Renesas 844003BG-01LF

Overview

844003BG-01LF from Renesas Electronics (formerly IDT) is a 3-output LVDS frequency synthesizer designed for Ethernet reference clock generation. It accepts a 19.53125 MHz or 25 MHz parallel-resonant crystal, delivers three differential LVDS outputs across two independent banks (Bank A: 1 pair; Bank B: 2 pairs), and achieves ≤0.58 ps typical RMS phase jitter at 125–625 MHz - meeting 10GbE jitter requirements. Its primary system role is low-jitter clock synthesis in high-speed networking PHYs and switches.

For engineers reviewing the 844003BG-01LF datasheet, 844003BG-01LF pinout, 844003BG-01LF application, or 844003BG-01LF equivalent, key selection considerations include bank-independent frequency configuration (625/312.5/156.25/125 MHz), 24-pin TSSOP-E package with exposed thermal pad, 3.3 V single-supply operation, LVDS output compliance, and crystal-to-LVDS conversion without external PLL components.

Technical Context

The 844003BG-01LF integrates a third-generation low-phase-noise VCO (490–680 MHz range) with dual independent output divider banks, each controlled by dedicated 2-bit DIV_SEL pins and selectable feedback dividers (÷25 or ÷32). It supports both crystal oscillator interface (18 pF parallel resonant) and single-ended LVCMOS/LVTTL REF_CLK input via XTAL_SEL control.

Its architecture enables simultaneous generation of up to three LVDS clock signals at different frequencies - e.g., 625 MHz on Bank A and 156.25 MHz on Bank B - with bank skew ≤33 ps and inter-bank output skew ≤170 ps. All inputs feature internal pullup/pulldown resistors (51 kΩ typical), and power domains are segregated (VDD, VDDA, VDDO_A, VDDO_B) to minimize noise coupling into sensitive analog and output stages.

Key Specifications

Pinout & Package

844003BG-01LF is housed in a lead-free, RoHS-compliant 24-pin TSSOP package with an exposed E-pad for thermal and electrical grounding. The package measures 4.40 mm × 7.80 mm × 0.925 mm and requires PCB land pattern matching the exposed pad area plus thermal vias to ground plane for optimal thermal performance.

Key Features

Applications

Equivalent & Alternatives

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

Compared with Si5338A-D-GM and ICS844002AGI-01LF, the 844003BG-01LF offers fixed-function simplicity, zero-configuration operation from crystal, and guaranteed 3-output LVDS capability - making it optimal for cost-sensitive, high-volume Ethernet PHY clocking where frequency flexibility is secondary to jitter performance and ease of use.

Availability

844003BG-01LF is available at Aetrix Electronics and suitable for 10GbE PHY clocking, data center switch fabric timing, optical transport network line cards, and industrial Ethernet controller applications requiring stable component supply, RoHS-compliant packaging, and commercial-temperature-grade reliability.

Supply support for 844003BG-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

Renesas Electronics Corporation is a global semiconductor leader formed through the merger of Renesas Technology and NEC Electronics, specializing in microcontrollers, analog, power, and timing solutions for automotive, industrial, and communications markets.

The 844003BG-01LF belongs to Renesas' FemtoClocks™ family of ultra-low-jitter clock synthesizers, engineered specifically for high-speed serial interface timing in Ethernet, OTN, and datacenter applications where phase noise and deterministic skew directly impact bit-error rate.

FAQ

What crystal specifications are required for reliable operation of the 844003BG-01LF?

The 844003BG-01LF is characterized for use with 18 pF parallel-resonant fundamental-mode crystals operating at 19.53125 MHz or 25 MHz. Crystals must have ESR ≤50 Ω and shunt capacitance ≈7 pF. Drive level must not exceed 1 mW. Using non-compliant crystals may result in start-up failure, frequency inaccuracy, or increased phase jitter beyond datasheet limits.

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

Yes, the 844003BG-01LF supports independent frequency configuration: Bank A uses DIV_SELA[1:0] and Bank B uses DIV_SELB[1:0], each paired with shared FB_DIV to set the PLL feedback ratio. For example, Bank A can output 625 MHz (DIV_SELA = 00, FB_DIV = 0) while Bank B outputs 156.25 MHz (DIV_SELB = 11, FB_DIV = 0), verified in Tables 3F and 3G of the datasheet.

How does the 844003BG-01LF achieve its low phase jitter specification?

The 844003BG-01LF achieves ≤0.58 ps RMS phase jitter using Renesas' third-generation low-noise VCO architecture (490–680 MHz), fully segregated analog (VDDA) and output (VDDO_A/VDDO_B) power domains, and optimized on-die divider design. Measured jitter values are specified over 1.875 MHz–20 MHz offset bandwidth and validated against 10GbE phase noise masks.

Is the 844003BG-01LF pin-compatible with other devices in the 84400x family?

The 844003BG-01LF shares the same 24-pin TSSOP package and core pinout with the 844002AGI-01LF (2-output variant), but is not pin-compatible with 844004 or 844005 variants due to differing pin functions and counts. Bank B pins (QB0/nQB0, QB1/nQB1, DIV_SELB[1:0]) are unused on the 844002AGI-01LF, requiring PCB redesign for substitution.

What is the purpose of the exposed thermal pad (E-pad) on the 844003BG-01LF package?

The exposed E-pad on the 844003BG-01LF serves dual purposes: thermal dissipation (reducing θJA from 32.1°C/W to <27°C/W with proper via array) and electrical grounding for noise suppression. It must be soldered to a PCB copper land pattern connected to ground via ≥6 thermal vias (12–13 mil diameter, 1 oz plating) to meet jitter and reliability specifications.