VSS PCI ExpressTM Clock Generator 841S02 DATA SHEET General Description Features The 841S02 is a PLL-based clock generator specifically designed for Two 0.7V current mode differential HCSL output pairs PCI Express Clock Generation applications. This device Crystal oscillator interface: 25MHz generates a 100MHz HCSL clock. The device offers a HCSL (Host Output frequency: 100MHz Clock Signal Level) clock output from a clock input reference of RMS period jitter: 3ps (maximum) 25MHz. The input reference may be derived from an external source or by the addition of a 25MHz crystal to the on-chip crystal oscillator. Output skew: 35ps (maximum) An external reference may be applied to the XTAL IN pin with the Cycle-to-cycle jitter: 35ps (maximum) XTAL OUT pin left floating. 2 I C support with readback capabilities up to 400kHz The device offers spread spectrum clock output for reduced EMI Spread Spectrum for electromagnetic interference (EMI) reduction 2 applications. An I C bus interface is used to enable or disable spread 3.3V operating supply mode spectrum operation as well as select either a down spread value of -0.35% or -0.5%. -40C to 85C ambient operating temperature Available in lead-free (RoHS 6) package Block Diagram Pin Assignment 25MHz V SS 1 20 VDD 2 XTAL IN SRCT 1:2 V 2 19 SDATA DD Divider OSC PLL 2 SRCT2 3 18 SCLK SRCC 1:2 Network nc XTAL OUT SRCC2 4 17 SRCT1 5 16 XTAL OUT Pullup SRCC1 6 15 XTAL IN SDATA V 2 SS 7 14 VDD 2 I C V 8 13 DD Pullup Logic SCLK V 9 12 VDDA SS IREF 10 11 VSS IREF 841S02 20-Lead TSSOP 6.5mm x 4.4mm x 0.925mm package body G Package Top View 841S02 Rev A 11/16/15 1 2015 Integrated Device Technology, Inc.841S02 DATA SHEET Table 1. Pin Descriptions Number Name Type Description 1, 7, 9, 11, 13 V Power Ground for core and SRC outputs. SS 2, 8, 14, 20 V Power Power supply for core and SRC outputs. DD 3, 4 SRCT2, SRCC2 Output Differential output pair. HCSL interface levels. 5, 6 SRCT1, SRCC1 Output Differential output pair. HCSL interface levels. An external fixed precision resistor (475) from this pin to ground provides a 10 IREF Input reference current used for differential current-mode SRCCx, SRCTx clock outputs. Power Analog power supply. 12 V DDA 15, XTAL IN, Input Crystal oscillator interface. XTAL IN is the input. XTAL OUT is the output. 16 XTAL OUT 17 nc Unused No connect. 2 I C SMBus compatible SCLK. This pin has an internal pullup resistor, but is in 18 SCLK Input Pullup high-impedance in power-down mode. LVCMOS/LVTTL interface levels. 2 I C SMBus compatible SDATA. This pin has an internal pullup resistor, but is 19 SDATA I/O Pullup in high-impedance in power-down mode. LVCMOS/LVTTL interface levels. NOTE: Pullup refers to internal input resistors. See Table 2, Pin Characteristics, for typical values. Table 2. Pin Characteristics Symbol Parameter Test Conditions Minimum Typical Maximum Units C Input Capacitance 4pF IN R Input Pullup Resistor 51 k PULLUP Rev A 11/16/15 2 PCI EXPRESSTM CLOCK GENERATOR