Part A
AD7631BSTZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7102 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7631BSTZ and AD7634BSTZRL are both 18-bit successive-approximation ADCs from the same Analog Devices family, sharing core architecture, supply requirements, and package footprint. The AD7634BSTZRL offers a higher throughput grade and additional interface flexibility, making it a viable functional upgrade candidate for the AD7631BSTZ in most designs, provided the system timing and digital interface configuration are validated against the target application.
Resolution and Architecture
High match
Package and Pinout
High match
Sampling Rate
Validation required
Digital Interface
Validation required
Parts at a glance
Part B
AD7634BSTZRL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7816 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - Analog to Digital Converters (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 | AD7631BSTZ | AD7634BSTZRL | Why it matters |
|---|---|---|---|
| Resolution | 18 bits | 18 bits | Bit depth determines the smallest signal change the ADC can resolve; both are 18-bit so resolution is equivalent. |
| Sampling Rate | 670 kSPS | 670 kSPS | Maximum throughput must meet the system's signal bandwidth and Nyquist requirements; identical rates allow direct substitution. |
| Input Type | Differential | Differential | Differential inputs improve common-mode rejection and noise immunity; matching input topology preserves signal-chain compatibility. |
| Number of Input Channels | 1 | 1 | Channel count determines how many signals can be digitized without external multiplexing; both are single-channel devices. |
| Interface Type | SPI / Parallel | SPI / Parallel | Digital interface must match the host controller; identical interface options allow drop-in replacement in existing designs. |
| Supply Voltage | 5 V analog, 2.7 V to 5.25 V digital | 5 V analog, 2.7 V to 5.25 V digital | Supply rails must be compatible with the board's power architecture; matching voltages avoid level-shifting or regulator changes. |
| Package / Mounting | 48-LQFP, surface mount | 48-LQFP, surface mount | Footprint and mounting style must match the PCB layout for physical interchangeability; identical packages allow direct board replacement. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range must cover the application environment; matching industrial ranges ensure equivalent reliability. |
| Reference Type | External | External | Reference configuration affects accuracy and drift; both requiring an external reference means the same reference circuit can be reused. |
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 | AD7631BSTZ | AD7634BSTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | PulSAR® | iCMOS®, PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 18 | 18 |
| Sampling Rate(Per Second) | 250k | 670k |
| Number of Inputs | 1 | 1 |
| Input Type | Differential | Differential |
| Data Interface | SPI, Parallel, DSP | SPI, Parallel, DSP |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External, Internal | External, Internal |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD7631BSTZ and the AD7634BSTZRL?
Both are 18-bit, 670 kSPS PulSAR analog-to-digital converters from Analog Devices in a 48-lead LQFP package. The AD7631 is specified for a ±10 V or ±5 V input range with a 5 V reference, while the AD7634 supports a wider programmable input range including ±10 V, ±5 V, and 0 V to 10 V. The AD7634BSTZRL is the tape-and-reel packaging variant of the AD7634BSTZ, whereas the AD7631BSTZ is supplied in tray form. Electrical resolution and throughput are the same, but input range flexibility and packaging differ.
Are the AD7631BSTZ and AD7634BSTZRL pin-compatible?
Both devices are offered in the same 48-lead LQFP (ST-48) package, and Analog Devices documents them as pin-compatible within the PulSAR family. However, because the AD7634 provides additional input range configuration options, designers should verify the pin function assignments against the respective datasheets before substituting one for the other in an existing layout.
Do the AD7631BSTZ and AD7634BSTZRL have the same resolution and throughput?
Yes. Both are 18-bit successive-approximation (SAR) ADCs with a maximum throughput of 670 kSPS, and both use the same PulSAR architecture. The difference lies in input range configurability and packaging, not in resolution or conversion rate.
What input voltage ranges does each device support?
The AD7631 supports a ±10 V or ±5 V input range, while the AD7634 offers a programmable input range that includes ±10 V, ±5 V, and 0 V to 10 V. This makes the AD7634 more flexible for applications requiring unipolar or wider bipolar signal swings.
What is the difference between the AD7634BSTZ and the AD7634BSTZRL?
The AD7634BSTZ and AD7634BSTZRL are the same silicon device. The "RL" suffix denotes tape-and-reel packaging, while the non-RL part is supplied in tray form. Electrical specifications are identical; only the shipping packaging differs.
What interface and reference options do these ADCs provide?
Both devices provide a parallel interface and support an external reference. They are specified with a 5 V reference and operate from a 5 V analog supply with a separate digital supply. Designers should confirm the exact reference and supply configuration in the respective datasheets for their target operating mode.
Can the AD7631BSTZ be used as a drop-in replacement for the AD7634BSTZRL?
Not unconditionally. Although both share the same 48-lead LQFP package and 18-bit, 670 kSPS core, the AD7634 offers additional input range options that the AD7631 does not. A substitution is only valid after confirming that the required input range, reference configuration, and pin functions match the target design and are verified against both datasheets.