MP2004-DUAL, LOW NOISE, HIGH PSRR, 200mA LINEAR REGULATOR
BLOCK DIAGRAM
Figure1—Functional Block Diagram
OPERATION
The MP2004 integrates two low noise, low
dropout, low quiescent current and high PSRR
linear regulators. It is intended for use in devices
that require very low voltage, low quiescent
current power such as wireless LAN, battery-
powered equipment and hand-held equipment.
The MP2004 uses internal PMOSs as the pass
elements and features internal thermal shutdown and
an internal current limit circuit.
Current Limit
The MP2004 includes two independent current
limit structures which monitor and control each
PMOS’s gate voltage limiting the guaranteed
maximum output current to 200mA.
Thermal Protection
Thermal protection turns off the PMOS when the
junction temperature exceeds +140ºC, allowing
the IC to cool. When the IC’s junction
temperature drops by 10ºC, the PMOS will be
turned on again. Thermal protection limits total
power dissipation in the MP2004. For reliable
operation, junction temperature should be limited
to 125 ºC maximum.
Dropout Voltage
Dropout voltage is the minimum input to output
differential voltage required for the regulator to
maintain an output voltage within 100mV of its
nominal value. Because the PMOS pass element
behaves as a low-value resistor, the dropout
voltage of MP2004 is very low.
Load-Transient Considerations
The output response of load-transient consists of
a DC shift and transient response. Because of
the excellent load regulation of MP2004, the DC
shift is very small. The output voltage transient
depends on the output capacitor’s value and the
ESR. Increasing the capacitance and decreasing
the ESR will improve the transient response.
Typical output voltage transient spike of MP2004
for a step change in the load current from 0mA to
80mA is tens mV.
Shutdown
The MP2004 can be switched ON or OFF by a
logic input at the EN pin. A high voltage at this
pin will turn the device on. When the EN pin is
low, the regulator output is off. The EN pin should
be tied to VIN to keep the regulator output always
on if the application does not require the
shutdown feature. Do not float the EN pin.
MP2004 Rev. 0.92
4/6/2010
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