IRU1205
IRU1205-18 / IRU1205-25 / IRU1205-28
IRU1205-30 / IRU1205-33 / IRU1205-36
Data Sheet No. PD94133
FEATURES
SOT-23 Package
Stable with 2.2mF Ceramic Capacitor
1% Voltage Reference Accuracy
Only 270mV Dropout at 300mA
and 170mV Dropout at 150mA
5mA Quiescent Current in Shutdown
Current Limit and Thermal Shutdown
Logic Input Enable Pin
300mA ULTRA LOW DROPOUT POSITIVE
ADJUSTABLE AND FIXED REGULATORS
DESCRIPTION
The IRU1205 device is an efficient linear voltage regula-
tor with better than 1% initial voltage accuracy, very low
dropout voltage and very low ground current designed
especially for hand held, battery powered applications.
Other features of the device are: TTL compatible enable/
shutdown control input, current limiting and thermal shut-
down.
The IRU1205 is available in fixed and adjustable output
voltage versions in a small SOT-23 5-Pin package.
APPLICATIONS
Laptop, Notebook & Palmtop computers
Battery Powered Equipments
PCMCIA Vcc & Vpp Regulator
Consumer Electronics
High Efficiency Linear Power Supplies
TYPICAL APPLICATION
V
IN
C1
2.2uF
1
2
V
IN
V
OUT
5
R1
C2
2.2uF
R2
V
OUT
Vo = 1.253 1+
Gnd
(
R1
R2
)
SD
Enable
3
En
Adj
4
Figure 1 - Typical application of the IRU1205 ajustable voltage regulator.
3.3V
C1
2.2uF
1
2
V
IN
V
OUT
5
C2
2.2uF
2.5V
Gnd
SD
Enable
3
En
C
BYP
4
C3
1000pF
Figure 2 - Typical application of the IRU1205-25 fixed voltage regulator.
PACKAGE ORDER INFORMATION
T
J
(°C)
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
Rev. 2.3
07/16/02
5-PIN
SOT-23 (L5)
IRU1205CL
IRU1205-18CL
IRU1205-25CL
IRU1205-28CL
IRU1205-30CL
IRU1205-33CL
IRU1205-36CL
SOT-23
MARKING
AT00
AT18
AT25
AT28
AT30
AT33
AT36
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OUTPUT
VOLTAGE
Adj
1.8V
2.5V
2.8V
3.0V
3.3V
3.6V
1
IRU1205
IRU1205-18 / IRU1205-25 / IRU1205-28
IRU1205-30 / IRU1205-33 / IRU1205-36
ABSOLUTE MAXIMUM RATINGS
Input Voltage (V
IN
) .....................................................
Enable Input Voltage .................................................
Storage Temperature Range .......................................
Operating Junction Temperature Range ......................
10V
10V
-65°C To 150°C
0°C To 150°C
PACKAGE INFORMATION
5-PIN SOT-23 (L5)
En Gnd V
IN
3
2
1
3
5-PIN SOT-23 (L5)
En Gnd V
IN
2
1
AT00
4
5
Adjustable
u
JA
=2568C/W
4
ATxx
5
Fixed
u
JA
=2568C/W
Adj
V
OUT
C
BYP
V
OUT
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over C =Co=22mF, Io=100mA, V
IN(MIN)
=2.5V(Adjustable
IN
devices) V
IN
=Vo + 1V(for fixed voltage devices), V
OUT
=V
FB
(for adjustable version only), C
BYP
=470pF(for AT18, AT25,
AT28, AT30, AT33 and AT36), V
ENB
=2V and T
A
=258C. Typical values refer to T
A
=258C. Low duty cycle pulse testing
is used which keeps junction and case temperatures equal to the ambient temperature.
PARAMETER
Reference Voltage
(See Table 1 for typical values)
Line Regulation
Load Regulation (Note 1)
Dropout Voltage (Note 2)
SYM
Vo
DV
I
DV
L
DV
I(O)
TEST CONDITION
(Note 4)
Vo + 1V<V
IN
<10V
1mA<Io<100mA
100mA<Io<300mA
Io=100mA
Io=100mA (Note 4)
Io=50mA
Io=50mA (Note 4)
Io=150mA
Io=150mA (Note 4)
Io=300mA
Io=300mA (Note 4)
V
EN
=2V, Io=100mA
Io=100mA (Note 4)
Io=50mA
Io=50mA (Note 4)
Io=150mA
Io=150mA (Note 4)
Io=300mA
Io=300mA (Note 4)
V
EN
=0V to 0.8V or Open
Vo=0V
V
IN
=10V, Io=150mA, 10ms Pulse
V
IN
=2.5V, Vo=V
ADJ
Regulator OFF
Regulator ON
V
EN(L)
=0V to 0.8V
V
EN(H)
=2V to V
IN
MIN
-1
-2
TYP
MAX UNITS
1
%
2
%/V
%
50
70
110
140
220
260
350
400
160
600
2900
9500
mA
mA
%/W
mA
V
V
mA
mA
mV
Ground Current (Note 3)
I
Q
Ground Current-SD Activated
Current Limit
Thermal Regulation
Adjust Pin Current
Enable Pin Input LO Voltage
Enable Pin Input HI Voltage
Enable Pin Input LO Current
Enable Pin Input HI Current
I
Q(SD)
I
CL
DV
P
I
ADJ
V
EN(L)
V
EN(H)
320
0.005
0.8
0.1
10
13
85
100
170
204
270
324
120
240
420
540
2200
2900
7200
9300
5
420
0.05
0.1
mA
0.8
2
0.01
20
2
www.irf.com
Rev. 2.3
07/16/02
IRU1205
IRU1205-18 / IRU1205-25 / IRU1205-28
IRU1205-30 / IRU1205-33 / IRU1205-36
Note 1:
Low duty cycle pulse testing with Kelvin con-
nections is required in order to maintain accurate data.
Note 2:
Dropout voltage is defined as the minimum dif-
ferential voltage between V
IN
and V
OUT
required to main-
tain regulation at V
OUT
. It is measured when the output
voltage drops 1% below its nominal value.
Note 3:
Ground current is the regulator quiescent cur-
rent plus the pass transistor current. The total current
from the supply is the sum of the load current plus the
ground pin current.
Note 4:
The specification applies for the junction tem-
perature of 0 to +1258C.
PIN DESCRIPTIONS
PIN #
1
PIN SYMBOL
V
IN
PIN DESCRIPTION
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
drop out voltage during the load transient response. This pin must always be higher
than V
OUT
by at least the amount of the dropout voltage and some margin in order for
the device to regulate properly.
Ground pin. This pin must be connected to the lowest potential in the system and all
other pins must be at higher potential with respect to this pin.
Enable pin. A low signal or left open on this pin shuts down the output. This pin must
be tied HI or to V
IN
for normal operation.
A resistor divider from this pin to the V
OUT
pin and ground sets the output voltage. To
minimize the error due to the error amplifier, select the values of the resistor dividers
to be less than 10KV.
A 470 to 1000pF bypass capacitor connected to this pin reduces the output noise.
2
Gnd
3
En
4
Adj
(Adjustable Only)
4
C
BYP
(Fixed Only)
V
OUT
5
The output of the regulator. A minimum of 2.2mF with max ESR of 1V capacitor must
be connected from this pin to ground to insure stability.
Output
Voltage
1.25V
1.8V
2.5V
2.8V
3.0V
3.3V
3.6V
The output voltage of the adjustable device can be set
using:
Vo = 1.253 1+
5-PIN
SOT-23
IRU1205
IRU1205-18
IRU1205-25
IRU1205-28
IRU1205-30
IRU1205-33
IRU1205-36
(
R1
R2
)
Where:
R1 = Resistor connected from output to the Adj pin
R2 = Resistor connected from Adj pin to Gnd
Table 1- Nominal output voltage vs. part number.
Rev. 2.3
07/16/02
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3
IRU1205
IRU1205-18 / IRU1205-25 / IRU1205-28
IRU1205-30 / IRU1205-33 / IRU1205-36
BLOCK DIAGRAM
V
IN
1
5 V
OUT
Adj
4
THERMAL
SHUTDOWN
+
1.25V
Gnd 2
Figure 3 - IRU1205 Adjustable output block diagram.
3 En
V
IN
1
5 V
OUT
C
BYP
4
+
THERMAL
SHUTDOWN
1.25V
Gnd 2
3 En
Figure 4 - IRU1205-18, IRU1205-25, IRU1205-28, IRU1205-30, IRU1205-33 and
IRU1205-36 Fixed output block diagram.
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
4
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Rev. 2.3
07/16/02
IRU1205
IRU1205-18 / IRU1205-25 / IRU1205-28
IRU1205-30 / IRU1205-33 / IRU1205-36
(L5) SOT-23 Package
5-Pin
B
e
L
E
E1
e1
D
a
C
A2
A
C
L
A1
SYMBOL
A
A1
A2
B
C
D
E
E1
e
e1
L
a
MIN
MAX
0.90
1.45
0.00
0.15
0.90
1.30
0.25
0.50
0.09
0.20
2.80
3.00
2.60
3.00
1.50
1.75
0.95 REF
1.90 REF
0.35
0.55
08
108
NOTE: ALL MEASUREMENTS
ARE IN MILLIMETERS.
Rev. 2.3
07/16/02
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5
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