Part A
AD9857ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6382 Stückzahl
- Package
- LQFP-80
- Series
- RF Verschiedene ICs und Module
Replacement verdict
Not a drop-in replacement
The AD9852ASTZ and AD9857ASTZ are not functionally interchangeable despite sharing the same 80-lead LQFP package and DDS/DAC architecture. The AD9852ASTZ is a dual 12-bit DDS/DAC synthesizer with 300 MHz internal clock and on-chip 12-bit DACs, while the AD9857ASTZ is a single-channel 14-bit quadrature digital upconverter with integrated 14-bit DAC and 200 MHz maximum clock. Their differing channel count, DAC resolution, clock rate, and signal-processing function make direct substitution impractical without redesign of the surrounding signal chain and clocking scheme.
Different channel count
Different DAC resolution
Different maximum clock rate
Different signal-processing function
Parts at a glance
Part B
AD9852ASTZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1641 Stückzahl
- Package
- LQFP-80
- Series
- Schnittstelle für digitale Synthese (DDS)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD9852ASTZ | AD9857ASTZ | Why it matters |
|---|---|---|---|
| Function Type | Direct Digital Synthesizer (DDS) | Quadrature Digital Upconverter (QDUC) | Defines the core signal-processing role; a DDS generates a single tone, while a QDUC performs interpolation and upconversion, so they are not functionally interchangeable. |
| Maximum DAC Update Rate | 300 MSPS | 200 MSPS | Sets the highest output frequency and bandwidth the device can synthesize; a lower update rate limits the achievable output spectrum. |
| DAC Resolution | 12 bit | 14 bit | Higher resolution yields lower quantization noise and better spurious-free dynamic range in the output signal. |
| On-Chip Input/Output Data Path | DDS core with 48-bit frequency tuning word | Interpolating QDUC with programmable FIR filters | Determines how input data is processed; the QDUC includes interpolation and filtering for baseband-to-IF conversion, which the DDS does not provide. |
| Package | 80-lead LQFP | 80-lead LQFP | Package compatibility affects PCB footprint and assembly; identical packages ease board-level substitution but do not guarantee pin compatibility. |
| Supply Voltage | 3.3 V | 3.3 V | Confirms power-rail compatibility; matching supply voltages simplify power design when evaluating substitution. |
| Primary Application | Frequency synthesis, clock generation, radar and test equipment | Digital upconversion for communications transmitters (baseband to IF) | Indicates the intended use case; differing target applications mean the parts serve different system roles despite similar packaging. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD9857ASTZ | AD9852ASTZ |
|---|---|---|
| Series | AD9857 | - |
| Part Status | Active | Active |
| Function | Upconverter | - |
| Frequency | 5MHz ~ 200MHz | - |
| RF Type | HFC Cable Network | - |
| Mounting Type | Surface Mount | Surface Mount |
| Resolution(Bits) | - | 12 b |
| Masterfclk | - | 200 MHz |
| Tuning Word Width(Bits) | - | 48 b |
| Voltage - Supply | - | 3.14V ~ 3.47V |
| Operating Temperature | - | -40°C ~ 85°C |
Frequently asked questions
What are the primary functional differences between the AD9852ASTZ and AD9857ASTZ?
The AD9852ASTZ is a complete direct digital synthesizer (DDS) with an integrated 12-bit DAC, capable of generating sine, cosine, and quadrature outputs up to 300 MSPS. The AD9857ASTZ is a quadrature digital upconverter (QDUC) that integrates a 14-bit DAC, a DDS, and a digital upconverter with interpolation filters, designed for transmit signal processing in communications systems. The AD9852 focuses on flexible waveform synthesis, while the AD9857 integrates upconversion and interpolation for baseband-to-IF transmit paths.
Are the AD9852ASTZ and AD9857ASTZ pin-compatible or package-compatible?
Both devices are offered in a 48-lead LQFP package, but they are not pin-compatible. The pin functions and internal signal routing differ because the AD9857 includes additional digital upconverter and interpolation circuitry. A direct PCB drop-in replacement is not supported; the datasheets must be consulted for pin assignments and layout differences.
What are the maximum DAC update rates and resolution for each device?
The AD9852ASTZ integrates a 12-bit DAC with a maximum update rate of 300 MSPS. The AD9857ASTZ integrates a 14-bit DAC with a maximum update rate of 200 MSPS. These parameters are specified in the respective manufacturer datasheets and should be verified against the exact grade and operating conditions.
Which device is better suited for quadrature amplitude modulation (QAM) transmit applications?
The AD9857ASTZ is specifically designed for transmit applications requiring quadrature upconversion, interpolation filtering, and a 14-bit DAC, making it suitable for QAM and other complex modulation schemes in communications transmitters. The AD9852ASTZ provides dual 12-bit DAC outputs and phase control for I/Q synthesis but lacks the integrated digital upconverter and interpolation filters of the AD9857. Selection depends on whether integrated upconversion and interpolation are required.
Do both devices support serial and parallel control interfaces?
Yes. Both the AD9852ASTZ and AD9857ASTZ support serial and parallel control interfaces for register programming, as documented in their respective datasheets. The exact interface modes, pin configurations, and timing requirements differ between the two devices and must be verified from the manufacturer documentation.
What are the typical power supply requirements for the AD9852ASTZ and AD9857ASTZ?
Both devices operate from a 3.3 V supply for the digital and analog sections, with separate supply pins for the DAC and digital circuitry as specified in the datasheets. The AD9857ASTZ includes additional digital upconverter circuitry that may affect total power consumption compared with the AD9852ASTZ. Exact current and power figures should be obtained from the manufacturer datasheets for the specific operating mode.
Can the AD9857ASTZ be used as a direct replacement for the AD9852ASTZ in an existing design?
No. Although both are 48-lead LQFP devices from the same manufacturer, they differ in pin functions, internal architecture, DAC resolution, maximum update rate, and integrated signal processing blocks. A direct replacement is not supported without redesigning the PCB, reprogramming the control interface, and revalidating the signal chain against the AD9857ASTZ datasheet.