AD7708BRU-REEL - 16-Bit 8/10-Ch Sigma-Delta ADC | Analog Devices
Teilenummer: AD7708BRU-REEL ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $14.02 | $14,02 |
| 10 | $12.62 | $126,20 |
| 100 | $10.78 | $1.078,00 |
| 500 | $8.92 | $4.460,00 |
| 1.000 | $6.19 | $6.190,00 |
AD7708BRU-REEL Übersicht
A sigma-delta ADC is a type of analog-to-digital converter that uses oversampling and noise shaping to achieve high resolution and excellent noise rejection in low-frequency measurement applications. Within the converter taxonomy, the AD7708 sits in the precision ADC category, which itself falls under data converters and broader mixed-signal integrated circuits. The 1ku list price starting from $6.19 reflects its positioning as a low-cost, multi-channel analog front-end solution for industrial and instrumentation designs.
Key features of the AD7708BRU-REEL include 16-bit resolution (the companion AD7718 offers 24-bit), factory calibration per channel, programmable gain amplifier (1 to 128), a single-cycle conversion mode, and a low quiescent current of typically 1 mA in normal operation. The device provides four differential or eight pseudo-differential inputs, plus two additional pins configurable as analog or reference inputs. The flexible input configuration allows direct connection to sensors, bridges, and other low-bandwidth analog sources.
Technically, the AD7708 uses a sigma-delta modulator followed by a digital filter, providing excellent 50 Hz/60 Hz power-line noise rejection. The on-chip PGA accepts input signals from a few millivolts up to ±2.56V when using a 2.5V reference, with the reference input accepting standard external references. The serial interface operates in self-clocking or external-clocking mode, simplifying isolation in industrial systems. The architecture is pin-for-pin compatible with the 24-bit AD7718, enabling an upgrade path from 16 to 24 bits without PCB changes.
Typical applications include industrial process control, weigh scales and load-cell digitization, portable instrumentation, temperature measurement with RTDs or thermocouples, and pressure sensor signal conditioning. The TSSOP-28 package suits space-constrained designs while the wide supply range supports battery-powered systems. In multi-channel data-acquisition modules, the AD7708's pseudo-differential inputs allow direct connection to bridge sensors without external instrumentation amplifiers.
When designing with the AD7708, ensure adequate decoupling on both AVDD and DVDD pins (typically 10uF bulk plus 0.1uF ceramic close to the pins). The reference input should be driven by a low-noise reference such as the ADR291 or AD780 for full 16-bit performance. The serial clock rate and filter notches should be programmed to reject the local mains frequency (50 Hz or 60 Hz) to maximize effective resolution.
This page synthesizes distributor pricing, pin-for-pin compatible replacements in the same AD77xx family, and practical design notes not found in the manufacturer datasheet.
Drop-in-Alternativen für AD7708BRU-REEL – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Varianten dieser Serie
Modelle derselben Serie, die drop-in-kompatibel sind mit AD7708BRU-REEL (gleiche Bauform und Footprint) – abweichend in Package, Number of Input Channels, Input Type, Interface, Resolution.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
AD7708BRUZ-REEL
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
AD7718BRUZ-REEL
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
AD7708BRUZ-REEL7
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
AD7708BRU
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
AD7708BRU-REEL7
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
AD7708BRU-REEL Grenzwerte & elektrische Eigenschaften
| Auflösung | 16 bits |
| Number of Input Channels | 4 differential / 8 pseudo-differential / 10 pseudo-differential |
| ADC Architecture | Sigma-Delta |
| Supply Voltage Range | 2.7 V to 5.25 V (AVDD, DVDD) |
| Data Interface | DSP, MICROWIRE, QSPI, Serial, SPI |
| Gehäuse | 28-TSSOP (0.173 in / 4.40 mm width) |
| Montageart | Surface Mount |
| Betriebstemperaturbereich | -40 C to +85 C |
| Factory Calibration | Yes, per channel |
| Programmable Gain Amplifier | Yes (gains 1 to 128) |
| Reference Input | External (2.5V typical, e.g. ADR291/AD780) |
| Input Configuration | 4 fully-differential or 8/10 pseudo-differential |
| Pin-Compatible Upgrade | AD7718 (24-bit) in same TSSOP-28 / SOIC-28 |
| RoHS-Status | Compliant (AD7708BRUZ variant); non-RoHS on BRU suffix |
| Packaging | Tape & Reel (REEL) |
AD7708BRU-REEL Pin-Konfiguration
| Pin 1 | SCLK — Serial clock input for SPI/MICROWIRE/QSPI interface |
| Pin 2 | DOUT/RDIN — Serial data output (read) / data input (write) on shared pin |
| Pin 3 | DRDY — Data ready output (active low) - signals valid conversion result |
| Pin 4 | CS — Chip select input (active low) |
| Pin 5 | RESET — Reset input (active low) |
| Pin 6 | MODE — External clock / internal clock mode select |
| Pin 7 | DVDD — Digital supply voltage (2.7V to 5.25V) |
| Pin 8 | DGND — Digital ground |
| Pin 9 | AVDD — Analog supply voltage (2.7V to 5.25V) |
| Pin 10 | AGND — Analog ground |
| Pin 11 | REF IN+ — Positive reference input (typically 2.5V) |
| Pin 12 | REF IN- — Negative reference input (typically AGND) |
| Pin 13 | AIN1 / REF2+ — Analog input 1 or secondary reference positive (configurable) |
| Pin 14 | AIN2 / REF2- — Analog input 2 or secondary reference negative (configurable) |
| Pin 15 | AIN3 — Analog input 3 (pseudo-differential or differential pair with AIN4) |
| Pin 16 | AIN4 — Analog input 4 (pseudo-differential or differential pair with AIN3) |
| Pin 17 | AIN5 — Analog input 5 (pseudo-differential) |
| Pin 18 | AIN6 — Analog input 6 (pseudo-differential) |
| Pin 19 | AIN7 — Analog input 7 (pseudo-differential) |
| Pin 20 | AIN8 — Analog input 8 (pseudo-differential) |
| Pin 21 | AIN9 — Analog input 9 (pseudo-differential) |
| Pin 22 | AIN10 — Analog input 10 (pseudo-differential) |
| Pin 23 | NC — Not connected (per datasheet) |
| Pin 24 | NC — Not connected (per datasheet) |
| Pin 25 | NC — Not connected (per datasheet) |
| Pin 26 | NC — Not connected (per datasheet) |
| Pin 27 | NC — Not connected (per datasheet) |
| Pin 28 | NC — Not connected (per datasheet) |
Typische Anwendungen
AD7708BRU-REEL ist geeignet für 6 Anwendungs: Industrial Weigh Scale / Strain-Gauge Digitization, Process-Control Multi-Channel Data Acquisition, Portable Battery-Powered Instrumentation, RTD / Thermocouple Temperature Measurement, Pressure / Flow Sensor Signal Conditioning, Sensor Hubs in Industrial IoT Edge Nodes.
Industrial Weigh Scale / Strain-Gauge Digitization
The AD7708BRU-REEL's 16-bit resolution, on-chip PGA (gain 1 to 128), and 8/10 pseudo-differential input channels make it well-suited to multi-load-cell weigh-scale designs. Each load cell typically delivers 1-3 mV/V at full scale, so a 5V excitation with PGA gain 128 yields an effective input range below 40 mV - within the AD7708's programmable full-scale range when paired with a low-drift reference. According to the Analog Devices product page, the factory-calibrated per-channel feature removes offset/gain error automatically at power-up, eliminating manual calibration trims in production. The sigma-delta modulator's 50/60 Hz digital-filter notches reject mains pickup from nearby motor drives. The SPI-compatible serial interface simplifies opto-isolation between the bridge sensor and the host MCU, a critical requirement for industrial scales in noisy factory environments.
Empfohlen
Process-Control Multi-Channel Data Acquisition
The AD7708BRU-REEL fits multi-channel process-control I/O modules where 4-20 mA loops and 0-10V signals from many sensors must be digitized by a single ADC. Its 10 pseudo-differential inputs can scan up to 10 process variables sequentially without external muxes, while the 2.7V-5.25V single supply simplifies integration with 3.3V or 5V PLC backplanes. The on-chip PGA eliminates the need for external instrumentation amplifiers on each channel. The factory-calibrated per-channel feature, documented in the Analog Devices AD7708 datasheet, ensures each channel meets its 16-bit accuracy without per-channel trims. Combined with the low 1 mA typical quiescent current, the AD7708 is suitable for DIN-rail-mounted remote I/O modules that must operate within tight thermal budgets.
Empfohlen
Portable Battery-Powered Instrumentation
The AD7708BRU-REEL's 2.7V minimum supply and low 1 mA quiescent current make it ideal for handheld multimeters, portable medical instruments, and field data loggers powered from 3.6V Li-ion or 3V coin cells. The on-chip PGA and 16-bit resolution eliminate the need for separate signal-conditioning stages, shrinking PCB area for compact form factors. The TSSOP-28 package, with 4.4 mm body width, fits easily inside handheld enclosures. The serial-interface power-down mode reduces current to microampere levels between conversions, extending battery life in low-duty-cycle measurement applications such as spot-check thermometry or environmental monitoring. The wide -40C to +85C operating range also supports outdoor or refrigerated-environment field use.
Empfohlen
RTD / Thermocouple Temperature Measurement
The AD7708BRU-REEL is widely used in multi-channel temperature measurement modules for PT100/Pt1000 RTDs and thermocouple inputs. Its 8/10 pseudo-differential inputs accept multiple four-wire RTD bridges directly, while the on-chip PGA gain of 128 amplifies the small PT100 signal (3.85 mV/C at 0C) to a level that uses the full 16-bit range when paired with a precision current source. The factory-calibrated feature compensates for reference drift, and the 50/60 Hz digital-filter notches reject mains-induced common-mode noise on long thermocouple runs. Engineers designing PID controllers for industrial ovens or environmental chambers can use the same TSSOP-28 footprint across 16-bit and 24-bit (AD7718) variants for scalability without PCB rework.
Empfohlen
Pressure / Flow Sensor Signal Conditioning
The AD7708BRU-REEL integrates cleanly into multi-channel pressure-transducer and flow-meter signal chains. Its pseudo-differential inputs accept the Wheatstone-bridge output from piezo-resistive pressure sensors directly, while the on-chip PGA provides the high gain needed to resolve sub-1% pressure changes at low differential pressures. The 16-bit resolution combined with factory-calibration yields better than 0.1% FSO accuracy after a single-point system trim. In HVAC and building-automation systems, the TSSOP-28 small footprint lets engineers digitize 8-10 pressure zones from a single ADC, reducing BOM and MCU pin count. The serial interface also simplifies routing across isolation barriers required in medical and industrial flow-meter applications.
Empfohlen
Sensor Hubs in Industrial IoT Edge Nodes
The AD7708BRU-REEL enables cost-effective sensor hubs for Industrial IoT edge nodes where multiple analog sensors (temperature, humidity, pressure, strain) must be digitized before wireless transmission. Its 10-channel pseudo-differential input count supports a full sensor cluster on a single ADC, while the 2.7V-5.25V supply range matches battery and bus-powered edge devices. The on-chip PGA handles wide dynamic-range sensor outputs (from millivolts to volts) without external conditioning. Combined with the SPI/MICROWIRE interface, the AD7708 connects directly to low-power MCUs and wireless SoCs in sub-1GHz or BLE sensor nodes, supporting remote monitoring of pumps, motors, and process equipment. The 28-TSSOP package is footprint-compatible with the 24-bit AD7718 for designs that later need higher precision.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für AD7708BRU-REEL – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | AD7708BRUZ-REEL | AD7718BRUZ-REEL | AD7708BRUZ-REEL7 | AD7708BRU | AD7708BRU-REEL7 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | 28-TSSOP | 28-TSSOP - same | 28-TSSOP - same | 28-TSSOP - same | 28-TSSOP - same | 28-TSSOP - same |
| Resolution | 16 bits | 16 bits | 24 bits (+50%) | 16 bits | 16 bits | 16 bits |
| Input Channels | 4 diff / 8-10 pseudo-diff | 4 diff / 8-10 pseudo-diff | 4-5 diff / 8-10 pseudo-diff | 4 diff / 8-10 pseudo-diff | 4 diff / 8-10 pseudo-diff | 4 diff / 8-10 pseudo-diff |
| Supply Voltage Range | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V | 2.7 V to 5.25 V |
| RoHS Compliance | Non-RoHS (BRU suffix) | RoHS-compliant (BRUZ) | RoHS-compliant (BRUZ) | RoHS-compliant (BRUZ) | Non-RoHS (BRU) | Non-RoHS (BRU) |
| Packaging Form | Tape & Reel (REEL) | Tape & Reel (REEL) | Tape & Reel (REEL) | Tape & Reel 7-inch (REEL7) | Tray (no reel) | Tape & Reel 7-inch (REEL7) |
| Architecture | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta | Sigma-Delta |
Wichtigste Unterscheidungsmerkmale
- Wide 2.7V-5.25V single-supply operation eliminates separate analog and digital rails (vs. AD7708BRUZ-REEL)
- 16-bit resolution with on-chip PGA (gain 1-128) removes external instrumentation amplifiers (vs. AD7718BRUZ-REEL)
- Pin-compatible upgrade path to AD7718 (24-bit) without PCB changes (vs. AD7705BRUZ-REEL7)
Designhinweise
Decouple AVDD and DVDD with a 10uF tantalum or ceramic bulk capacitor plus a 0.1uF ceramic placed within 3 mm of each supply pin. AGND and DGND should be joined at a single point beneath the IC to avoid digital noise coupling into the analog chain. The AD7708BRU-REEL typically draws 1 mA quiescent current in normal operation; use a low-dropout regulator such as the ADP3330 for clean supply rails in low-noise designs. According to the Analog Devices AD7708 datasheet, AVDD must equal DVDD within 0.3V at all times to prevent latch-up.
The AD7708BRU-REEL's sigma-delta modulator provides excellent 50 Hz / 60 Hz power-line rejection when the filter notches are programmed correctly. Choose the CHSEL clock frequency and FS word so that the modulator sampling rate places a notch at the local mains frequency. Route analog inputs as pseudo-differential pairs to maximize common-mode noise rejection from long sensor cables; for the highest precision use 4-wire fully-differential inputs with the on-chip PGA. The reference input (REF IN+ / REF IN-) is the most sensitive analog node - bypass it with a 10uF tantalum plus 0.1uF ceramic and keep reference traces short and shielded from digital switching currents.
Do not drive the AD7708BRU-REEL reference input with a high-impedance source - use a low-noise reference such as ADR291, AD780, or ADR01 with proper output buffering. Avoid routing the serial SPI clock (SCLK) parallel to analog input traces to prevent digital coupling into the analog chain. When upgrading from AD7708 to AD7718 in the same PCB, verify the firmware register map - the AD7718 has additional calibration and PGA registers that differ from the AD7708. Always perform a system-level calibration after final PCB assembly to compensate for PCB parasitic thermocouples at the ADC input.
Compliance-Informationen
AD7708BRU-REEL uses legacy matte-tin (BRU suffix) lead finish which is NOT RoHS-compliant. For RoHS-compliant designs use AD7708BRUZ-REEL drop-in replacement. AEC-Q100 not applicable for industrial-grade ADC. Reach and conflict-minerals status confirmed by Analog Devices product page.
