Low Dropout Voltage (500mV at 1A)
1% Voltage Reference Accuracy
Low Ground Current
1mA 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)
APPLICATIONS
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)
TYPICAL APPLICATION
V
OUT
IRU1206-
XX
Gnd
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 features of the family of the parts are: micro-power shutdown capability and output UVLO detection where Flag
pin is switched low when output is below 5% of its nominal point.
V
3
2
C2
OUT
V
IN
1
V
IN
C1
Figure 1 - Typical application of the 1206-XX in a 3-Pin SOT-223 package.
PACKAGE ORDER INFORMATION
TJ (°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 VIN, VOUT, Gnd
0 To 125 IRU1206-25CD IRU1206-25CY NA 2.5V VIN, VOUT, Gnd
0 To 125 IRU1206-33CD IRU1206-33CY NA 3.3V VIN, VOUT, Gnd
0 To 125 NA NA IRU1207-18CS 1.8V VIN, VOUT, Gnd, Enable, Flag
0 To 125 NA NA IRU1207-25CS 2.5V VIN, VOUT, Gnd, Enable, Flag
0 To 125 NA NA IRU1207-33CS 3.3V VIN, VOUT, Gnd, Enable, Flag
0 To 125 NA NA IRU1208CS Adj VIN, VOUT, Gnd, Flag, Adj
0 To 125 NA NA IRU1209CS Adj VIN, VOUT, Gnd, Enable, Adj
Rev. 2.3
08/02/02
www.irf.com
1
IRU1206 / IRU1207 / IRU1208 / IRU1209
ABSOLUTE MAXIMUM RATINGS
Input Voltage (V IN) .................................................... 12V
Enable Input Voltage ................................................ 12V
Storage Temperature Range ...................................... -65°C To 150°C
Operating Junction Temperature Range ..................... 0°C To 135°C
Unless otherwise specified, these specifications apply over CIN=COUT=10mF, VIN=Vo+1V, VOUT=VFB (For adjustable
version only), and TA=25°C. Typical values refer to TA=25°C. Low duty cycle pulse testing is used which keeps
junction and case temperatures equal to the ambient temperature.
PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS
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
Vo
DVI
DVL
DVO(T)
DVI(O)
IQ
ICL
VIN(min)
IADJ
IO(min)
Io=10mA, TA=258C
(Note 4)
Vo + 1V<VIN<12
10mA<Io<1A
1mA<Io<150mA
Io=100mA (Note 4)
Io=500mA (Note 4)
Io=1000mA (Note 4)
VIN=Vo + 1 for all conditions:
Io=100mA (Note 4)
Io=500mA (Note 4)
Io=1000mA (Note 4)
Vo=5% Below Regulation Point
VIN=2.5V, Vo=VADJ (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/8C
mV
mA
A
V
mA
mA
2
www.irf.com
Rev. 2.3
08/02/02
IRU1206 / IRU1207 / IRU1208 / IRU1209
PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS
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
IQ(SD)
VEN(L)
VEN(L)
VTH(FG)
VHYS
VF(SAT)
Enable=Open
Regulator OFF (Note 4)
Regulator ON (Note 4)
VEN(L)=0V to 0.8V (Note 4)
VEN(L)=2V to Vin (Note 4)
Output Ramping Up
Io=5mA
Io=500mA
0.01
2
0.1
100
5
0.8
400
230
1
0.8
2
600
mA
V
V
mA
mA
%VO
%VO
mV
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.
PIN DESCRIPTIONS
PIN SYMBOL PIN DESCRIPTION
VIN
(All devices)
VOUT
(All devices)
Gnd
(All devices)
Enable
(IRU1207, IRU1209)
Flag
(IRU1207, IRU1208)
Adj
(IRU1208, IRU1209)
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 VOUT in order
for the device to regulate properly.
The output of the regulator. A minimum of 2.2mF 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 VIN 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 VOUT pin and ground sets the output voltage.
Note 3: Ground current is the regulator quiescent current 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 temperature of 0 to +1258C.
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 mF
capacitance and the ESR in the range of 0.5 to 2V in-
sures the stability of the system.