HDMP-1685A Datasheet, PDF (12/21 Pages) Agilent(Hewlett-Packard) – 1.25 Gbps Four Channel SerDes with 5-pin DDR SSTL-2 Parallel Interface

HDMP-1685A I/O Type Definitions
I/O Type
Definition
I-LVTTL
Input LVTTL, floats high when left open
I-SSTL2
Input SSTL_2, floats low when left open
O-SSTL2
Output SSTL_2
HS_OUT
50 Ω matched Output Driver. Will drive AC coupled 50 Ω loads. PECL level compatible (Figure 10).
HS_IN
PECL level compatible. Must be AC coupled (Figure 10).
C
External Circuit Node
S
Power Supply or Ground
HDMP-1685A Pin Input Capacitance (TRx)
Symbol
Parameter
C_INPUT
Input Capacitance on SSTL input pins
Units
pF
Typ.
Max.
1.6
I_TTL
V_CC
V_CC
V_BB 1.4 V
GND
ESD
PROTECTION
GND
Figure 9. LVTTL input simplified circuit schematic (for RFCT).
HS_OUT
Zo
Zo
V_CCP
V_CC
HS_IN
V_CC
V_CC
+
–+
–
ESD
PROTECTION
SO[0:3]+
0.01 µF
SO[0:3]–
0.01 µF
GND
GND
Zo = 50 Ω
2 * Zo
= 100 Ω
SI[0:3]+
Zo = 50 Ω
SI[0:3]–
GND
GND
ESD
PROTECTION
NOTES:
1. HS_IN INPUTS SHOULD NEVER BE CONNECTED TO GROUND AS PERMANENT DAMAGE TO THE DEVICE MAY RESULT.
2. CAPACITORS MAY BE PLACED AT THE SENDING END OR THE RECEIVING END.
Figure 10. HS_OUT and HS_IN simplified circuit schematic.
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