LD3985
SERIES
ULTRA LOW DROP-LOW NOISE BICMOS VOLTAGE
REGULATORS LOW ESR CAPACITORS COMPATIBLE
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INPUT VOLTAGE FROM 2.5V TO 6V
STABLE WITH LOW ESR CERAMIC
CAPACITORS
ULTRA LOW DROPOUT VOLTAGE (100mV
TYP. AT 150mA LOAD, 0.4mV TYP. AT 1mA
LOAD)
VERY LOW QUIESCENT CURRENT (85µA
TYP. AT NO LOAD, 170µA TYP. AT 150mA
LOAD; MAX 1.5µA IN OFF MODE)
GUARANTEED OUTPUT CURRENT UP TO
150mA
WIDE RANGE OF OUTPUT VOLTAGE: 1.2V;
1.22V; 1.25V; 1.35V; 1.5V; 1.8V; 2V; 2.1V;
2.2V; 2.4V; 2.5V; 2.6V; 2.7V; 2.8V; 2.85V;
2.9V; 3V; 3.1V; 3.2V; 3.3V; 4.7V; 5V
FAST TURN-ON TIME: TYP. 200µs [C
O
=1µF,
C
BYP
= 10nF AND I
O
=1mA]
LOGIC-CONTROLLED ELECTRONIC
SHUTDOWN
INTERNAL CURRENT AND THERMAL LIMIT
OUTPUT LOW NOISE VOLTAGE 30µVRMS
OVER 10Hz to 100KHz
S.V.R. OF 60dB AT 1KHz, 50dB AT 10KHz
TEMPERATURE RANGE: -40°C TO 125°C
Flip-Chip
(1.57x1.22)
SOT23-5L
TSOT23-5L
DESCRIPTION
The LD3985 provides up to 150mA, from 2.5V to
6V input voltage.
Figure 1: Schematic Diagram
The ultra low drop-voltage, low quiescent current
and low noise make it suitable for low power
applications and in battery powered systems.
Regulator ground current increases only slightly in
dropout, further prolonging the battery life. Power
supply rejection is better than 60 dB at low
frequencies and starts to roll off at 10KHz. High
power supply rejection is maintained down to low
input voltage levels common to battery operated
circuits. Shutdown Logic Control function is
available, this means that when the device is used
as local regulator, it is possible to put a part of the
board in standby, decreasing the total power
consumption. The LD3985 is designed to work
with low ESR ceramic capacitors. Typical
applications are in mobile phone and similar
battery powered wireless systems.
October 2004
Rev. 8
1/14
STMICROELECTRONICS [ STMICROELECTRONICS ]
