IRU1206 / IRU1207 / IRU1208 / IRU1209
1
Rev. 2.3
08/02/02
www.irf.com
TYPICAL APPLICATION
DESCRIPTION
The IRU1206 family of devices are ultra low dropout 1A
regulators using PNP transistor as the pass element.
These products are ideal when a single input supply is
only available and the dropout voltage is less than 1V,
exceeding the minimum dropout characteristics of NPN/
PNP hybrid regulators. One common application of these
regulators is where input is 3.3V and a 2.5V output is
needed.
Besides the low dropout of less than 0.5V, other fea-
tures of the family of the parts are: micro-power shut-
down capability and output UVLO detection where Flag
pin is switched low when output is below 5% of its nomi-
nal point.
1A VERY LOW DROPOUT POSITIVE
FIXED AND ADJUSTABLE REGULATORS
PACKAGE ORDER INFORMATION
T
J
(C) 2-PIN TO-252 3-PIN 8-PIN PLASTIC VOLTAGE PIN FUNCTIONS
(D-PAK) SOT-223 (Y) SOIC (S)
0 To 125 IRU1206-18CD IRU1206-18CY NA 1.8V V
IN
, V
OUT
, Gnd
0 To 125 IRU1206-25CD IRU1206-25CY NA 2.5V V
IN
, V
OUT
, Gnd
0 To 125 IRU1206-33CD IRU1206-33CY NA 3.3V V
IN
, V
OUT
, Gnd
0 To 125 NA NA IRU1207-18CS 1.8V V
IN
, V
OUT
, Gnd, Enable, Flag
0 To 125 NA NA IRU1207-25CS 2.5V V
IN
, V
OUT
, Gnd, Enable, Flag
0 To 125 NA NA IRU1207-33CS 3.3V V
IN
, V
OUT
, Gnd, Enable, Flag
0 To 125 NA NA IRU1208CS Adj V
IN
, V
OUT
, Gnd, Flag, Adj
0 To 125 NA NA IRU1209CS Adj V
IN
, V
OUT
, Gnd, Enable, Adj
Data Sheet No. PD94134
Figure 1 - Typical application of the 1206-XX in a 3-Pin SOT-223 package.
Low Dropout Voltage (500mV at 1A)
1% Voltage Reference Accuracy
Low Ground Current
1
m
A Maximum Quiescent Current in Shutdown
(IRU1207, IRU1208)
Fast Transient Response
Current Limit and Thermal Shutdown
Error Flag Signal for Output out of Regulation
(IRU1207, IRU1208)
FEATURES
2.5V Supply from 3.3V Input for the new
generation of Logic ICs
Computer Mother Board, Add-On Cards
High Efficiency Post Regulator in Switch Mode
Power Supply (SMPS)
APPLICATIONS
V
IN
V
OUT
C1
C2
IRU1206-
XX
3
1
2
V
OUT
Gnd
V
IN
2
Rev. 2.3
08/02/02
IRU1206 / IRU1207 / IRU1208 / IRU1209
www.irf.com
ABSOLUTE MAXIMUM RATINGS
Input Voltage (V
IN
) .................................................... 12V
Enable Input Voltage ................................................ 12V
Storage Temperature Range ...................................... -65C To 150C
Operating Junction Temperature Range ..................... 0C To 135C
PACKAGE INFORMATION
JA
=55
C/W
for 1" Sq pad
2-PIN PLASTIC TO-252 (D-Pak)
3-PIN PLASTIC SOT-223 (Y)
IRU1206
IRU1206
JA
=70
C/W for
0.5" Sq pad
JA
=90
C/W for
0.4" Sq pad
8-PIN PLASTIC SOIC (S)
IRU1207 IRU1208 IRU1209
JA
=55
C/W
for 1" Sq pad
JA
=55
C/W
for 1" Sq pad
ELECTRICAL SPECIFICATIONS
Unless otherwise specified, these specifications apply over C
IN
=C
OUT
=10
m
F, V
IN
=Vo+1V, V
OUT
=V
FB
(For adjustable
version only), and T
A
=25C. Typical values refer to T
A
=25C. Low duty cycle pulse testing is used which keeps
junction and case temperatures equal to the ambient temperature.
V
IN
V
OUT
Tab is
Gnd
1
3
FRONT VIEW
V
IN
Gnd
V
OUT
Tab is
Gnd
3
1
2
TOP VIEW
Gnd
Flag
V
OUT
V
IN
Enable
Gnd
Gnd
Gnd
4
3
2
1
5
6
7
8
TOP VIEW
Gnd
Adj
V
OUT
V
IN
Flag
Gnd
Gnd
Gnd
4
3
2
1
5
6
7
8
TOP VIEW
Gnd
Adj
V
OUT
V
IN
Enable
Gnd
Gnd
Gnd
4
3
2
1
5
6
7
8
TOP VIEW
Initial Voltage Accuracy
(see Table 1 for nominal values)
Line Regulation
Load Regulation (Note 1)
Output Voltage Temp Coef.
Dropout Voltage (Note 2)
Ground Current (Note 3)
Current Limit
Minimum Input Voltage
IRU1208, IRU1209
Adjust Pin Current
Minimum Load Current
PARAMETER
SYM TEST CONDITION MIN TYP MAX UNITS
Vo
D
V
I
D
V
L
D
V
O(T)
D
V
I(O)
I
Q
I
CL
V
IN(min)
I
ADJ
I
O(min)
Io=10mA, T
A
=25
8
C
(Note 4)
Vo + 1V<V
IN
<12
10mA<Io<1A
1mA<Io<150mA
Io=100mA (Note 4)
Io=500mA (Note 4)
Io=1000mA (Note 4)
V
IN
=Vo + 1 for all conditions:
Io=100mA (Note 4)
Io=500mA (Note 4)
Io=1000mA (Note 4)
Vo=5% Below Regulation Point
V
IN
=2.5V, Vo=V
ADJ
(Note 4)
-1
-1.3
1.1
1
0.5
0.5
20
100
300
500
1.4
2.1
1
1.3
1
0.7
0.5
100
200
400
650
3
15
50
2.3
0.1
%
%
%
ppm/
8
C
mV
mA
A
V
m
A
mA
IRU1206 / IRU1207 / IRU1208 / IRU1209
3
Rev. 2.3
08/02/02
www.irf.com
PIN DESCRIPTIONS
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 0.6V higher than V
OUT
in order
for the device to regulate properly.
The output of the regulator. A minimum of 2.2
m
F capacitor must be connected from this pin
to ground.
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.
An open collector output that switches low when the output voltage drops about 4% below
its expected regulated voltage.
A resistor divider from this pin to the V
OUT
pin and ground sets the output voltage.
APPLICATION INFORMATION
Stability
The IRU120X series of regulators require the use of an
output capacitor as part of the frequency compensation
in order to make the regulator stable. A minimum of 2.2
m
F
capacitance and the ESR in the range of 0.5 to 2
V
in-
sures the stability of the system.
Part Number Output
Voltage
IRU1206-18 1.8V
IRU1206-25 2.5V
IRU1206-33 3.3V
IRU1207-18 1.8V
IRU1207-25 2.5V
IRU1207-33 3.3V
IRU1208 1.24V
IRU1209 1.24V
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.
IRU1207, IRU1209
Ground Current - SD Activated
Enable Pin Input LO Voltage
Enable Pin Input HI Voltage
Enable Pin Input LO Current
Enable Pin Input HI Current
IRU1207, IRU1208
Flag Output Threshold Voltage
Flag Output Hysteresis Voltage
Flag Output Saturation Voltage
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 +125
8
C.
V
IN
(All devices)
V
OUT
(All devices)
Gnd
(All devices)
Enable
(IRU1207, IRU1209)
Flag
(IRU1207, IRU1208)
Adj
(IRU1208, IRU1209)
Table 1 - Output voltage vs. part number.
PIN SYMBOL PIN DESCRIPTION
I
Q(SD)
V
EN(L)
V
EN(L)
V
TH(FG)
V
HYS
V
F(SAT)
Enable=Open
Regulator OFF (Note 4)
Regulator ON (Note 4)
V
EN(L)
=0V to 0.8V (Note 4)
V
EN(L)
=2V to Vin (Note 4)
Output Ramping Up
Io=5mA
Io=500
m
A
PARAMETER
SYM TEST CONDITION MIN TYP MAX UNITS
2
0.01
0.1
100
5
0.8
400
230
1
0.8
2
600
m
A
V
V
m
A
m
A
%V
O
%V
O
mV
4
Rev. 2.3
08/02/02
IRU1206 / IRU1207 / IRU1208 / IRU1209
www.irf.com
Ref Desig
Description
Qty
Part #
Manuf
C1
Capacitor
1
10
m
F, Tantalum
AVX
C2
Capacitor
1
10
m
F, Tantalum
AVX
R1
Resistor
1
10K
V
, 5%
Panasonic
TYPICAL APPLICATION
Ref Desig
Description
Qty
Part #
Manuf
C1
Capacitor
1
10
m
F, Tantalum
AVX
C2
Capacitor
1
10
m
F, Tantalum
AVX
Figure 2 - Typical application of IRU1206.
Figure 3 - Typical application of IRU1207.
Note: Tab must also be
connected to ground.
V
IN
V
OUT
C1
C2
IRU1206-
XX
3
1
2
V
OUT
Gnd
V
IN
V
IN
V
OUT
R1
C1
C2
SD Enable
IRU1207
Error Flag
1
2
3
4
Enable
V
IN
Gnd
V
OUT
Flag
Gnd
Gnd
Gnd
8
7
6
5
IRU1206 / IRU1207 / IRU1208 / IRU1209
5
Rev. 2.3
08/02/02
www.irf.com
TYPICAL APPLICATION
Figure 4 - Typical application of IRU1208 in 3.3V to 2.5V regulator.
Ref Desig
Description
Qty
Part #
Manuf
C1
Capacitor
1
10
m
F, Tantalum
AVX
C2
Capacitor
1
10
m
F, Tantalum
AVX
R1
Resistor
1
127
V
, 1%
R2
Resistor
1
124
V
, 1%
R3
Resistor
1
10K
V
, 5%
V
IN
V
OUT
R1
R2
C1
C2
IRU1208
R3
Error Flag
1
2
3
4
Flag
V
IN
Gnd
V
OUT
Adj
Gnd
Gnd
Gnd
8
7
6
5
Vo = 1.24
3
1 +
R1
R2
(
)
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