IRU1117-18
1
Rev. 1.1
06/29/01
TYPICAL APPLICATION
DESCRIPTION
The IRU1117-18 is a low dropout three-terminal fixed out-
put regulator with minimum of 800mA output current ca-
pability. This product is specifically designed to provide
well regulated supply for low voltage IC applications as
well as generating clock supply for PC applications. The
IRU1117-18 is guaranteed to have <1.2V dropout at full
load current making it ideal to provide well regulated with
3.8V input supply. The IRU1117-18 is specifically de-
signed to be stable with low cost aluminum capacitors
while maintaining stability with low ESR tantalum caps.
800mA LOW DROPOUT POSITIVE
FIXED 1.8V REGULATOR
Figure 1 - Typical set-up of the IRU1117-18 in a 3.3V to 1.8V regulator application
PRELIMINARY DATA SHEET
Data Sheet No. PD94137
3.3V
1.8V / 800mA
C1
10uF
C2
10uF
IRU1117-18
3
1
2
Vin
Vout
Gnd
Tj (C) 2-PIN PLASTIC 3-PIN PLASTIC 2-PIN PLASTIC 8-PIN PLASTIC
TO-252 (D-Pak) SOT-223 (Y) Ultra Thin-Pak (P) SOIC (S)
0 To 125 IRU1117-18CD IRU1117-18CY IRU1117-18CP IRU1117-18CS
PACKAGE ORDER INFORMATION
FEATURES
Guaranteed < 1.2V Dropout at 800mA Load
Current
Fast Transient Response
1% Voltage Reference Initial Accuracy
Built-In Thermal Shutdown
Available in SOT-223, D-Pak, Ultra Thin-Pak and
8-Pin SOIC Surface-Mount Packages
APPLICATIONS
Low Voltage IC Supply Applications
PC Clock Supply Voltage
2
Rev. 1.1
06/29/01
IRU1117-18
ABSOLUTE MAXIMUM RATINGS
Input Voltage (Vin) .................................................... 7V
Power Dissipation ..................................................... Internally Limited
Storage Temperature Range ...................................... -65C To 150C
Operating Junction Temperature Range ..................... 0C To 125C
PACKAGE INFORMATION
2-PIN PLASTIC TO-252 (D-Pak) 3-PIN PLASTIC SOT-223 (Y) 2-PIN ULTRA THIN-PAK (P) 8-PIN PLASTIC SOIC (S)
JA
=70
C/W for 0.5" Sq pad
JA
=90
C/W for 0.4" Sq pad
JA
=70
C/W for 0.5" Sq pad
JA
=55
C/W for 1" Sq pad
PARAMETER
SYM
TEST CONDITION
MIN
TYP
MAX
UNITS
Output Voltage
Vo
Io=10mA, Tj=25!C
1.782 1.800
1.818 V
Io=10mA
1.764 1.800
1.896
Line Regulation
Io=10mA, 4.75V<Vin<7V
7
mV
Load Regulation (Note 1)
10mA<Io<800mA
17
mV
Dropout Voltage (Note 2)
Io=1A
1.2
1.3
V
Io=800mA
1.1
1.2
Current Limit
dVo=100mV
1.1
A
Thermal Regulation
30ms Pulse, Io=800mA
0.01
%/W
Ripple Rejection
f=120Hz, Co=25F Tantalum,
Io=0.5A
70 dB
Temperature Stability
Io=10mA
0.5
%
Long Term Stability
Tj=125!C, 1000Hrs
0.3
%
RMS Output Noise
Tj=25!C, 10Hz<f<10KHz
0.003
%Vo
Unless otherwise specified, these specifications apply over Cin=1F, Vin=5V,Cout=10F, and Tj=0 to 125!C.
Typical values refer to Tj=25!C.
ELECTRICAL SPECIFICATIONS
Note 1: Low duty cycle pulse testing with Kelvin connections is required in order to maintain accurate data.
Note 2: Dropout voltage is defined as the minimum differential voltage between Vin and Vout required to maintain
regulation at Vout. It is measured when the output voltage drops 1% below its nominal value.
Gnd
Vout
Vin
Tab is
Vout
3
1
2
TOP VIEW
Tab is
Vout
Gnd
Vin
FRONT VIEW
1
3
Gnd
Tab is
Vout
Vin
1
3
FRONT VIEW
Vout
Gnd
NC
NC
Vin
Vout
Vout
Vout
4
3
2
1
5
6
7
8
TOP VIEW
IRU1117-18
3
Rev. 1.1
06/29/01
PIN DESCRIPTIONS
Ground pin. This pin must be connected to ground plane using a low inductance short
connection.
The output of the regulator. This pin is also connected to the tab of the package. An output
capacitor must be connected to this pin to insure stability of the regulator.
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.
1117-18blk1-1.0
Vin 3
1 Gnd
2 Vout
THERMAL
SHUTDOWN
CURRENT
LIMIT
1.25V
+
+
BLOCK DIAGRAM
Figure 2 - Simplified block diagram of the IRU1117-18
PIN# PIN SYMBOL PIN DESCRIPTION
1
2
3
Gnd
Vout
Vin
4
Rev. 1.1
06/29/01
IRU1117-18
IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: (310) 252-7105
TAC Fax: (310) 252-7903
Visit us at www.irf.com for sales contact information.
Data and specifications subject to change without notice. 02/01
Notes
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