74VCX16839 Low Voltage 20-Bit Selectable Register/Buffer with 3.6V Tolerant Inputs and Outputs
July 1997
Revised April 1999
74VCX16839
Low Voltage 20-Bit Selectable Register/Buffer with 3.6V
Tolerant Inputs and Outputs
General Description
The VCX16839 contains twenty non-inverting selectable
buffered or registered paths. The device can be configured
to operate in a registered, or flow through buffer mode by
utilizing the register enable (REGE) and Clock (CP) sig-
nals. The device operates in a 20-bit word wide mode. All
outputs can be placed into 3-STATE through use of the OE
pin. These devices are ideally suited for buffered or regis-
tered 168 pin and 200 pin SDRAM DIMM memory mod-
ules.
The 74VCX16839 is designed for low voltage (1.65V to
3.6V) V
CC
applications with I/O compatibility up to 3.6V.
The 74VCX16839 is fabricated with an advanced CMOS
technology to achieve high speed operation while maintain-
ing low CMOS power dissipation.
Features
s
Compatible with PC100 and PC133 DIMM module
specifications
s
1.65V鈥?.6V V
CC
supply operation
s
3.6V tolerant inputs and outputs
s
t
PD
(CP to O
n
)
3.2 ns max for 3.0V to 3.6V V
CC
4.4 ns max for 2.3V to 2.7V V
CC
8.8 ns max for 1.65V to 1.95V V
CC
s
Power-off high impedance inputs and outputs
s
Supports live insertion and withdrawal (Note 1)
s
Static Drive (I
OH
/I
OL
)
鹵24
mA @ 3.0V V
CC
鹵18
mA @ 2.3V V
CC
鹵6
mA @ 1.65V V
CC
s
Uses patented noise/EMI reduction circuitry
s
Latch-up performance exceeds 300 mA
s
ESD performance:
Human body model
>
2000V
Machine model
>
200V
Note 1:
To ensure the high-impedance state during power up or power
down, OE should be tied to V
CC
through a pull-up resistor; the minimum
value of the resistor is determined by the current-sourcing capability of the
driver.
Ordering Code:
Order Number
74VCX16839MTD
Package Number
MTD56
Package Descriptions
56-Lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153, 6.1mm Wide
Devices also available in Tape and Reel. Specify by appending suffix letter 鈥淴鈥?to the ordering code.
Logic Symbol
Pin Descriptions
Pin Names
OE
I
0
鈥揑
19
O
0
鈥揙
19
CP
REGE
Description
Output Enable Input (Active LOW)
Inputs
Outputs
Clock Pulse Input
Register Enable Input
漏 1999 Fairchild Semiconductor Corporation
DS500105.prf
www.fairchildsemi.com
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