Microchip Technology ZL30301GAG

Overview

ZL30301GAG from Zarlink Semiconductor is a Timing over Packet (ToP) IC designed for precise clock recovery and distribution in packet-switched networks. It recovers up to four independent clocks (1.544 MHz–10 MHz), achieves average frequency accuracy better than ±15 ppb, supports Master/Slave/Repeater modes, and interfaces via dual MII or MII+GMII/TBI - enabling synchronization in VoIP gateways and TDM-over-IP systems.

For engineers reviewing the ZL30301GAG datasheet, ZL30301GAG pinout, ZL30301GAG application, or ZL30301GAG equivalent, key selection considerations include packet-based timing recovery performance, Stratum 3 TCXO system clock compatibility, holdover behavior during network outages, and flexible host CPU interface (PowerQUICC™-compatible 32-bit bus).

Technical Context

The ZL30301GAG implements adaptive and differential clock recovery algorithms to track frequency offset between master and slave nodes despite packet delay variation. It cross-references timestamped timing packets against the local TS_CLKi reference clock and feeds phase/frequency error data to an external host processor for clock synthesis control.

It supports full-layer classification (L2–L5) and multi-protocol encapsulation (Ethernet, VLAN, IPv4/6, MPLS, L2TPv3, UDP, RTP), with dual configurable packet interfaces and JTAG boundary-scan for test and debug. The device enters holdover mode upon loss of timing packets, maintaining output stability using its internal TCXO-referenced system clock.

Key Specifications

Pinout & Package

The ZL30301GAG is housed in a 324-ball PBGA package (23 mm × 23 mm, 1.00 mm pitch, 22×22 ball matrix, 2.03 mm thickness). Ball assignments are defined per Table 1 of the datasheet, with dedicated signal groups for clock I/O, dual MII/GMII/TBI packet interfaces, 32-bit CPU bus, JTAG, and system management.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar packet-based timing recovery applications.

Compared with ZL30302GAG and ARC-3000, the ZL30301GAG delivers field-proven Stratum 3 timing recovery with minimal host CPU involvement, making it ideal for established CESoP, VoIP gateway, and IP-PBX platforms where reliability and integration simplicity outweigh cutting-edge protocol support.

Availability

ZL30301GAG is available at Aetrix Electronics and suitable for VoIP gateways, circuit emulation services (CESoP), and IP-PBX systems requiring stable component supply, long-term lifecycle support, and traceable sourcing for telecom infrastructure programs.

Supply support for ZL30301GAG 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

Zarlink Semiconductor was a fabless semiconductor company specializing in timing, networking, and communications ICs before its acquisition by Microsemi in 2011. It pioneered Timing over Packet technology for telecom synchronization.

The ZL30301GAG belongs to Zarlink's Timing over Packet (ToP) product line, engineered specifically to distribute Stratum 3–grade clock synchronization across asynchronous IP/MPLS/Ethernet networks - targeting wireless infrastructure, circuit emulation, and VoIP timing applications.

FAQ

What is the primary function of the ZL30301GAG in a packet-based timing architecture?

The ZL30301GAG serves as a dedicated packet timing recovery IC that extracts highly stable clock signals from timestamped network packets. It does not generate timing autonomously but relies on an external host processor to synthesize recovered clocks using phase/frequency error data. Its core function is to enable Stratum 3–compliant synchronization in environments where traditional physical-layer timing distribution is impractical - such as VoIP gateways and CESoP edge nodes.

Does the ZL30301GAG support IEEE 1588 Precision Time Protocol (PTP)?

No, the ZL30301GAG does not natively support IEEE 1588 PTP. It recovers timing from proprietary or standards-based timing packets (e.g., RTP-based or custom UDP packets) using adaptive/differential algorithms. IEEE 1588v2 support was introduced in later family members like the ZL30302GAG. For PTP-aware designs, ZL30301GAG users must implement timestamping and packet handling in the host processor.

What package type and thermal characteristics apply to the ZL30301GAG?

The ZL30301GAG uses a 324-ball PBGA package measuring 23 mm × 23 mm with 1.00 mm pitch and 2.03 mm total thickness. Its specified operating temperature range is –40°C to +85°C. Thermal resistance (θ_JA) is not published in the datasheet, but the device requires standard PBGA thermal pad layout per Zarlink's design guidelines - including exposed center thermal ball (IC_GND) connected to internal ground plane for effective heat dissipation.

How does the ZL30301GAG handle network congestion or timing packet loss?

Upon detection of missing or delayed timing packets, the ZL30301GAG automatically enters holdover mode. In this state, it sustains clock output using its internal system clock (driven by an external Stratum 3 TCXO), with accuracy dependent on the TCXO's stability. Holdover duration and drift are directly tied to oscillator quality - typical drift is <1 ppm over 24 hours with a ±0.1 ppm TCXO. Recovery is seamless once timing packets resume.

Can the ZL30301GAG operate without an external host processor?

No, the ZL30301GAG cannot operate autonomously. It lacks on-chip clock synthesis logic and requires continuous interaction with an external host processor (e.g., PowerQUICC™ MPC8260) to compute and configure recovered clock parameters. The host runs Zarlink's timing recovery algorithm, reads statistics via the 32-bit CPU interface, and writes control registers - making the ZL30301GAG a co-processor rather than a standalone timing solution.