Document
TC74VHCT138AF/AFK
TOSHIBA CMOS Digital Integrated Circuit Silicon Monolithic
TC74VHCT138AF, TC74VHCT138AFK
3-to-8 Line Decoder
TC74VHCT138AF
The TC74VHCT138 is an advanced high speed CMOS 3-to-8 LINE DECODER fabricated with silicon gate C2MOS technology. It achieves the high speed operation similar to equivalent Bipolar Schottky TTL while maintaining the CMOS low power dissipation.
When the device is enabled, 3 Binary Select inputs (A, B and C) determine which one of the outputs ( Y0 to Y7 ) will go low.
When enable input G1 is held low or either G2A or G2B is held high, decoding function is inhibited and all outputs go high. G1, G2A , and G2B inputs are provided to ease cascade connection and for use as an address decoder for memory systems.
The input voltage are compatible with TTL output voltage. This device may be used as a level converter for interfacing 3.3 V to 5 V system. Input protection and output circuit ensure that 0 to 5.5 V can be applied to the input and output (Note) pins without regard to the supply voltage. These structure prevents device destruction due to mismatched supply and input/output voltages such as battery back up, hot board insertion, etc.
Note: VCC = 0 V
Features
TC74VHCT138AFK
Weight SOP16-P-300-1.27A VSSOP16-P-0030-0.50
High speed: tpd = 7.6 ns (typ.) at VCC = 5 V
Low power dissipation: ICC = 4 μA (max) at Ta = 25°C
Compatible with TTL inputs:
VIL = 0.8 V (max) VIH = 2.0 V (min)
Power down protection is provided on all inputs and outputs
Balanced propagation delays: tpLH ≈ tpHL
Pin and function compatible with the 74 series (74AC/HC/F/ALS/LS etc.) 138 type.
: 0.18 g (typ.) : 0.02 g (typ.)
© 2019
1
Toshiba Electronic Devices & Storage Corporation
Start of commercial production
1995-12
2019-01-31
Pin Assignment
TC74VHCT138AF/AFK
A1 B2 C3
4 5 G1 6 7 GND 8
(top view)
16 VCC 15 14 13 12 11 10 9
IEC Logic Symbol
A (1)
BIN/OCT
1
0
(15)
B (2)
2
1
(14)
C (3)
4
2
(13)
3
(12)
G1 (6)
&
4
(11)
5
(10)
(4)
EN
6
(9)
(5)
7
(7)
A (1)
DMUX
0
0
(15)
B (2)
1
(14)
C (3)
2
2
(13)
3
(12)
G1 (6)
&
4
(11)
5
(10)
(4)
6
(9)
(5)
7
(7)
Truth Table
Inputs
Enable
Select
G1 G2A G2B C
B
A
L
X
X
X
X
X
X
H
X
X
X
X
X
X
H
X
X
X
H
L
L
L
L
L
H
L
L
L
L
H
H
L
L
L
H
L
H
L
L
L
H
H
H
L
L
H
L
L
H
L
L
H
L
H
H
L
L
H
H
L
H
L
L
H
H
H
X: Don’t care
Outputs
Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
L
H
H
H
H
H
H
H
H
L
Selected Output
None None None
Y0 Y1 Y2 Y3 Y4 Y5 Y6 Y7
© 2019
2
Toshiba Electronic Devices & Storage Corporation
2019-01-31
System Diagram
1 A
Select inputs
2 B
3 C
Enable inputs
4 5 6 G1
TC74VHCT138AF/AFK
15
14
13
12
Data
11
outputs
10
9
7
Absolute Maximum Ratings (Note 1)
Characteristics
Symbol
Rating
Unit
Supply voltage range DC input voltage
DC output voltage
Input diode current Output diode current DC output current DC VCC/ground current Power dissipation Storage temperature
VCC VIN
VOUT
IIK IOK IOUT ICC PD Tstg
−0.5 to 7.0
V
−0.5 to 7.0
V
−0.5 to 7.0
(Note 2)
V
−0.5 to VCC + 0.5 (Note 3)
−20
mA
±20
(Note 4) mA
±25
mA
±75
mA
180
mW
−65 to 150
°C
Note 1:
Exceeding any of the absolute maximum ratings, even briefly, lead to deterioration in IC performance or even destruction. Using continuously under heavy loads (e.g. the application of high temperature/current/voltage and the significant change in temperature, etc.) may cause this product to decrease in the reliability significantly even if the operating conditions (i.e. operating temperature/current/voltage, etc.) are within the absolute maximum ratings and the operating ranges. Please design the appropriate reliability upon reviewing the Toshiba Semiconductor Reliability Handbook (“Handling Precautions”/“Derating Concept and Methods”) and individual reliability data (i.e. reliability test report and estimated failure rate, etc).
Note 2: VCC = 0 V
Note 3: High or low state. IOUT absolute maximum rating must be observed.
Note 4: VOUT GND, VOUT VCC
© 2019
3
Toshiba Electronic Devices & Storage Corporation
2019-01-31
Operating Ranges (Note 1)
TC74VHCT138AF/AFK
Characteristics
Symbol
Rating
Unit
Supply voltage Input voltage
Output voltage
Operating temperature Input rise and fall time
VCC VIN
VOUT
Topr dt/dV
4.5 to 5.5 0 to 5.5 0 to 5.5 0 to VCC −40 to 85 0 to 20
(Note 2) (Note 3)
V V
V
°C ns/V
Note 1: The operating ranges must be maintained to ensure the normal operation of the device. Unused inputs must be tied to either VCC or GND.
Note 2: VCC = 0 V Note 3: High or low state
Electrical Characteristics
DC Characteristics
Characteristics
Symbol
Test C.