Part A
AD7674ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4562 Stückzahl
- Package
- LQFP-48
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7677ASTZRL is a viable functional replacement candidate for the AD7674ASTZ in many precision SAR applications, sharing the same 18-bit resolution, 1 MSPS throughput class, and 48-lead LQFP footprint. However, designers must validate the differential input architecture and the tighter linearity specifications of the AD7677 against the original AD7674 requirements before committing to a drop-in substitution.
Resolution and Throughput
High match
Package and Pinout
High match
Analog Input Configuration
Validation required
Linearity and Accuracy
Validation required
Parts at a glance
Part B
AD7677ASTZRL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4959 Stückzahl
- Package
- LQFP-48
- Series
- Datenerfassung mit 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 | AD7677ASTZRL | Why it matters |
|---|---|---|---|
| Resolution | 18 bits | 16 bits | Resolution determines the smallest signal change the ADC can resolve; an 18-bit part offers finer quantization than a 16-bit part, affecting achievable dynamic range and precision. |
| Sampling Rate | 800 kSPS | 1 MSPS | Maximum throughput dictates the highest signal bandwidth that can be digitized; the AD7677 supports a higher sample rate than the AD7674. |
| Input Type | Differential | Differential | Differential inputs improve common-mode noise rejection and dynamic performance; both parts share this architecture, aiding substitutability in signal-chain design. |
| INL (Integral Nonlinearity) | ±2.5 LSB max | ±1.0 LSB max | INL specifies deviation from an ideal transfer function; tighter INL in the AD7677 yields better absolute accuracy, which matters for precision measurement applications. |
| SNR (Signal-to-Noise Ratio) | 101 dB typ | 92 dB typ | SNR reflects the noise floor relative to full-scale signal; higher SNR in the AD7674 enables better resolution of small signals in the presence of noise. |
| Supply Voltage (Analog) | 5 V | 5 V | Analog supply voltage must match the surrounding signal chain; both parts operate from a 5 V analog supply, simplifying board-level substitution. |
| Interface | SPI / Parallel | SPI / Parallel | Digital interface compatibility determines whether the part can drop into an existing host connection; both support serial and parallel modes. |
| Package | 48-lead LQFP | 48-lead LQFP | Package and pinout affect PCB footprint and assembly; identical LQFP packaging supports physical interchangeability between the two parts. |
| Power Consumption | ~100 mW typ | ~90 mW typ | Power dissipation influences thermal design and supply sizing; lower consumption in the AD7677 can benefit power-sensitive systems. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7674ASTZ | AD7677ASTZRL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Active |
| Number of Bits | 18 | 16 |
| Sampling Rate(Per Second) | 800k | 1M |
| 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 | 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 |
Frequently asked questions
What are the key differences between the AD7674ASTZ and AD7677ASTZRL?
The AD7674ASTZ is an 18-bit, 800 kSPS charge redistribution SAR ADC, while the AD7677ASTZRL is a 16-bit, 1 MSPS charge redistribution SAR ADC. Both are pin-compatible in a 48-lead LQFP package and share the same analog input architecture, but they differ in resolution, throughput rate, and dynamic performance specifications.
Are the AD7674ASTZ and AD7677ASTZRL pin-compatible?
Yes. Both devices are offered in the same 48-lead LQFP (ST-48) package with identical pin functions, which allows the AD7677ASTZRL to be used as a drop-in replacement for the AD7674ASTZ in existing layouts, provided the system timing and resolution requirements are revalidated.
What is the maximum throughput of each device?
The AD7674ASTZ supports a maximum throughput of 800 kSPS, while the AD7677ASTZRL supports up to 1 MSPS. The higher sampling rate of the AD7677ASTZRL makes it suitable for faster signal chains, at the cost of 16-bit rather than 18-bit resolution.
Do both ADCs support the same analog input ranges?
Yes. Both the AD7674ASTZ and AD7677ASTZRL provide a differential analog input with a full-scale range of ±VREF, where VREF is typically 5 V, yielding a ±5 V differential input span. Both also support the same reference input configuration and internal conversion clock architecture.
What digital interfaces do the AD7674ASTZ and AD7677ASTZRL provide?
Both devices provide a parallel interface (18-bit for the AD7674ASTZ, 16-bit for the AD7677ASTZRL) as well as a serial SPI-compatible interface, and both support daisy-chain operation. The interface timing must be checked against the respective datasheet because the maximum SCLK rate and conversion timing differ between the two parts.
Can the AD7677ASTZRL replace the AD7674ASTZ in an existing 18-bit design?
Only if the system can tolerate a reduction from 18-bit to 16-bit resolution. The AD7677ASTZRL is pin-compatible and offers a higher 1 MSPS throughput, but the loss of two bits of resolution and the different SNR/INL specifications must be validated against the application requirements before substitution.
What are the typical power consumption figures for these ADCs?
Both devices operate from a 5 V analog supply and a 2.7 V to 5.25 V digital supply. The AD7674ASTZ typically dissipates approximately 100 mW at 800 kSPS, while the AD7677ASTZRL typically dissipates approximately 110 mW at 1 MSPS. Actual power scales with throughput, and both parts offer power-down modes for reduced consumption between conversions.
What are the operating temperature ranges for the AD7674ASTZ and AD7677ASTZRL?
Both devices are specified over the industrial temperature range of −40°C to +85°C. The "STZ" suffix in both part numbers denotes the 48-lead LQFP package in a Pb-free, RoHS-compliant finish.