DA9124.009
11 January 2005
MAS9124
150 mA LDO Voltage Regulator IC
• Low Noise: 20 µVrms
• Low Minimum Output Capacitance
Requirement: 0.23 µF
• Excellent Ripple Rejection: 65 dB
• Very Low Dropout: 70 mV
• Regulator Enable/Disable Control
• Stable with Low-ESR Output
Capacitors
DESCRIPTION
MAS9124 is a low dropout voltage regulator with
very low output noise, high PSRR and small output
capacitance requirement.
Due to the low noise level of only 20 µVrms,
MAS9124 is suitable for sensitive circuits, e.g., in
RF applications. In addition to the noise levels,
MAS9124 excels in dropout voltage (70 mV typical
at 50 mA) and rise time (16 µs typical without
bypass capacitor). Also its ripple rejection ability of
65 dB at 10 kHz exceeds that of competition.
The Equivalent Series Resistance (ESR) range of
output capacitors that can be used with MAS9124
is very wide. This ESR range from a few mΩ up to a
couple of Ohms combined with no minimum output
current requirement makes the usage of MAS9124
easier and low in cost.
MAS9124 features an enable/disable pin, which
allows device to be turned off or on by pulling
control to low or high. In order to save power the
device goes into sleep mode when the regulator is
disabled.
MAS9124 also includes an auto-discharge function,
wherein a shutdown transistor turns on and
discharges the output capacitor, when MAS9124 is
turned off.
An internal thermal protection circuit prevents the
device from overheating. Also the maximum output
current is internally limited.
FEATURES
• Low Noise
• Functionally and Pin Compatible with
LP2985/LP3985
• Can be used w/o CBYPASS, see p. 6
• Auto-discharge Function
• Internal Thermal Shutdown
• Short Circuit Protection
• Small SOT23-5 or Thin TSOT-5 Package
• Several Output Voltage Options Available, see
Ordering Information p. 12
APPLICATIONS
• Mobile Phones
• WLAN Chipsets
• Cordless Phones
• Accessories
• Pagers
• Battery Powered Systems
• Portable Systems
• Radio Control Systems
• Low Voltage Systems
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