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-3 are both four-channel simultaneous-sampling 14-bit ADCs from Analog Devices, sharing a comparable architecture and parallel interface, but they differ in package footprint, speed grade, and input configuration. The AD7864AS-3 offers a faster conversion rate and flexible input ranges, while the AD7865BSZ-1 provides a different pinout and package. Designers should validate board layout, timing margins, and input signal conditioning before substituting one for the other in an existing design.
Package Type
Validation required
Resolution and Channel Count
Validation required
Conversion Speed
Validation required
Input Configuration
Validation required
Parts at a glance
Part B
AD7864AS-3
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 915 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-3 | 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 precision versus 12-bit on the AD7864. |
| Sampling Rate | 350 kSPS | 500 kSPS | Maximum throughput affects 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 source; both accept ±10 V bipolar inputs, so signal conditioning requirements are similar. |
| Supply Voltage | 5 V single supply | 5 V single supply | Supply voltage compatibility determines whether the part can drop into an existing power rail; both operate from a single 5 V supply. |
| Interface Type | Parallel | Parallel | The digital interface must match the host controller; both use a parallel interface, simplifying bus-level substitution. |
| Package / Mounting | 44-Lead MQFP | 44-Lead MQFP | Package and footprint compatibility affect PCB layout; both are 44-lead MQFP devices, allowing potential board-level interchange. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range must cover the application environment; both are specified for industrial temperature operation. |
| Power Consumption | ~100 mW (typical) | ~90 mW (typical) | Power dissipation affects thermal design and energy budget; the AD7864 is slightly more power-efficient in typical operation. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7865BSZ-1 | AD7864AS-3 |
|---|---|---|
| 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 AD7864AS-3?
The AD7865BSZ-1 is a 14-bit, 4-channel simultaneous-sampling ADC with a 3.5 µs conversion time and a 100 kSPS throughput rate, specified over the industrial temperature range and housed in a 44-lead MQFP. The AD7864AS-3 is a 12-bit, 4-channel simultaneous-sampling ADC with a 1.65 µs conversion time and a 500 kSPS throughput rate, specified over the industrial temperature range and housed in a 44-lead MQFP. The key differences are resolution (14-bit vs 12-bit), throughput (100 kSPS vs 500 kSPS), and conversion time.
Are the AD7865BSZ-1 and AD7864AS-3 pin-compatible?
Both devices are offered in a 44-lead MQFP package, but pin compatibility cannot be assumed from package type alone. The pin functions and digital interface timing differ between the two data sheets, so a direct drop-in replacement should not be made without verifying each pin against both manufacturer data sheets.
Can the AD7864AS-3 be used as a direct replacement for the AD7865BSZ-1 in an existing design?
No. The AD7865BSZ-1 provides 14-bit resolution at 100 kSPS, while the AD7864AS-3 provides 12-bit resolution at 500 kSPS. The difference in resolution, throughput, conversion timing, and interface behavior means the system timing, firmware, and accuracy budget must be revalidated before substitution.
What is the throughput rate of each device?
The AD7865BSZ-1 has a specified throughput rate of 100 kSPS. The AD7864AS-3 has a specified throughput rate of 500 kSPS. The higher throughput of the AD7864AS-3 comes with 12-bit resolution, whereas the AD7865BSZ-1 offers 14-bit resolution at the lower rate.
How many analog input channels do these ADCs provide?
Both the AD7865BSZ-1 and the AD7864AS-3 are 4-channel simultaneous-sampling ADCs. Each device samples all four analog inputs simultaneously, which is suitable for applications requiring phase-coherent acquisition across multiple channels.
What is the conversion time of the AD7865BSZ-1 and AD7864AS-3?
The AD7865BSZ-1 has a conversion time of 3.5 µs. The AD7864AS-3 has a conversion time of 1.65 µs. These values are specified in the respective manufacturer data sheets and directly affect the maximum achievable throughput of each part.
What package type do the AD7865BSZ-1 and AD7864AS-3 use?
Both the AD7865BSZ-1 and the AD7864AS-3 are supplied in a 44-lead MQFP (Metric Quad Flat Package). Designers should still confirm the exact package outline and thermal characteristics against the manufacturer data sheet for each specific part number.