CDCM1804_17 Datasheet, PDF (1/27 Pages) Texas Instruments – 1:3 LVPECL CLOCK BUFFER + ADDITIONAL LVCMOS OUTPUT AND PROGRAMMABLE DIVIDER

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CDCM1804
SCAS697E – JULY 2003 – REVISED MAY 2005
1:3 LVPECL CLOCK BUFFER + ADDITIONAL
LVCMOS OUTPUT AND PROGRAMMABLE DIVIDER
FEATURES
• Distributes One Differential Clock Input to
Three LVPECL Differential Clock Outputs and
One LVCMOS Single-Ended Output
• Programmable Output Divider for Two
LVPECL Outputs and LVCMOS Output
• Low-Output Skew 15 ps (Typical) for
Clock-Distribution Applications for LVPECL
Outputs; 1.6-ns Output Skew Between
LVCMOS and LVPECL Transitions Minimizing
Noise
• V_CC Range 3 V–3.6 V
• Signaling Rate Up to 800-MHz LVPECL and
200-MHz LVCMOS
• Differential Input Stage for Wide
Common-Mode Range
• Provides VBB Bias Voltage Output for
Single-Ended Input Signals
• Receiver Input Threshold ±75 mV
• 24-Terminal QFN Package (4 mm × 4 mm)
• Accepts Any Differential Signaling:
LVDS, HSTL, CML, VML, SSTL-2, and
Single-Ended: LVTTL/LVCMOS
DESCRIPTION
The CDCM1804 clock driver distributes one pair of
differential clock inputs to three pairs of LVPECL
differential clock outputs Y[2:0] and Y[2:0], with mini-
mum skew for clock distribution. The CDCM1804 is
specifically designed for driving 50-Ω transmission
lines. Additionally, the CDCM1804 offers a
single-ended LVCMOS output Y3. This output is
delayed by 1.6 ns over the three LVPECL output
stages to minimize noise impact during signal tran-
sitions.
The CDCM1804 has three control terminals, S0, S1,
and S2, to select different output mode settings. The
S[2:0] terminals are 3-level inputs and therefore allow
up to 3³ = 27 combinations. Additionally, an enable
terminal (EN) is provided to disable or enable all
outputs simultaneously. The EN terminal is a 3-level
input as well and extends the number of settings to
2 × 27 = 54. See Table 1 for details.
The CDCM1804 is characterized for operation from
–40°C to 85°C.
For use in single-ended driver applications, the
CDCM1804 also provides a VBB output terminal that
can be directly connected to the unused input as a
common-mode voltage reference.
RGE PACKAGE
(TOP VIEW)
EN
V_DDPECL
IN
IN
V_DDPECL
VBB
24 23 22 21 20 19
1
18
2
17
3
V_SS(1)
16
4
15
5
14
6
13
7 8 9 10 11 12
S0
V_DD1
Y1
Y1
V_DD1
V_DD3
(1) _{Thermal pad must be connected to VSS.}
RTH PACKAGE
(TOP VIEW)
P0024-01
EN 1
V_DDPECL 2
IN 3
IN 4
V_DDPECL 5
VBB 6
V_SS(1)
18 S0
17 V_DD1
16 Y1
15 Y1
14 V_DD1
13 V_DD3
(1) _{Thermal pad must be connected to VSS.}
P0025-01
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Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2003–2005, Texas Instruments Incorporated