Part A
AD7665ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3003 PCS
- Package
- LQFP-48
- Series
- Data Acquisition - Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7667AST is a strong functional replacement candidate for the AD7665ASTZ, sharing the same 16-bit SAR architecture, 570 kSPS throughput, and 5 V single-supply operation in a pin-compatible 48-lead LQFP package. Designers should validate the serial interface configuration and confirm timing margins against the specific system requirements before committing to production.
Resolution and Architecture
High match
Sample Rate
High match
Digital Interface
Validation required
Package and Pinout
High match
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7665ASTZ | AD7667AST | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Both are 16-bit SAR ADCs, so nominal resolution is identical and does not differentiate substitutability. |
| Sampling Rate | 570 kSPS | 1 MSPS | The AD7667 offers a higher maximum throughput, which matters for higher-bandwidth signal acquisition and faster system update rates. |
| Number of Input Channels | 4 (single-ended) / 2 (differential) | 1 (single-ended) / 1 (differential) | The AD7665 supports multiplexed multi-channel input, while the AD7667 is single-channel; this affects system architecture and channel count. |
| Input Type | Single-ended or differential (multiplexed) | Single-ended or differential | Both support differential inputs, but the AD7665 adds multiplexed single-ended/differential channel selection. |
| Interface | Parallel and Serial (SPI/QSPI/MICROWIRE/DSP) | Parallel and Serial (SPI/QSPI/MICROWIRE/DSP) | Both offer flexible parallel and serial interfaces, so digital host connectivity is largely interchangeable. |
| Supply Voltage (Analog) | 5 V | 5 V | Identical analog supply requirements simplify power-rail reuse when substituting parts. |
| Package | 48-Lead LQFP | 48-Lead LQFP | Same package and pin count support drop-in PCB compatibility, though pin functions must be verified. |
| Power Consumption | Typical 87 mW at 570 kSPS | Typical 100 mW at 1 MSPS | The AD7667 consumes more power at its higher throughput, which affects thermal and power budget considerations. |
| INL (Integral Nonlinearity) | ±2.5 LSB max | ±2.5 LSB max | Matching linearity specifications indicate comparable DC accuracy for precision measurement applications. |
| SNR (Signal-to-Noise Ratio) | 90 dB typ | 90 dB typ | Equivalent noise performance means both are suitable for similar dynamic-range requirements. |
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 | AD7665ASTZ | AD7667AST |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 570k | 1M |
| Number of A/D Converters | 1 | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Number of Inputs | 1 | - |
| Input Type | Differential | - |
| Data Interface | SPI, Parallel, DSP | - |
| Configuration | S/H-ADC | - |
| Ratio - S / H: ADC | 1:1 | - |
| Architecture | SAR | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Features | True Bipolar | - |
Frequently asked questions
What are the key differences between the AD7665ASTZ and the AD7667AST?
The AD7665ASTZ is a 16-bit, 570 kSPS PulSAR ADC, while the AD7667AST is a 16-bit, 1 MSPS PulSAR ADC. The AD7667AST offers a higher maximum throughput rate (1 MSPS vs. 570 kSPS) and a faster serial interface capability, while both share the same 16-bit resolution, SAR architecture, and 48-lead LQFP package footprint.
Are the AD7665ASTZ and AD7667AST pin-compatible?
Yes. Both devices are offered in the same 48-lead LQFP (ST-48) package and share a common pinout, which allows the AD7667AST to be used as a drop-in replacement for the AD7665ASTZ in existing layouts, provided the higher 1 MSPS throughput and associated timing requirements are supported by the host system.
What is the resolution and architecture of these ADCs?
Both the AD7665ASTZ and AD7667AST are 16-bit successive-approximation-register (SAR) analog-to-digital converters featuring a charge redistribution DAC architecture, offering no pipeline delay and inherent 16-bit no-missing-code performance.
What are the maximum sampling rates of the AD7665ASTZ and AD7667AST?
The AD7665ASTZ has a maximum throughput of 570 kSPS, whereas the AD7667AST supports a maximum throughput of 1 MSPS. The higher rate of the AD7667AST requires the corresponding faster serial clock (SCLK) and acquisition timing to be met.
Do both parts support the same analog input ranges and reference options?
Yes. Both devices provide a flexible analog input structure supporting bipolar ±10 V, ±5 V, and unipolar 0 V to 10 V, 0 V to 5 V, and 0 V to 2.5 V ranges, and both support either an internal 2.5 V reference or an external reference, allowing a common analog front-end design.
What digital interfaces do the AD7665ASTZ and AD7667AST provide?
Both converters provide a serial SPI/QSPI/MICROWIRE/DSP-compatible interface and a parallel 16-bit word interface, with a dedicated BUSY and CONVST signal for conversion control. The AD7667AST's faster serial interface timing is required to sustain its 1 MSPS throughput.
What are the power supply and power consumption characteristics of these devices?
Both devices operate from a 5 V analog supply (AVDD) and a 5 V digital supply (DVDD), with a separate VIO supply for the digital interface. Typical power dissipation is on the order of 100 mW at full throughput, with power scaling down at lower sampling rates; the AD7667AST dissipates somewhat more at its higher 1 MSPS rate.
In which applications would the AD7667AST be preferred over the AD7665ASTZ?
The AD7667AST is preferred where higher throughput is required, such as in faster data acquisition systems, multiplexed multi-channel scanning, and applications needing 1 MSPS 16-bit sampling. The AD7665ASTZ is suitable where 570 kSPS is sufficient and lower power or cost is prioritized.