DS90CR481 Datasheet, PDF (17/21 Pages) National Semiconductor (TI) – 48-Bit LVDS Channel Link SER/DES − 65 - 112 MHz

DS90CR481 Pin Descriptions—Channel Link Transmitter
Pin Name
TxIN
TxOUTP
TxOUTM
TxCLKIN
TxCLKP
TxCLKM
PD
PLLSEL
PRE
DS_OPT
BAL
V_CC
GND
PLLV_CC
PLLGND
LVDSV_CC
LVDSGND
NC
I/O
Description
I
TTL level input. (Note 10).
O
Positive LVDS differential data output.
O
Negative LVDS differential data output.
I
TTL level clock input. The rising edge acts as data strobe.
O
Positive LVDS differential clock output.
O
Negative LVDS differential clock output.
I
TTL level input. Assertion (low input) tri-states the outputs, ensuring low
current at power down. (Note 10).
I
PLL range select. This pin must be tied to V_CC. NC or tied to Ground is
reserved for future use. (Note 10)
I
Pre-emphasis “level” select. Pre-emphasis is active when input is tied to V_CC
through external pull-up resistor. Resistor value determines Pre-emphasis
level (See Applications Information Section). For normal LVDS drive level
(No Pre-emphasis) leave this pin open (do not tie to ground).
I
Cable Deskew performed when TTL level input is low. No TxIN data is
sampled during Deskew. To perform Deskew function, input must be held
low for a minimum of 4 clock cycles. The Deskew operation is normally
conducted after the TX and RX PLLs have locked. It should also be
conducted after a system reset, or a reconfiguration event. It must be
peformed at least once when "DESKEW" is enabled. (Note 10)
I
TTL level input. This pin was previously labeled as V_CC, which enabled the
DC Balance function. But when tied low or left open, the DC Balance
function is disabled. Please refer to (Figures 15, 16) for LVDS data bit
mapping respectively. (Note 10), (Note 12)
I
Power supply pins for TTL inputs and digital circuitry. Bypass not required
on Pins 20 and 21.
I
Ground pins for TTL inputs and digital circuitry.
I
Power supply pin for PLL circuitry.
I
Ground pins for PLL circuitry.
I
Power supply pin for LVDS outputs.
I
Ground pins for LVDS outputs.
No Connect. Make NO Connection to these pins - leave open.
Note 10: Inputs default to “low” when left open due to internal pull-down resistor.
17
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