Analog Devices Inc. AD9578BCPZ

Overview

AD9578BCPZ from Analog Devices is a dual PLL precision clock synthesizer for jitter attenuation and asynchronous clocking in high-performance telecom, networking, and SERDES applications. It delivers four independently programmable outputs (up to 919 MHz), <405 fs rms jitter (12 kHz–20 MHz), 0.1 ppb frequency resolution, and supports LVPECL/LVDS/HCSL/LVCMOS output formats using 22–54 MHz crystals or 20–60 MHz reference clocks.

For engineers reviewing the AD9578BCPZ datasheet, AD9578BCPZ pinout, AD9578BCPZ application, or AD9578BCPZ equivalent, key selection criteria include ultralow jitter performance under integer/fractional synthesis, dual-reference input flexibility, on-the-fly SPI reconfiguration (up to 50 MHz), and mixed-technology output buffer programmability across four channels.

Technical Context

The AD9578BCPZ integrates two independent fractional-N PLLs-each with dedicated VCOs, charge pumps, and dual output dividers-enabling four fully configurable clock outputs. Its architecture supports numerically controlled oscillator (NCO) mode for FPGA-based digital PLLs with dynamically adjustable loop bandwidths.

Reference inputs accept LVPECL, LVDS, or 1.8 V LVCMOS signals (20–60 MHz) or fundamental-mode AT-cut crystals (22–54 MHz); output drivers are individually configurable per channel with independent VDDOx supplies and selectable logic families (LVPECL, LVDS, HCSL, LVCMOS).

Key Specifications

Pinout & Package

AD9578BCPZ is housed in a 48-lead LFCSP package (7 mm × 7 mm, 0.75 mm height) with exposed thermal pad. Pin assignments support dual PLL signal routing, independent output power domains, and flexible reference input options.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar precision clock synthesizer applications.

Compared with Si5341-B-GM and LTC6957IUF-3#PBF, the AD9578BCPZ uniquely combines factory-configurable power-on operation, true dual-PLL independence with four programmable outputs, and FPGA-accessible NCO functionality-making it optimal for applications demanding both deterministic startup behavior and runtime frequency agility.

Availability

AD9578BCPZ is available at Aetrix Electronics and suitable for optical transport networks, broadcast video infrastructure, wireless baseband processing, and industrial precision timing applications requiring stable component supply and long-term lifecycle support.

Supply support for AD9578BCPZ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Analog Devices, Inc. is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, headquartered in Norwood, MA.

The AD9578BCPZ belongs to Analog Devices' precision clock synthesis product line, designed specifically for jitter-critical telecommunications, high-speed data acquisition, and synchronized distributed systems where phase accuracy and timing integrity are non-negotiable.

FAQ

What is the minimum output frequency supported by the AD9578BCPZ?

The AD9578BCPZ supports output frequencies as low as 11.8 MHz across all driver types (LVPECL, LVDS, HCSL, LVCMOS). This lower bound applies regardless of reference input source-whether crystal (22–54 MHz) or external clock (20–60 MHz)-and is maintained under both integer and fractional synthesis modes. The AD9578BCPZ achieves this while preserving <410 fs typical rms jitter (12 kHz–20 MHz) and full programmability via its 50 MHz SPI interface.

Does the AD9578BCPZ support both integer and fractional-N PLL modes?

Yes, the AD9578BCPZ supports both integer and fractional-N synthesis modes. In integer mode, it achieves <290 fs rms jitter (12 kHz–20 MHz) using a 25 MHz square wave reference; in fractional mode, jitter remains <405 fs rms under identical conditions. Mode selection is register-configurable per PLL, and both modes retain full 0.1 ppb frequency resolution and on-the-fly SPI reprogramming capability-key for AD9578BCPZ deployment in adaptive timing systems like CPRI and IEEE 1588.

How many reference inputs does the AD9578BCPZ have, and what signal types are accepted?

The AD9578BCPZ has four reference input pins (XO1, XO2, XO3, XO4), organized as two pairs-one for each PLL. Each pair accepts either a fundamental-mode AT-cut crystal (22–54 MHz) or differential clock signals (LVPECL/LVDS, 20–60 MHz) or single-ended 1.8 V LVCMOS (20–60 MHz on XO2/XO4). This dual-reference architecture enables redundancy, holdover operation, or asynchronous domain bridging-core to AD9578BCPZ use in telecom and broadcast timing systems.

Can the AD9578BCPZ outputs drive different logic families simultaneously?

Yes, the AD9578BCPZ supports simultaneous mixed-format outputs: OUT1 may be configured as LVPECL, OUT2 as LVDS, OUT3 as HCSL, and OUT4 as LVCMOS-all independently powered via dedicated VDDOx supplies (VDDO1–VDDO4). This eliminates external level shifters and simplifies PCB layout in systems requiring multiple interface standards, such as SERDES PHYs, FPGAs, and ASICs sharing a common timing backbone-defining AD9578BCPZ's value in complex timing architectures.

What is the purpose of the REFOUT/REFOUT pins on the AD9578BCPZ?

The REFOUT/REFOUT pins (Pins 20 and 21) provide a buffered, low-jitter copy of the selected reference source-either the crystal oscillator output (XO1/XO2 or XO3/XO4) or an external reference clock. This output operates up to 60 MHz and is fully programmable via SPI register control. It serves as a clean synchronization signal for auxiliary circuitry (e.g., ADC sampling clocks or FPGA configuration logic), reducing dependency on external buffers and enhancing system-level timing integrity in AD9578BCPZ-based designs.