Part A
AD7678ASTZRL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3901 Stückzahl
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7677ASTZ and AD7678ASTZRL are both 16-bit successive-approximation ADCs from Analog Devices in the same LQFP-48 package, sharing a common pinout and reference architecture, so the AD7678ASTZRL can serve as a functional substitute for the AD7677ASTZ in most designs. The primary distinction is throughput: the AD7677ASTZ offers a faster maximum sampling rate, while the AD7678ASTZRL trades some speed for lower power consumption. Engineers should confirm that the reduced sample rate and power profile of the AD7678ASTZRL satisfy the timing and thermal budget of the target application before committing to the swap.
Resolution
High match
Package Type
High match
Maximum Sampling Rate
Validation required
Power Consumption
Validation required
Parts at a glance
Part B
AD7677ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1648 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 | AD7677ASTZ | AD7678ASTZRL | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 18 | Higher resolution provides finer quantization and lower theoretical noise floor, directly affecting achievable accuracy and dynamic range. |
| Sampling Rate (max) | 1 MSPS | 570 kSPS | Maximum throughput determines the highest signal bandwidth that can be digitized and whether the part meets system timing requirements. |
| INL (max) | ±1.0 LSB | ±2.5 LSB | Integral nonlinearity bounds the deviation from an ideal transfer function, which affects absolute accuracy in precision measurement applications. |
| DNL (max) | ±0.5 LSB | ±0.9 LSB | Differential nonlinearity indicates monotonicity and code-transition uniformity; tighter DNL ensures no missing codes and better small-signal fidelity. |
| SNR (typ) | 94 dB | 101 dB | Signal-to-noise ratio defines the usable dynamic range and noise-limited resolution for AC signal acquisition. |
| THD (typ) | -110 dB | -115 dB | Total harmonic distortion quantifies spectral purity; lower THD is critical for high-fidelity signal processing and spectral analysis. |
| Power Consumption (typ) | 110 mW | 85 mW | Power dissipation affects thermal design, supply sizing, and suitability for power-sensitive or portable systems. |
| Analog Input Type | Differential | Differential | Differential inputs improve common-mode rejection and noise immunity; matching input topology ensures the same front-end circuitry can be reused. |
| Supply Voltage (analog) | 5 V | 5 V | Analog supply voltage must match the system rail and affects input range and interface levels for drop-in compatibility. |
| Package | 48-LQFP | 48-LQFP | Package and pinout determine PCB footprint compatibility and whether a direct board-level substitution is possible. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7678ASTZRL | AD7677ASTZ |
|---|---|---|
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Active |
| Base Product Number | AD7678 | - |
| Number of Bits | 18 | 16 |
| Sampling Rate (Per Second) | 100k | - |
| 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 |
| Mounting Type | Surface Mount | - |
| Packaging | Tape & Reel (TR) | - |
| Sampling Rate(Per Second) | - | 1M |
| Number of A/D Converters | - | 1 |
Frequently asked questions
What are the key differences between the AD7677ASTZ and the AD7678ASTZRL?
Both are 16-bit, 1 MSPS successive-approximation ADCs from Analog Devices in a 48-lead LQFP package, but they differ in their analog input range and reference configuration. The AD7677 is a true differential input ADC with a ±VREF input range and an internal 2.5 V reference, while the AD7678 is a pseudo-differential input ADC with a 0 V to VREF unipolar input range and requires an external reference. The AD7678ASTZRL is the tape-and-reel packaging variant of the AD7678ASTZ.
Are the AD7677ASTZ and AD7678ASTZRL pin-compatible?
Yes. Both devices are offered in the same 48-lead LQFP (ST-48) package with an identical pinout, which allows a common PCB footprint. However, pin-compatibility does not guarantee functional interchangeability because the analog input configuration and reference requirements differ between the two parts.
Can the AD7677ASTZ be used as a drop-in replacement for the AD7678ASTZRL?
Not without design changes. The AD7677 accepts a true differential bipolar input (±VREF) and includes an internal reference, whereas the AD7678 requires a unipolar 0 V to VREF input and an external reference. The signal conditioning, reference circuitry, and digital output coding must be revalidated before substitution.
What is the difference in packaging between the AD7677ASTZ and the AD7678ASTZRL?
The AD7677ASTZ is supplied in a tray (tube) format, while the AD7678ASTZRL suffix indicates tape-and-reel packaging intended for automated pick-and-place assembly. Both use the same 48-lead LQFP body, so the choice is a matter of production handling rather than electrical performance.
Do both parts offer the same resolution and throughput?
Yes. Both the AD7677 and AD7678 are 16-bit successive-approximation ADCs specified for a maximum throughput of 1 MSPS, making them suitable for high-speed data acquisition, medical instrumentation, and industrial control applications.
What reference voltage does each device require?
The AD7677 includes an internal 2.5 V reference and can also be driven by an external reference, with its input range defined as ±VREF. The AD7678 does not include an internal reference and requires an external reference voltage, with its input range defined as 0 V to VREF. Designers must account for this difference when selecting the reference source.
Which serial interface do these ADCs support?
Both devices provide a serial digital interface compatible with SPI, QSPI, MICROWIRE, and DSP host ports, allowing direct connection to most microcontrollers and digital signal processors without additional glue logic.
Are the AD7677ASTZ and AD7678ASTZRL specified over the same temperature range?
Yes. Both parts are rated for the industrial temperature range of −40 °C to +85 °C, so the operating environment does not distinguish one from the other in a comparison.