Part A
AD7801BRZ
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 5137 個数
- Package
- SOIC-20
- Series
- データ取得 - デジタル/アナログコンバータ (DAC)
Replacement verdict
Not a drop-in replacement
The AD7801BRZ and AD7805CR are not drop-in replacements for one another. Although both are 8-bit voltage-output DACs from Analog Devices, they differ in resolution-related architecture, interface protocol, reference configuration, and package footprint, so a direct substitution is not possible without design changes.
Different interface protocol
Different reference configuration
Different package footprint
Different channel count
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7801BRZ | AD7805CR | Why it matters |
|---|---|---|---|
| Resolution | 8-bit | 10-bit | Resolution determines the number of discrete output levels; a 10-bit DAC offers 4x finer granularity than an 8-bit DAC, affecting precision of the analog output. |
| Number of DAC Channels | 1 | 4 | Channel count defines how many independent analog outputs are available; a single-channel part cannot directly replace a quad-channel part in multi-output systems. |
| Interface Type | Parallel | Parallel | The digital interface must match the host controller's bus; both use a parallel interface, easing drop-in compatibility at the digital side. |
| Supply Voltage (VDD) | 2.7 V to 5.5 V | 3.3 V to 5.5 V | Operating supply range must cover the system rail; the AD7801 supports lower 2.7 V operation, while the AD7805 requires at least 3.3 V. |
| Settling Time | 1 µs | 1.5 µs | Settling time affects how quickly the DAC output reaches its final value, which is critical for high-speed waveform generation and control loops. |
| Output Voltage Range | 0 V to VREF | 0 V to VREF (buffered) | The output span determines the usable analog range; both are rail-to-reference types, but the AD7805 provides buffered outputs for driving loads more robustly. |
| Package Type | 20-lead SOIC | 28-lead SOIC | Package footprint and pin count must match the PCB layout; differing packages prevent direct board-level substitution without redesign. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | The temperature range must cover the application environment; identical industrial ranges mean both suit the same thermal conditions. |
| Reference Input | External | External | Both require an external voltage reference, so the reference design can be shared, but accuracy depends on the external reference chosen. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7801BRZ | AD7805CR |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 8 | 10 |
| Number of D/A Converters | 1 | 4 |
| Settling Time | 2µs | 4µs |
| Output Type | Voltage - Buffered | Voltage - Buffered |
| Differential Output | No | No |
| Data Interface | Parallel | Parallel |
| Reference Type | External | External, Internal |
| Voltage - Supply, Analog | 2.7V ~ 5.5V | 3V ~ 5.5V |
| Voltage - Supply, Digital | 2.7V ~ 5.5V | 3V ~ 5.5V |
| INL / DNL(LSB) | ±1 (Max), ±1 (Max) | ±3 (Max), ±0.125 |
| Operating Temperature | -40°C ~ 105°C | -40°C ~ 85°C |
| Architecture | Current Source | - |
Frequently asked questions
What are the key differences between the AD7801BRZ and AD7805CR?
The AD7801BRZ is an 8-bit voltage-output DAC in a 20-lead SOIC package, while the AD7805CR is a 10-bit voltage-output DAC in a 28-lead SOIC package. The AD7805CR offers higher resolution (10-bit vs 8-bit) and additional features such as a programmable output range and a parallel interface with more control pins, whereas the AD7801BRZ provides a simpler 8-bit parallel interface in a smaller package.
Are the AD7801BRZ and AD7805CR pin-compatible?
No. The AD7801BRZ uses a 20-lead SOIC package, and the AD7805CR uses a 28-lead SOIC package. The pin counts and pin functions differ, so they are not drop-in replacements and require different PCB land patterns.
What is the resolution of each DAC?
The AD7801BRZ is an 8-bit DAC (256 output levels), and the AD7805CR is a 10-bit DAC (1024 output levels). The AD7805CR therefore provides four times finer output resolution than the AD7801BRZ.
Do both parts support the same digital interface?
Both devices use a parallel digital interface, but the AD7801BRZ is an 8-bit parallel interface, while the AD7805CR provides a 10-bit parallel interface with additional control signals. The interface timing and control pin functions differ, so firmware and glue logic must be adapted accordingly.
What are the supply voltage requirements for these DACs?
Both the AD7801BRZ and AD7805CR operate from a single +2.7 V to +5.5 V supply, making them suitable for 3 V and 5 V systems. Designers should verify the exact supply range and decoupling requirements in the respective manufacturer datasheets.
Can the AD7801BRZ be used as a direct substitute for the AD7805CR in an existing design?
No. Because of the different package sizes (20-lead vs 28-lead SOIC), different resolutions (8-bit vs 10-bit), and different interface control signals, the AD7801BRZ is not a direct substitute for the AD7805CR. A redesign of the PCB footprint and interface logic would be required.
Which part is better suited for higher-precision applications?
The AD7805CR is better suited for higher-precision applications because it provides 10-bit resolution compared with the 8-bit resolution of the AD7801BRZ. The AD7805CR also offers a programmable output range, which can improve effective precision in systems with a restricted output span.