DS90C124_08 Datasheet, PDF (12/26 Pages) National Semiconductor (TI) – 5-35MHz DC-Balanced 24-Bit LVDS Serializer and Deserializer

DS90C241 Serializer Pin Descriptions
Pin # Pin Name
I/O
Description
LVCMOS PARALLEL INTERFACE PINS
4-1, DIN[23:0]
48-44,
41-32,
29-25
LVCMOS_I Transmitter Parallel Interface Data Input Pins. Tie LOW if unused, do not float.
10 TCLK
LVCMOS_I Transmitter Parallel Interface Clock Input Pin. Strobe edge set by TRFB configuration pin.
CONTROL AND CONFIGURATION PINS
9
TPWDNB LVCMOS_I Transmitter Power Down Bar
TPWDNB = H; Transmitter is Enabled and ON
TPWDNB = L; Transmitter is in power down mode (Sleep), LVDS Driver D_OUT (+/-) Outputs are
in TRI-STATE stand-by mode, PLL is shutdown to minimize power consumption.
18 DEN
LVCMOS_I
Transmitter Data Enable
DEN = H; LVDS Driver Outputs are Enabled (ON).
DEN = L; LVDS Driver Outputs are Disabled (OFF), Transmitter LVDS Driver D_OUT (+/-) Outputs
are in TRI-STATE, PLL still operational and locked to TCLK.
23 PRE
LVCMOS_I
Pre-emphasis Level Select
PRE = NC (No Connect); Pre-emphasis is Disabled (OFF).
Pre-emphasis is active when input is tied to VSS through external resistor R_PRE. Resistor value
determines pre-emphasis level. Recommended value R_PRE ≥ 3 kΩ; I_max = [(1.2/R)*20], R_min =
3 kΩ
11 TRFB
LVCMOS_I
Transmitter Clock Edge Select Pin
TRFB = H; Parallel Interface Data is strobed on the Rising Clock Edge.
TRFB = L; Parallel Interface Data is strobed on the Falling Clock Edge
12 VODSEL
LVCMOS_I VOD Level Select
VODSEL = L; LVDS Driver Output is ≈±400 mV (R_L = 100Ω)
VODSEL = H; LVDS Driver Output is ≈±750 mV (R_L = 100Ω)
For normal applications, set this pin LOW. For long cable applications where a larger VOD is
required, set this pin HIGH.
5
DCAOFF
LVCMOS_I Reserved. This pin MUST be tied LOW.
8
DCBOFF
LVCMOS_I Reserved. This pin MUST be tied LOW.
13
RESRVD
LVCMOS_I Reserved. This pin MUST be tied LOW.
LVDS SERIAL INTERFACE PINS
20 DOUT+
LVDS_O
Transmitter LVDS True (+) Output.
This output is intended to be loaded with a 100Ω load to the D_OUT+ pin. The interconnect should
be AC Coupled to this pin with a 100 nF capacitor.
19 DOUT−
LVDS_O
Transmitter LVDS Inverted (-) Output
This output is intended to be loaded with a 100Ω load to the D_OUT- pin. The interconnect should
be AC Coupled to this pin with a 100 nF capacitor.
POWER / GROUND PINS
22 VDDDR
VDD
Analog Voltage Supply, LVDS Output Power
21 VSSDR
GND
Analog Ground, LVDS Output Ground
16 VDDPT0
VDD
Analog Voltage supply, VCO Power
17 VSSPT0
GND
Analog Ground, VCO Ground
14 VDDPT1
VDD
Analog Voltage supply, PLL Power
15 VSSPT1
GND
Analog Ground, PLL Ground
30 VDDT
VDD
Digital Voltage supply, Tx Serializer Power
31 VSST
GND
Digital Ground, Tx Serializer Ground
7
VDDL
VDD
Digital Voltage supply, Tx Logic Power
6
VSSL
GND
Digital Ground, Tx Logic Ground
42 VDDIT
VDD
Digital Voltage supply, Tx Input Power
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