
1
PS8535C 10/04/04
V
CC
EN1
EN2
EN3
SEL
EN4
EN5
EN6
CEN
GND
CLK
SCLK
CLK
GND
D
CLK6
OUT–
GND
CLK6
OUT+
16
15
17
13
14
11
12
9
8
7
6
5
4
3
2
1
10
CLK5
OUT–
CLK5
OUT+
18
19
CLK4
OUT–
CLK4
OUT+
20
21
CLK3
OUT–
CLK3
OUT+
22
23
CLK2
OUT–
CLK2
OUT+
24
25
CLK1
OUT–
CLK1
OUT+
V
CC
26
27
28
Q
D
Q
D
Q
D
Q
D
Q
D
Q
1
0
PI90LVOnly110
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Features
Meets or Exceeds Requirements of ANSI TIA/EIA-644-1995
Designed for Clocking Rates up to 320MHz
Operates from a single 3.3-V Supply
Low-Voltage Differential Signaling (LVDS) with Output
Voltages of ±350mV into a 100-ohm load
Choice between LVDS or TTL clock input
Synchronous Enable/Disable
Multiplexed clock input
– Internal 300 kohm pullup resistor on all control pins
– CLK and CLK have 110-ohm termination (PI90LVT211)
Common and individual Enable/Disable control
50ps Output-to-Output Skew
±24ps Period Jitter
Bus Pins are High Impedance when disabled or with V
CC
<1.5V
TTL Inputs are 5V Tolerant
Power Dissipation at 300 MHz
P190LV211 is functionally compatible with Motorola’s
(PECL) MC 10E211/MC100E211
>12kV ESD Protection
Packaging (Pb-free & Green available):
- 28-pin TSSOP (L)
- 28-pin QSOP (Q)
PI90LV211/PI90LVT211
Block Diagram & Pin Configuration
Description
The PI90LV211 implements low voltage differential signaling (LVDS)
to achieve clocking rates as high as 320 MHz with low skew. The
PI90LV211 is a low skew 1:6 fanout device designed explicitly for low
skew clock distribution applications. The device features a multi-
plexed clock input to allow for the distribution of a lower speed scan
or test clock with the high-speed system clock. When LOW the SEL
pin will select the differential clock input.
Both a common enable and individual output enables are provided.
When asserted the positive output will go LOW on the next negative
transition of the CLK (or SCLK) input. The enable function is
synchronous so that the outputs will only be enabled/disabled when
they are already in the LOW state. This avoids any chance of
generating a runt clock pulse when the device is enabled/disabled
as can happen with an asynchronous
control. The internal flip flop
is clocked on the falling edge of the input clock, therefore all
associated specification limits are referenced to the negative edge
of the clock input.
Individual synchronous enable controls and multiplexed clock in-
puts make this device ideal as the first level distribution unit in a
distribution tree. The individual enables could be used to allow for the
disabling of individual cards on a backplane in fault tolerant designs.
K
L
C
/
K
L
C
K
L
C
S
L
E
S
x
N
E
N
E
C
)
T
U
O
K
L
C
L
H
X
↓
↓
X
L
H
↓
↓
L
H
X
H
L
L
H
L
L
L
L
H
K
K
L
*
Z
*
*
Z
L
C
C
S
Function Table
*
**
↓
= Negative transition of CLK or SCLK
Z = High Impedance
ENx disables individual banks
CEN disables all six banks
1:6 Differential Clock Distribution Chip