NXP Semiconductors MPC99J93FA

Overview

MPC99J93FA from Freescale Semiconductor is an Intelligent Dynamic Clock Switch (IDCS) PLL clock driver designed for redundant clock tree architectures in high-availability systems. It accepts two differential LVPECL input clocks (CLK0, CLK1), generates five LVPECL outputs - two 1× (Qa0, Qa1) and three 2× (Qb0–Qb2) - with phase-aligned frequency multiplication, and operates at 3.3 V across –40°C to +85°C industrial temperature range.

For engineers reviewing the MPC99J93FA datasheet, MPC99J93FA pinout, MPC99J93FA application, or MPC99J93FA equivalent, this device is critical for failover-capable timing subsystems requiring minimal phase disturbance during dynamic clock switching, precise static phase offset control (±0.17 ns), and deterministic skew management (≤80 ps intra-device).

Technical Context

The MPC99J93FA integrates a fully self-contained PLL with ÷4 feedback divider and intelligent switch logic that monitors both LVPECL inputs continuously. Upon detecting a stuck-HIGH or stuck-LOW condition lasting ≥1 Ext_FB period, it latches Inp0bad/Inp1bad and automatically selects the healthy reference without manual intervention.

Its IDCS circuitry enables seamless clock switchover with <0.17 ns static phase offset (SPO) and eliminates typical phase bumps via slew-to-alignment on the next negative edge of the newly selected reference. The PLL supports VCO frequencies from 200 MHz to 360 MHz and delivers output frequencies up to 180 MHz (QB outputs) with ≤25 ps RMS cycle-to-cycle jitter.

Key Specifications

Pinout & Package

Package: 32-lead LQFP (Case 873A-03), lead-free compliant, 7 mm × 7 mm body, 0.8 mm pitch.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar clock switching and multiplication applications.

Compared with ICS853S01I and PI6C557-03, the MPC99J93FA uniquely integrates PLL, IDCS, and dual-multiplication in one 32-pin LQFP package-enabling single-chip redundant clock trees without external logic or discrete PLL components.

Availability

MPC99J93FA is available at Aetrix Electronics and suitable for telecom infrastructure, industrial PLCs, and avionics data concentrators requiring stable component supply, long-lifecycle support, and guaranteed industrial temperature performance.

Supply support for MPC99J93FA 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

Freescale Semiconductor (now part of NXP Semiconductors) was a leading designer of high-performance analog and mixed-signal ICs for communications, automotive, and industrial markets.

The MPC99J93FA belongs to Freescale's Advanced Clock Drivers family, engineered specifically for fault-tolerant, phase-coherent clock distribution in carrier-grade and safety-critical systems.

FAQ

What is the function of the Ext_FB pins on the MPC99J93FA?

The Ext_FB and Ext_FB pins on the MPC99J93FA form a differential LVPECL feedback path that closes the internal PLL loop. One of the Qa0 or Qa1 output pairs must be connected to these pins to maintain frequency lock; without this connection, the PLL cannot achieve or sustain lock, and all outputs will be undefined. The Ext_FB signal also defines the reference period used for input fault detection (Inp0bad/Inp1bad assertion).

Does the MPC99J93FA support automatic clock switching without external microcontroller intervention?

Yes, the MPC99J93FA supports fully autonomous clock switching via its built-in Intelligent Dynamic Clock Switch (IDCS) logic. When Man_Override is LOW, the device continuously monitors both CLK0 and CLK1 inputs. If either input fails (stuck HIGH or LOW for ≥1 Ext_FB period), the corresponding Inp0bad or Inp1bad flag latches HIGH and the device immediately selects the healthy clock as the PLL reference-no external controller or software is required.

What is the maximum output frequency achievable from the MPC99J93FA QB outputs?

The MPC99J93FA QB outputs (Qb0–Qb2) deliver 2× frequency multiplication of the selected input reference. With a maximum input reference frequency of 90 MHz (under ÷4 feedback), the QB outputs operate up to 180 MHz. This is confirmed in Table 5 of the datasheet under "fMAX Output Frequency" for QB[2:0], with full AC specification compliance across –40°C to +85°C.

How does the MPC99J93FA minimize phase disturbance during clock switching?

The MPC99J93FA minimizes phase disturbance during clock switching by initiating a controlled slew-to-alignment sequence: upon selecting a new reference clock, the PLL aligns the next positive edge pair of Ext_FB and the newly selected reference within one cycle. This eliminates the typical "phase bump" seen in basic mux-based solutions, achieving a worst-case static phase offset of only +0.17 ns-critical for maintaining timing margins in high-speed digital systems.

Can the MPC99J93FA operate with only one input clock source?

Yes, the MPC99J93FA can operate with only one valid input clock source. When only CLK0 or CLK1 is present and stable, the device locks to that source and generates all five outputs normally. However, Inp0bad or Inp1bad will assert if the unused input remains static (e.g., unterminated), so unused inputs should be properly terminated to VCC–2 V or grounded via 50 Ω to avoid false fault detection. Manual selection via Sel_Clk remains functional.