Part A
AD7865BSZ-1
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5453 Stückzahl
- Package
- QFP-44
- Series
- Datenerfassung mit Analog to Digital Converters (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7865BSZ-1 and AD7864AS-2 are both four-channel simultaneous-sampling 14-bit ADCs from Analog Devices, sharing a compatible MQFP-44 package and parallel interface, making the AD7864AS-2 a viable functional replacement candidate for the AD7865BSZ-1 in many applications. However, designers must validate the differing conversion throughput, analog input range, and specified operating temperature range against their system requirements before substituting, as these parameters are not identical between the two devices.
Conversion Throughput
Validation required
Analog Input Range
Validation required
Package Type
High match
Operating Temperature Range
Validation required
Parts at a glance
Part B
AD7864AS-2
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 146 Stückzahl
- Package
- QFP-44
- 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 | AD7865BSZ-1 | AD7864AS-2 | Why it matters |
|---|---|---|---|
| Number of ADC Channels | 4 | 4 | Channel count determines how many analog signals can be sampled; both are 4-channel devices, so channel capacity is equivalent. |
| Resolution | 14 bits | 12 bits | Higher resolution provides finer quantization and better dynamic range; the AD7865 offers 14-bit versus 12-bit on the AD7864, affecting measurement precision. |
| Sampling Rate (max) | 350 kSPS | 500 kSPS | Maximum throughput limits the highest signal frequency that can be captured; the AD7864 supports a faster conversion rate. |
| Input Voltage Range | ±10 V (bipolar) | ±10 V (bipolar) | Input range must match the sensor or signal amplitude; both accept ±10 V bipolar inputs, so front-end scaling requirements are the same. |
| Supply Voltage | 5 V single supply | 5 V single supply | Supply voltage determines power rail compatibility; both operate from a single 5 V supply, simplifying board-level substitution. |
| Interface Type | Parallel | Parallel | The digital interface must match the host controller; both use a parallel interface, so bus timing and pinout compatibility should be reviewed. |
| Package / Mounting | 44-Lead MQFP | 44-Lead MQFP | Package and footprint affect PCB layout and assembly; identical MQFP packages allow potential drop-in replacement with layout verification. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range defines the environments where the part is reliable; both cover the industrial range, so environmental suitability is equivalent. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7865BSZ-1 | AD7864AS-2 |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 14 | 12 |
| Sampling Rate(Per Second) | 350k | 520k |
| 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 primary differences between the AD7865BSZ-1 and the AD7864AS-2?
The AD7865BSZ-1 is a 14-bit, 4-channel simultaneous-sampling ADC with a 3.5 µs conversion time and a throughput rate of 350 kSPS, housed in a 44-lead MQFP. The AD7864AS-2 is a 12-bit, 4-channel simultaneous-sampling ADC with a 1.65 µs conversion time and a throughput rate of 500 kSPS, housed in a 44-lead MQFP. The AD7865BSZ-1 offers higher resolution (14-bit vs 12-bit), while the AD7864AS-2 offers faster throughput (500 kSPS vs 350 kSPS).
Are the AD7865BSZ-1 and AD7864AS-2 pin-compatible?
Both devices are offered in a 44-lead MQFP package, but they are not pin-compatible. The AD7865BSZ-1 and AD7864AS-2 have different pin functions and configurations, so a direct drop-in replacement is not possible without PCB redesign and validation against the respective datasheets.
What is the resolution and throughput of each device?
The AD7865BSZ-1 provides 14-bit resolution with a maximum throughput of 350 kSPS. The AD7864AS-2 provides 12-bit resolution with a maximum throughput of 500 kSPS. The AD7864AS-2 is faster, while the AD7865BSZ-1 offers higher resolution.
How many analog input channels do these ADCs support?
Both the AD7865BSZ-1 and the AD7864AS-2 are 4-channel, simultaneous-sampling ADCs. Each device can sample four analog inputs simultaneously, making them suitable for applications requiring phase-coherent multi-channel acquisition.
What are the analog input voltage ranges for each part?
The AD7865BSZ-1 supports selectable input ranges of ±10 V, ±5 V, and ±2.5 V. The AD7864AS-2 supports input ranges of ±10 V and ±5 V. Designers should confirm the exact range configuration against the respective manufacturer datasheets for their specific grade and application.
Do both devices operate from a single 5 V supply?
Yes, both the AD7865BSZ-1 and the AD7864AS-2 operate from a single 5 V analog supply. The AD7865BSZ-1 also requires a separate 5 V digital supply, while the AD7864AS-2 includes an on-chip reference and operates from a single 5 V supply for both analog and digital functions. Refer to the datasheets for exact supply and decoupling requirements.
Which device is better suited for higher-resolution applications?
The AD7865BSZ-1 is better suited for higher-resolution applications because it provides 14-bit resolution, compared to the 12-bit resolution of the AD7864AS-2. For applications where dynamic range and measurement precision are critical, the AD7865BSZ-1 is the preferred choice, provided its 350 kSPS throughput meets the system requirements.
Which device is better suited for higher-speed sampling applications?
The AD7864AS-2 is better suited for higher-speed sampling applications because it offers a maximum throughput of 500 kSPS and a 1.65 µs conversion time, compared to 350 kSPS and 3.5 µs for the AD7865BSZ-1. For systems requiring faster acquisition cycles, the AD7864AS-2 is the appropriate selection.