MIC29710 Datasheet, PDF (8/8 Pages) Micrel Semiconductor – 7.5A Fast-Response LDO Regulator

MIC29710/29712
Adjustable Regulator Design
The adjustable regulator version, MIC29712, allows pro-
gramming the output voltage anywhere between 1.25V and
the 16V maximum operating rating of the family. Two resis-
tors are used. Resistors can be quite large, up to 100kΩ,
because of the very high input impedance and low bias
current of the sense comparator. The resistor values are
calculated by:
V_OUT
R1 = R2 × ( ——— – 1)
1.240
Micrel
Enable Input
The MIC29712 versions features an enable (EN) input that
allows ON/OFF control of the device. Special design allows
“zero” current drain when the device is disabled—only micro-
amperes of leakage current flows. The EN input has TTL/
CMOS compatible thresholds for simple interfacing with
logic, or may be directly tied to V_IN. Enabling the regulator
requires approximately 20µA of current into the EN pin.
Where V_O is the desired output voltage. Figure 4 shows
component definition.
MIC29712BT
VIN
4.75 to 5.25
10µF
R1
100k
R2
56.2k
VOUT
3.45V
33µF
Voltage
Standard (Ω)
R1
R2
2.85
100k
76.8k
2.9
100k
75.0k
3.0
100k
69.8k
3.1
100k
66.5k
3.15
100k
64.9k
3
3.3
100k
60.4k
3.45
100k
56.2k
3.525
93.1k
51.1k
3.6
100k
52.3k
3.8
100k
48.7k
4.0
100k
45.3k
4.1
100k
43.2k
Figure 5. MIC29712 Resistor Table
VOUT = 1.240V × [1 + (R1 / R2)]
Figure 4. Adjustable Regulator with Resistors
1997
3-111