SN74FB2040
8-BIT TTL/BTL TRANSCEIVER
SCBS173N 鈥?NOVEMBER 1991 鈥?REVISED MARCH 2002
D
D
D
Compatible With IEEE Std 1194.1-1991
(BTL)
TTL A Port, Backplane Transceiver Logic
(BTL) B Port
Open-Collector B-Port Outputs Sink
100 mA
D
D
D
RC PACKAGE
(TOP VIEW)
High-Impedance State During Power Up
and Power Down
BIAS V
CC
Pin Minimizes Signal Distortion
During Live Insertion or Withdrawal
B-Port Biasing Network Preconditions the
Connector and PC Trace to the BTL
High-Level Voltage
AO2
AI1
AO1
V
CC
BIAS V
CC
OEA
OEB
OEB
TCK
V
CC
1
2
3
4
5
6
7
8
9
10
11
12
13
52 51 50 49 48 47 46 45 44 43 42 41 40
TMS
GND
B1
39
38
37
36
35
34
33
32
31
30
29
28
27
GND
AI2
AI3
AO3
GND
AO4
GND
AI4
AI5
AO5
GND
AO6
GND
14 15 16 17 18 19 20 21 22 23 24 25 26
GND
B2
GND
B3
GND
B4
GND
B5
GND
B6
GND
B7
GND
AI6
GND
AO7
BG V
CC
AI7
BG GND
AO8
TDO
TDI
V
CC
AI8
GND
description
The SN74FB2040 is an 8-bit transceiver designed to translate signals between TTL and backplane transceiver
logic (BTL) environments.
The B port operates at BTL-signal levels. The open-collector B ports are specified to sink 100 mA. Two output
enables (OEB and OEB) are provided for the B outputs. When OEB is high and OEB is low, the B port is active
and reflects the inverse of the data present at the A-input pins. When OEB is low, OEB is high, or V
CC
is less
than 2.1 V, the B port is turned off.
The A port operates at TTL-signal levels and has separate input and output pins. The A outputs reflect the
inverse of the data at the B port when the A-port output enable (OEA) is high. When OEA is low or when V
CC
is less than 2.1 V, the A outputs are in the high-impedance state.
The pins TMS, TCK, TDI, and TDO are nonfunctional, i.e., not intended for use with the IEEE Std 1149.1 (JTAG)
test bus. TMS and TCK are not connected, and TDI is shorted to TDO.
BIAS V
CC
establishes a voltage between 1.62 V and 2.1 V on the BTL outputs when V
CC
is not connected.
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
Copyright
錚?/div>
2002, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
POST OFFICE BOX 655303
鈥?/div>
DALLAS, TEXAS 75265
B8
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