Part A
AD7703BRZ-REEL
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 7082 PCS
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Not a drop-in replacement
The AD7705BR and AD7703BRZ-REEL are not drop-in replacements for one another. The AD7705BR is a dual-channel, 16-bit sigma-delta ADC with an SPI-compatible serial interface, while the AD7703BRZ-REEL is a single-channel, 20-bit sigma-delta ADC with a different serial interface and package. Designers must account for differences in channel count, resolution, interface protocol, and package footprint before considering substitution.
Different channel count
Different resolution
Different interface type
Different package footprint
Parts at a glance
Part B
AD7705BR
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 6867 PCS
- Package
- SOIC-16
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | AD7705BR | AD7703BRZ-REEL | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 20 | Higher resolution allows detection of smaller signal changes, which is critical for precision measurement applications. |
| Number of ADC Input Channels | 2 (differential) | 1 (differential) | Channel count determines how many independent signals can be measured without external multiplexing. |
| Sampling Rate (max) | 500 SPS | 4 kSPS | Maximum output rate affects how fast the system can capture changing input signals. |
| Interface Type | SPI / 3-wire serial | Serial (SPI-compatible) | The digital interface must match the host microcontroller to ensure reliable communication and firmware compatibility. |
| Supply Voltage (nominal) | 3 V or 5 V | 5 V | Supply voltage compatibility determines whether the part can operate in the target system's power rail without level shifting. |
| Package Type | 16-lead SOIC | 20-lead SOIC | Package footprint and pin count must match the PCB layout for a drop-in replacement. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range confirms suitability for industrial versus commercial environments. |
| Input Type | Differential (2 channels) | Differential (single channel) | Differential inputs reject common-mode noise, but the number of differential pairs affects system architecture. |
| On-chip PGA | Yes (gain 1 to 128) | No | An integrated programmable gain amplifier allows direct connection of low-level sensors without external amplification. |
| Power Consumption (typical) | ~1 mW | ~25 mW | Lower power consumption is essential for battery-powered and energy-sensitive designs. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7703BRZ-REEL | AD7705BR |
|---|---|---|
| Part Status | Active | Obsolete |
| Number of Bits | 20 | 16 |
| Sampling Rate (Per Second) | 4k | - |
| Number of Inputs | 1 | 2 |
| Input Type | Single Ended | Differential |
| Data Interface | SPI | SPI, DSP |
| Configuration | S/H-ADC | MUX-PGA-ADC |
| Ratio - S / H: ADC | 1:1 | - |
| Number of A / D Converters | 1 | - |
| Architecture | Sigma-Delta | Sigma-Delta |
| Reference Type | External | External |
| Voltage - Supply, Analog | 5V | 2.7V ~ 3.3V, 5V |
| Voltage - Supply, Digital | 5V | 2.7V ~ 3.3V, 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | - |
| Base Product Number | AD7703 | - |
| Sampling Rate(Per Second) | - | 500 |
| Number of A/D Converters | - | 1 |
| Features | - | PGA |
Frequently asked questions
What are the key architectural differences between the AD7705BR and the AD7703BRZ-REEL?
The AD7705BR is a 2-channel, 16-bit sigma-delta ADC with an on-chip programmable gain amplifier (PGA) and a serial interface, housed in a 16-lead SOIC package. The AD7703BRZ-REEL is a single-channel, 20-bit sigma-delta ADC with a serial interface, supplied in a 20-lead SOIC package on tape and reel. The AD7705 offers two differential input channels and selectable gain, while the AD7703 provides one channel with 20-bit resolution.
Do the AD7705BR and AD7703BRZ-REEL have the same resolution and channel count?
No. The AD7705BR provides 16-bit resolution with two differential input channels, whereas the AD7703BRZ-REEL provides 20-bit resolution with a single channel. Designs requiring higher resolution should consider the AD7703, while multi-channel low-to-medium resolution applications may favor the AD7705.
Are the AD7705BR and AD7703BRZ-REEL pin-to-pin compatible?
No. The AD7705BR is packaged in a 16-lead SOIC, and the AD7703BRZ-REEL is packaged in a 20-lead SOIC. The differing package sizes and pin counts mean they are not pin-to-pin compatible and cannot be dropped into the same PCB footprint without redesign.
Can the AD7705BR and AD7703BRZ-REEL share the same serial interface configuration?
Both devices use a serial interface for communication with a host controller, but their register maps, command structures, and interface timing differ because they are different product families. Firmware and interface logic must be written specifically for each device; the AD7705 uses an on-chip register set for channel selection and gain configuration, while the AD7703 has its own control and data output format.
Which device is better suited for multi-channel sensor applications?
The AD7705BR is better suited for multi-channel sensor applications because it integrates two differential input channels with a programmable gain amplifier, allowing direct connection of low-level sensors without external signal conditioning. The AD7703BRZ-REEL is a single-channel device and would require external multiplexing for multi-channel systems.
What supply voltage and reference requirements apply to these two ADCs?
Both the AD7705BR and AD7703BRZ-REEL operate from a single supply in the 2.7 V to 5.25 V range (with the AD7705 also supporting dual-supply operation) and require an external reference voltage for accurate conversion. The reference input range and absolute maximum ratings should be confirmed against the respective manufacturer datasheets before finalizing a design.
Is the AD7703BRZ-REEL supplied in a tape-and-reel format suitable for automated assembly?
Yes. The "-REEL" suffix in AD7703BRZ-REEL indicates tape-and-reel packaging, which is compatible with automated pick-and-place assembly lines. The AD7705BR is typically supplied in tube or tray packaging; the exact packaging option should be verified with the distributor or manufacturer before ordering for production.