5-1
FAST AND LS TTL DATA
4 x 4 REGISTER FILE
OPEN-COLLECTOR
The TTL / MSI SN54 / 74LS170 is a high-speed, low-power 4 x 4 Register
File organized as four words by four bits. Separate read and write inputs, both
address and enable, allow simultaneous read and write operation.
Open-collector outputs make it possible to connect up to 128 outputs in a
wired-AND configuration to increase the word capacity up to 512 words. Any
number of these devices can be operated in parallel to generate an n-bit
length.
The SN54 / 74LS670 provides a similar function to this device but it features
3-state outputs.
Simultaneous Read / Write Operation
Expandable to 512 Words of n-Bits
Typical Access Time of 20 ns
Low Leakage Open-Collector Outputs for Expansion
Typical Power Dissipation of 125 mW
NOTE:
The Flatpak version
has the same pinouts
(Connection Diagram) as
the Dual In-Line Package.
CONNECTION DIAGRAM DIP (TOP VIEW)
14
13
12
11
10
9
1
2
3
4
5
6
7
16
15
8
VCC
D2
D1
WA
WB
EW
Q1
ER
Q2
D3
D4
RB
RA
Q4
Q3
GND
PIN NAMES
LOADING (Note a)
HIGH
LOW
D1 D4
WA, WB
EW
RA, RB
ER
Q1 Q4
Data Inputs
Write Address Inputs
Write Enable (Active LOW) Input
Read Address Inputs
Read Enable (Active LOW) Input
Outputs (Note b)
0.5 U.L.
0.5 U.L.
1.0 U.L.
0.5 U.L.
1.0 U.L.
Open-Collector
0.25 U.L.
0.25 U.L.
0.5 U.L.
0.25 U.L.
0.5 U.L.
5 (2.5) U.L.
NOTES:
a. 1 TTL Unit Load (U.L.) = 40
A HIGH/1.6 mA LOW.
b. The Output LOW drive factor is 2.5 U.L. for Military (54) and 5 U.L. for Commercial (74)
b.
Temperature Ranges. The Output HIGH drive must be supplied by an external resistor to VCC.
SN54/74LS170
4 x 4 REGISTER FILE
OPEN-COLLECTOR
LOW POWER SCHOTTKY
J SUFFIX
CERAMIC
CASE 620-09
N SUFFIX
PLASTIC
CASE 648-08
16
1
16
1
ORDERING INFORMATION
SN54LSXXXJ
Ceramic
SN74LSXXXN
Plastic
SN74LSXXXD
SOIC
16
1
D SUFFIX
SOIC
CASE 751B-03
LOGIC SYMBOL
VCC = PIN 16
GND = PIN 8
12
15 1 2 3
13
14
4
5
11
10 9
7 6
EW
WA
WB
RB
RA
ER
D2 D3 D4
D1
Q4
Q3
Q1 Q2
5-2
FAST AND LS TTL DATA
SN54/74LS170
LOGIC DIAGRAM
D2
D3
D4
RB
RA
Q4
Q3
D1
WA
WB
EW
ER
Q1
Q2
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
G
D
Q
D
G
D
Q
WORD
0
WORD
1
WORD
2
WORD
3
14
1
2
6
7
3
4
5
9
11
12
10
13
15
G
D
Q
VCC = PIN 16
GND = PIN 8
= PIN NUMBERS
5-3
FAST AND LS TTL DATA
SN54/74LS170
WRITE FUNCTION TABLE (SEE NOTES A, B, AND C)
READ FUNCTION TABLE (SEE NOTES A AND D)
WRITE INPUTS
WORD
READ INPUTS
OUTPUTS
WB
WA
EW
0
1
2
3
RB
RA
ER
Q1
Q2
Q3
Q4
L
L
L
Q = D
Q0
Q0
Q0
L
L
L
W0B1
W0B2
W0B3
W0B4
L
H
L
Q0
Q = D
Q0
Q0
L
H
L
W1B1
W1B2
W1B3
W1B4
H
L
L
Q0
Q0
Q = D
Q0
H
L
L
W2B1
W2B2
W2B3
W2B4
H
H
L
Q0
Q0
Q0
Q = D
H
H
L
W3B1
W3B2
W3B3
W3B4
X
X
H
Q0
Q0
Q0
Q0
X
X
H
H
H
H
H
NOTES: A. H = HIGH Level. L = LOW Level, X = Irrelevant.
NOTES:
B. (Q = D) = The four selected internal flip-flop outputs will assume the states applied to the four external data inputs.
NOTES:
C. Q0 = the level of Q before the indicated input conditions were established.
NOTES:
D. W0B1 = The first bit of word 0, etc.
GUARANTEED OPERATING RANGES
Symbol
Parameter
Min
Typ
Max
Unit
VCC
Supply Voltage
54
74
4.5
4.75
5.0
5.0
5.5
5.25
V
TA
Operating Ambient Temperature Range
54
74
55
0
25
25
125
70
C
VOH
Output Voltage -- High
54, 74
5.5
V
IOL
Output Current -- Low
54
74
4.0
8.0
mA
DC CHARACTERISTICS OVER OPERATING TEMPERATURE RANGE
(unless otherwise specified)
Symbol
Parameter
Limits
Unit
Test Conditions
Symbol
Parameter
Min
Typ
Max
Unit
Test Conditions
VIH
Input HIGH Voltage
2.0
V
Guaranteed Input HIGH Voltage for
All Inputs
VIL
Input LOW Voltage
54
0.7
V
Guaranteed Input LOW Voltage for
All Inputs
VIL
Input LOW Voltage
74
0.8
V
Guaranteed Input LOW Voltage for
All Inputs
VIK
Input Clamp Diode Voltage
0.65
1.5
V
VCC = MIN, IIN = 18 mA
IOH
Output HIGH Current
54, 74
100
A
VCC = MIN, VOH = MAX
VOL
Output LOW Voltage
54, 74
0.25
0.4
V
IOL = 4.0 mA
VCC = VCC MIN,
VIN = VIL or VIH
per Truth Table
VOL
Output LOW Voltage
74
0.35
0.5
V
IOL = 8.0 mA
VIN = VIL or VIH
per Truth Table
IIH
Input HIGH Current
Any D, R, W
ER, EW
20
40
A
VCC = MAX, VIN = 2.4 V
IIH
Any D, R, W
ER, EW
0.1
0.2
mA
VCC = MAX, VIN = 7.0 V
IIL
Input LOW Current
Any D, R, W
ER, EW
0.4
0.8
mA
VCC = MAX, VIN = 0.4 V
ICC
Power Supply Current
40
mA
VCC = MAX
5-4
FAST AND LS TTL DATA
SN54/74LS170
AC CHARACTERISTICS
(TA = 25
C)
Symbol
Parameter
Limits
Unit
Test Conditions
Symbol
Parameter
Min
Typ
Max
Unit
Test Conditions
tPLH
tPHL
Propagation Delay, Negative-
Going ER to Q Outputs
20
20
30
30
ns
Figure 1
VCC = 5.0 V
CL = 15 pF
RL = 2.0 k
tPLH
tPHL
Propagation Delay, RA or RB
to Q Outputs
25
24
40
40
ns
Figure 2
VCC = 5.0 V
CL = 15 pF
RL = 2.0 k
tPLH
tPHL
Propagation Delay, Negative-
Going EW to Q Outputs
30
26
45
40
ns
Figure 1
CL = 15 pF
RL = 2.0 k
tPLH
tPHL
Propagation Delay, Data Inputs
to Q Outputs
30
22
45
35
ns
Figure 1
AC SETUP REQUIREMENTS
(TA = 25
C)
Symbol
Parameter
Limits
Unit
Test Conditions
Symbol
Parameter
Min
Typ
Max
Unit
Test Conditions
tW
Pulse Width, ER, EW
25
ns
VCC = 5.0 V
RL = 2.0 k
ts
Setup Time, Data to EW
10
ns
VCC = 5.0 V
RL = 2.0 k
ts
Setup Time, WA, WB to EW
15
ns
VCC = 5.0 V
RL = 2.0 k
th
Hold Time, Data to EW
15
ns
VCC = 5.0 V
RL = 2.0 k
th
Hold Time, WA, WB to EW
5.0
ns
tLATCH
Latch Time
25
ns
VOLTAGE WAVEFORMS
Figure 1
Figure 2
WRITE-SELECT
INPUT WA or WB
DATA INPUT
D1, D2, D3 or D4
WRITE-ENABLE
INPUT EW
READ-SELECT
INPUT RA or RB
READ-ENABLE
INPUT ER
OUTPUT
Q1, Q2, Q3 or Q4
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
Vref
3 V
0 V
3 V
3 V
3 V
3 V
0 V
0 V
0 V
0 V
VOH
VOL
tPHL
tPLH
3 V
0 V
3 V
3 V
3 V
3 V
0 V
0 V
0 V
VOH
VOL
0 V
DATA INPUT
D1, D2, D3 or D4
WRITE-ENABLE
INPUT EW
OUTPUT
Q1, Q2, Q3 or Q4
DATA INPUT
D1, D2, D3 or D4
WRITE-ENABLE
INPUT EW
OUTPUT
Q1, Q2, Q3 or Q4
tsu(W)
th(W)
th(D)
tsu(D)
tPHL
tPLH
tPLH
tPLH
tPHL
tW
tPHL
tlatch
tw
Vref
Vref
Vref
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