Part A
ADF4351BCPZ-RL7
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 4291 PCS
- Package
- LFCSP-32
- Series
- Horloge Timing - générateur d'horloge, PLL, synthétiseur de fréquence
Replacement verdict
Compatible functional replacement candidate
The ADF4356BCPZ is a higher-performance successor to the ADF4351BCPZ-RL7, offering a wider frequency range, lower phase noise, and improved spurious performance while maintaining the same 32-lead LFCSP footprint and 3.3 V supply architecture. However, the two devices are not register-compatible, and firmware reconfiguration is mandatory before the ADF4356BCPZ can be used as a substitute. Designers should validate the SPI register map, lock-detect behavior, and reference input requirements on the target board before committing to a replacement.
Frequency Range
Validation required
Package Type
Validation required
Register Compatibility
Not compatible
Phase Noise Performance
Validation required
Parts at a glance
Part B
ADF4356BCPZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 2460 PCS
- Package
- LFCSP-32
- Series
- Horloge Timing - générateur d'horloge, PLL, synthétiseur de fréquence
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADF4351BCPZ-RL7 | ADF4356BCPZ | Why it matters |
|---|---|---|---|
| Frequency Range (Max) | 4.4 GHz | 6.8 GHz | The upper tuning range determines the highest output frequency the PLL/synthesizer can generate, directly limiting which applications the part can serve. |
| Frequency Range (Min) | 35 MHz | 53.125 MHz | The lower tuning limit affects low-band coverage; a higher minimum means the device cannot synthesize lower frequencies without external division. |
| Normalized Phase Noise Floor | -220 dBc/Hz | -227 dBc/Hz | A lower phase noise floor yields cleaner spectral output, which is critical for high-performance RF and communication systems. |
| Maximum RF Output Power | 5 dBm | 7 dBm | Output power affects the ability to drive downstream stages directly and influences link budget and required external amplification. |
| Supply Voltage (Typical) | 3.3 V | 3.3 V (analog/digital), 5 V (charge pump/VCO) | Supply requirements determine power-rail design; the ADF4356 needs an additional 5 V rail, complicating board-level power architecture. |
| Package | 32-Lead LFCSP (5x5 mm) | 32-Lead LFCSP (5x5 mm) | Package footprint and pinout affect PCB layout compatibility and whether a drop-in replacement is physically possible. |
| Integrated VCO | Yes | Yes | An integrated VCO reduces external component count and board area, simplifying the synthesizer design. |
| RF Output Channels | 1 differential output | 2 differential outputs | Multiple outputs enable multi-channel or redundant architectures without additional synthesizers, affecting system flexibility. |
| Operating Temperature Range | -40 to +85 °C | -40 to +85 °C | The temperature range defines the environments in which the device can reliably operate, important for industrial and outdoor applications. |
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 | ADF4351BCPZ-RL7 | ADF4356BCPZ |
|---|---|---|
| Part Status | Active | Active |
| Type | Fanout Distribution, Fractional N, Integer N, Clock/Frequency Synthesizer (RF) | Fanout Distribution, Fractional N, Integer N, Clock/Frequency Synthesizer (RF) |
| PLL | Yes | Yes |
| Input | CMOS, TTL | Clock |
| Output | Clock | Clock |
| Number of Circuits | 1 | 1 |
| Ratio - Input: Output | 1:2 | 1:2 |
| Differential - Input: Output | No/Yes | Yes/No |
| Frequency - Max | 4.4GHz | 6.8GHz |
| Divider / Multiplier | Yes/Yes | Yes/Yes |
| Voltage - Supply | 3V ~ 3.6V | 3.15V ~ 3.45V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What is the fundamental difference between the ADF4351BCPZ-RL7 and the ADF4356BCPZ?
The ADF4351BCPZ-RL7 is a fractional-N/integer-N PLL frequency synthesizer with an integrated VCO covering 35 MHz to 4400 MHz. The ADF4356BCPZ is a higher-performance fractional-N/integer-N PLL synthesizer with an integrated VCO covering 53.125 MHz to 6800 MHz, offering lower phase noise and higher PFD frequency capability.
Are the ADF4351BCPZ-RL7 and ADF4356BCPZ pin-compatible?
No. Both devices are supplied in a 32-lead LFCSP package, but the pin assignments and functions differ between the two products. The ADF4356BCPZ includes additional features such as a higher-frequency VCO and different register map, so they are not drop-in replacements.
What is the maximum RF output frequency of each device?
The ADF4351BCPZ-RL7 provides a fundamental output range of 35 MHz to 4400 MHz. The ADF4356BCPZ provides a fundamental output range of 53.125 MHz to 6800 MHz.
How do the phase noise specifications compare between the ADF4351BCPZ-RL7 and ADF4356BCPZ?
The ADF4356BCPZ delivers lower phase noise than the ADF4351BCPZ-RL7. At 1 GHz output, the ADF4356BCPZ specifies normalized phase noise floor of approximately -227 dBc/Hz, while the ADF4351BCPZ-RL7 specifies approximately -220 dBc/Hz. The ADF4356BCPZ is therefore preferred for applications requiring lower jitter and cleaner spectral performance.
What are the supply voltage and power consumption differences?
Both devices operate from a nominal 3.3 V supply. The ADF4351BCPZ-RL7 typically draws about 70 mA from the 3.3 V supply (excluding output stage), while the ADF4356BCPZ typically draws about 85 mA. Exact current depends on configuration and output power settings.
Can the ADF4356BCPZ replace the ADF4351BCPZ-RL7 in an existing design?
Not directly. Although both are 32-lead LFCSP fractional-N synthesizers with integrated VCOs, the ADF4356BCPZ has a different register map, different pin functions, a wider VCO range, and different loop filter requirements. A redesign of the PCB layout, register programming, and loop filter is required.
Which device is better suited for high-frequency applications above 4.4 GHz?
The ADF4356BCPZ is the appropriate choice because its integrated VCO covers up to 6800 MHz, whereas the ADF4351BCPZ-RL7 is limited to 4400 MHz. For output frequencies above 4.4 GHz, the ADF4356BCPZ can generate the signal directly without external frequency multiplication.
What are the operating temperature ranges for both devices?
Both the ADF4351BCPZ-RL7 and ADF4356BCPZ are specified for operation over the industrial temperature range of -40°C to +85°C.