MIC29312WU Micrel Inc, MIC29312WU Datasheet - Page 8

• Manufacturer Part Number: MIC29312WU
• Description: IC,VOLT REGULATOR,ADJUSTABLE,+1.24 TO +15V,BIPOLAR,SIP,5PIN,PLASTIC
• Manufacturer: Micrel Inc

Specifications of MIC29312WU

• Rohs Compliant: YES
• Regulator Topology: Positive Adjustable
• Voltage - Output: 1.24 ~ 15 V
• Voltage - Input: 2.3 ~ 16 V
• Voltage - Dropout (typical): 0.6V @ 3A
• Number Of Regulators: 1
• Current - Output: 3A
• Current - Limit (min): 3A
• Operating Temperature: 0°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: TO-263-5, D²Pak (5 leads + Tab), TO-263BA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 576-1751-5; MIC29312WU

and the output voltage rises. A 10mA minimum load current
is necessary for proper regulation.
Adjustable Regulator Design
The adjustable regulator version, MIC29312, allows program-
ming the output voltage anywhere between 1.25V and the
15V maximum operating rating of the family. Two resistors
are used. Resistors can be quite large, up to 1MΩ, because
of the very high input impedance and low bias current of the
sense comparator. The resistor values are calculated by:
Resistor Value Table for the MIC29312 Adjustable Regulator
Note: This regulator has a minimum load requirement. “Standard” values assume the load meets this requirement. “Minimum
Load” values are calculated to draw 10mA and allow regulation with an open load (the minimum current drawn from the load
may be zero).
MIC29310/29312
Voltage
2.85
2.9
3.0
3.1
3.15
3.3
3.45
3.6
3.8
4.0
4.1
Figure 4. Adjustable Regulator with Resistors
100k
100k
100k
100k
100k
100k
100k
100k
100k
100k
100k
R1
Standard (Ω)
76.8k
75.0k
69.8k
66.5k
64.9k
60.4k
56.2k
52.3k
48.7k
45.3k
43.2k
R2
162
165
174
187
191
205
221
237
255
274
287
R1
Min. Load (Ω)
124
124
124
124
124
124
124
124
124
124
124
R2
8
Where V
component defi nition. Applications with widely varying load
currents may scale the resistors to draw the minimum load
current required for proper operation (see the table below).
Enable Input
The MIC29312 version features an enable (EN) input that
allows ON/OFF control of the device. Special design al-
lows “zero” current drain when the device is disabled—only
microamperes of leakage current fl ows. The EN input has
TTL/CMOS compatible thresholds for simple interfacing with
logic, or may be directly tied to V
requires approximately 20µA of current into the EN pin.
O
is the desired output voltage. Figure 4 shows
R1 = R2 × ( –—— – 1 )
1.240
V
OUT
IN
. Enabling the regulator
November 2006