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 AD7808BR are not drop-in replacements for one another. The AD7801BRZ is a single 8-bit voltage-output DAC in an SOIC-8 package, while the AD7808BR is an octal 8-bit DAC in a wider package with a different digital interface and reference architecture. Designers must account for differences in channel count, package footprint, output configuration, and interface timing before considering any substitution.
Different channel count
Different package footprint
Different output configuration
Different digital interface
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 | AD7808BR | Why it matters |
|---|---|---|---|
| Resolution (bits) | 8 | 10 | 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 | 8 | Channel count defines how many independent analog outputs are available; a single-channel part cannot directly replace a multi-channel part in multi-output systems. |
| Interface Type | Parallel | Serial (SPI/QSPI/MICROWIRE) | The digital interface must match the host controller; parallel and serial interfaces are not pin- or protocol-compatible, requiring different board routing and firmware. |
| Supply Voltage Range | 2.7 V to 5.5 V | 4.5 V to 5.5 V | The supply range determines compatibility with the system power rail; the AD7801 supports lower-voltage operation down to 2.7 V, while the AD7808 requires a 5 V rail. |
| Package Type | 20-Lead SOIC (Wide) | 20-Lead SOIC (Wide) | Package footprint and pinout must match for board-level substitution; identical package outlines simplify replacement but pin functions may still differ. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | The temperature range indicates the environments in which the device is guaranteed to meet specifications; matching ranges support equivalent thermal robustness. |
| Output Type | Voltage Output | Voltage Output | Output type (voltage vs. current) must match the load and signal chain; both are voltage-output DACs, so the analog interface style is compatible. |
| Settling Time | 1 µs (typical) | 5 µs (typical) | Settling time affects the maximum update rate and dynamic performance; the faster AD7801 is better suited to higher-speed control loops. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7801BRZ | AD7808BR |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 8 | 10 |
| Number of D/A Converters | 1 | 8 |
| Settling Time | 2µs | 4µs |
| Output Type | Voltage - Buffered | Voltage - Buffered |
| Differential Output | No | No |
| Data Interface | Parallel | SPI |
| 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) | ±4 (Max), ±0.125 |
| Operating Temperature | -40°C ~ 105°C | -40°C ~ 85°C |
| Architecture | Current Source | - |
Frequently asked questions
Are the AD7801BRZ and AD7808BR functionally interchangeable?
No. The AD7801BRZ is a single 8-bit voltage-output DAC, while the AD7808BR is an 8-bit octal (eight-channel) DAC. They differ in channel count, package, and interface architecture, so they are not direct substitutes.
What is the resolution and channel count of each device?
The AD7801BRZ provides one 8-bit DAC channel. The AD7808BR provides eight 8-bit DAC channels in a single package.
How do the digital interfaces of the AD7801BRZ and AD7808BR differ?
The AD7801BRZ uses a parallel microprocessor-compatible interface for loading its single DAC. The AD7808BR uses a serial interface to address and load its eight DAC channels, reducing pin count but requiring serial data framing.
Do the AD7801BRZ and AD7808BR use the same package type?
No. The AD7801BRZ is supplied in a 20-lead SOIC (R-20) package, while the AD7808BR is supplied in a 24-lead SOIC (R-24) package. The different lead counts and pinouts prevent a drop-in PCB replacement.
What are the supply voltage requirements for these DACs?
Both devices operate from a single +2.7 V to +5.5 V supply, making them suitable for 3 V and 5 V mixed-signal systems.
Which device is better suited for multi-channel control applications?
The AD7808BR is better suited for multi-channel control because it integrates eight DAC channels in one package, saving board space and simplifying control of multiple setpoints compared with using eight separate AD7801BRZ devices.
Can the AD7801BRZ replace one channel of an AD7808BR in an existing design?
Not directly. Although both are 8-bit DACs with similar supply ranges, the AD7801BRZ uses a parallel interface and a 20-lead package, whereas the AD7808BR uses a serial interface and a 24-lead package. Any substitution requires interface and layout redesign validated against the manufacturer datasheets.