Part A
AD7678ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4894 PCS
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7678ASTZ and AD7679ASTZRL are both 18-bit, 570 kSPS PulSAR analog-to-digital converters in the same 48-lead LQFP package with identical pinout and a parallel interface, making them strong functional replacement candidates. The AD7679ASTZRL is supplied in tape-and-reel packaging, so the primary distinction is the ordering format rather than the core conversion architecture. Designers should confirm the specific grade and any application-specific accuracy requirements before substituting one for the other.
Resolution and Sample Rate
High match
Package and Pinout
High match
Digital Interface
High match
Ordering Format and Grade
Validation required
Parts at a glance
Part B
AD7679ASTZRL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6051 PCS
- Package
- LQFP-48
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (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 | AD7679ASTZRL | Why it matters |
|---|---|---|---|
| Resolution | 18 bits | 18 bits | Bit depth determines the finest analog signal change the ADC can resolve; both are 18-bit so resolution is equivalent. |
| Sampling Rate | 100 kSPS | 570 kSPS | Maximum throughput dictates the highest signal bandwidth that can be digitized; the AD7679 supports significantly faster sampling. |
| Input Type | Differential | Differential | Differential inputs reject common-mode noise and improve dynamic range; both devices use the same input topology. |
| Number of Input Channels | 1 | 1 | Channel count determines how many signals can be measured without external multiplexing; both are single-channel devices. |
| Supply Voltage (Analog) | 5 V | 5 V | Analog supply defines the input voltage range and interface levels; identical 5 V supplies allow drop-in compatibility. |
| Interface | SPI / DSP / Parallel | SPI / DSP / Parallel | Digital interface compatibility determines whether the part can connect to the host processor without glue logic; both support the same interfaces. |
| Package / Case | 48-LQFP | 48-LQFP | Package footprint and pinout must match for board-level substitution; both use the same 48-lead LQFP. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range defines the environments where the part is guaranteed to meet specifications; both cover the industrial range. |
| Power Consumption | ~85 mW typical | ~120 mW typical | Power dissipation affects thermal design and battery life; the higher-speed AD7679 consumes more power. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7678ASTZ | AD7679ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 18 | 18 |
| Sampling Rate(Per Second) | - | 570k |
| 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 |
| 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 AD7679ASTZRL?
Both are 18-bit, 570 kSPS PulSAR analog-to-digital converters from Analog Devices in a 48-lead LQFP package. The AD7678ASTZ is a single-channel fully differential ADC, while the AD7679ASTZRL is a dual-channel (two independent ADCs) version. The AD7679ASTZRL is supplied in tape-and-reel packaging (RL suffix), whereas the AD7678ASTZ is supplied in tray form. Both share the same pinout family and similar SAR architecture but differ in channel count and packaging format.
Are the AD7678ASTZ and AD7679ASTZRL pin-compatible?
No. The AD7678ASTZ is a single-channel 18-bit PulSAR ADC, while the AD7679ASTZRL is a dual-channel device. Because the AD7679 integrates two ADC cores, its pin functions and internal signal routing differ from the single-channel AD7678. Designers must verify pin assignments against the respective Analog Devices datasheets before considering any layout reuse.
What is the resolution and throughput of these converters?
Both the AD7678ASTZ and AD7679ASTZRL are 18-bit successive-approximation (SAR) ADCs with a maximum throughput of 570 kSPS per channel. The AD7678 provides one fully differential input channel, while the AD7679 provides two independent channels, each capable of 570 kSPS operation.
What analog input configuration do these ADCs support?
The AD7678ASTZ features a fully differential analog input, which provides good common-mode rejection and improved dynamic performance. The AD7679ASTZRL contains two independent ADCs, each with its own differential input structure, allowing simultaneous or sequential sampling of two signal channels. Both devices are intended for applications requiring high accuracy, such as medical instrumentation, data acquisition, and industrial measurement.
What digital interface do the AD7678ASTZ and AD7679ASTZRL use?
Both devices provide a serial digital interface compatible with SPI and similar serial host controllers, along with a parallel interface option. The AD7678ASTZ offers a flexible serial/parallel host interface, and the AD7679ASTZRL provides a similar interface arrangement for each of its two channels. Designers should consult the specific Analog Devices datasheet for timing and mode configuration details.
What package and operating temperature range do these parts use?
Both the AD7678ASTZ and AD7679ASTZRL are offered in a 48-lead LQFP package. The "ASTZ" suffix indicates an RoHS-compliant LQFP package. Both are specified for the industrial temperature range of −40 °C to +85 °C, consistent with Analog Devices' PulSAR converter family documentation.
Can the AD7678ASTZ be used as a drop-in replacement for the AD7679ASTZRL?
No. The AD7678ASTZ is a single-channel ADC, while the AD7679ASTZRL is a dual-channel ADC. Although they belong to the same PulSAR family and share similar resolution and throughput, the channel count difference means they are not functionally interchangeable. A system requiring two simultaneous channels cannot use the single-channel AD7678ASTZ without adding an external multiplexer or second ADC, and the pinouts are not identical.
What are typical applications for the AD7678ASTZ and AD7679ASTZRL?
These 18-bit, 570 kSPS SAR converters are suited to high-accuracy data acquisition systems, medical instrumentation, industrial process control, and test and measurement equipment. The AD7678ASTZ is used where a single high-resolution differential channel is sufficient, while the AD7679ASTZRL is chosen when two independent channels must be digitized, such as in multi-sensor or I/Q signal acquisition designs.