IRU1205(PbF
IRU1205-18 / IRU1205-25 / IRU1205-28
IRU1205-30 / IRU1205-33 / IRU1205-36
Data Sheet No. PD94133revA
300mA ULTRA LOW DROPOUT POSITIVE
ADJUSTABLE AND FIXED REGULATORS
FEATURES
SOT-23 Package
Stable with 2.2µF Ceramic Capacitor
1% Voltage Reference Accuracy
Only 270mV Dropout at 300mA
and 170mV Dropout at 150mA
5µA Quiescent Current in Shutdown
Current Limit and Thermal Shutdown
Logic Input Enable Pin
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
V
IN
2
Gnd
V
OUT
5
R1
C2
2.2uF
R2
V
OUT
Vo = 1.253 1+
(
R1
R2
)
SD
Enable
3
En
Adj
4
Figure 1 - Typical application of the IRU1205 ajustable voltage regulator.
3.3V
C1
2.2uF
1
V
IN
2
Gnd
3
En
V
OUT
5
C2
2.2uF
2.5V
SD
Enable
C
BYP
4
C3
1000pF
Figure 2 - Typical application of the IRU1205-25 fixed voltage regulator.
Rev. 2.3
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1
IRU1205(PbF)
IRU1205-18 / IRU1205-25 / IRU1205-28
IRU1205-30 / IRU1205-33 / IRU1205-36
PACKAGE ORDER INFORMATION
Basic Part (Non-Lead Free)
T
J
(°C)
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
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
OUTPUT
VOLTAGE
Adj
1.8V
2.5V
2.8V
3.0V
3.3V
3.6V
Leadfree Part
T
J
(°C)
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
0 To 125
5-PIN
SOT-23 (L5)
IRU1205CLPbF
IRU1205-18CLPbF
IRU1205-25CL PbF
IRU1205-28CLPbF
IRU1205-30CLPbF
IRU1205-33CLPbF
IRU1205-36CLPbF
SOT-23
MARKING
AT00
AT18
AT25
AT28
AT30
AT33
AT36
OUTPUT
VOLTAGE
Adj
1.8V
2.5V
2.8V
3.0V
3.3V
3.6V
2
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Rev. 2.3
IRU1205(PbF
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
5-PIN SOT-23 (L5)
En Gnd V
IN
3
2
1
AT00
Adj
4
Adjustable
5
ATxx
C
BYP
4
Fixed
5
V
OUT
υ
JA
=2568C/W
V
OUT
υ
JA
=2568C/W
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over C
IN
=Co=22µF, Io=100µA, V
IN(MIN)
=2.5V(Adjustable
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
∆V
I
∆V
L
∆V
I(O)
TEST CONDITION
(Note 4)
Vo + 1V<V
IN
<10V
1mA<Io<100mA
100mA<Io<300mA
Io=100µA
Io=100µA (Note 4)
Io=50mA
Io=50mA (Note 4)
Io=150mA
Io=150mA (Note 4)
Io=300mA
Io=300mA (Note 4)
V
EN
=2V, Io=100µA
Io=100µA (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
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MIN
-1
-2
TYP
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
0.01
20
MAX UNITS
%
1
2
%/V
%
50
70
110
140
220
260
350
400
160
600
2900
9500
µ
A
mA
%/W
µ
A
V
V
µ
A
µ
A
mV
Ground Current (Note 3)
I
Q
µ
A
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
Rev. 2.3
I
Q(SD)
I
CL
∆V
P
I
ADJ
V
EN(L)
V
EN(H)
320
0.8
2
3
IRU1205(PbF)
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 10Kς.
A 470 to 1000pF bypass capacitor connected to this pin reduces the output noise.
The output of the regulator. A minimum of 2.2µF with max ESR of 1ς 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 = 1.25
x
1+
2
3
4
Gnd
En
Adj
(Adjustable Only)
C
BYP
(Fixed Only)
V
OUT
4
5
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.
4
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Rev. 2.3
IRU1205(PbF
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
1.25V
+
THERMAL
SHUTDOWN
Gnd 2
3 En
Figure 4 - IRU1205-18, IRU1205-25, IRU1205-28, IRU1205-30, IRU1205-33 and
IRU1205-36 Fixed output block diagram.
Rev. 2.3
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