Part A
AD7678ASTZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 4894 PCS
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7678ASTZ and AD7676ASTZRL are both 16-bit successive-approximation ADCs from Analog Devices in the same LQFP-48 package and share a compatible digital interface, making the AD7678ASTZ a viable functional replacement candidate for the AD7676ASTZRL. However, the two devices differ in sample rate and analog input architecture, so the design must be validated against the target application's throughput and input drive requirements before substitution.
Resolution
High match
Package Type
High match
Sample Rate
Validation required
Analog Input Type
Validation required
Parts at a glance
Part B
AD7676ASTZRL
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 5733 PCS
- Package
- LQFP-48
- Series
- Acquisition de données - Convertisseur analogique - numérique (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 | AD7676ASTZRL | Why it matters |
|---|---|---|---|
| Resolution | 18 bits | 16 bits | Resolution determines the smallest signal change the ADC can distinguish; an 18-bit part offers 4x finer quantization than a 16-bit part, affecting achievable dynamic range and precision. |
| Sample Rate | 100 kSPS | 500 kSPS | Maximum throughput limits the bandwidth of signals that can be digitized; the AD7676 supports five times the sampling rate, enabling faster acquisition or wider signal bandwidth. |
| INL (Integral Nonlinearity) | ±2.5 LSB max | ±1.0 LSB max | INL describes deviation from an ideal transfer function; tighter INL improves absolute accuracy and linearity of the digitized output. |
| SNR (Signal-to-Noise Ratio) | 101 dB typ | 92 dB typ | SNR reflects the noise floor relative to full-scale signal; higher SNR enables detection of smaller signals and better effective resolution. |
| THD (Total Harmonic Distortion) | -110 dB typ | -100 dB typ | THD quantifies harmonic distortion introduced by the converter; lower distortion preserves signal fidelity in AC measurement applications. |
| Power Consumption | 65 mW typ | 110 mW typ | Power dissipation affects thermal design and suitability for low-power or portable systems; the AD7678 consumes substantially less power. |
| Analog Input Type | Differential | Differential | Differential inputs reject common-mode noise and improve dynamic performance; both parts share this architecture, aiding substitutability. |
| Supply Voltage | 5 V (analog and digital) | 5 V (analog and digital) | Supply requirements determine compatibility with the surrounding system rails; identical 5 V operation simplifies board-level substitution. |
| Package | 48-lead LQFP | 48-lead LQFP | Package and pinout compatibility are essential for drop-in replacement; matching LQFP packages allow the same PCB footprint. |
| Interface | SPI / Parallel | SPI / Parallel | Digital interface compatibility ensures the host processor can communicate with either part without redesign of the data bus. |
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 | AD7676ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 18 | 16 |
| Sampling Rate(Per Second) | - | 500k |
| 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 |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Base Product Number | AD7678 | - |
| Sampling Rate (Per Second) | 100k | - |
| Number of A / D Converters | 1 | - |
| Mounting Type | Surface Mount | - |
| Packaging | Tray | - |
Frequently asked questions
What are the key differences between the AD7678ASTZ and the AD7676ASTZRL?
The AD7678ASTZ is a 16-bit, 100 kSPS PulSAR analog-to-digital converter, while the AD7676ASTZRL is a 16-bit, 500 kSPS PulSAR ADC. The AD7676ASTZRL offers a higher maximum throughput rate, whereas the AD7678ASTZ is optimized for lower-speed, lower-power applications. Both are pin-compatible in the same 48-lead LQFP package.
Are the AD7678ASTZ and AD7676ASTZRL pin-compatible?
Yes. Both devices are offered in the same 48-lead LQFP (ST-48) package and share a common pinout, which allows the AD7676ASTZRL to be used as a higher-speed drop-in upgrade for the AD7678ASTZ in many designs, provided the rest of the signal chain supports the increased sampling rate.
What is the maximum sampling rate of each device?
The AD7678ASTZ supports a maximum throughput of 100 kSPS, while the AD7676ASTZRL supports a maximum throughput of 500 kSPS. The higher rate of the AD7676ASTZRL requires the digital host and analog front end to accommodate the faster conversion timing.
Do both parts use the same analog input architecture?
Yes. Both are 16-bit charge-redistribution successive-approximation (SAR) ADCs with a differential analog input range of ±VREF and an on-chip track-and-hold. This common architecture means the analog front-end design and reference requirements are largely transferable between the two parts.
What is the difference in power consumption between the two devices?
The AD7678ASTZ typically dissipates about 15 mW at 100 kSPS, while the AD7676ASTZRL typically dissipates about 60 mW at 500 kSPS. Power scales with throughput, so the lower-speed AD7678ASTZ is preferable when minimizing power is the priority.
What digital interface do the AD7678ASTZ and AD7676ASTZRL provide?
Both devices provide a parallel digital interface with a flexible host connection and support both 5 V and 3 V digital logic supplies. The interface timing must be revalidated when moving from the 100 kSPS AD7678ASTZ to the 500 kSPS AD7676ASTZRL because of the shorter conversion and read cycles.
Can the AD7676ASTZRL directly replace the AD7678ASTZ in an existing design?
In many cases yes, because the two parts are pin-compatible and share the same SAR architecture and package. However, the replacement must be validated against the higher 500 kSPS throughput, the increased power dissipation, and the tighter digital timing of the AD7676ASTZRL before it is adopted in a production design.