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RC5058
17
P
Example:
Suppose that the static limits are +89mV/-79mV,
transient limits are ±134mV, current I is 14.2A, and the
nominal voltage is 2.000V, using MOSFET current sensing.
We have V
S+
= 0.089, |V
S-
| = 0.079, V
T+
= |V
T-
| = 0.134, I
O
= 14.2, V
nom
= 2.000, and
R
D
= 1.67. We calculate:
Since Y > X, we choose Y, and round up to find we need 7
capacitors for C
OUT
.
A detailed explanation of this calculation may be found in
Applications Bulletin AB-24.
2
5
2.000
5
2.000
*
14.2
C
in
2
3.47
4 caps
=
–
=
=
=
3.48K
18 * (0.089 + 0.079 – .024 * 2.000)
14400 * 14.2 * 0.020 * (1 + 0.67) * 1.1
R5
=
=
10.5K
45 * 10
-6
14.2 * 0.020 * (1 + 0.67)
R7
=
=
20.3
*1000
1.01 * 2.000
0.089 – .024 * 2.000
R
offset
3.57
0.134 + 0.089 – .024 * 2.00
0.044 * 14.2
X
=
=
6.14
18 * 3640 * 1.1
14400 * 14.2 * 0.020
0.134 – 0.089
0.044 * 14.2
Y
=
+
=