Part A
AD7678ASTZ
ADI公司
- Lifecycle
- Active
- Stock
- 4894 件
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Compatible functional replacement candidate
The AD7678ASTZ and AD7675AST are both 16-bit successive-approximation ADCs from Analog Devices in the same LQFP-48 package, sharing a compatible digital interface and reference architecture. The AD7678ASTZ offers a faster 100 kSPS throughput versus 100 kSPS-class operation of the AD7675AST, so it can serve as a functional replacement in most designs provided the timing budget and power envelope are validated against the target application.
Resolution
High match
Package Type
High match
Sampling Rate
Validation required
Power Consumption
Validation required
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7678ASTZ | AD7675AST | Why it matters |
|---|---|---|---|
| Resolution | 18 bits | 16 bits | Higher resolution provides finer quantization and lower quantization noise, directly affecting achievable accuracy and dynamic range in precision measurement systems. |
| Sampling Rate | 100 kSPS | 100 kSPS | Maximum throughput determines how fast the ADC can digitize signals; matching rates allow similar system timing budgets. |
| Input Type | Differential | Differential | Differential inputs reject common-mode noise and improve signal integrity in noisy or low-level signal environments. |
| INL (Integral Nonlinearity) | ±2.5 LSB max | ±1.5 LSB max | INL defines deviation from an ideal transfer function; tighter INL yields better absolute accuracy and linearity in precision applications. |
| SNR (Signal-to-Noise Ratio) | 101 dB typ | 92 dB typ | SNR sets the noise floor and effective dynamic range; higher SNR enables detection of smaller signals and better measurement fidelity. |
| Supply Voltage | 5 V analog, 5 V digital | 5 V analog, 5 V digital | Supply requirements determine power rail compatibility and interface levels with surrounding logic and analog front ends. |
| Package | 48-lead LQFP | 48-lead LQFP | Package and pinout affect PCB footprint, thermal behavior, and drop-in substitutability on an existing board. |
| Interface | SPI / QSPI / MICROWIRE / DSP compatible serial | SPI / QSPI / MICROWIRE / DSP compatible serial | Serial interface compatibility ensures the ADC can communicate with the host controller without redesigning the digital bus. |
| Power Consumption | 100 mW typ | 100 mW typ | Power dissipation impacts thermal design and supply sizing, especially in densely packed or battery-sensitive systems. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7678ASTZ | AD7675AST |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 18 | 16 |
| Sampling Rate(Per Second) | - | 100k |
| Number of A/D Converters | - | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Base Product Number | AD7678 | - |
| Sampling Rate (Per Second) | 100k | - |
| Number of Inputs | 1 | - |
| Input Type | Differential | - |
| Data Interface | SPI, Parallel, DSP | - |
| Configuration | S/H-ADC | - |
| Ratio - S / H: ADC | 1:1 | - |
| Number of A / D Converters | 1 | - |
| Architecture | SAR | - |
| Reference Type | External, Internal | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Mounting Type | Surface Mount | - |
| Packaging | Tray | - |
Frequently asked questions
What are the key differences between the AD7678ASTZ and the AD7675AST?
The AD7678ASTZ is a 16-bit, 1 MSPS successive-approximation ADC with a serial interface, while the AD7675AST is a 16-bit, 100 kSPS SAR ADC. The AD7678ASTZ offers a significantly higher throughput rate (1 MSPS vs 100 kSPS) and is specified for a different speed/power operating point, so the two are not drop-in replacements for each other in most designs.
Are the AD7678ASTZ and AD7675AST pin-compatible?
Both devices are offered in a 48-lead LQFP package, but pin compatibility must be confirmed against the respective manufacturer pinouts and the target PCB land pattern. Because the two parts have different speed grades and interface timing, designers should verify pin functions and timing requirements from the official datasheets before considering any substitution.
What is the resolution and throughput of each device?
The AD7678ASTZ provides 16-bit resolution at a maximum throughput of 1 MSPS. The AD7675AST provides 16-bit resolution at a maximum throughput of 100 kSPS. Both are SAR-type ADCs, but the AD7678ASTZ is intended for higher-speed acquisition applications.
Do both parts support a serial interface?
Yes. Both the AD7678ASTZ and the AD7675AST provide a serial digital interface for connection to host processors or DSPs. The exact interface timing, clock requirements, and readback protocol differ between the two speed grades and should be taken from the respective manufacturer datasheets.
Can the AD7675AST be used as a lower-speed substitute for the AD7678ASTZ?
Only after validating the system requirements. The AD7675AST has a much lower maximum throughput (100 kSPS vs 1 MSPS), so it cannot meet applications that require the AD7678ASTZ's 1 MSPS sampling rate. Any substitution must be checked against timing, interface, and accuracy requirements in the official datasheets.
What package type do these ADCs use?
Both the AD7678ASTZ and the AD7675AST are supplied in a 48-lead LQFP package. Designers should confirm the exact package outline, thermal characteristics, and land pattern from the manufacturer datasheet before layout or replacement decisions.
Are these parts suitable for high-speed data acquisition systems?
The AD7678ASTZ, with its 1 MSPS throughput and 16-bit resolution, is suited to higher-speed data acquisition and instrumentation applications. The AD7675AST, at 100 kSPS, is better matched to lower-speed, precision measurement channels. Selection should be based on the required sampling rate and the verified specifications in each datasheet.