These programmable array logic devices feature high speed and functional equivalency when compared with
currently available devices. These IMPACT-X circuits combine the latest Advanced Low-Power Schottky
technology with proven titanium-tungsten fuses to provide reliable, high-performance substitutes for
conventional TTL logic. Their easy programmability allows for quick design of custom functions and typically
results in a more compact circuit board.
The TIBPAL20’ C series is characterized from 0°C to 75°C. The TIBPAL20’ M series is characterized for
operation over the full military temperature range of –55°C to 125°C.
These devices are covered by U.S. Patent 4,410,987.
IMPACT-X is a trademark of Texas Instruments Incorporated.
PAL is a registered trademark of Advanced Micro Devices Inc.
This document contains information on products in more than one
phase of development. The status of each device is indicated on the
page(s) specifying its electrical characteristics.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Copyright 1992, Texas Instruments Incorporated
1
Page 2
TIBPAL20R4-5C, TIBPAL20R6-5C, TIBPAL20R8-5C
TIBPAL20R4-7M, TIBPAL20R6-7M, TIBPAL20R8-7M
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
CIRCUITS
TIBPAL20R4’
C SUFFIX . . . JT OR NT PACKAGE
M SUFFIX . . . JT PACKAGE
(TOP VIEW)
24
23
22
21
20
19
18
17
16
15
14
13
24
23
22
21
20
19
18
17
16
15
14
13
V
I
I/O
I/O
Q
Q
Q
Q
I/O
I/O
I
OE
V
I
I/O
Q
Q
Q
Q
Q
Q
I/O
I
OE
CC
CC
1
CLK
2
I
3
I
4
I
5
I
6
I
7
I
8
I
9
I
10
I
11
I
12
GND
TIBPAL20R6’
C SUFFIX . . . JT OR NT PACKAGE
M SUFFIX . . . JT PACKAGE
(TOP VIEW)
1
CLK
2
I
3
I
4
I
5
I
6
I
7
I
8
I
9
I
10
I
11
I
12
GND
TIBPAL20R4’
C SUFFIX . . . FN PACKAGE
M SUFFIX . . . FK PACKAGE
(TOP VIEW)
CC
I
I
4
3 2 1 282726
5I/O
I
6
I
7
I
8
NC
9
I
10
I
11
I
12 13 14 15 16 17 18
I
I
TIBPAL20R6’
C SUFFIX . . . FN PACKAGE
M SUFFIX . . . FK PACKAGE
(TOP VIEW)
I
I
4
3 2 1 282726
5Q
I
6
I
7
I
8
NC
9
I
10
I
1119
I
12 13 14 15 16 17 18
I
I
V
CLKNCI
NC
OE
GND
CC
V
CLKNCI
OE
NC
GND
I/O
25
Q
24
Q
23
NC
22
Q
21
Q
20
19
I/O
I
I/O
I/O
25
Q
24
Q
23
NC
22
Q
21
Q
20
Q
I
I/O
TIBPAL20R8’
C SUFFIX . . . JT OR NT PACKAGE
M SUFFIX . . . JT PACKAGE
(TOP VIEW)
1
CLK
2
I
3
I
4
I
5
I
6
I
7
I
8
I
9
I
10
I
11
I
12
GND
Pin assignments in operating mode
2
24
23
22
21
20
19
18
17
16
15
14
13
V
CC
I
Q
Q
Q
Q
Q
Q
Q
Q
I
OE
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
TIBPAL20R8’
C SUFFIX . . . FN PACKAGE
M SUFFIX . . . FK PACKAGE
(TOP VIEW)
I
I
4
3 2 1 282726
5Q
I
6
I
7
I
8
NC
9
I
10
I
1119
I
12 13 14 15 16 17 18
I
I
NC – No internal connection
CC
CLKNCI
V
OE
NC
GND
Q
25
Q
24
Q
23
NC
22
Q
21
Q
20
Q
I
Q
Page 3
functional block diagrams (positive logic)
TIBPAL20L8-5C, TIBPAL20R4-5C
TIBPAL20L8-7M, TIBPAL20R4-7M
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
TIBPAL20L8’
CIRCUITS
OE
CLK
1420
I
20 x
&
40 X 64
206
TIBPAL20R4’
7
7
7
7
7
7
7
7
6
EN
≥1
O
O
I/O
I/O
I/O
I/O
I/O
I/O
EN 2
C1
denotes fused inputs
1220
I
4
20 x
1D
I = 0
2
Q
Q
Q
Q
I/O
I/O
I/O
I/O
&
40 X 64
204
8
8
8
8
7
7
7
7
4
≥1
≥1
EN
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
3
Page 4
TIBPAL20R6-5C, TIBPAL20R8-5C
TIBPAL20R6-7M, TIBPAL20R8-7M
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
functional block diagrams (positive logic)
CIRCUITS
TIBPAL20R6’
OE
CLK
1220
I
6
20 x
EN 2
C1
1D
I = 0
2
Q
Q
Q
Q
Q
Q
I/O
I/O
&
40 X 64
202
8
8
8
8
8
8
7
7
2
≥1
≥1
EN
6
CLK
denotes fused inputs
OE
1220
I
20 x
TIBPAL20R8’
EN 2
C1
1D
I = 0
2
Q
Q
Q
Q
Q
Q
Q
Q
&
40 X 64
208
8
8
8
8
8
8
8
8
8
≥1
4
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Page 5
logic diagram (positive logic)
1
I
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
Increment
TIBPAL20L8-5C
TIBPAL20L8-7M
CIRCUITS
2
I
First Fuse
Numbers
120
160
200
240
280
3
I
320
360
400
440
480
520
560
600
4
I
640
680
720
760
800
840
880
920
5
I
960
1000
1040
1080
1120
1160
1200
1240
6
I
1280
1320
1360
1400
1440
1480
1520
1560
7
I
1600
1640
1680
1720
1760
1800
1840
1880
8
I
1920
1960
2000
2040
2080
2120
2160
2200
9
I
2240
2280
2320
2360
2400
2440
2480
2520
10
I
11
I
48121620242832
0
40
80
36390
23
I
22
O
21
I/O
20
I/O
19
I/O
18
I/O
17
I/O
16
I/O
15
O
14
I
13
I
Fuse number = First fuse number + Increment
Pin numbers shown are for JT and NT packages.
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
5
Page 6
TIBPAL20R4-5C
TIBPAL20R4-7M
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
logic diagram (positive logic)
1
CLK
Increment
CIRCUITS
2
I
First Fuse
Numbers
0
40
80
120
160
200
240
280
3
I
320
360
400
440
480
520
560
600
4
I
640
680
720
760
800
840
880
920
5
I
960
1000
1040
1080
1120
1160
1200
1240
6
I
1280
1320
1360
1400
1440
1480
1520
1560
7
I
1600
1640
1680
1720
1760
1800
1840
1880
8
I
1920
1960
2000
2040
2080
2120
2160
2200
9
I
2240
2280
2320
2360
2400
2440
2480
2520
10
I
11
I
Fuse number = First fuse number + Increment
Pin numbers shown are for JT and NT packages.
48121620242832
36390
23
I
22
I/O
21
I/O
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
20
19
18
17
16
15
14
13
Q
Q
Q
Q
I/O
I/O
I
OE
6
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Page 7
logic diagram (positive logic)
1
CLK
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
Increment
TIBPAL20R6-5C
TIBPAL20R6-7M
CIRCUITS
2
I
First Fuse
Numbers
0
40
80
120
160
200
240
280
3
I
320
360
400
440
480
520
560
600
4
I
640
680
720
760
800
840
880
920
5
I
960
1000
1040
1080
1120
1160
1200
1240
6
I
1280
1320
1360
1400
1440
1480
1520
1560
7
I
1600
1640
1680
1720
1760
1800
1840
1880
8
I
1920
1960
2000
2040
2080
2120
2160
2200
9
I
2240
2280
2320
2360
2400
2440
2480
2520
10
I
11
I
Fuse number = First fuse number + Increment
Pin numbers shown are for JT and NT packages.
48121620242832
36390
23
I
22
I/O
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
21
20
19
18
17
16
15
14
13
Q
Q
Q
Q
Q
Q
I/O
I
OE
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
7
Page 8
TIBPAL20R8-5C
TIBPAL20R8-7M
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
logic diagram (positive logic)
1
CLK
Increment
CIRCUITS
2
I
First Fuse
Numbers
0
40
80
120
160
200
240
280
3
I
320
360
400
440
480
520
560
600
4
I
640
680
720
760
800
840
880
920
5
I
960
1000
1040
1080
1120
1160
1200
1240
6
I
1280
1320
1360
1400
1440
1480
1520
1560
7
I
1600
1640
1680
1720
1760
1800
1840
1880
8
I
1920
1960
2000
2040
2080
2120
2160
2200
9
I
2240
2280
2320
2360
2400
2440
2480
2520
10
I
11
I
Fuse number = First fuse number + Increment
Pin numbers shown are for JT and NT packages.
48121620242832
36390
23
I
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
I = 0
1D
C1
22
21
20
19
18
17
16
15
14
13
Q
Q
Q
Q
Q
Q
Q
Q
I
OE
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Page 9
TIBPAL20L8-5C
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
NOTE 1: These ratings apply except for programming pins during a programming cycle or during a preload cycle.
recommended operating conditions
MINNOMMAXUNIT
V
CC
V
IH
V
IL
I
OH
I
OL
T
A
NOTE 2: These are absolute voltage levels with respect to the ground pin of the device and include all overshoots due to system and/or tester
Supply voltage4.7555.25V
High-level input voltage (see Note 2)25.5V
Low-level input voltage (see Note 2)0.8V
High-level output current–3.2mA
Low-level output current24mA
Operating free-air temperature02575°C
noise. Testing these parameters should not be attempted without suitable equipment.
CIRCUITS
electrical characteristics over recommended operating free-air temperature range
PARAMETERTEST CONDITIONSMINTYP†MAXUNIT
V
IK
V
OH
V
OL
‡
I
OZH
‡
I
OZL
I
I
‡
I
IH
‡
I
IL
§
I
OS
I
CC
C
i
C
o
†
All typical values are at VCC = 5 V, TA = 25°C.
‡
I/O leakage is the worst case of I
§
Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second. VO is set at 0.5 V to
avoid test problems caused by test equipment ground degradation.
switching characteristicsover recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
FROM
(INPUT)
I, I/OO, I/O
t
pd
t
en
t
dis
I, I/OO, I/O
I, I/OO, I/O2727ns
I, I/OO, I/O2727ns
TO
(OUTPUT)
with up to 4 outputs
switching
with more than 4
outputs switching
TEST
CONDITIONS
R1 = 200 Ω,
R2 = 200 Ω,
See Figure 8
TIBPAL20L8-5CFN
MINMAXMINMAX
1.551.55
1.551.55.5
TIBPAL20L8-5CJT
TIBPAL20L8-5CNT
UNITPARAMETER
ns
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 • DALLAS, TEXAS 75265
9
Page 10
TIBPAL20R4-5C, TIBPAL20R6-5C
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
NOTE 1: These ratings apply except for programming pins during a programming cycle or during a preload cycle.
recommended operating conditions
V
CC
V
IH
V
IL
I
OH
I
OL
f
clock
w
t
su
t
h
T
A
NOTE 2: These are absolute voltage levels with respect to the ground pin of the device and include all overshoots due to system and/or tester
Supply voltage4.7555.25V
High-level input voltage (see Note 2)25.5V
Low-level input voltage (see Note 2)0.8V
High-level output current–3.2mA
Low-level output current24mA
Clock frequency0125MHz
Pulse duration, clockt
Setup time, input or feedback before clock↑4.5ns
Hold time, input or feedback after clock↑0ns
Operating free-air temperature02575°C
noise. Testing these parameters should not be attempted without suitable equipment.
CIRCUITS
High4
Low4
MINNOMMAXUNIT
ns
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.
10
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Page 11
TIBPAL20R4-5C, TIBPAL20R6-5C
HIGH-PERFORMANCE IMPACT -X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
electrical characteristics over recommended operating free-air temperature range
switching characteristicsover recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
TIBPAL20R4-5CJT
FROM
(INPUT)
without feedback125125
¶
f
max
t
pd
t
pd
t
pd
t
en
t
dis
t
en
t
dis
t
r
t
f
t
sk(o)
†
All typical values are at VCC = 5 V, TA = 25°C.
‡
I/O leakage is the worst case of I
§
Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second. VO is set at 0.5 V to
avoid test problems caused by test equipment ground degradation.
¶
See ’f
max
#
t
is the skew time between registered outputs.
sk(o)
with internal feedback (counter configuration)125125MHz
with external feedback117111
CLK↑Q1.541.54.5ns
CLK↑Internal feedbackR1 = 200 Ω,3.53.5ns
I, I/OI/OR2 = 200 Ω,1.551.55ns
OE↓QSee Figure 81.561.56ns
OE↑Q16.517ns
I, I/OI/O2727ns
I, I/OI/O2727ns
#
Specification’ near the end of this data sheet.
Skew between registered outputs0.50.5ns
and IIL or I
OZL
TO
(OUTPUT)
and IIH, respectively.
OZH
TEST
CONDITIONS
TIBPAL20R4-5CFN
TIBPAL20R6-5CFN
MIN TYP†MAXMIN TYP†MAX
1.51.5ns
1.51.5ns
TIBPAL20R4-5CNT
TIBPAL20R6-5CJT
TIBPAL20R6-5CNT
UNITPARAMETER
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 • DALLAS, TEXAS 75265
11
Page 12
TIBPAL20R8-5C
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
NOTE 1: These ratings apply except for programming pins during a programming cycle or during a preload cycle.
recommended operating conditions
V
CC
V
IH
V
IL
I
OH
I
OL
f
clock
w
t
su
t
h
T
A
NOTE 2: These are absolute voltage levels with respect to the ground pin of the device and include all overshoots due to system and/or tester
Supply voltage4.7555.25V
High-level input voltage (see Note 2)25.5V
Low-level input voltage (see Note 2)0.8V
High-level output current–3.2mA
Low-level output current24mA
Clock frequency0125MHz
Pulse duration, clockt
Setup time, input or feedback before clock↑4.5ns
Hold time, input or feedback after clock↑0ns
Operating free-air temperature02575°C
noise. Testing these parameters should not be attempted without suitable equipment.
CIRCUITS
High4
Low4
MINNOMMAXUNIT
ns
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.
12
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
Page 13
TIBPAL20R8-5C
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
electrical characteristics over recommended operating free-air temperature range
switching characteristicsover recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
FROM
(INPUT)
without feedback125125
§
f
max
t
pd
¶
t
pd
t
en
t
dis
t
r
t
f
t
sk(o)
†
All typical values are at VCC = 5 V, TA = 25°C.
‡
Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second. VO is set at 0.5 V to
avoid test problems caused by test equipment ground degradation.
§
See ’f
max
¶
This parameter is calculated from the measured f
#
t
is the skew time between registered outputs.
sk(o)
with internal feedback (counter configuration)125125MHz
with external feedback117111
CLK↑Q
CLK↑Q
CLK↑Internal feedback3.53.5ns
OE↓Q1.561.56ns
OE↑Q16.517ns
#
Specification’ near the end of this data sheet.
Skew between outputs0.50.5ns
TO
(OUTPUT)
with up to 4 outputs
switching
with more than 4
outputs switching
with internal feedback in a counter configuration (see Figure 4 for illustration).
max
TEST
CONDITIONS
R1 = 200 Ω,
R2 = 200 Ω,
See Figure 8
TIBPAL20R8-5CFN
MIN TYP†MAXMIN TYP†MAX
1.541.54
1.541.54.5
1.51.5ns
1.51.5ns
TIBPAL20R8-5CJT
TIBPAL20R8-5CNT
UNITPARAMETER
ns
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 • DALLAS, TEXAS 75265
13
Page 14
TIBPAL20L8-7M, TIBPAL20R4-7M, TIBPAL20R6-7M, TIBPAL20R8-7M
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
NOTE 1: These ratings apply except for programming pins during a programming cycle or during a preload cycle.
recommended operating conditions
V
CC
V
IH
V
IL
I
OH
I
OL
f
clock
†
w
†
t
su
†
t
h
T
A
†
f
clock
NOTE 2: These are absolute voltage levels with respect to the ground pin of the device and include all overshoots due to system and/or tester
Supply voltage4.555.5V
High-level input voltage (see Note 2)25.5V
Low-level input voltage (see Note 2)0.8V
High-level output current–2mA
Low-level output current12mA
†
Clock frequency0100MHz
Pulse duration, clockt
Setup time, input or feedback before clock↑7ns
Hold time, input or feedback after clock↑0ns
Operating free-air temperature–5525125°C
, tw, tsu, and th do not apply to TIBPAL16L8’
noise. Testing these parameters should not be attempted without suitable equipment.
CIRCUITS
High5
Low5
MINNOMMAXUNIT
ns
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other specifications
are design goals. Texas Instruments reserves the right to change or
discontinue these products without notice.
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
electrical characteristics over recommended operating free-air temperature range
PARAMETERTEST CONDITIONSMIN TYP†MAXUNIT
V
IK
V
OH
V
OL
I
OZH
I
OZL
I
I
I
IH
I
IL
I
OS
I
CC
i
C
o
†
All typical values are at VCC = 5 V, TA = 25°C.
‡
Not more than one output should be shorted at a time, and the duration of the short circuit should not exceed one second. VO is set at 0.5 V to
avoid test problems caused by test equipment ground degradation.
switching characteristicsover recommended ranges of supply voltage and operating free-air
temperature (unless otherwise noted)
PARAMETER
§
f
max
t
pd
t
pd
t
en
t
dis
t
en
t
dis
§
See ’f
and is calculated from the equation found in the f
Specification’ near the end of this data sheet. f
max
FROM
(INPUT)
without feedback100
with internal feedback
(counter configuration)
with external feedbackR1 = 390 Ω,74
I, I/OO, I/OR2 = 750 Ω,17ns
CLKQSee Figure 817ns
OE↓Q18ns
OE↑Q110ns
I, I/OO, I/O19ns
I, I/OO, I/O110ns
TO
(OUTPUT)
does not apply for TIBPAL20L8 ′. f
max
specifications section.
max
TEST CONDITIONMINMAXUNIT
100MHz
with external feedback is not production tested
max
PRODUCT PREVIEW information concerns products in the formative or
design phase of development. Characteristic data and other specifications
are design goals. Texas Instruments reserves the right to change or
discontinue these products without notice.
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
programming information
Texas Instruments programmable logic devices can be programmed using widely available software and
inexpensive device programmers.
Complete programming specifications, algorithms, and the latest information on hardware, software, and
firmware are available upon request. Information on programmers capable of programming T exas Instruments
programmable logic is also available, upon request, from the nearest TI field sales office, local authorized TI
distributor, or by calling Texas Instruments at (214) 997-5666.
asynchronous preload procedure for registered outputs (see Figure 1 and Note 3)
The output registers can be preloaded to any desired state during device testing. This permits any state to be
tested without having to step through the entire state-machine sequence. Each register is preloaded individually
by following the steps given below.
Step 1.With V
Step 2.Apply either VIL or VIH to the output corresponding to the register to be preloaded.
Step 3.Lower Pin 13 to 5 V.
Step 4.Remove output voltage, then lower Pin 13 to VIL. Preload can be verified by observing the
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
power-up reset, see Figure 2
Following power up, all registers are reset to zero. This feature provides extra flexibility to the system designer
and is especially valuable in simplifying state-machine initialization. To ensure a valid power-up reset, it is
important that the rise of VCC be monotonic. Following power-up reset, a low-to-high clock transition must not
occur until all applicable input and feedback setup times are met.
V
CC
Active Low
Registered Output
Clock
4 V
†
t
pd
(600 ns typ, 1000 ns MAX)
1.5 V
1.5 V
t
w
‡
t
su
5 V
V
V
V
V
OH
OL
IH
IL
†
This is the power-up reset time and applies to registered outputs only. The values shown are from characterization data.
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
without feedback, see Figure 3
f
max
In this mode, data is presented at the input to the flip-flop and clocked through to the Q output with no feedback.
Under this condition, the clock period is limited by the sum of the data setup time and the data hold time (t
However, the minimum fmax is determined by the minimum clock period (t
f
Thus,
without feedback
max
+
(twhigh
CIRCUITS
f
SPECIFICATIONS
max
1
)
twlow)
CLK
or
1
(tsu)
th)
high + tw low).
w
.
su
+ th).
f
with internal feedback, see Figure 4
max
Logic
Array
tsu + t
tw high + tw low
Figure 3. f
h
or
Without Feedback
max
C1
1D
This configuration is most popular in counters and on-chip state-machine designs. The flip-flop inputs are
defined by the device inputs and flip-flop outputs. Under this condition, the period is limited by the internal delay
from the flip-flop outputs through the internal feedback and logic array to the inputs of the next flip-flop.
Thus,
f
with internal feedback
max
+
(tsu)
1
tpdCLK*to*FB)
.
Where tpd CLK-to-FB is the deduced value of the delay from CLK to the input of the logic array.
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
f
SPECIFICATIONS
max
with external feedback, see Figure 5
f
max
This configuration is a typical state-machine design with feedback signals sent off-chip. This external feedback
could go back to the device inputs or to a second device in a multi-chip state machine. The slowest path defining
the period is the sum of the clock-to-output time and the input setup time for the external signals
+ tpd CLK-to-Q).
(t
su
Thus,
f
with external feedback
max
+
CLK
(tsu)
1
tpdCLK*to*Q)
.
CIRCUITS
Logic
Array
t
su
Figure 5. f
C1
1D
tpd CLK-to-Qt
With External Feedback
max
Next Device
su
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
19
Page 20
TIBPAL20R8-5C
HIGH-PERFORMANCE IMPACT-X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
THERMAL INFORMATION
thermal management of the TIBPAL20R8-5C
Thermal management of the TIBPAL20R8-5CNT and TIBPAL20R8-5CFN is necessary when operating at
certain conditions of frequency , output loading, and outputs switching simultaneously. The device and system
application will determine the appropriate level of management.
CIRCUITS
Determining the level of thermal management is based on factors such as power dissipation (P
), ambient
D
temperature (TA), and transverse airflow (FPM). Figures 6 (a) and 6 (b) show the relationship between ambient
temperature and transverse airflow at given power dissipation levels. The required transverse airflow can be
determined at a particular ambient temperature and device power dissipation level in order to ensure the device
specifications.
Figure 7 illustrates how power dissipation varies as a function of frequency and the number of outputs switching
simultaneously . It should be noted that all outputs are fully loaded (C
= 50 pF). Since the condition of eight fully
L
loaded outputs represents the worst-case condition, each application must be evaluated accordingly.
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
PARAMETER MEASUREMENT INFORMATION
From Output
Under Test
CIRCUITS
5 V
S1
R1
Test
Point
Timing
Input
Data
Input
Input
In-Phase
Output
Out-of-Phase
Output
(see Note D)
1.5 V
t
su
1.5 V
VOLTAGE WAVEFORMS
SETUP AND HOLD TIMES
1.5 V1.5 V
t
pd
80 %
20 %
t
pd
20 %
80 %
VOLTAGE WAVEFORMS
PROPAGATION DELAY TIMES
1.5 V
1.5 V1.5 V
1.5 V
t
r
t
f
(see Note A)
t
h
t
pd
1.5 V
t
f
t
pd
t
r
C
L
LOAD CIRCUIT FOR
3-STATE OUTPUTS
3 V
0
3 V
0
(see Note B)
3 V
0
V
OH
V
OL
V
OH
V
OL
R2
High-Level
Pulse
Low-Level
Pulse
Output
Control
(low-level
enabling)
Waveform 1
S1 Closed
(see Note C)
Waveform 2
S1 Open
(see Note C)
1.5 V1.5 V
t
1.5 V1.5 V
VOLTAGE WAVEFORMS
PULSE DURATIONS
1.5 V1.5 V
t
en
t
en
t
1.5 V
1.5 V
t
dis
dis
3 V
0
w
3 V
0
(see Note B)
3 V
0
(see Note B)
≈ 2.7 V
VOL + 0.5 V
V
OL
V
OH
VOH – 0.5 V
≈ 0 V
ENABLE AND DISABLE TIMES, 3-STATE OUTPUTS
NOTES: A. CL includes probe and jig capacitance and is 50 pF for tpd and ten, 5 pF for t
B. All input pulses have the following characteristics: For C suffix, PRR ≤ 1 MHz, tr = tf = 2 ns, duty cycle = 50%; For M suffix,
PRR ≤ 10 MHz, tr = tf ≤ 2 ns, duty cycle = 50%
C. W aveform 1 is for an output with internal conditions such that the output is low except when disabled by the output control. Waveform 2
is for an output with internal conditions such that the output is high except when disabled by the output control.
D. When measuring propagation delay times of 3-state outputs, switch S1 is closed.
E. Equivalent loads may be used for testing.
Figure 8. Load Circuit and Voltage Waveforms
22
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
VOLTAGE WAVEFORMS
.
dis
Page 23
TIBPAL20R4-5C, TIBPAL20R6-5C, TIBPAL20R8-5C
C1
CIRCUITS
HIGH-PERFORMANCE IMPACT -X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
metastable characteristics of TIBPAL20R4-5C, TIBPAL20R6-5C, and TIBPAL20R8-5C
At some point a system designer is faced with the problem of synchronizing two digital signals operating at two
different frequencies. This problem is typically overcome by synchronizing one of the signals to the local clock
through use of a flip-flop. However, this solution presents an awkward dilemma since the setup and hold time
specifications associated with the flip-flop are sure to be violated. The metastable characteristics of the flip-flop
can influence overall system reliability.
Whenever the setup and hold times of a flip-flop are violated, its output response becomes uncertain and is said
to be in the metastable state if the output hangs up in the region between V
lasts until the flip-flop falls into one of its two stable states, which takes longer than the specified maximum
propagation delay time (CLK to Q max).
From a system engineering standpoint, a designer cannot use the specified data sheet maximum for
propagation delay time when using the flip-flop as a data synchronizer – how long to wait after the specified data
sheet maximum must be known before using the data in order to guarantee reliable system operation.
The circuit shown in Figure 9 can be used to evaluate MTBF (Mean Time Between Failure) and ∆t for a selected
flip-flop. Whenever the Q output of the DUT is between 0.8 V and 2 V , the comparators are in opposite states.
When the Q output of the DUT is higher than 2 V or lower than 0.8 V , the comparators are at the same logic level.
The outputs of the two comparators are sampled a selected time (∆t) after SCLK. The exclusive OR gate detects
the occurrence of a failure and increments the failure counter.
1D
DUT
C1
V
IH
Comparator
V
IL
Comparator
1D
C1
1D
C1
Noise
Generator
Data in
SCLK
and VIH. This metastable condition
IL
1D
MTBF
Counter
+
SCLK + ∆t
Figure 9. Metastable Evaluation Test Circuit
In order to maximize the possibility of forcing the DUT into a metastable state, the input data signal is applied
so that it always violates the setup and hold time. This condition is illustrated in the timing diagram in Figure 10.
Any other relationship of SCLK to data will provide less chance for the device to enter into the metastable state.
Data
SCLK
SCLK + ∆t
MTBF
t
rec
Time (sec)
+
# Failures
= ∆t – CLK to Q (max)
∆t
∆t
Figure 10. Timing Diagram
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
23
Page 24
TIBPAL20R4-5C, TIBPAL20R6-5C, TIBPAL20R8-5C
HIGH-PERFORMANCE IMPACT -X PAL
SRPS010F – D3353, OCTOBER 1989 – REVISED SEPTEMBER 1992
By using the described test circuit, MTBF can be determined for several different values of ∆t (see Figure 9).
Plotting this information on semilog scale demonstrates the metastable characteristics of the selected flip-flop.
Figure 11 shows the results for the TIBPAL20’-5C operating at 1 MHz.
9
10
10
10
10
10
MTBF (s)
10
10
10
10
10 yr
8
1 yr
7
1 mo
6
1 wk
5
1 day
4
1 hr
3
2
1 min
10 s
1
0 10203040506070
CIRCUITS
∆t (ns)
f
clk
f
data
= 1 MHz
= 500 kHz
Figure 11. Metastable Characteristics
From the data taken in the above experiment, an equation can be derived for the metastable characteristics at
other clock frequencies.
The metastable equation:
1
MTBF
+
f
SCLK
xf
data
xC1e
(*C2 xDt)
The constants C1 and C2 describe the metastable characteristics of the device. From the experimental data,
–3
these constants can be solved for: C1 = 4.37 X 10
and C2 = 2.01
Therefore
MTBF
1
+
f
SCLK
xf
x4.37x10
data
*
3e(*2.01 xDt)
definition of variables
DUT (Device Under Test): The DUT is a 5-ns registered PLD programmed with the equation Q : = D.
MTBF (Mean Time Between Failures): The average time (s) between metastable occurrences that cause a
violation of the device specifications.
f
(system clock frequency): Actual clock frequency for the DUT.
SCLK
f
(data frequency): Actual data frequency for a specified input to the DUT.
data
C1: Calculated constant that defines the magnitude of the curve.
C2: Calculated constant that defines the slope of the curve.
t
(metastability recovery time): Minimum time required to guarantee recovery from metastability , at a given
rec
MTBF failure rate. t
∆t: The time difference (ns) from when the synchronizing flip-flop is clocked to when its output is sampled.
= ∆t – tpd (CLK to Q, max)
rec
The test described above has shown the metastable characteristics of the TIBP AL20R4/R6/R8-5C series. For
additional information on metastable characteristics of Texas Instruments logic circuits, please refer to TI
Applications publication SDAA004, ”Metastable Characteristics, Design Considerations for ALS, AS, and LS
Circuits.’’
T exas Instruments and its subsidiaries (TI) reserve the right to make changes to their products or to discontinue
any product or service without notice, and advise customers to obtain the latest version of relevant information
to verify, before placing orders, that information being relied on is current and complete. All products are sold
subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those
pertaining to warranty, patent infringement, and limitation of liability.
TI warrants performance of its semiconductor products to the specifications applicable at the time of sale in
accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
TI deems necessary to support this warranty . Specific testing of all parameters of each device is not necessarily
performed, except those mandated by government requirements.
CERTAIN APPLICA TIONS USING SEMICONDUCT OR PRODUCTS MAY INVOLVE POTENTIAL RISKS OF
DEATH, PERSONAL INJURY, OR SEVERE PROPERTY OR ENVIRONMENTAL DAMAGE (“CRITICAL
APPLICATIONS”). TI SEMICONDUCTOR PRODUCTS ARE NOT DESIGNED, AUTHORIZED, OR
WARRANTED TO BE SUITABLE FOR USE IN LIFE-SUPPORT DEVICES OR SYSTEMS OR OTHER
CRITICAL APPLICA TIONS. INCLUSION OF TI PRODUCTS IN SUCH APPLICATIONS IS UNDERST OOD TO
BE FULLY AT THE CUSTOMER’S RISK.
In order to minimize risks associated with the customer’s applications, adequate design and operating
safeguards must be provided by the customer to minimize inherent or procedural hazards.
TI assumes no liability for applications assistance or customer product design. TI does not warrant or represent
that any license, either express or implied, is granted under any patent right, copyright, mask work right, or other
intellectual property right of TI covering or relating to any combination, machine, or process in which such
semiconductor products or services might be or are used. TI’s publication of information regarding any third
party’s products or services does not constitute TI’s approval, warranty or endorsement thereof.
Copyright 1998, Texas Instruments Incorporated
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