Renesas 844003BGI-01LF

Overview

844003BGI-01LF from IDT is a 3-output LVDS frequency synthesizer IC designed for Ethernet reference clock generation. It accepts 19.53125 MHz or 25 MHz parallel-resonant crystals and delivers independently configurable differential outputs at 625 MHz, 312.5 MHz, 156.25 MHz, or 125 MHz across two banks (Bank A: 1 pair; Bank B: 2 pairs). It achieves ≤0.56 ps typical RMS phase jitter at 156.25 MHz (1.875–20 MHz offset) and operates from a single 3.3 V supply over –40°C to +85°C.

For engineers reviewing the 844003BGI-01LF datasheet, 844003BGI-01LF pinout, 844003BGI-01LF application, or 844003BGI-01LF equivalent, this page provides verified technical context, bank-specific frequency configuration logic, LVDS output skew and jitter performance, thermal design guidance for the 24-pin TSSOP E-Pad package, and validated alternative options for Ethernet clock synthesis.

Technical Context

The 844003BGI-01LF integrates a third-generation low-phase-noise VCO (490–680 MHz), dual independent PLL output divider banks with dedicated DIV_SELA[1:0] and DIV_SELB[1:0] control, and selectable crystal or LVCMOS/LVTTL reference input via XTAL_SEL. Feedback division is set to ÷25 (default) or ÷32 via FB_DIV.

Each bank features separate output supply rails (VDDO_A, VDDO_B), independent output enable (OEA/OEB), and LVDS-compliant differential outputs with 250–450 mV differential voltage and 1.25–1.41 V common-mode offset. Bank skew is ≤33 ps; inter-bank output skew is ≤75 ps at same frequency.

Key Specifications

Pinout & Package

24-pin TSSOP with exposed E-pad (G package), RoHS-compliant lead-free finish. Thermal pad must be soldered to PCB ground plane via ≥6 thermal vias (12–13 mil diameter, 1 oz plating) for reliable operation at full power dissipation (786.6 mW max).

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-A-GM and ICS8430I-01T, the 844003BGI-01LF uniquely combines sub-0.55 ps jitter at 625 MHz, dual isolated output supplies, and hardware-only frequency selection - making it optimal for fixed-frequency, jitter-critical Ethernet infrastructure where configuration overhead and supply noise coupling must be minimized.

Availability

844003BGI-01LF is available at Aetrix Electronics and suitable for 10GbE switch design, Synchronous Ethernet base station deployment, and OTN line card manufacturing requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant lead-free packaging.

Supply support for 844003BGI-01LF 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

Integrated Device Technology (IDT), now part of Renesas Electronics, is a fabless semiconductor company specializing in timing, memory interface, RF, and sensor solutions for communications and computing markets.

The 844003BGI-01LF belongs to IDT's FEMTOCLOCKS™ family of ultra-low-jitter clock synthesizers, engineered specifically for Ethernet, SyncE, and OTN infrastructure where deterministic phase noise and bank-isolated LVDS outputs are critical.

FAQ

What crystal specifications are required for stable operation of the 844003BGI-01LF?

The 844003BGI-01LF is characterized for use with 18 pF parallel-resonant crystals operating at either 19.53125 MHz or 25 MHz. The crystal must meet fundamental-mode oscillation, ESR ≤50 Ω, shunt capacitance ≈7 pF, and drive level ≤1 mW. Deviations outside these parameters may cause start-up failure or increased phase jitter. The 844003BGI-01LF datasheet specifies FB_DIV-dependent frequency ranges: ÷25 mode supports 19.6–27.2 MHz; ÷32 mode supports 15.313–21.25 MHz.

How does the VCO_SEL pin affect the 844003BGI-01LF's output behavior?

When VCO_SEL is driven LOW, the 844003BGI-01LF bypasses its internal PLL and passes the selected reference (crystal or REF_CLK) directly to the output dividers - effectively converting the device into a programmable divider-only clock generator. This mode disables VCO-related jitter but limits output frequencies to integer divisions of the input. By default (VCO_SEL = HIGH, internal pullup), the PLL is active, enabling multiplication and the full 490–680 MHz VCO range for low-jitter synthesis.

Can the 844003BGI-01LF generate different frequencies on Bank A and Bank B simultaneously?

Yes, the 844003BGI-01LF supports fully independent frequency configuration: Bank A uses DIV_SELA[1:0] and Bank B uses DIV_SELB[1:0], each selecting from ÷1/÷2/÷3/÷4 (Bank A) or ÷2/÷4/÷5/÷8 (Bank B), combined with FB_DIV (÷25 or ÷32) to produce distinct output frequencies. For example, Bank A can output 156.25 MHz while Bank B outputs 312.5 MHz - confirmed in Tables 3F and 3G of the 844003BGI-01LF datasheet.

What is the recommended termination for the 844003BGI-01LF's LVDS outputs?

IDT specifies 90–132 Ω differential termination for the 844003BGI-01LF's LVDS outputs, with 100 Ω being optimal for standard point-to-point layouts. Termination must be placed as close as possible to the receiving device. Unused LVDS pairs should be either left floating (with no attached trace) or terminated with 100 Ω across the differential pair. The 844003BGI-01LF's LVDS drivers comply with ANSI TIA/EIA-644, delivering 250–450 mV differential swing and 1.25–1.41 V common-mode voltage.

Does the 844003BGI-01LF require separate power supply filtering for each VDDO rail?

Yes - the 844003BGI-01LF mandates individual 0.01 µF ceramic bypass capacitors on VDDO_A and VDDO_B, in addition to separate decoupling on VDD and VDDA. This isolation prevents switching noise from one bank's outputs from modulating the other bank's supply and degrading phase noise. VDDA further requires a 10 Ω series resistor and 10 µF bulk capacitor. Layout guidelines specify direct via connections from each supply pin to the PCB ground plane to minimize inductance.