JBL ES250PW, Service Manual

Page: 33 / 56

Philips Semiconductors Product specification
8-bit parallel-in/serial-out shift register 74HC/HCT165
FEATURES
•
Asynchronous 8-bit parallel load
•
Synchronous serial input
•
Output capability: standard
•
I
CC
category: MSI
GENERAL DESCRIPTION
The 74HC/HCT165 are high-speed Si-gate CMOS devices
and are pin compatible with low power Schottky TTL
(LSTTL). They are specified in compliance with JEDEC
standard no. 7A.
The 74HC/HCT165 are 8-bit parallel-load or serial-in shift
registers with complementary serial outputs (Q
7
and
Q
7
) available from the last stage. When the parallel load
(PL) input is LOW, parallel data from the D
0
to
D
7
inputs are loaded into the register asynchronously.
When PL is HIGH, data enters the register serially at the
D
s
input and shifts one place to the right
(Q
0
→
Q
1
→
Q
2
, etc.) with each positive-going clock
transition. This feature allows parallel-to-serial converter
expansion by tying the Q
7
output to the D
S
input of the
succeeding stage.
The clock input is a gated-OR structure which allows one
input to be used as an active LOW clock enable (CE) input.
The pin assignment for the CP and CE inputs is arbitrary
and can be reversed for layout convenience. The
LOW-to-HIGH transition of input CE should only take
place while CP HIGH for predictable operation. Either the
CP or the CE should be HIGH before the
LOW-to-HIGH transition of PL to prevent shifting the data
when PL is activated.
APPLICATIONS
•
Parallel-to-serial data conversion
QUICK REFERENCE DATA
GND = 0 V; T
amb
= 25
°
C; t
r
= t
f
= 6 ns
Notes
1. C
PD
is used to determine the dynamic power dissipation (P
D
in
µ
W):
P
D
= C
PD
×
V
CC
2
×
f
i
+ ∑
(C
L
×
V
CC
2
×
f
o
) where:
f
i
= input frequency in MHz
f
o
= output frequency in MHz
∑
(C
L
×
V
CC
2
×
f
o
) = sum of outputs
C
L
= output load capacitance in pF
V
CC
= supply voltage in V
2. For HC the condition is V
I
= GND to V
CC
For HCT the condition is V
I
= GND to V
CC
−
1.5 V
ORDERING INFORMATION
See
“74HC/HCT/HCU/HCMOS Logic Package Information”
.
SYMBOL PARAMETER CONDITIONS
TYPICAL
UNIT
HC HCT
t
PHL
/ t
PLH
propagation delay
CP to Q
7,
Q
7
PL to Q
7,
Q
7
D
7
to Q
7,
Q
7
C
L
= 15 pF; V
CC
= 5 V
16
15
11 14
17
11 ns
ns
ns
f
max
maximum clock frequency 56 48 MHz
C
I
input capacitance 3.5 3.5 pF
C
PD
power dissipation capacitance per
package notes 1 and 2 35 35 pF
ES250PW
32
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