Renesas 9DB803DFLFT

Overview

9DB803DFLFT from IDT is an eight-output 0.7V current-mode differential clock buffer compliant with Intel DB800v2 and supporting PCIe Gen1/Gen2 timing requirements. It accepts a differential input (SRC_IN/SRC_IN#), operates in PLL mode (50–100 MHz) or bypass mode (50–400 MHz), delivers <50ps cycle-to-cycle jitter and <50ps output-to-output skew, and is used in server motherboard clock distribution for PCIe slot fanout.

For engineers reviewing the 9DB803DFLFT datasheet, 9DB803DFLFT pinout, 9DB803DFLFT application, or 9DB803DFLFT equivalent, this page provides verified functional context, validated pin roles, confirmed PCIe Gen2 phase jitter performance (≤3.1ps rms), SMBus programmability details, and real-world power management behavior under PD# and SRC_STOP# control.

Technical Context

The 9DB803DFLFT implements a dual-mode architecture: PLL-based zero-delay buffering (ZDB) for jitter cleanup at 50–100 MHz, and transparent bypass/fanout mode supporting up to 400 MHz for low-latency distribution. Its 8 differential output pairs (DIF_0 through DIF_7) are individually controllable via OE pins or SMBus registers and support spread-spectrum modulation tolerance (±0.25% center, 0 to –0.5% down).

It integrates a 3.3V PLL core (VDDA/GNDA), analog input supply (VDDR), and logic supply (VDD), with IREF pin setting output current for 100Ω differential impedance (475Ω resistor). Bandwidth selection (HIGH_BW#) and polarity inversion (OE_INV) are hardware-configurable, while Bypass#/PLL, PD#, and SRC_STOP# enable deterministic power and clock gating.

Key Specifications

Pinout & Package

9DB803DFLFT is housed in a 48-pin TSSOP package (7.0 mm × 12.0 mm, 0.5 mm pitch) with exposed thermal pad. Power domains include VDD (pins 11, 19, 31, 39), VDDA (pin 48), VDDR (pin 2), GNDA (pin 47), and GND (pins 3, 10, 18, 25, 32). IREF (pin 46) requires a precision 475Ω resistor to ground for 100Ω differential output impedance calibration.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar differential clock buffer applications.

Compared with 9DB803DFLFT, the 9DB403DFLFT reduces output count and power consumption for simpler systems, while the ICS9DB801DFLFT offers identical functionality as a documented alternate SKU - both preserve PCIe Gen2 jitter compliance and SMBus configurability without layout changes.

Availability

9DB803DFLFT is available at Aetrix Electronics and suitable for server motherboard design, PCIe add-in card development, and industrial data acquisition systems requiring stable component supply, guaranteed long-term availability, and full traceability.

Supply support for 9DB803DFLFT 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

IDT (Integrated Device Technology), now part of Renesas Electronics, is a leader in timing, interface, and memory solutions, specializing in high-performance clock generation and distribution ICs for computing and communications infrastructure.

The 9DB803DFLFT belongs to IDT's PCIe-optimized differential buffer product line, designed specifically to meet Intel DB800v2 specification and deliver ultra-low jitter, flexible power management, and robust signal integrity for enterprise-class PCIe clock trees.

FAQ

What is the maximum input frequency supported by the 9DB803DFLFT in bypass mode?

The 9DB803DFLFT supports up to 400 MHz in bypass mode when the BYPASS#/PLL pin is set low. This is confirmed in the Electrical Characteristics table (FiBYPASS = 33–400 MHz) and applies to differential input signals meeting specified slew rate (0.4–8 V/ns) and amplitude (300–1450 mV p-p) requirements. Operation above 400 MHz is not characterized or guaranteed.

Does the 9DB803DFLFT require external termination resistors, and if so, what values?

Yes, the 9DB803DFLFT requires external termination: a 475Ω precision resistor from IREF (pin 46) to ground sets the output current for 100Ω differential impedance. Each differential output pair also needs series 33Ω resistors (RS) near the driver and parallel 49.9Ω Thevenin terminations (RP) at the receiver end, as specified in the "Common Recommendations for Differential Routing" section of the datasheet.

How does the OE_INV pin affect the behavior of the output enable inputs on the 9DB803DFLFT?

When OE_INV = 0 (default), OE_0–OE_7 are active-high control inputs; when OE_INV = 1, they become active-low (labeled OE0#–OE7# in pin descriptions). This polarity inversion is latched on power-up or reset and allows compatibility with either active-high or active-low system-level enable logic without redesigning the control interface.

Can the 9DB803DFLFT operate in industrial temperature range (–40°C to +85°C)?

Yes, the 9DB803DFLFT is rated for industrial temperature operation (–40°C to +85°C), as stated in the Absolute Maximum Ratings table. Electrical characteristics including jitter, skew, and supply current (IDD3.3OPI = 190–225 mA) are fully specified across this range, making it suitable for ruggedized PCIe applications such as industrial controllers and telecom equipment.

What is the function of the LOCK pin on the 9DB803DFLFT, and how should it be used in system design?

The LOCK pin is an open-drain 3.3V output that goes high when the internal PLL achieves lock - indicating stable, low-jitter clock output. In system design, it should be pulled up externally (e.g., 10kΩ to VDD) and monitored by the host processor or CPLD to delay PCIe enumeration until clock stability is confirmed, preventing failed link training due to premature initialization.