
9EX21831
IDT
Eighteen Output Differential Buffer w/2 input mux for PCIe Gen1/2/3
1678D—03/23/12
Eighteen Output Differential Buffer w/2 input mux for PCIe
Gen1/2/3
1
DATASHEET
Recommended Application:
18 Output PCIe G3 Differential Buffer with 2:1 input mux
General Description
The ICS9EX21831 provides 18 output clocks for PCIe Gen1/
2/3 applications. The 9EX21831 has 4 selectable SMBus
addresses, and dedicated CKPWRGD/PD# and VDDA pins
for easy board design. A differential clock from a CK410B+
or CK420BQ main clock generator, such as the ICS932S421,
drives the ICS9EX21831. In fanout mode, the 9EX21831
provides outputs up to 166MHz.
Output Features:
18 - 0.7V current mode differential HCSL output pairs
Features/Benefits:
Pin compatible to 9EX21801/ Easy PCIe Gen3
upgrade
4 Selectable SMBus Addresses/Mulitple devices can
share the same SMBus Segment
10 dedicated and 2 group OE# pins/Hardware control
of the outputs
PLL or bypass mode/PLL can dejitter incoming clock
Selectable PLL bandwidth/minimizes jitter peaking in
downstream PLL's
Spread Spectrum Compatible/tracks spreading input
clock for low EMI
SMBus Interface/unused outputs can be disabled
Undriven differential outputs in Power Down mode/
Easy power management
Key Specifications:
Cycle-to-cycle jitter <50ps
Output-to-output skew < 150 ps
PCIe Gen3 phase jitter < 1.0ps RMS
Functional Block Diagram
CLKA_IN
CLKA_IN#
DIF(17:0)
HIBW_BYPM_LOBW#
SEL_A_B#
SMBDAT
SMBCLK
CKPWRGD/PD#
18
IREF
OE(17:15)#
OE(14:5)#,
OE_01234#
12
SMB_A0
SMB_A1
CLKB_IN
CLKB_IN#
PLL
(SS Compatible)
Logic