Part A
AD7865BSZ-1
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5453 PCS
- Package
- QFP-44
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7865BSZ-1 and AD7865AS-3 are both four-channel simultaneous-sampling 14-bit ADCs from the AD7865 family, sharing the same 44-lead MQFP footprint and parallel interface, so they are functionally interchangeable in most designs. The BSZ-1 grade offers a faster 3.5 µs conversion time and a wider specified temperature range, while the AS-3 grade provides a 5.5 µs conversion time with a narrower temperature specification. Designers should confirm timing margin and operating-temperature requirements before substituting one grade for the other.
Resolution and Channel Count
High match
Package and Pinout
High match
Conversion Time
Validation required
Operating Temperature Range
Validation required
Parts at a glance
Part B
AD7865AS-3
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 8475 PCS
- Package
- QFP-44
- 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 | AD7865BSZ-1 | AD7865AS-3 | Why it matters |
|---|---|---|---|
| Number of ADC Channels | 4 | 4 | Both devices provide four simultaneous-sampling input channels, so channel count is functionally equivalent. |
| Resolution | 14 bits | 14 bits | Identical resolution ensures the same quantization step size and measurement precision. |
| Sampling Rate | 100 kSPS | 100 kSPS | Matching throughput allows the same signal bandwidth and timing budget in the application. |
| Input Voltage Range | ±10 V (bipolar) | ±10 V (bipolar) | The same bipolar input span means external signal conditioning and front-end scaling can remain unchanged. |
| Supply Voltage | 5 V | 5 V | Identical single 5 V supply simplifies power rail design and ensures electrical compatibility. |
| Interface Type | Parallel | Parallel | Both use a parallel interface, so the host processor bus connection and firmware timing remain compatible. |
| Package / Mounting | 44-Lead MQFP (surface mount) | 44-Lead MQFP (surface mount) | Same package and footprint allow a drop-in board replacement without layout changes. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent temperature ratings ensure the same environmental operating envelope for the end product. |
| Grade / Accuracy Class | B grade | A grade | The B grade typically offers tighter linearity and offset specifications than the A grade, which can affect measurement accuracy in precision applications. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7865BSZ-1 | AD7865AS-3 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 14 | 14 |
| Sampling Rate(Per Second) | 350k | 350k |
| Data Interface | Parallel | Parallel |
| Number of A/D Converters | 1 | 1 |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Number of Inputs | 4 | - |
| Input Type | Single Ended | - |
| Configuration | S/H-MUX-ADC | - |
| Ratio - S / H: ADC | 4:1 | - |
| Architecture | SAR | - |
| Reference Type | External, Internal | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
| Features | Simultaneous Sampling | - |
Frequently asked questions
What are the key differences between the AD7865BSZ-1 and AD7865AS-3?
Both are four-channel, 14-bit successive-approximation ADCs from Analog Devices in the AD7865 family, but they differ in speed grade and temperature/quality grade. The AD7865BSZ-1 is specified for a 3.5 µs conversion time (fast option) and is offered in the industrial temperature range with a lead-free (Pb-free) package designation, while the AD7865AS-3 is the slower 5 µs conversion-time version in the standard commercial/industrial grade. Designers should confirm the exact grade suffix definitions against the Analog Devices AD7865 datasheet before substitution.
Are the AD7865BSZ-1 and AD7865AS-3 pin-compatible?
Yes. Both devices are members of the same AD7865 family and are offered in the same 44-lead MQFP package with an identical pinout. Pin functions, including the analog inputs, reference, parallel data bus, and control lines, are the same across the family, so board-level pin compatibility is maintained between these two orderable variants.
What is the resolution and architecture of these ADCs?
Both the AD7865BSZ-1 and AD7865AS-3 are 14-bit successive-approximation register (SAR) analog-to-digital converters with four analog input channels. They feature a parallel microprocessor-compatible interface and on-chip track-and-hold circuitry, allowing simultaneous sampling of multiple channels for applications requiring multichannel data acquisition.
How do the conversion speeds of the two variants compare?
The AD7865BSZ-1 is the faster grade with a specified conversion time of 3.5 µs, while the AD7865AS-3 has a conversion time of 5 µs. The faster grade supports higher throughput in time-critical acquisition systems, whereas the 5 µs version may be adequate for lower-speed multichannel designs. Always verify the timing specification against the specific grade in the Analog Devices datasheet.
What analog input range do these converters support?
The AD7865 family provides bipolar analog input ranges, typically ±10 V and ±5 V, selectable by the input range configuration. Both the AD7865BSZ-1 and AD7865AS-3 support these bipolar ranges, making them suitable for industrial signal-conditioning applications where bipolar sensor or transducer outputs must be digitized.
What is the difference in operating temperature grade between the two parts?
The AD7865BSZ-1 is specified over the industrial temperature range, while the AD7865AS-3 is specified over the commercial temperature range. The industrial-grade device is intended for applications with wider ambient temperature excursions, whereas the commercial-grade part is suited to controlled-environment equipment. Confirm the exact temperature limits for each grade in the manufacturer datasheet.
Does the "Z" suffix in AD7865BSZ-1 indicate a lead-free package?
Yes. In Analog Devices nomenclature, the "Z" suffix denotes a lead-free (Pb-free) package that is RoHS-compliant. The AD7865BSZ-1 therefore carries the Pb-free designation, while the AD7865AS-3 does not include the Z suffix and should be checked for its specific package finish and RoHS status in the datasheet or product page.
Can the AD7865AS-3 be used as a drop-in replacement for the AD7865BSZ-1?
Because both parts share the same package, pinout, resolution, and architecture, they are functionally similar, but they are not identical: the AD7865BSZ-1 offers the faster 3.5 µs conversion time and Pb-free package, while the AD7865AS-3 is the 5 µs commercial-grade version. A substitution is only appropriate after verifying that the slower conversion time and commercial temperature range meet the system requirements and that the package finish is acceptable.