Part A
ADF4355-2BCPZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 1557 PCS
- Package
- WFQFN-32
- Series
- Horloge Timing - générateur d'horloge, PLL, synthétiseur de fréquence
Replacement verdict
Compatible functional replacement candidate
The ADF4355-2BCPZ is a higher-performance successor to the ADF4351BCPZ, offering a wider output frequency range and improved phase noise while retaining the same 32-lead LFCSP footprint and 3.3 V supply architecture. It is a viable functional replacement candidate for designs requiring extended frequency coverage, but the differing integer/fractional divider architecture, register map, and output power characteristics require schematic and firmware validation before substitution.
Output Frequency Range
Validation required
Package Type
High match
Supply Voltage
Validation required
Register Map Compatibility
Not compatible
Parts at a glance
Part B
ADF4351BCPZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 2243 PCS
- Package
- VFQFN-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 | ADF4355-2BCPZ | Why it matters |
|---|---|---|---|
| Frequency Range (Max) | 4.4 GHz | 4.4 GHz | Both cover the same upper frequency, so maximum output frequency is not a differentiator for substitution. |
| Frequency Range (Min) | 35 MHz | 53.125 MHz | The ADF4351 reaches lower frequencies, so it can cover applications below ~53 MHz that the ADF4355-2 cannot. |
| Normalized Phase Noise Floor | -220 dBc/Hz | -225 dBc/Hz | Lower phase noise floor improves spectral purity, which is critical for high-performance synthesizer and RF signal-chain designs. |
| Maximum RF Output Power | 5 dBm | 5 dBm | Output power level affects drive capability into mixers and amplifiers; equal values ease direct substitution. |
| Supply Voltage | 3.0 V to 3.6 V | 3.15 V to 3.45 V | The narrower supply window of the ADF4355-2 may require tighter regulation, affecting power-supply design compatibility. |
| Package | 32-Lead LFCSP (5x5 mm) | 32-Lead LFCSP (5x5 mm) | Identical package and footprint allow drop-in PCB replacement without layout changes. |
| Integrated VCO | Yes | Yes | Both integrate a VCO, reducing external component count and board area for the synthesizer loop. |
| Maximum PFD Frequency | 32 MHz | 125 MHz | A higher phase-frequency detector rate enables wider loop bandwidth and faster lock times in the ADF4355-2. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Matching industrial temperature ranges ensure equivalent environmental robustness for both parts. |
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 | ADF4355-2BCPZ | ADF4351BCPZ |
|---|---|---|
| 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 | Clock | CMOS, TTL |
| Output | Clock | Clock |
| Number of Circuits | 1 | 1 |
| Ratio - Input: Output | 1:2 | 1:2 |
| Differential - Input: Output | No/No | No/Yes |
| Frequency - Max | 4.4GHz | 4.4GHz |
| Divider / Multiplier | Yes/Yes | Yes/Yes |
| Voltage - Supply | 3.15V ~ 3.45V | 3V ~ 3.6V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the ADF4351BCPZ and ADF4355-2BCPZ fractional-N PLL synthesizers?
The ADF4351BCPZ integrates a VCO covering 2.2 GHz to 4.4 GHz with a maximum RF output of 4.4 GHz, while the ADF4355-2BCPZ integrates a VCO covering 3.4 GHz to 6.8 GHz with a maximum RF output of 6.8 GHz. The ADF4355-2BCPZ offers higher frequency operation, a higher maximum phase detector frequency (up to 125 MHz versus 32 MHz for the ADF4351), and improved normalized phase noise floor, making it better suited for higher-frequency applications.
Are the ADF4351BCPZ and ADF4355-2BCPZ 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 ADF4355-2BCPZ includes additional features such as a differential RF output pair and different supply pin groupings, so the PCB layout must be designed specifically for each device. They are not drop-in replacements.
What is the maximum RF output frequency of each device?
The ADF4351BCPZ provides a fundamental RF output range of 35 MHz to 4400 MHz. The ADF4355-2BCPZ provides a fundamental RF output range of 53.125 MHz to 6800 MHz. Both devices also support divided-down outputs for lower frequencies.
How do the phase noise specifications compare between the ADF4351BCPZ and ADF4355-2BCPZ?
The ADF4355-2BCPZ specifies a normalized phase noise floor of -230 dBc/Hz (typical), while the ADF4351BCPZ specifies -220 dBc/Hz (typical). The ADF4355-2BCPZ also achieves lower in-band phase noise at comparable frequencies, which is advantageous for high-performance signal generation and communications systems.
What are the maximum phase detector (PFD) frequencies for these two synthesizers?
The ADF4351BCPZ supports a maximum phase detector frequency of 32 MHz. The ADF4355-2BCPZ supports a maximum phase detector frequency of 125 MHz, enabling wider loop bandwidths and faster lock times in applicable designs.
Do both devices support fractional-N and integer-N operation?
Yes. Both the ADF4351BCPZ and ADF4355-2BCPZ are fractional-N synthesizers that also support integer-N mode. Both include an integrated VCO and programmable dual-modulus prescaler, and both are programmed via a 3-wire SPI-compatible serial interface.
What are the supply voltage requirements for the ADF4351BCPZ and ADF4355-2BCPZ?
Both devices operate from a nominal 3.3 V supply. The ADF4351BCPZ requires 3.0 V to 3.6 V for the VCO and charge pump supplies, with a separate 1.8 V to 3.3 V digital supply. The ADF4355-2BCPZ similarly operates from a 3.3 V analog supply with a 1.8 V to 3.3 V digital interface supply. Designers should consult the respective datasheets for exact supply rail tolerances and decoupling requirements.
Which device should be selected for a 5 GHz application?
The ADF4355-2BCPZ is the appropriate choice for a 5 GHz application because its integrated VCO and RF output extend to 6.8 GHz, allowing fundamental operation at 5 GHz. The ADF4351BCPZ tops out at 4.4 GHz and would require external frequency multiplication or a different architecture to reach 5 GHz, which adds complexity and degrades performance.