MB4053 Fujitsu Microelectronics, Inc., MB4053 Datasheet - Page 12

• Manufacturer Part Number: MB4053
• Description: 6-channel 8-bit A/D Converter
• Manufacturer: Fujitsu Microelectronics, Inc.

12
MB4053
APPLICATION EXAMPLES
Examples of analog voltage (0
ERROR vs AMBIENT TEMPERATURE Ta” and “SUPPLY CURRENT vs AMBIENT TEMPERATURE”.
Reference Voltage: V
Ramp Current: I
Input Voltage: = V
Ramp Time: t
=
V
I
t
t
If the ramp time is counted with a 1 MHz clock, the following
resolution is obtained.
R
SL
Rmax
REF
=
R
X
=
.
=
R
.
+ R
V
X
Temperature
CC
Sensor
C
I
3 k
R
A
B
H
C
(min)
REF
- V
H
5 k
R
V
REF
I
.
= V
- I
R
(1 +
REF
V
R
.
5 k
REF
R
=
IN
IN
1000 s
=
R
=
REF
1 s
R
R
1
R
C
=
2
1
R
I
+ R
R
B
R
H
=
1
=
X
8 V = 5 V
8 V - 5 V
R
) C
120 k
2
+ R
5000 pF (5 V + 0.7 V)
R
X
= 1000 = 2
1
R
5000 pF
B
R
H
+ R
X
150 A - 25 A
R
2
REF
R
1
25 A
2
.
V
REF
.
R
3 k
R
5 k
CC
1
2
to
V
= 25 A
10
To other
Sensor
................. 7-4
CC
V
................ 7-3
5 V
5 V) A/D conversion with 10-bit resolution are shown in “PEAK LINEARITY
CC
............ 7-1
......... 7-2
= 1000 s
= 228 s
I
I
I
I
I
I
V
1
2
3
4
5
6
REF
V
MB4053
CC
V
GND
As shown in this example, the voltage output of the sensor is
proportional to V
(Eq. 7-1), the sensor output conversion results (Eq. 7-4) are not
influenced by power supply voltage fluctuation. Such a conversion
is called ratio metric conversion and is effective for minimizing the
effects of conversion error. Supply voltage fluctuations during
discharge do result in error, however.
CC
= 8 V
START
RAMP
RAMP
STOP
R
REF
C
A
A
A
H
2
1
0
120 k
R
REF
CC
I
R
(Eq. 7-3) and V
5 V
20 k
REF
is also proportional to V
C
Control input/output from
MPU
H
= 5000 pF
CC