Part A
AD7621ASTZ
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 6501 PCS
- Package
- LQFP-48
- Series
- 데이터 수집 - 아날로그 변환기(ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7621ASTZ is a functionally compatible replacement candidate for the AD7621AST, with matching core converter specifications and package footprint; the primary distinction is the RoHS-compliant lead finish on the ASTZ suffix, which should be validated against your assembly and compliance requirements before substitution.
Resolution and Architecture
High match
Package Type
High match
RoHS Compliance
Validation required
Operating Temperature Range
High match
Parts at a glance
Part B
AD7621AST
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 2390 PCS
- Package
- LQFP-48
- Series
- 데이터 수집 - 아날로그 변환기(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 | AD7621ASTZ | AD7621AST | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 16 bit | Determines the number of discrete levels the ADC can represent; both parts provide identical conversion resolution. |
| Sampling Rate | 3 MSPS | 3 MSPS | Sets the maximum throughput of the converter; identical rates mean equivalent signal bandwidth capability. |
| Number of Inputs | 1 differential | 1 differential | Defines the input channel configuration; both support a single differential input for the same signal chain topology. |
| Architecture | SAR | SAR | Successive-approximation architecture affects latency and power; identical architecture ensures equivalent behavior in the system. |
| Supply Voltage | 5 V analog / 2.5 V digital | 5 V analog / 2.5 V digital | Determines power rail requirements; matching rails allow the same board design and power sequencing. |
| Interface Type | Serial (SPI/QSPI/MICROWIRE/DSP) | Serial (SPI/QSPI/MICROWIRE/DSP) | Defines how the ADC connects to the host processor; identical interfaces ensure drop-in digital compatibility. |
| Package / Case | 48-LQFP | 48-LQFP | Footprint and thermal characteristics must match for physical substitutability on an existing PCB. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Confirms both parts are rated for the same environmental conditions in industrial applications. |
| RoHS / Lead-Free Status | RoHS compliant, lead-free | Contains lead (non-RoHS) | The "Z" suffix denotes lead-free/RoHS compliance; this affects regulatory compliance and solder process selection. |
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 | AD7621ASTZ | AD7621AST |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Series | PulSAR® | PulSAR® |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 16 |
| Sampling Rate(Per Second) | 3M | 2M |
| 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, Internal | - |
| Voltage - Supply, Analog | 2.37V ~ 2.63V | - |
| Voltage - Supply, Digital | 2.37V ~ 2.63V | - |
Frequently asked questions
What is the difference between the AD7621ASTZ and the AD7621AST?
The AD7621ASTZ and AD7621AST are functionally identical 16-bit, 3 MSPS PulSAR analog-to-digital converters. The primary difference is the suffix "Z," which indicates that the AD7621ASTZ is a lead-free (Pb-free) package that is RoHS-compliant, whereas the AD7621AST is the older lead-containing (Pb) package version. Both are specified for the same 48-lead LQFP package and industrial temperature range.
Are the AD7621ASTZ and AD7621AST pin-compatible?
Yes. Both devices are offered in the same 48-lead LQFP (ST-48) package with identical pin assignments. The "Z" suffix denotes the lead-free/RoHS-compliant molding compound and lead finish, not a change in pinout or package footprint, so they are drop-in compatible on the same PCB land pattern.
Can the AD7621ASTZ be used as a direct replacement for the AD7621AST?
Yes, from a functional and footprint standpoint the AD7621ASTZ can directly replace the AD7621AST, since both share the same die, specifications, and 48-lead LQFP pinout. The substitution is typically made to achieve RoHS compliance. Designers should confirm their assembly process and solder profile are compatible with the lead-free finish of the "Z" version.
What are the key performance specifications shared by the AD7621ASTZ and AD7621AST?
Both parts are 16-bit, 3 MSPS successive-approximation (PulSAR) ADCs featuring a pseudo-differential input, an internal 2.5 V reference, and a serial LVDS/SPI-compatible interface. They deliver 16-bit no-missing-codes performance with SNR of approximately 90 dB and operate from a 2.5 V analog supply with a separate 2.5 V to 3.3 V digital supply, in the industrial temperature range of -40°C to +85°C.
Does the "Z" suffix on the AD7621ASTZ affect its electrical performance?
No. The "Z" designation is a package/environmental compliance indicator for lead-free (Pb-free) and RoHS-compliant construction. The electrical specifications, timing, and functional behavior of the AD7621ASTZ are the same as those of the AD7621AST, as both are covered by the same device datasheet.
Which version should be selected for a new RoHS-compliant design?
For new designs requiring RoHS compliance and lead-free assembly, the AD7621ASTZ should be selected. The AD7621AST (non-Z) is the legacy lead-containing version and is generally not recommended for new RoHS-restricted products. Both remain available from authorized distributors, but the "Z" version is the preferred choice for current production.
Are the AD7621ASTZ and AD7621AST available in the same package and temperature grade?
Yes. Both are supplied in the 48-lead LQFP package and are specified over the industrial temperature range of -40°C to +85°C. The only documented distinction between the two orderable part numbers is the lead-free/RoHS-compliant ("Z") versus leaded package construction.