Part A
AD7709ARUZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1974 PCS
- Package
- TSSOP-24
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7709ARUZ and AD7705BRU-REEL are both 16-bit sigma-delta ADCs from Analog Devices in a TSSOP-16 package, sharing a compatible serial interface and core conversion architecture. However, the AD7709ARUZ integrates additional on-chip features such as a programmable current source and expanded input multiplexing, while the AD7705BRU-REEL offers a simpler two-channel differential input path. Designers should validate channel configuration, input range, and any current-source dependency before substituting one for the other in a given application.
Resolution and Architecture
High match
Package Type
High match
Input Channel Configuration
Validation required
On-Chip Current Source
Validation required
Parts at a glance
Part B
AD7705BRU-REEL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2250 PCS
- Package
- TSSOP-16
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7709ARUZ | AD7705BRU-REEL | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 16 | Both are 16-bit sigma-delta ADCs, so resolution is equivalent for precision measurement applications. |
| Number of input channels | 4 (differential) / 8 (pseudo-differential) | 2 (differential) | The AD7709 offers more input channels, allowing more sensors to be multiplexed to a single ADC, which affects system architecture and channel count. |
| On-chip PGA gain range | 1 to 128 | 1 to 128 | Both provide programmable gain up to 128, enabling direct interfacing with low-level sensor signals without external amplification. |
| Output data rate (max) | 105 Hz | 500 Hz | The AD7705 supports a higher maximum output data rate, which matters for applications requiring faster sampling or wider signal bandwidth. |
| On-chip current sources | Yes (for RTD/sensor excitation) | No | The AD7709 integrates excitation current sources useful for resistive sensor (e.g., RTD) measurements, reducing external component count. |
| On-chip temperature sensor | Yes | No | An integrated temperature sensor enables on-chip temperature compensation or monitoring without additional components. |
| Supply voltage range | 2.7 V to 5.25 V | 2.7 V to 5.25 V | Identical supply range means both can operate from the same low-voltage rails, simplifying power supply design and substitution. |
| Interface | SPI-compatible (3-wire serial) | SPI-compatible (3-wire serial) | Both use a compatible serial interface, so firmware and microcontroller connections are largely interchangeable. |
| Package | 24-lead TSSOP | 16-lead TSSOP | Different package pin counts and footprints affect PCB layout and require board redesign if substituting one for the other. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings ensure both are suitable for the same industrial and commercial environments. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7709ARUZ | AD7705BRU-REEL |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 105 | 500 |
| Number of Inputs | 2, 4 | 2 |
| Input Type | Differential, Pseudo-Differential | Differential |
| Data Interface | SPI, DSP | SPI, DSP |
| Configuration | MUX-PGA-ADC | MUX-PGA-ADC |
| Number of A/D Converters | 1 | 1 |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External |
| Voltage - Supply, Analog | 2.7V ~ 3.3V, 5V | 2.7V ~ 3.3V, 5V |
| Voltage - Supply, Digital | 2.7V ~ 3.3V, 5V | 2.7V ~ 3.3V, 5V |
| Features | PGA | PGA |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD7709ARUZ and the AD7705BRU-REEL?
The AD7709ARUZ is a 16-bit sigma-delta ADC with an on-chip PGA, two differential input channels, and a 200 µA excitation current source, housed in a 24-lead TSSOP. The AD7705BRU-REEL is a 16-bit sigma-delta ADC with two differential input channels and an on-chip PGA, supplied in a 16-lead TSSOP on tape and reel. The AD7709 integrates additional features such as excitation current sources and a more extensive on-chip register set, while the AD7705 is a more compact two-channel device.
Are the AD7709ARUZ and AD7705BRU-REEL pin-compatible?
No. The AD7709ARUZ is packaged in a 24-lead TSSOP, whereas the AD7705BRU-REEL is packaged in a 16-lead TSSOP. The different pin counts and pin assignments mean they are not drop-in replacements for each other.
Do both devices support a programmable gain amplifier (PGA)?
Yes. Both the AD7709ARUZ and the AD7705BRU-REEL include an on-chip PGA that allows direct interfacing of low-level analog signals. The gain settings and register configuration should be verified against the respective datasheets for the target design.
What is the resolution and architecture of these ADCs?
Both the AD7709ARUZ and the AD7705BRU-REEL are 16-bit sigma-delta (Σ-Δ) analog-to-digital converters. They are intended for low-frequency, high-resolution measurement applications.
How many analog input channels does each device provide?
Both the AD7709ARUZ and the AD7705BRU-REEL provide two differential analog input channels. The AD7709 additionally integrates excitation current sources, which can be useful for sensor excitation in bridge or RTD applications.
What supply voltage range do these devices require?
Both devices operate from a single supply in the 2.7 V to 5.25 V range, with a separate digital supply pin (VDD) for interfacing. Designers should confirm the exact supply and interface voltage requirements in the respective datasheets before finalizing the schematic.
What serial interface do the AD7709ARUZ and AD7705BRU-REEL use?
Both devices use a three-wire serial interface compatible with SPI, QSPI, MICROWIRE, and DSP interface standards. This allows direct connection to most microcontrollers and digital signal processors.
Can the AD7705BRU-REEL be used as a substitute for the AD7709ARUZ in an existing design?
Not directly. Although both are 16-bit sigma-delta ADCs with two differential channels and a PGA, they differ in package (16-lead vs 24-lead TSSOP), pinout, and integrated features such as excitation current sources. A substitution requires a full review of the schematic, PCB layout, and register map against the manufacturer datasheets.