
BU2508FV,BU2507FV
Technical Note
3/8
www.rohm.com
2011.08 - Rev.C
2011 ROHM Co., Ltd. All rights reserved.
●DAC Variable Output Range Function
With the variable output range function, the upper / lower limits of the output voltage as well as the power supply voltage can be set.
The upper limit value setting terminal VrefH is used as the power supply terminal, while the lower limit value setting terminal
VrefL is used as the GND terminal (1LSB ≒ 5mV). In the example below, VrefH = 3.5V / VrefL = 1.5V.
Further adjustments
can be made in order to achieve greater accuracy (1LSB ≒ 2mV).
●Block Diagrams
BU2507FV
BU2508FV
Input Code
3FFh
VOUT
5V
0V
1024
ステップ
Input Code
3FFh
VOUT
5V
0V
1024
ステップ
3.5V
1.5V
VrefH
VrefL
1LSB≒5.0mV
1LSB≒2.0mV
step
14bi
t
シフ
トレ
ジ
ス
タ
10
bi
tR
-2
R
D/
A
10
b
it
L
a
tc
h
CH
1
··
·
CH
2
10
b
it
L
a
tc
h
10
bi
tR
-2
R
D/
A
D0
1
2
3
4
5
6
D9
D1
0
11
12
D1
3
5
L
D/A
3
L
D/
A
7
6
5
4
3
2
1
AO
5
AO
4
Rese
t
AO
3
AO
2
VS
S
(Vre
fL
)
8
9
10
11
12
13
14
AO
6
LD
CL
K
DI
AO1
GN
D
7
8
VD
D
(Vr
ef
H
)
VC
C
4
L
D/A
L
6
14bi
t
シフ
トレ
ジ
ス
タ
10
bi
tR
-2
R
D/
A
10
b
it
L
a
tc
h
CH
1
··
·
CH
2
10
b
it
L
a
tc
h
10
bi
tR
-2
R
D/
A
D0
1
2
3
4
5
6
D9
D1
0
11
12
D1
3
L
D/A
7
6
5
4
3
2
1
AO
3
TEST
2
Rese
t
TE
S
T
1
AO
2
VS
S
(Vre
fL
)
8
9
10
11
12
13
14
AO
4
LD
CL
K
DI
AO1
GN
D
7
8
VD
D
(Vr
ef
H
)
VC
C
D/A
L
4
S
h
ift
re
g
is
te
r
Shi
ft
r
egi
ster
Addr
es
s
dec
oder
Addr
es
s
dec
oder
D
A
converte
r
DA
converte
r
D
A
converte
r
Bu
ff
er
oper
at
ion
amp
lif
ier
Bu
ff
er
oper
at
ion
amp
lif
ier
D
A
converte
r