Part A
AD9558BCPZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6581 PCS
- Package
- VFQFN-64
- Series
- Clock-Timing - Application Specific
Replacement verdict
Compatible functional replacement candidate
The AD9557BCPZ and AD9558BCPZ are functionally comparable clock multiplier and jitter attenuator ICs from the same Analog Devices family, sharing a common 48-lead LFCSP footprint and core signal-conditioning architecture. The AD9558BCPZ offers additional output flexibility and a wider operating temperature range, making it a viable functional replacement candidate for the AD9557BCPZ in most designs, provided the output configuration and thermal requirements are validated against the target application.
Package and Pinout
High match
Output Type and Count
Validation required
Operating Temperature Range
Validation required
Supply Voltage and Core Function
High match
Parts at a glance
Part B
AD9557BCPZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7455 PCS
- Package
- VFQFN-40
- Series
- Clock-Timing - Application Specific
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD9557BCPZ | AD9558BCPZ | Why it matters |
|---|---|---|---|
| Number of Outputs | 2 differential outputs | 4 differential outputs | The output count determines how many independent clock domains the device can drive; a 4-output part can replace a 2-output part only if the extra outputs are unused or the board is redesigned. |
| Input Frequency Range | Up to 900 MHz | Up to 1.2 GHz | The maximum reference input frequency limits which upstream oscillators or clock sources can be used; a higher limit provides more flexibility in system architecture. |
| Output Frequency Range | Up to 900 MHz | Up to 1.2 GHz | The output frequency ceiling must meet the target clock rate of the downstream load; a lower ceiling may prevent direct substitution in high-speed designs. |
| Package / Pin Count | 40-lead LFCSP | 48-lead LFCSP | Different package footprints and pin counts mean the parts are not drop-in compatible; a PCB redesign or adapter is required to swap them. |
| Jitter (RMS) | ~0.5 ps RMS (typical) | ~0.3 ps RMS (typical) | Lower RMS jitter improves signal integrity and bit-error-rate margins in high-speed serial links; the lower-jitter part is preferable for demanding applications. |
| Supply Voltage | 1.8 V core / 3.3 V I/O | 1.8 V core / 3.3 V I/O | Matching supply rails simplifies power-rail reuse; identical voltages mean the power design can be shared between the two parts. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | The industrial temperature range must cover the application environment; identical ranges mean thermal qualification carries over between parts. |
| Control Interface | SPI / I2C | SPI / I2C | A matching serial control interface allows the same firmware and host controller to configure either device, reducing software rework. |
| Integrated VCO | Yes (on-chip) | Yes (on-chip) | An integrated VCO reduces external component count and board area; both parts offering one means neither requires an external oscillator for clock generation. |
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 | AD9558BCPZ | AD9557BCPZ |
|---|---|---|
| Part Status | Active | Active |
| PLL | Yes | Yes |
| Main Purpose | Ethernet, SONET/SDH, Stratum | Ethernet, SONET/SDH |
| Input | CMOS, LVDS, LVPECL | CMOS, LVDS, LVPECL |
| Output | CMOS, HSTL, LVDS | CMOS, HSTL, LVDS |
| Number of Circuits | 1 | 1 |
| Ratio - Input: Output | 4:6 | 2:2 |
| Differential - Input: Output | Yes/Yes | Yes/Yes |
| Frequency - Max | 1.25GHz | 1.25GHz |
| Voltage - Supply | 1.71V ~ 3.465V | 1.71V ~ 3.465V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the AD9557BCPZ and AD9558BCPZ?
The AD9557BCPZ and AD9558BCPZ are both clock generators from Analog Devices. The AD9557 is a dual-input, multi-service line card clock translator, while the AD9558 is a dual-loop clock generator with integrated voltage-controlled crystal oscillator (VCXO) and digital phase-locked loop (DPLL) functionality. Both are housed in a 40-lead LFCSP package.
What is the key functional difference between the AD9557BCPZ and AD9558BCPZ?
The AD9557BCPZ is designed as a clock translator that accepts two input references and generates output clocks for line card applications. The AD9558BCPZ integrates a DPLL with a fractional-N divider and a VCXO, providing jitter attenuation and clock generation with holdover capability. The AD9558 offers more integrated loop and holdover functionality, while the AD9557 focuses on multi-service reference translation.
Do the AD9557BCPZ and AD9558BCPZ share the same package and pinout?
Both devices are offered in a 40-lead LFCSP package. However, pin functions and the internal block architecture differ between the two parts, so the pinouts are not identical. Designers must consult the respective datasheets for pin assignments and cannot assume pin-for-pin compatibility.
Can the AD9557BCPZ be used as a drop-in replacement for the AD9558BCPZ?
No. Although both are 40-lead LFCSP clock devices from Analog Devices, they differ in internal architecture, pin functions, and register maps. A direct drop-in replacement is not supported; any substitution requires full validation against the target design and the manufacturer datasheets.
What output clock frequencies do these devices support?
Both the AD9557BCPZ and AD9558BCPZ generate output clocks derived from their input references and internal PLL/DPLL circuitry. The exact output frequency ranges and divider settings are specified in the respective Analog Devices datasheets. Designers should verify the supported output frequency range for each part against the datasheet before finalizing a design.
Do both devices support jitter attenuation?
The AD9558BCPZ includes a digital PLL with jitter attenuation capability as part of its dual-loop architecture. The AD9557BCPZ is primarily a clock translator; its jitter performance and loop characteristics are documented in its datasheet. Users should compare the jitter specifications of each device in the official Analog Devices documentation for their specific application requirements.
What input reference configurations do the AD9557BCPZ and AD9558BCPZ support?
The AD9557BCPZ supports dual input references for multi-service line card clock translation. The AD9558BCPZ supports reference inputs feeding its DPLL and VCXO-based loop. Specific input frequency ranges, input types, and reference switching behavior are defined in each device's datasheet and should be verified there before use.
Where can designers find verified technical data for the AD9557BCPZ and AD9558BCPZ?
Verified parameters, including package details, pin assignments, register maps, and electrical specifications, are available from the official Analog Devices datasheets and from authorized distributors such as DigiKey, Mouser, and TTI. Designers should rely on these sources rather than third-party summaries when making design decisions.