
1
Standard ICs
8-bit static shift register
BU4021B / BU4021BF
The BU4021B and BU4021BF are 8-bit static shift registers consisting of 8 register cells, each of which has parallel
input. Control of the parallel / serial control input (P / S) enables serial input / serial output with clock synchronization,
as well as parallel input / serial output conversions.
•
Logic circuit diagram
•
Truth table
Serial operation
D
Ds
(11)
P / S
(9)
CLOCK
(10)
Q
C
DQCDQ
C
DQ
C
DQCDQ
Q
C
DQ
Q
C
D
Q
C
(2)
Q
6
P8
(1)
P
7
(15)
P
6
(14)
P
5
(13)
P
4
(4)
P
3
(5)
P
2
(6)
P
1
(7)
(12)
Q
7
(3)
Q
8
t CLOCK
nLL0??
n + 1HL10?
n + 2 LL010
n + 3 HL101
XL
Q
6
Q
7
Q
8
Q
6
Q
7
Q
8
DSP / S
(t = n + 6) (t = n + 7) (t = n + 8)
2
Q
6
P8
P4
P3
P2
P1
Q8
3
4
5
6
7
8
15
14
13
12
11
10
9
V
SS
1
P
7
VDD
P5
Q7
DS
CLOCK
P
6
P / S
16
Q6
P8
P4
P3
P2
P1
Q8
P7
P5
Q7
DS
CLOCK
P
6
P / S
CLOCK
XHL L
XHH H
DS Dm Qm
∗
X: Irrelevant
∗
: Q6, Q7, and Q8 are external
P / S
•
Absolute maximum ratings (VSS = 0V, Ta = 25°C)
Parameter Symbol Limits Unit
Power supply voltage V
DD V
Power dissipation mW
Operating temperature Topr
°C
Storage temperature Tstg °C
Input voltage V
IN – 0.3 ~ VDD + 0.3 V
1000 (DIP), 500 (SOP) Pd
– 0.3 ~ + 18
– 40 ~ + 85
– 55 ~ + 150

2
Standard ICs BU4021B / BU4021BF
Parameter Symbol Min. Typ. Max. Unit Conditions
Input high level voltage V
IH
3.5 ——
V
5
—7.0 —— 10
11.0 —— 15
Input low level voltage V
IL
——1.5
V
5
———3.0 10
——4.0 15
Input high level current I
IH ——0.3 µ
A15V
IH = 15V
Input low level current I
IL ——– 0.3 µ
A15V
IL = 0V
Output high level voltage V
OH
4.95 ——
V
5
I
O = 0mA9.95 —— 10
14.95 —— 15
Output low level voltage V
OL
——0.05
V
5
I
O = 0mA——0.05 10
——0.05 15
Output high level current I
OH
– 0.16 ——
mA
5VOH = 4.6V
– 0.4 —— 10 V
OH = 9.5V
– 1.2 —— 15 V
OH = 13.5V
Output low level current I
OL
0.44 ——
mA
5VOL = 0.4V
1.1 —— 10 V
OL = 0.5V
3.0 —— 15 V
OL = 1.5V
Static current dissipation I
DD
——20
µ
A
5
V
I = VDD, GND——40 10
——80 15
V
DD (V)
•
Electrical characteristics
DC characteristics (unless otherwise noted, Ta = 25°C, V
SS = 0V)

3
Standard ICs BU4021B / BU4021BF
Output fall time
Parameter Symbol Min. Typ. Max. Unit Conditions
Measurement
circuit
VDD (V)
t
TLH
—
180
—
ns
5
—
Fig.1
—
90
—
10
—
65
—
15
t
THL
—
100
—
ns
5
—
Fig.1
—
50
—
10
—
40
—
15
t
PLH
—
400
—
ns
5
—
Fig.1
—
170
—
10
—
115
—
15
t
PHL
—
400
—
ns
5
—
Fig.1
—
170
—
10
—
115
—
15
Setup time t
su
—
150
—
ns
5
—
Fig.1
—
50
—
10
—
30
—
15
Minimum clock
pulse width
t
W (CLK
)
—
150
—
ns
5
—
Fig.1
—
75
—
10
—
40
—
15
Maximum clock
frequency
f
(
CLK) Max.
—
3.0
—
MHz
5
—
Fig.1
—
6.0
—
10
—
8.0
—
15
Maximum clock
rise / fall time
t
r (CLK
)
t
f (CLK
)
——
15
µ
s
5
—
Fig.1
——
5.0 10
——
4.0 15
Minimum P / S
control pulse width
t
w (P / S
)
—
150
—
ns
5
———
75
—
10
—
40
—
15
Input capacitance C
IN
—
5
—
pF
—— —
"L" to "H"
propagation delay time
CLOCK to Q, P / S to Q
"H" to "L"
propagation delay time
CLOCK to Q, P / S to Q
Output rise time
Switching characteristics (unless otherwise noted, VSS = 0V, Ta = 25°C, CL = 50pF)

4
Standard ICs BU4021B / BU4021BF
SW2
CL
VDD
SW1
P.G.
P.G.
P / S
CLK
P
1
P2
P3
P4
P5
P6
P7
P8
DS
Q6
Q7
Q8
VSS
Fig.1 Switching characteristics measurement circuit
GND
20ns 20ns
tsu
tw
VDD
tr
Parallel or
Serial Data
CLOCK or P / S
OUTPUT
t
PLH
tf
tTLH tTHL
tPHL
90%
50%
10%
GND
VDD
GND
VOH
VOL
Fig.2 Switching characteristics waveform
POWER DISSIPATION: Pd (mW)
1200
1000
800
600
400
200
0
0255075100125150
AMBIENT TEMPERATURE: Ta (°C)
SOP16
DIP16
Fig.3 Power dissipation vs.
ambient temperature
•
Electrical characteristic curve

5
Standard ICs BU4021B / BU4021BF
DIP16 SOP16
BU4021B BU4021BF
0.51Min.
0.3
± 0.1
916
81
6.5 ± 0.3
3.2
±
0.2
4.25
±
0.3
0.5 ± 0.1
19.4 ± 0.3
2.54
0° ~ 15°
7.62
0.4 ± 0.11.27
0.15
0.15 ± 0.1
0.3Min.
4.4 ± 0.2
6.2 ± 0.3
0.11
1.5 ± 0.1
1
16
10.0 ± 0.2
8
9
•
External dimensions (Units: mm)