Part A
ADF4157BCPZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6114 PCS
- Package
- WFQFN-20
- Series
- Clock-Timing - Clock Generators, PLLs, Frequency Synthesizers
Replacement verdict
Not a drop-in replacement
The ADF4157BCPZ and ADF4111BCP are both fractional-N PLL synthesizers, but they differ fundamentally in maximum operating frequency, phase detector frequency, and package footprint, so the ADF4157BCPZ cannot serve as a direct drop-in substitute for the ADF4111BCP without redesign and revalidation.
Different maximum RF frequency
Different phase detector frequency
Different package footprint
Different supply voltage range
Parts at a glance
Part B
ADF4111BCP
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 9249 PCS
- Package
- WFQFN-20
- Series
- Clock-Timing - Clock Generators, PLLs, Frequency Synthesizers
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADF4157BCPZ | ADF4111BCP | Why it matters |
|---|---|---|---|
| Maximum RF Input Frequency | 6 GHz | 4 GHz | Determines the highest frequency the PLL can synthesize; a higher limit allows use in higher-band applications. |
| Maximum PFD Frequency | 32 MHz | 55 MHz | Sets the phase detector comparison rate, which affects phase noise and loop bandwidth capability. |
| Normalized Phase Noise Floor | -216 dBc/Hz | -212 dBc/Hz | A lower phase noise floor yields cleaner synthesized signals, critical for sensitive RF systems. |
| RF Input Sensitivity | -10 dBm | -15 dBm | Indicates the minimum input power needed to drive the prescaler reliably; better sensitivity eases VCO interface design. |
| Supply Voltage Range | 2.7 V to 3.3 V | 2.7 V to 5.5 V | Defines the operating supply window; a wider range offers flexibility with different system rails. |
| Package | 20-Lead LFCSP (4x4 mm) | 20-Lead LFCSP (4x4 mm) | Footprint and thermal characteristics must match for board-level drop-in compatibility. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Ensures reliable operation across the intended environmental conditions of the application. |
| Charge Pump Current (Programmable) | 0.3 mA to 5 mA | 0.3 mA to 5 mA | Affects loop filter design and lock time; matching ranges preserve loop dynamics. |
| Fractional-N Capability | Yes (fractional-N) | No (integer-N) | Fractional-N allows finer frequency resolution and lower phase noise for a given channel spacing, changing the synthesis architecture. |
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 | ADF4157BCPZ | ADF4111BCP |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Type | Fractional N Synthesizer (RF) | Clock/Frequency Synthesizer (RF) |
| PLL | Yes | Yes |
| Input | CMOS, TTL | Clock |
| Output | Clock | Clock |
| Ratio - Input: Output | 2:1 | 2:1 |
| Differential - Input: Output | Yes/No | Yes/No |
| Frequency - Max | 6GHz | 1.2GHz |
| Divider / Multiplier | Yes/Yes | Yes/No |
| Voltage - Supply | 2.7V ~ 3.3V | 2.7V ~ 5.5V |
| Mounting Type | Surface Mount | Surface Mount |
| Number of Circuits | 1 | - |
| Operating Temperature | -40°C ~ 85°C | - |
Frequently asked questions
What are the key differences between the ADF4157BCPZ and the ADF4111BCP?
The ADF4157BCPZ is a 6 GHz fractional-N PLL frequency synthesizer with a 25-bit fixed modulus, while the ADF4111BCP is a 1.2 GHz integer-N PLL synthesizer. The ADF4157BCPZ supports fractional-N operation for finer frequency resolution, whereas the ADF4111BCP uses integer-N architecture. Both are housed in 20-lead LFCSP packages but differ in maximum RF input frequency and synthesizer type.
What is the maximum RF input frequency for each device?
The ADF4157BCPZ operates up to 6 GHz at the RF input, while the ADF4111BCP operates up to 1.2 GHz. Designs requiring frequencies above 1.2 GHz must use the ADF4157BCPZ or an external prescaler with the ADF4111BCP.
Do the ADF4157BCPZ and ADF4111BCP share the same package and pinout?
Both devices are offered in a 20-lead LFCSP package, but they are not pin-for-pin identical. The ADF4157BCPZ and ADF4111BCP have different pin functions and internal architectures, so PCB layouts must be designed per the respective datasheet and cannot be treated as drop-in replacements.
What is the difference in synthesizer architecture between the two parts?
The ADF4157BCPZ is a fractional-N synthesizer with a 25-bit fixed modulus, enabling fine frequency step resolution without requiring a low reference frequency. The ADF4111BCP is an integer-N synthesizer, where the output frequency is an integer multiple of the phase detector frequency, requiring a lower reference frequency for fine step sizes.
What supply voltage range do these devices require?
Both the ADF4157BCPZ and ADF4111BCP operate from a 2.7 V to 3.3 V supply. Designs should follow the recommended decoupling and layout guidelines in the respective manufacturer datasheets to ensure stable operation.
Can the ADF4111BCP be used as a direct replacement for the ADF4157BCPZ in an existing design?
No. The ADF4111BCP is an integer-N synthesizer limited to 1.2 GHz, while the ADF4157BCPZ is a fractional-N synthesizer operating up to 6 GHz. Differences in frequency range, synthesizer architecture, register maps, and pin functions prevent direct substitution without redesign and validation against the manufacturer datasheet.
Which device is better suited for fine frequency resolution applications?
The ADF4157BCPZ is better suited for fine frequency resolution because its fractional-N architecture with a 25-bit fixed modulus allows small frequency steps without requiring a very low phase detector frequency. The ADF4111BCP, as an integer-N synthesizer, requires a lower reference frequency to achieve comparable step resolution.