Part A
AD7678ASTZRL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3901 PCS
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7678ASTZRL is a strong functional replacement candidate for the AD7674ASTZ, sharing the same 18-bit SAR architecture, 48-lead LQFP package, and identical pinout. The primary distinction is throughput: the AD7678 offers a lower maximum sampling rate, so the substitution is valid only where the system timing budget accommodates the reduced conversion speed. Designers should confirm the sampling-rate margin and digital timing before committing to the swap.
Resolution
High match
Package Type
High match
Sampling Rate
Validation required
Interface Type
High match
Parts at a glance
Part B
AD7674ASTZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4562 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 | AD7674ASTZ | AD7678ASTZRL | Why it matters |
|---|---|---|---|
| Resolution | 18 bit | 18 bit | Both are 18-bit SAR ADCs, so resolution is identical and not a differentiator for substitutability. |
| Sampling Rate | 800 kSPS | 100 kSPS | The AD7674 offers 8x the throughput, which directly affects achievable signal bandwidth and system update rate. |
| Number of Input Channels | 1 (differential) | 1 (differential) | Both are single-channel differential devices, so channel count does not affect interchangeability. |
| Input Type | Differential | Differential | Identical differential input architecture means the same front-end signal conditioning can be reused. |
| Supply Voltage (Analog) | 5 V | 5 V | Same analog supply simplifies power rail design when swapping parts. |
| Interface | SPI / Parallel / Daisy-chain | SPI / Parallel / Daisy-chain | Matching digital interfaces allow the same host controller and firmware to be used with either device. |
| Package | 48-Lead LQFP | 48-Lead LQFP | Identical package and pinout enable drop-in board replacement without layout changes. |
| Power Consumption | ~90 mW (typical) | ~25 mW (typical) | The lower-power AD7678 suits battery or thermally constrained designs, while the AD7674 trades power for speed. |
| INL (Integral Nonlinearity) | ±2.5 LSB max | ±2.5 LSB max | Equivalent linearity means both meet the same accuracy class for precision measurement applications. |
| SNR | ~101 dB | ~101 dB | Comparable signal-to-noise ratio indicates similar dynamic performance for AC signal acquisition. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7678ASTZRL | AD7674ASTZ |
|---|---|---|
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Active |
| Base Product Number | AD7678 | - |
| Number of Bits | 18 | 18 |
| Sampling Rate (Per Second) | 100k | - |
| 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 | - |
| 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 |
| Mounting Type | Surface Mount | - |
| Packaging | Tape & Reel (TR) | - |
| Sampling Rate(Per Second) | - | 800k |
| Number of A/D Converters | - | 1 |
Frequently asked questions
What are the key differences between the AD7674ASTZ and AD7678ASTZRL?
The AD7674ASTZ is an 18-bit, 800 kSPS charge redistribution SAR ADC, while the AD7678ASTZRL is an 18-bit, 100 kSPS SAR ADC. Both are pin-compatible in a 48-lead LQFP package and share the same analog input architecture, but they differ in maximum throughput rate and therefore in power consumption and timing specifications.
Are the AD7674ASTZ and AD7678ASTZRL pin-compatible?
Yes. Both devices are offered in the same 48-lead LQFP (ST-48) package with identical pin functions, allowing the AD7678ASTZRL to be used as a lower-speed drop-in alternative to the AD7674ASTZ when the system timing and throughput requirements permit.
What is the maximum sampling rate of each device?
The AD7674ASTZ supports a maximum throughput of 800 kSPS, whereas the AD7678ASTZRL supports a maximum throughput of 100 kSPS. The choice between them depends on the required conversion rate of the target application.
Do both parts offer the same analog input range and interface options?
Yes. Both the AD7674ASTZ and AD7678ASTZRL provide a differential analog input with a selectable input range of 0 V to 5 V or ±2.5 V, and both support parallel and serial (SPI-compatible) digital interfaces, along with a separate digital supply for flexible logic interfacing.
How does power consumption compare between the AD7674ASTZ and AD7678ASTZRL?
Because power scales with throughput, the AD7674ASTZ (800 kSPS) consumes more operating power than the AD7678ASTZRL (100 kSPS). Both devices feature power-down modes that reduce consumption between conversions, making the lower-speed AD7678ASTZRL advantageous in power-sensitive designs.
Can the AD7678ASTZRL replace the AD7674ASTZ in an existing design?
It can be considered only if the system's maximum required sampling rate is 100 kSPS or less and the timing, power, and interface requirements are revalidated against the AD7678ASTZRL datasheet. The pinout and package are identical, but the reduced throughput must be acceptable for the application.
What is the significance of the "RL" suffix on AD7678ASTZRL?
The "RL" suffix denotes tape-and-reel packaging, which is intended for automated high-volume assembly. The AD7674ASTZ is supplied in standard tray packaging. The electrical performance of the device is unaffected by the packaging option.