IRU1010 International Rectifier, IRU1010 Datasheet - Page 3

• Manufacturer Part Number: IRU1010
• Description: 1A LOW DROPOUT POSITIVE ADJUSTABLE REGULATOR
• Manufacturer: International Rectifier

PIN DESCRIPTIONS
PIN #
BLOCK DIAGRAM
APPLICATION INFORMATION
Introduction
The IRU1010 adjustable Low Dropout (LDO) regulator is
a three-terminal device which can easily be programmed
with the addition of two external resistors to any volt-
ages within the range of 1.25 to 5.5V. This regulator,
unlike the first generation of the three-terminal regula-
tors such as LM117 that required 3V differential between
the input and the regulated output, only needs 1.3V dif-
ferential to maintain output regulation. This is a key re-
quirement for today’s low voltage IC applications that
typically need 3.3V supply and are often generated from
the 5V supply. Other applications such as high speed
Rev. 1.4
06/29/01
1
2
3
Vin 3
PIN SYMBOL
Vout
Adj
Vin
SHUTDOWN
THERMAL
CURRENT
LIMIT
A resistor divider from this pin to the Vout pin and ground sets the output voltage.
The output of the regulator. A minimum of 10µF capacitor must be connected from this pin
to ground to insure stability.
The input pin of the regulator. Typically a large storage capacitor is connected from this
pin to ground to insure that the input voltage does not sag below the minimum dropout
voltage during the load transient response. This pin must always be 1.3V higher than Vout
in order for the device to regulate properly.
PIN DESCRIPTION
Figure 2 - Simplified block diagram of the IRU1010
+
memory termination need to switch the load current from
zero to full load in tens of nanoseconds at their pins,
which translates to an approximately 300 to 500ns cur-
rent step at the regulator. In addition, the output voltage
tolerances are sometimes tight and they include the tran-
sient response as part of the specification.
The IRU1010 is specifically designed to meet the fast
current transient needs as well as providing an accurate
initial voltage, reducing the overall system cost with the
need for fewer output capacitors.
1010blk1-1.0
1.25V
+
IRU1010
2 Vout
1 Adj
3