
SN54GTL16622A, SN74GTL16622A
18-BIT LVTTL-TO-GTL/GTL+ BUS TRANSCEIVERS
SCBS673D – AUGUST 1996 – REVISED DECEMBER 1999
2
POST OFFICE BOX 655303
DALLAS, TEXAS 75265
description (continued)
Data flow in each direction is controlled by the output-enable (OEAB and OEBA) and clock (CLKAB and CLKBA)
inputs. The clock-enable (CEAB and CEBA) inputs are designed to control each 9-bit transceiver independently,
which makes the device more versatile.
For A-to-B data flow, the device operates on the low-to-high transition of CLKAB if CEAB is low. When OEAB
is low, the outputs are active. When OEAB is high, the outputs are in the high-impedance state. Data flow for
B to A is similar to that of A to B, but uses OEBA, CLKBA, and CEBA.
These devices are fully specified for partial-power-down applications using I
off
. The I
off
circuitry disables the
outputs, preventing damaging current backflow through the device when it is powered down.
Active bus-hold circuitry holds unused or undriven LVTTL inputs at a valid logic state. Use of pullup or pulldown
resistors with the bus-hold circuitry is not recommended.
To ensure the high-impedance state during power up or power down, OE should be tied to V
CC
through a pullup
resistor; the minimum value of the resistor is determined by the current-sinking capability of the driver.
The SN54GTL16622A is characterized for operation over the full military temperature range of –55
°
C to 125
°
C.
The SN74GTL16622A is characterized for operation from –40
°
C to 85
°
C.
1
G
1
1
G
N
G
1
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
9
8
7
6
5
4
3
2
1 68 67 66 65 64 63 62 61
G
2
2
G
2
C
2
G
2
2
SN54GTL16622A . . . HV PACKAGE
(TOP VIEW)
V
C
O
C
1
1
1
1
1
V
C
2
N
NC – No internal connection
O
2
2
V
R
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
GND
1A5
1A6
GND
1A7
1A8
GND
1A9
NC
2A1
GND
2A2
2A3
GND
2A4
2A5
GND
1B4
1B5
1B6
GND
1B7
1B8
GND
1B9
NC
2B1
GND
2B2
2B3
GND
2B4
2B5
2B6
V
C