HD74LS194A Datasheet, PDF (1/8 Pages) Hitachi Semiconductor – 4-bit Bidirectional Universal Shift Registers

HD74LS194A
4-bit Bidirectional Universal Shift Register
REJ03D0456–0300
Rev.3.00
Jul.15.2005
The bidirectional shift register is designed to incorporate virtually all of the features a system designer may want in a
shift register. The circuit contains 46 equivalent gates and features parallel inputs, parallel outputs, right-shift and left-
shift serial inputs. Operating-mode-control inputs, and a direct overriding clear line. The register has four distinct
modes of operation, namely;
• Parallel (broadside) load
• Shift right (in the direction Q_A toward Q_D)
• Shift left (in the direction Q_D toward Q_A)
• Inhibit clock (do nothing)
Synchronous parallel loading is accomplished by applying the four bits of data and taking both mode control inputs, S₀
and S₁, high. The data are loaded into the associated flip-flops and appear at the outputs after the positive transition of
the clock input. During loading, serial data flow is inhibited. Shift right is accomplished synchronously with the rising
edge of the clock pulse when S₀ is high and S₁ is low. Serial data for this mode is entered at the shift-right data input.
When S₀ is low and S₁ is high, data shifts left synchronously and new data is entered at the shift-left serial input.
Clocking of the flip-flop is inhibited when both mode control inputs are low.
• Ordering Information
Part Name
Package Type
Package Code
(Previous Code)
Package
Abbreviation
HD74LS194AP
DILP-16 pin
PRDP0016AE-B
(DP-16FV)
P
HD74LS194AFPEL SOP-16 pin (JEITA)
PRSP0016DH-B
FP
(FP-16DAV)
Note: Please consult the sales office for the above package availability.
Taping Abbreviation
(Quantity)
—
EL (2,000 pcs/reel)
Pin Arrangement
Clear 1
Shift Right
Serial Input
2
A3
Parallel ^{B 4}
Inputs _{C 5}
D6
Shift Left
Serial Input
7
GND 8
CLR
R
Q_A
A
Q_B
B
Q_C
C
Q_D
D _CK
L
S₁
S₀
(Top view)
16 V_CC
15 Q_A
14 Q_{B Parallel}
13 _QC ^Outputs
12 Q_D
11 _Clock
10 _S1
9 S₀
Mode
Control
Rev.3.00, Jul.15.2005, page 1 of 7