Part A
AD7849BRZ
ADI公司
- Lifecycle
- Active
- Stock
- 5626 件
- Package
- SOIC-20
- Series
- 資料獲取-數模轉換器（DAC）
Replacement verdict
Not a drop-in replacement
The AD7849BRZ and AD7847AR are not drop-in replacements for one another. Although both are Analog Devices voltage-output DACs, they differ in resolution, channel count, digital interface, and package, so a direct board-level substitution is not possible without redesign.
Different resolution
Different channel count
Different digital interface
Different package
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7849BRZ | AD7847AR | Why it matters |
|---|---|---|---|
| Resolution | 16 bit | 12 bit | Resolution determines the smallest output step; a 16-bit DAC offers 16x finer granularity than a 12-bit DAC, which is critical for precision control loops. |
| Number of DAC Channels | 1 | 2 | Channel count affects how many independent analog outputs can be driven; a dual DAC can replace two single DACs in multi-channel designs. |
| DAC Architecture | String DAC | R-2R Ladder | Architecture influences monotonicity, settling behavior, and glitch performance, which affect dynamic accuracy in control applications. |
| Output Voltage Range | 0 V to 10 V (unipolar) / ±10 V (bipolar) | 0 V to 10 V (unipolar) / ±10 V (bipolar) | Output range must match the load or amplifier input span; both support similar spans but differ in resolution over that range. |
| Supply Voltage | ±12 V to ±15 V (dual supply) | ±12 V to ±15 V (dual supply) | Supply requirements determine power rail compatibility; both use similar bipolar supplies, easing board-level substitution. |
| Interface Type | Serial (SPI-compatible) | Parallel | Interface type dictates microcontroller pin count and firmware; serial saves pins while parallel offers faster updates. |
| Package | 20-Lead SOIC (Wide) | 24-Lead PDIP | Package footprint and mounting type affect PCB layout and rework; SOIC vs PDIP are not drop-in compatible. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range confirms suitability for industrial environments; matching ranges support similar application profiles. |
| Integral Nonlinearity (INL) | ±1 LSB (typical) | ±0.5 LSB (typical) | INL measures deviation from ideal transfer function; lower INL yields better absolute accuracy in precision systems. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7849BRZ | AD7847AR |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 16 | 12 |
| Number of D/A Converters | 1 | 2 |
| Settling Time | 10µs (Typ) | 5µs |
| Output Type | Voltage - Buffered | Voltage - Buffered |
| Differential Output | No | No |
| Data Interface | SPI | Parallel |
| Reference Type | External | External |
| Voltage - Supply, Analog | ±14.25V ~ 15.75V | ±14.25V ~ 15.75V |
| INL / DNL(LSB) | ±16 (Max), ±0.9 (Max) | ±1 (Max), ±1 (Max) |
| Architecture | String DAC | R-2R |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Voltage - Supply, Digital | 5V | - |
Frequently asked questions
What are the key architectural differences between the AD7849BRZ and AD7847AR?
The AD7849BRZ is a 16-bit voltage-output DAC with a serial interface, while the AD7847AR is a 12-bit voltage-output DAC with a parallel interface. The AD7849BRZ offers higher resolution (16-bit vs 12-bit) and uses a serial (SPI-compatible) interface, whereas the AD7847AR uses a parallel microprocessor interface. Both are manufactured by Analog Devices.
Are the AD7849BRZ and AD7847AR pin-compatible?
No. The AD7849BRZ is offered in a 24-lead SOIC (R-24) package, while the AD7847AR is offered in a 24-lead SOIC (R-24) package as well, but the pin functions differ due to the serial versus parallel interface architecture. The AD7849BRZ uses serial data pins (SDIN, SCLK, SYNC), while the AD7847AR uses parallel data bus pins (DB0–DB11) plus address and control lines. They are not directly interchangeable without redesign.
What is the resolution and accuracy difference between the AD7849BRZ and AD7847AR?
The AD7849BRZ provides 16-bit resolution with ±1 LSB integral nonlinearity (INL) typical, while the AD7847AR provides 12-bit resolution with ±1/2 LSB INL typical. The AD7849BRZ therefore offers 16 times finer resolution and is suited for higher-precision applications, whereas the AD7847AR targets general-purpose 12-bit control applications.
Do the AD7849BRZ and AD7847AR have the same output voltage range?
Both devices support bipolar output voltage ranges. The AD7849BRZ offers selectable output ranges of ±10 V, ±5 V, and 0 V to +10 V. The AD7847AR offers a fixed ±10 V output range (with a 10 V reference). The AD7849BRZ provides greater flexibility in output span selection.
What are the interface differences between the AD7849BRZ and AD7847AR?
The AD7849BRZ uses a 3-wire serial interface compatible with SPI, QSPI, and MICROWIRE, operating at clock rates up to 10 MHz. The AD7847AR uses a parallel 12-bit microprocessor-compatible interface with data bus pins DB0–DB11 and standard chip-select, write, and address control signals. The serial interface of the AD7849BRZ reduces pin count and simplifies isolation, while the parallel interface of the AD7847AR offers higher throughput for direct bus-connected systems.
How do the power supply requirements compare between the AD7849BRZ and AD7847AR?
Both devices operate from dual supplies. The AD7849BRZ operates from ±12 V to ±15 V supplies (with a +5 V logic supply option). The AD7847AR operates from ±12 V to ±15 V supplies as well. Both are specified for the commercial temperature range of 0°C to +70°C (the "A" and "B" grade suffixes indicate grade, not temperature range). Designers should verify exact supply tolerances against the respective datasheets.
Can the AD7849BRZ directly replace the AD7847AR in an existing design?
No. Direct replacement is not possible because the two devices differ in resolution (16-bit vs 12-bit), interface type (serial vs parallel), pin functions, and output range configurability. A redesign of the digital interface, PCB layout, and possibly the analog output stage would be required. The AD7849BRZ is a higher-resolution, serial-interface alternative, not a drop-in replacement.
Which device is better suited for high-precision industrial control applications?
The AD7849BRZ is better suited for high-precision applications due to its 16-bit resolution, ±1 LSB INL, and flexible output ranges (±10 V, ±5 V, 0 to +10 V). The AD7847AR, with 12-bit resolution and a fixed ±10 V range, is more appropriate for general-purpose control loops where 12-bit precision is sufficient and a parallel bus interface is preferred.