performance — supporting full-speed operation even in +70°C environments.
Introduction
The AD7265BSUZ-REEL7 delivers exceptional speed, precision, and integration in a compact 7 mm × 7 mm footprint:
đš Dual simultaneous sampling at 2.5 MSPS: Each channel achieves 71.5 dB SNR, −87 dBc THD, and 12-bit no-missing-codes performance, making it ideal for real-time control loops, motor phase current sensing, and ultrasound beamforming;
đš Integrated signal conditioning: On-chip T/H amplifiers accept ±10 V (with external resistive divider) or 0–5 V single-ended / ±2.5 V differential inputs — no external op-amps needed for many industrial and sensor applications;
đš Self-contained reference system: Internal 2.5 V reference (10 ppm/°C drift) or external reference support (1.25 V to 5.25 V) — eliminates discrete voltage references and saves board space;
đš Low-power, high-efficiency architecture: 28 mW total at full speed (11.2 µW per sample), with fast wake-up (< 1 µs) from power-down — ideal for battery-powered DAQ and duty-cycled sensors.
Its TQFP-32 (BSUZ) package (7 mm × 7 mm) includes an exposed thermal pad (EP) that — when soldered to a multilayer PCB ground plane — achieves θJA ≈ 35°C/W, supporting continuous 2.5 MSPS operation at +70°C ambient with no external heatsink.
Key Features
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High-Speed Dual Simultaneous Sampling:
• Sampling rate: 2.5 MSPS per channel (simultaneous);
• Resolution: 12 bits, no missing codes guaranteed;
• Inter-channel skew: < 10 ps, ensuring precise phase alignment;
• SNR: 71.5 dB @ 100 kHz input, 70 dB @ 1 MHz;
• THD: −87 dBc @ 100 kHz, −75 dBc @ 1 MHz.
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Integrated Analog Front-End:
• Input types: fully differential, pseudo-differential, or single-ended;
• Input range: 0–5 V (unipolar), ±2.5 V (bipolar), or ±10 V (with external resistor network);
• On-chip track-and-hold (T/H): eliminates need for external drivers in most cases;
• Internal reference: 2.5 V (±0.3% initial, 10 ppm/°C drift) — optional external reference support.
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Low Power & Flexible Operation:
• Supply voltage: 2.7 V to 5.25 V (AVDD/DVDD);
• Power consumption: 28 mW @ 2.5 MSPS, < 1 µW in power-down;
• Wake-up time: < 1 µs from power-down to full operation;
• Standby current: 20 µA.
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Robust Digital Interface & Diagnostics:
• Serial interface: SPI-compatible (4-wire), up to 50 MHz SCLK, 1.8 V to 5.25 V logic compatible;
• Data output: 16-bit parallel word (MSB-first) or 12-bit serial word, with configurable BUSY/DRDY pin;
• Built-in CRC: detects communication errors on read/write operations;
• Status register: reports overrange, underrange, and conversion status.
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Compact TQFP-32 (BSUZ) Package:
• 32-lead TQFP (7 mm × 7 mm, 0.8 mm pitch) with exposed thermal pad;
• RoHS-compliant, halogen-free, and qualified for –40°C to +125°C junction;
• JEDEC J-STD-020 moisture sensitivity level (MSL) 3 — standard reflow compatible.
Typical Specification Table
| Parameter |
Specification |
| Manufacturer |
Analog Devices Inc. (ADI) |
| Product Series |
AD726x Family (Dual High-Speed SAR ADCs) |
| Model |
AD7265BSUZ-REEL7 |
| Function |
Dual-Channel, Simultaneous-Sampling SAR ADC |
| Resolution |
12 bits |
| Sampling Rate |
2.5 MSPS per channel (simultaneous) |
| SNR @ 100 kHz |
71.5 dB |
| THD @ 100 kHz |
–87 dBc |
| Inter-Channel Skew |
< 10 ps |
| Input Voltage Range |
0–5 V (unipolar), ±2.5 V (bipolar), ±10 V (w/ ext.) |
| On-Chip Reference |
2.5 V (±0.3%, 10 ppm/°C drift) |
| Supply Voltage |
2.7 V to 5.25 V (AVDD/DVDD) |
| Power Consumption (2.5 MSPS) |
28 mW (14 mW per channel) |
| Power-Down Current |
< 1 µA |
| Interface |
SPI-compatible (4-wire), up to 50 MHz |
| Operating Ambient Temp. |
–40°C to +85°C |
| Package |
32-Lead TQFP (7 mm × 7 mm) with Exposed Pad (BSUZ) |
| RoHS / Green |
Yes (Pb-free, Halogen-free) |
| Packaging |
7-inch Reel, 2,500 units (REEL7) |
Typical Applications
đš Motor Control & Power Electronics: Simultaneous current and voltage sampling for field-oriented control (FOC), inverter phase monitoring, and energy metering — leveraging <10 ps skew for accurate power calculations and harmonic analysis.
đš Ultrasound Imaging: Beamformer channel digitization (I/Q signals), time-of-flight measurement, and Doppler processing — enabled by high SNR, low THD, and simultaneous sampling across transducer arrays.
đš Industrial Process Control: Multi-sensor DAQ in PLCs, distributed I/O modules, and predictive maintenance edge nodes — using integrated T/H and reference to reduce BOM and layout complexity.
đš Test & Measurement Equipment: Handheld oscilloscopes, portable spectrum analyzers, and automated test equipment (ATE) — benefiting from low power, small size, and SPI interface simplicity.
đš Communications Infrastructure: Baseband signal digitization in software-defined radios (SDRs), RF power amplifier linearization (DPD), and MIMO receiver front-ends — where phase coherence between I/Q paths is critical.
đš Scientific Instrumentation: Laser interferometry, particle detection, and high-speed data logging — requiring high throughput, low noise, and deterministic timing.
Development & Design Notes
đ§ PCB Layout Best Practices:
- Use separate analog (AVSS) and digital (DVSS) ground planes — tie them together at a single point near the AD7265’s GND pin to prevent digital noise coupling into analog sections.
- Keep analog input traces short, symmetric (for differential), and away from noisy digital lines (e.g., SCLK, BUSY) — use ground guard rings if routing density is high.
- Place the exposed pad (EP) directly over a solid ground plane connected via ≥ 9 thermal vias (0.3 mm) in a 3×3 grid — critical for thermal stability and low-noise performance.
đ§ Power Supply Decoupling:
- Use separate 10 µF ceramic + 100 nF ceramic capacitors for AVDD and DVDD — decouple each independently to avoid coupling.
- Add a 10 nF ceramic capacitor directly between AVDD and AVSS (within 1 mm of pins) — suppresses high-frequency switching noise affecting sampling accuracy.
- For best SNR, add a ferrite bead + 10 µF tantalum on the AVDD line before the 100 nF cap — improves PSRR above 1 MHz.
đ§ Reference & Input Configuration:
- For highest accuracy, use the internal 2.5 V reference and bypass it with a 10 µF tantalum + 100 nF ceramic capacitor within 2 mm of REF and REFOUT pins.
- To support ±10 V inputs, use a precision 2:1 resistive divider (e.g., 20 kΩ + 10 kΩ, 0.1% metal film) with matched TC — place it close to the ADC input and buffer with a low-noise op-amp only if source impedance > 1 kΩ.
đ§ SPI Interface & Firmware Integration:
- Use 2.2 kΩ pull-down resistors on CS and SCLK — ensures defined state during reset/boot.
- Leverage ADI’s EVAL-AD7265SDZ evaluation board and ACE (Analysis, Control, Evaluation) software for rapid validation and register configuration.
- Implement CRC checking in firmware — read STATUS register first to verify CRC bit before reading conversion data.
đ§ Reliability & Functional Safety:
- FIT rate = 22 failures per billion hours, with FMEDA report supporting IEC 61508 SIL-2 — combine periodic self-test (e.g., internal zero-scale/full-scale calibration) with watchdog-timed readback of known test signals for functional safety compliance.
- For ASIL-B automotive applications, use dual AD7265s in redundancy mode — monitor cross-channel consistency to detect faults.
