Datasheet
SN54LVTH18646A, SN54LVTH182646A, SN74LVTH18646A, SN74LVTH182646A
3.3-V ABT SCAN TEST DEVICES
WITH 18-BIT TRANSCEIVERS AND REGISTERS
SCBS311D – MARCH 1994 – REVISED JUNE 1997
2
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
description (continued)
In the test mode, the normal operation of the SCOPE bus transceivers and registers is inhibited, and the test
circuitry is enabled to observe and control the I/O boundary of the device. When enabled, the test circuitry
performs boundary-scan test operations according to the protocol described in IEEE Std 1149.1-1990.
Four dedicated test pins are used to observe and control the operation of the test circuitry: test data input (TDI),
test data output (TDO), test mode select (TMS), and test clock (TCK). Additionally, the test circuitry performs
other testing functions such as parallel-signature analysis (PSA) on data inputs and pseudo-random pattern
generation (PRPG) from data outputs. All testing and scan operations are synchronized to the TAP interface.
Active bus-hold circuitry is provided to hold unused or floating data inputs at a valid logic level.
The B-port outputs of ’LVTH182646A, which are designed to source or sink up to 12 mA, include equivalent 25-Ω
series resistors to reduce overshoot and undershoot.
The SN54LVT18646 and SN54LVTH182646A are characterized for operation over the full military temperature
range of –55°C to 125°C. The SN74LVTH18646A and SN74LVTH182646A are characterized for operation from
–40°C to 85°C.
1B4
1B5
1B6
GND
1B7
1B8
1B9
V
CC
NC
2B1
2B2
2B3
2B4
GND
2B5
2B6
2B7
1A3
1A4
1A5
GND
1A6
1A7
1A8
1A9
NC
V
CC
2A1
2A2
2A3
GND
2A4
2A5
2A6
V
NC
TMS
1CLKBA
1A2
1A1
1OE
GND
1SAB
1CLKAB
TDO
NC
TCK
2CLKBA
2SBA
2A9
GND
2OE
2SAB
2CLKAB
TDI
2A7
2A8
1SBA
1DIR
GND
2DIR
2B9
2B8
GND
1B1
1B2
1B3
28 29
60
59
58
57
56
55
54
53
52
51
50
49
48
47
46
45
44
30
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
31 32 33 34
87 65493168672
35 36 37 38 39
66 65
27
64 63 62 61
40 41 42 43
SN54LVTH18646A, SN54LVTH182646A . . . HV PACKAGE
(TOP VIEW)
CC
V
CC
NC – No internal connection