Microchip Technology ZL30302GAG

Overview

ZL30302GAG 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 output clocks (1.544–10 MHz), achieves ±15 ppb average frequency accuracy, supports Master/Slave/Repeater modes, and interfaces via dual MII or MII+GMII/TBI - enabling synchronization for TDM-over-IP and wireless base station backhaul.

For engineers reviewing the ZL30302GAG datasheet, ZL30302GAG pinout, ZL30302GAG application, or ZL30302GAG equivalent, this device is critical for timing-critical packet infrastructure where Stratum 3-grade holdover stability, adaptive+differential clock recovery algorithms, and IEEE 1149 JTAG debug support are required.

Technical Context

The ZL30302GAG implements adaptive and differential clock recovery algorithms that jointly track phase drift between master and slave nodes while tolerating packet delay variation (PDV). Its timestamp engine cross-references incoming packet arrival times against the local TS_CLKi reference to compute frequency offset.

It features a flexible 32-bit Motorola PowerQUICC-compatible CPU interface, dual configurable packet engines (MII/GMII/TBI), and on-chip clock synthesis driven by host-processed timing recovery algorithms. The device operates across Layer 2 and Layer 3 networks using Ethernet, VLAN, IPv4/6, MPLS, L2TPv3, UDP, and RTP encapsulation.

Key Specifications

Pinout & Package

The ZL30302GAG is housed in a 324-ball PBGA package (23 mm × 23 mm, 1.00 mm pitch, 22×22 ball matrix), with VDD_IO, VDD_CORE, GND, and dedicated signal balls for clock I/O, packet interfaces, CPU bus, JTAG, and system control.

Key Features

Applications

Equivalent & Alternatives

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

Compared with ZL30301GAG and EP4CGX150DF27I7, the ZL30302GAG delivers integrated, standards-compliant timing recovery with dual-packet-interface flexibility and zero FPGA development overhead - making it optimal for time-to-market-critical telecom edge hardware.

Availability

ZL30302GAG is available at Aetrix Electronics and suitable for VoIP gateway timing, TDM-over-IP infrastructure, and wireless base station synchronization requiring stable component supply across extended product lifecycles.

Supply support for ZL30302GAG 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, communications, and RF solutions before its acquisition by Microsemi in 2011. It pioneered Timing over Packet technology for telecom infrastructure.

The ZL30302GAG belongs to Zarlink's Timing over Packet (ToP) family, engineered specifically to replace legacy TDM timing distribution with packet-based synchronization while meeting Stratum 3 accuracy and ITU-T compliance requirements.

FAQ

What is the primary function of the ZL30302GAG in a packet network?

The ZL30302GAG recovers and distributes highly accurate timing across asynchronous packet networks. It receives time-stamped packets, computes frequency/phase offset relative to its local TS_CLKi reference, and synthesizes up to four stable output clocks (CLKo[0]–CLKo[3]). This enables Stratum 3–compliant synchronization for TDM-over-IP, wireless backhaul, and VoIP systems without dedicated timing links. The ZL30302GAG performs this using adaptive and differential recovery algorithms implemented in conjunction with an external host processor.

Does the ZL30302GAG support both Master and Slave timing modes?

Yes, the ZL30302GAG supports Master, Slave, and Timing Repeater modes. In Master mode, it generates timestamped timing packets referenced to its TS_CLKi input. In Slave mode, it recovers clocks from incoming timing packets. In Repeater mode, it forwards and retimes synchronization signals across network segments. All three modes are software-configurable via the 32-bit CPU interface, and the ZL30302GAG maintains ±15 ppb accuracy in Slave mode when paired with a Stratum 3 TCXO.

What packet interface configurations does the ZL30302GAG support?

The ZL30302GAG supports two dual-interface configurations: (1) two independent MII ports (M0 and M1), or (2) one MII port plus one GMII/TBI port. This allows 10/100 Mbps timing transport on MII and 1000 Mbps on GMII/TBI. Both configurations support full Layer 2–5 packet classification and multi-protocol encapsulation (Ethernet, VLAN, IPv4/6, MPLS, UDP, RTP). The ZL30302GAG uses these interfaces to ingest timing packets in Slave mode and transmit them in Master mode.

How does the ZL30302GAG handle network interruptions or packet loss?

When timing packet flow is interrupted due to network failure or severe congestion, the ZL30302GAG automatically enters holdover mode. In this state, it sustains clock output using its local TCXO reference; accuracy degrades only according to the oscillator's inherent drift (e.g., ±15 ppb typical with Stratum 3 TCXO). Holdover duration and stability are design-determined by the external oscillator quality. The ZL30302GAG resumes normal recovery once valid timing packets resume, with smooth phase/frequency reacquisition.

Is JTAG debugging supported on the ZL30302GAG?

Yes, the ZL30302GAG includes a full IEEE 1149 JTAG boundary-scan interface (TCK, TMS, TDI, TDO, TRST). This enables board-level testing, in-circuit programming, and real-time debug access independent of the host CPU or packet traffic. JTAG is used during manufacturing test, firmware bring-up, and field diagnostics - providing visibility into internal registers, clock status, and packet engine states without disrupting ZL30302GAG operation.