Part A
AD7634BSTZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7383 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7634BSTZ and AD7631BSTZRL are both 18-bit PulSAR successive-approximation ADCs from Analog Devices in the same 48-lead LQFP package, sharing a common architecture and reference family. However, they differ in input configuration and throughput, so the AD7631BSTZRL is a viable functional candidate only after validating the input signal chain and timing budget against the AD7634BSTZ requirements.
Input Configuration
Validation required
Sample Rate
Validation required
Resolution
High match
Package Type
High match
Parts at a glance
Part B
AD7631BSTZRL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6625 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 | AD7634BSTZ | AD7631BSTZRL | Why it matters |
|---|---|---|---|
| Resolution | 18 bits | 18 bits | Both are 18-bit SAR ADCs, so resolution is identical and not a differentiator for substitutability. |
| Sampling Rate | 670 kSPS | 250 kSPS | The AD7634 offers a higher throughput, which matters for applications requiring faster conversion rates. |
| Input Type | Differential | Differential | Both accept differential inputs, so signal conditioning requirements are the same. |
| Number of Input Channels | 1 | 1 | Single-channel architecture in both parts means channel-count requirements are met identically. |
| Supply Voltage (Analog) | 5 V | 5 V | Matching analog supply simplifies power design and allows drop-in replacement in the same rail architecture. |
| Interface | SPI / Parallel | SPI / Parallel | Both support serial and parallel interfaces, so host-side digital connectivity is compatible. |
| Package / Case | 48-LQFP | 48-LQFP | Identical package footprint enables direct PCB substitution without layout changes. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Same industrial temperature range means both suit the same environmental conditions. |
| Power Consumption | ~110 mW (typical) | ~85 mW (typical) | Lower power in the AD7631 benefits thermally constrained or battery-powered designs, while the AD7634 trades power for speed. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7634BSTZ | AD7631BSTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Series | iCMOS®, PulSAR® | PulSAR® |
| Part Status | Active | Active |
| Number of Bits | 18 | 18 |
| Sampling Rate(Per Second) | 670k | 250k |
| 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 AD7634BSTZ and the AD7631BSTZRL?
Both are 18-bit, successive-approximation analog-to-digital converters from Analog Devices in a 48-lead LQFP package. The AD7634 is a fully differential input PulSAR ADC with a maximum throughput of 670 kSPS, while the AD7631 is a 250 kSPS device. The AD7634 also offers higher signal-to-noise ratio and faster conversion timing, whereas the AD7631 is optimized for lower power and lower speed applications. The "RL" suffix on the AD7631BSTZRL indicates tape-and-reel packaging.
Are the AD7634BSTZ and AD7631BSTZRL pin-compatible?
Yes. Both devices are offered in the same 48-lead LQFP (STZ) package and share the same pinout family for the AD763x series. However, designers should confirm the specific pin functions and configuration options against the respective datasheets before substituting one for the other in an existing layout.
What is the maximum sampling rate of each device?
The AD7634BSTZ supports a maximum throughput of 670 kSPS. The AD7631BSTZRL supports a maximum throughput of 250 kSPS. The higher rate of the AD7634 makes it suitable for faster data-acquisition channels, while the AD7631 targets lower-speed, lower-power designs.
Do both parts support the same analog input configuration?
Both are 18-bit PulSAR ADCs with differential analog inputs and an on-chip track-and-hold. The AD7634 is specified as a fully differential input device, and the AD7631 is likewise a differential-input SAR converter. Exact input voltage range and reference configuration should be verified in each device's datasheet, as the two parts are specified for different throughput and power budgets.
How do the power consumption figures compare?
The AD7631 is designed for lower power operation at its 250 kSPS rate, while the AD7634 consumes more power to support its 670 kSPS throughput. Because power scales with sampling rate and configuration, the exact supply current and power dissipation for each part should be taken from the respective Analog Devices datasheet rather than assumed.
What does the "RL" suffix on the AD7631BSTZRL mean?
The "RL" suffix denotes tape-and-reel packaging, which is intended for automated pick-and-place assembly lines. The AD7634BSTZ is supplied in standard tray or tube packaging. The silicon device itself is the same as the corresponding base part number; only the packaging and shipping format differ.
Can the AD7631BSTZRL be used as a drop-in replacement for the AD7634BSTZ?
Not unconditionally. Although both share the 48-lead LQFP package and belong to the same AD763x family, they differ in maximum throughput (250 kSPS vs. 670 kSPS), power consumption, and timing specifications. A substitution is only valid after verifying that the lower sampling rate and different dynamic performance of the AD7631 meet the system requirements and that the interface timing is compatible.
What interface do these ADCs use to connect to a host processor?
Both devices provide a parallel digital interface for output data, with additional serial configuration and control pins. The AD7634 and AD7631 support a high-speed parallel interface suitable for direct connection to DSPs, FPGAs, and microcontrollers. Designers should consult the datasheets for the exact timing, voltage levels, and pin assignments of the parallel port on each part.