Part A
AD7678ASTZ
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 4894 個数
- Series
- データ取得 - アナログ/デジタルコンバータ (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7678ASTZ and AD7677ASTRL are both 16-bit successive-approximation ADCs from Analog Devices in the same LQFP-48 package family, sharing core architecture and digital interface characteristics. However, they differ in throughput rate and analog input configuration, so the AD7677ASTRL can serve as a functional substitute for the AD7678ASTZ only after validating sampling-rate requirements and input-range compatibility in the target design.
Resolution and Architecture
Validation required
Sampling Rate
Validation required
Analog Input Configuration
Validation required
Package Type
High match
Parts at a glance
Part B
AD7677ASTRL
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 5280 個数
- Package
- LQFP-48
- Series
- データ取得 - アナログ/デジタルコンバータ (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 | AD7678ASTZ | AD7677ASTRL | Why it matters |
|---|---|---|---|
| Resolution | 18 bits | 16 bits | Resolution determines the smallest signal change the ADC can distinguish; an 18-bit device offers 4x finer quantization than a 16-bit device, affecting achievable dynamic range and precision. |
| Maximum Sampling Rate | 100 kSPS | 1 MSPS | The throughput rate limits the maximum input signal bandwidth that can be digitized; the 10x faster AD7677 supports higher-speed signals while the AD7678 trades speed for resolution. |
| INL (Integral Nonlinearity) | ±2.5 LSB max | ±1.5 LSB max | INL quantifies deviation from an ideal transfer function; tighter INL means better absolute accuracy and less distortion, which is critical for precision measurement applications. |
| DNL (Differential Nonlinearity) | ±1 LSB max | ±0.9 LSB max | DNL indicates code transition uniformity; values within ±1 LSB guarantee monotonicity, which is essential to avoid missing codes in closed-loop and control systems. |
| SNR (Signal-to-Noise Ratio) | 101 dB typ | 92 dB typ | SNR reflects the noise floor relative to full-scale input; higher SNR enables detection of smaller signals and better effective resolution in the application. |
| THD (Total Harmonic Distortion) | -110 dB typ | -100 dB typ | THD measures harmonic distortion introduced by the converter; lower distortion preserves spectral purity, important for AC measurement and audio-band signal processing. |
| Power Consumption | 65 mW typ | 115 mW typ | Power dissipation affects thermal design and battery life; the lower-power AD7678 is preferable for portable or thermally constrained systems. |
| Analog Input Type | Differential | Differential | Differential inputs reject common-mode noise and improve dynamic performance; both parts share this architecture, so input front-end design is compatible. |
| Supply Voltage | 5 V (analog and digital) | 5 V (analog and digital) | Matching supply requirements allows the same power rail design to be reused, simplifying substitution in existing boards. |
| Package | 48-lead LQFP | 48-lead LQFP | Identical package and pinout enable drop-in replacement on the PCB without layout changes, which is a key factor for functional substitutability. |
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 | AD7678ASTZ | AD7677ASTRL |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 18 | 16 |
| Sampling Rate(Per Second) | - | 1M |
| 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 AD7677ASTRL?
The AD7678ASTZ is a 16-bit, 100 kSPS PulSAR analog-to-digital converter, while the AD7677ASTRL is a 16-bit, 1 MSPS PulSAR ADC. The AD7677ASTRL offers a significantly higher sampling rate (1 MSPS vs 100 kSPS), whereas the AD7678ASTZ is optimized for lower-power, lower-speed precision applications. Both are 16-bit successive-approximation ADCs from Analog Devices in 48-lead LQFP packages.
Are the AD7678ASTZ and AD7677ASTRL pin-compatible?
Both devices are offered in a 48-lead LQFP (ST-48) package from Analog Devices. However, pin compatibility should be confirmed against the respective official datasheets, as pin functions and configurations may differ between the two speed grades. Designers must verify the pinout before considering a direct board-level substitution.
What is the maximum sampling rate of each device?
The AD7678ASTZ supports a maximum throughput of 100 kSPS, while the AD7677ASTRL supports a maximum throughput of 1 MSPS. The AD7677ASTRL is therefore suited to higher-speed acquisition applications, while the AD7678ASTZ targets lower-speed, high-precision designs.
Do both ADCs offer the same resolution and interface?
Yes. Both the AD7678ASTZ and AD7677ASTRL are 16-bit PulSAR ADCs and provide a parallel interface for data output. Both are specified as 16-bit resolution successive-approximation converters, making them comparable in resolution and digital interface style, though their speed grades differ.
Can the AD7677ASTRL be used as a drop-in replacement for the AD7678ASTZ?
Not without validation. Although both are 16-bit PulSAR ADCs in 48-lead LQFP packages, the AD7677ASTRL operates at a higher sampling rate (1 MSPS vs 100 kSPS), which affects timing, power, and possibly external component requirements. A substitution must be verified against both official datasheets and the target design's timing and power budgets.
Which device is better suited for low-power applications?
The AD7678ASTZ, with its lower 100 kSPS throughput, is generally intended for lower-power, precision-oriented designs, while the AD7677ASTRL's 1 MSPS operation typically demands more power to support the higher conversion rate. Designers should consult the official power specifications in each datasheet to confirm suitability for a given power budget.
Are both parts manufactured by Analog Devices?
Yes. Both the AD7678ASTZ and AD7677ASTRL are Analog Devices PulSAR successive-approximation ADCs. The "ASTZ" and "ASTRL" suffixes denote package and packaging options (48-lead LQFP, with "RL" indicating tape-and-reel packaging for the AD7677ASTRL).