mic4043bm4 Micrel Semiconductor, mic4043bm4 Datasheet - Page 5

• Manufacturer Part Number: mic4043bm4
• Description: Mic4043 Low-voltage Secondary-side Shunt Regulator
• Manufacturer: Micrel Semiconductor

Functional Diagram
Functional Description
The MIC4043 combines a G
reference, and a pass transistor in a single package.
The operation of the MIC4043 is similar to conventional shunt
regulators such as the industry standard ’431. In a closed
loop system, the MIC4043 maintains the desired feedback
voltage at the FB pin by sinking current onto the SNK pin
proportional to the error voltage at the FB pin. The ratio of sink
current to error voltage is the transconductance of the device.
November 2000
MIC4043
m
amplifier, precision 1.245V
1.245V
MIC4043
V
REF
5
IN
GND
Reference
The MIC4043 uses a high-side reference . External voltage
dividers providing feedback to the MIC4043 will be inverted
when compared to those used with ’ 431-equivalent devices.
Behavior
The external feedback voltage is compared to the internal
high-side 1.245V reference.
If the feedback voltage, V
amplifier provides no drive to the sink transistor. If the
feedback voltages is greater than V
drives the pass transistor which sinks current to ground.
SNK
FB
FB
, is less than V
IN
– V
REF
IN
, the amplifier
– V
MIC4043
REF
Micrel
, the