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 AD7845ARZ are not functionally interchangeable. Although both are Analog Devices 12-bit voltage-output DACs in a 24-lead SOIC package, they differ in resolution architecture, reference configuration, interface timing, and output amplifier characteristics, so the AD7845ARZ cannot be substituted for the AD7849BRZ without a full design review and validation.
Different DAC architecture
Different reference configuration
Different interface timing
Different output amplifier
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 | AD7845ARZ | Why it matters |
|---|---|---|---|
| Resolution (bits) | 16 | 12 | Resolution determines the smallest output step and overall precision; a 16-bit DAC offers 16x finer granularity than a 12-bit DAC, which is critical for high-accuracy control loops. |
| Number of DAC channels | 1 | 1 | Channel count defines how many independent analog outputs are available; both are single-channel, so channel count is not a differentiator here. |
| DAC architecture | String DAC (segmented R-2R) | Multiplying R-2R ladder | Architecture affects settling behavior, glitch performance, and whether the DAC can be used in multiplying (AC reference) applications; the R-2R multiplying type supports four-quadrant multiplication. |
| Output type | Voltage output | Current output (multiplying) | Voltage-output DACs drive loads directly, while current-output multiplying DACs require an external op-amp; this fundamentally changes the external circuit design and substitutability. |
| Supply voltage | ±12 V to ±15 V (dual) | ±12 V to ±15 V (dual) | Supply requirements must match the host system rails; both parts operate on similar dual supplies, so power-rail compatibility is maintained. |
| Interface | Serial (SPI-compatible) | Parallel | Serial vs parallel interface dictates the digital bus, pin count, and microcontroller compatibility; this is a major factor preventing drop-in substitution. |
| Package | 20-lead SOIC (R-20) | 24-lead SOIC (R-24) | Package footprint and pin count must match the PCB layout; differing lead counts mean the parts are not footprint-compatible. |
| Operating temperature range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range confirms suitability for industrial environments; both share the same industrial range, so thermal compatibility is equivalent. |
| Integral nonlinearity (INL) | ±1 LSB (B grade) | ±1/2 LSB (A grade) | INL specifies worst-case deviation from an ideal transfer function; it directly bounds achievable accuracy and must be evaluated against system error budgets. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7849BRZ | AD7845ARZ |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC,Analog Devices Inc. |
| Part Status | Active | Active |
| Number of Bits | 16 | 12 |
| Number of D/A Converters | 1 | 1 |
| 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 AD7845ARZ?
The AD7849BRZ is a 16-bit voltage-output DAC with a serial interface, while the AD7845ARZ is a 12-bit multiplying DAC with a parallel interface. The AD7849BRZ integrates an output amplifier and reference, whereas the AD7845ARZ requires an external op-amp and reference for voltage-output operation.
Are the AD7849BRZ and AD7845ARZ pin-compatible?
No. The AD7849BRZ is offered in a 20-lead SOIC (R-20) package, and the AD7845ARZ is offered in a 24-lead SOIC (R-24) package. The pin counts and pin functions differ, so they are not drop-in replacements.
What are the resolution and accuracy specifications of each device?
The AD7849BRZ provides 16-bit resolution with ±1 LSB integral nonlinearity (INL) and ±1 LSB differential nonlinearity (DNL) at 25°C. The AD7845ARZ provides 12-bit resolution with ±1/2 LSB INL and ±1 LSB DNL at 25°C.
How do the digital interfaces of the AD7849BRZ and AD7845ARZ differ?
The AD7849BRZ uses a serial interface compatible with SPI, QSPI, and MICROWIRE, operating at clock rates up to 10 MHz. The AD7845ARZ uses a 12-bit parallel interface with standard CS, WR, and data bus control signals.
What are the output voltage ranges and reference requirements for each part?
The AD7849BRZ has a fixed output range of 0 V to VREF and requires an external reference; with a 2.5 V reference, the output spans 0 V to 2.5 V. The AD7845ARZ is a current-output multiplying DAC that requires an external op-amp and reference to produce a voltage output, with the output range set by the external components.
How do the supply voltage and power consumption compare?
The AD7849BRZ operates from a single +5 V supply (or ±5 V) and typically consumes 10 mW. The AD7845ARZ operates from ±15 V supplies and typically consumes 30 mW.
What are the operating temperature ranges for the AD7849BRZ and AD7845ARZ?
Both the AD7849BRZ and AD7845ARZ are specified for the industrial temperature range of −40°C to +85°C.
Can the AD7845ARZ be used as a direct replacement for the AD7849BRZ in an existing design?
No. The AD7845ARZ has a different package, pinout, resolution, interface type, and output configuration. A direct replacement is not possible without a PCB redesign and validation of the system requirements.