Datasheet IRU1160CM, IRU1160CP Datasheet (IRF)

Data Sheet No. PD94130

IRU1160

6A ULTRA LOW DROPOUT POSITIVE

ADJUSTABLE REGULATOR

FEATURES

0.62V Dropout at 6A
Fast Transient Response
1% Voltage Reference Initial Accuracy
Built-In Thermal Shutdown

APPLICATIONS

VGA Card Applications
On-Board Low Voltage Regulator Supply such
as 3.3V to 2.8V

TYPICAL APPLICATION

3.3V

100uF

V

IN

V

CTRL

DESCRIPTION

The IRU1160 is a 6A regulator with extremely low drop­out voltage using a proprietary bipolar process that
achieves comparable equivalent on resistance to that of
discrete MOSFETs. This product is specifically designed
to provide well regulated supply for applications requir­ing 2.8V or lower voltages from 3.3V ATX power supplies
where high efficiency of a switcher can be achieved with­out the cost and complexity associated with switching
regulators.

C1

5
4

V

OUT

Adj

SENSE

3
2
1

C2
100uF

IRU1160

V

5V

Figure 1 - Typical application of IRU1160 in a 3.3V to 2.8V.

PACKAGE ORDER INFORMATION

TJ (°C) 5-PIN PLASTIC 5-PIN PLASTIC
TO-263 (M) Ultra Thin-PakTM (P)

0 To 125 IRU1160CM IRU1160CP

R1
100
1%

R2
124
1%

2.7V

C3
100uF

Rev. 1.4
08/20/02

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1

IRU1160

ABSOLUTE MAXIMUM RATINGS

Input Voltage (V IN) .................................................... 7V

Control Input Voltage (V CTRL) ..................................... 14V

Power Dissipation ..................................................... Internally Limited

Storage Temperature Range ...................................... -65°C To 150°C

Operating Junction Temperature Range ..................... 0°C To 150°C

PACKAGE INFORMATION

V

IN

V

CTRL

V

OUT

Adj
V

SENSE

TM

(P)

1.225

1.225

6.2

60

1.250

1.250

1.00

1.10

1.20

0.15

0.40

0.55

5

0.01

70

1.275

1.275

3

6

1.30

0.20

0.52

0.62

10

0.02

V

mV

mV

V

V

A

mA

%/W

dB

5-PIN PLASTIC TO-263 (M) 5-PIN PLASTIC ULTRA THIN-PAK

Tab is

VOUT

FRONT VIEW

5
4
3
2
1

V

IN

V

CTRL

V

OUT

Adj
V

SENSE

Tab is

VOUT

FRONT VIEW

5
4
3
2
1

θJA=35°C/W for 0.5" square pad θJA=35°C/W for 0.5" square pad

ELECTRICAL SPECIFICATIONS

Unless otherwise specified, these specifications apply over CIN=mF, COUT=10mF, and TJ=0 to 1258C.
Typical values refer to TJ=258C. VOUT=VSENSE.

PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS

Reference Voltage

Line Regulation

Load Regulation (Note 1)

Dropout Voltage (Note 2)
(VCTRL - VOUT)

Dropout Voltage (Note 2)
(VIN - VOUT)

Current Limit

Minimum Load Current (Note 3)
Thermal Regulation
Ripple Rejection

VREF

VCTRL=2.75, V IN=2V, Io=10mA,

TJ=258C, VADJ=0V

VCTRL=2.7 to 12V, V IN=2.05V to 5.5V,

Io=10mA to 6A, VADJ=0V

VCTRL=2.5V to 7V, V IN=1.75V to 5.5V,

Io=10mA, VADJ=0V
VCTRL=2.75V, VIN=2.1V,
Io=10mA to 6A, VADJ=0V
VADJ=0V for all conditions below:
VIN=2.05V, Io=1.5A
VIN=2.05V, Io=5A
VIN=2.05V, Io=6A
VADJ=0V for all conditions below:
VCTRL=2.75V, Io=1.5A
VCTRL=2.75V, Io=5A
VCTRL=2.75V, Io=6A
VCTRL=2.75V, VIN=2.05V,
DVo=100mV, VADJ=0V
VCTRL=5V, VIN=3.3V, VADJ=0V
30ms Pulse
VCTRL=5V, VIN=5V, Io=5A, VADJ=0V,
TJ=258C, VRIPPLE=1VPP at 120Hz

2

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Rev. 1.4

08/20/02

IRU1160

PARAMETER SYM TEST CONDITION MIN TYP MAX UNITS

Control Pin Current

Adjust Pin Current

VADJ=0V for all below conditions:
VCTRL=2.75V, VIN=2.05V, Io=1.5A
VCTRL=2.75V, VIN=2.05V, Io=5A
VCTRL=2.75V, VIN=2.05V, Io=6A
VCTRL=2.75V, VIN=2.05V, VADJ=0V

15
50
60
50 120

mA

mAIADJ

Note 1: Low duty cycle pulse testing with Kelvin con­nections are required in order to maintain accurate data.

Note 2: Dropout voltage is defined as the minimum dif­ferential 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 # PIN SYMBOL PIN DESCRIPTION

1
2

3
4

5

VSENSE

Adj

VOUT

VCTRL

VIN

This pin is the positive side of the reference which allows remote load sensing to achieve
excellent load regulation.
A resistor divider from this pin to the VOUT pin and ground sets the output voltage.
The output of the regulator. A minimum of 10mF capacitor must be connected from this
pin to ground to insure stability.
This pin is the supply pin for the internal control circuitry as well as the base drive for the
pass transistor. This pin must always be higher than the VOUT pin in order for the device to
regulate. (See specifications)
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 dropout
voltage during the load transient response. This pin must always be higher than VOUT in
order for the device to regulate. (See specifications)

Note 3: Minimum load current is defined as the mini­mum current required at the output in order for the out­put voltage to maintain regulation. Typically the resistor
dividers are selected such that it automatically main­tains this current.

BLOCK DIAGRAM

V

IN

5

V

CTRL

Rev. 1.4
08/20/02

4

CURRENT

LIMIT

THERMAL

SHUTDOWN

+

1.25V

Figure 2 - Simplified block diagram of the IRU1160.

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V

OUT

3

V

SENSE

1

+

2

Adj

3

IRU1160

APPLICATION INFORMATION

Introduction

The IRU1160 adjustable regulator is a five-terminal de­vice designed specifically to provide extremely low drop­out voltages comparable to the PNP type without the
disadvantage of the extra power dissipation due to the
base current associated with PNP regulators. This is
done by bringing out the control pin of the regulator that
provides the base current to the power NPN and con­necting it to a voltage that is grater than the voltage present
at the VIN pin. This flexibility makes the IRU1160 ideal
for applications where dual inputs are available such as
a computer mother board with an ATX style power sup­ply that provides 5V and 3.3V to the board. One such
application is the new graphic chip sets that require any­where from 2.4V to 2.7V supply such as the Intel I740
chip set. The IRU1160 can easily be programmed with
the addition of two external resistors to any voltages
within the range of 1.25 to 5.5 V. Another major require­ment of these graphic chips such as the Intel I740 is the
need to switch the load current from zero to several amps
in tens of nanoseconds at the processor pins, which
translates to an approximately 300 to 500ns of current
step at the regulator. In addition, the output voltage tol­erances are also extremely tight and they include the
transient response as part of the specification.

The IRU1160 is specifically designed to meet the fast
current transient needs as well as providing an accurate
initial voltage, reducing the overall system cost with the
need for fewer number of output capacitors. Another fea­ture of the device is its true remote sensing capability
which allows accurate voltage setting at the load rather
than at the device.

Output Voltage Setting

The IRU1160 can be programmed to any voltages in the
range of 1.25V to 5.5V with the addition of R1 and R2
external resistors according to the following formula:

VOUT = VREF3 1+ +IADJ3R2

R2

( )

R1

Where:
VREF = 1.25V Typically
IADJ = 50mA Typically
R1 & R2 as shown in Figure 3:

V

V

IN

CTRL

VIN

IRU1160

VCTRL

Adj

VOUT

VSENSE

VREF

IADJ = 50uA

R2

R1

V

OUT

Figure 3 - Typical application of the IRU1160

for programming the output voltage.

The IRU1160 keeps a constant 1.25V between the VSENSE
pin and the VADJ pin. By placing a resistor R1 across
these two pins and connecting the VSENSE and VOUT pin
together, a constant current flows through R1, adding to
the IADJ current and into the R2 resistor producing a volt-
age equal to the (1.25/R1)3R2 + IADJ3R2. This voltage
is then added to the 1.25V to set the output voltage.
This is summarized in the above equation. Since the
minimum load current requirement of the IRU1160 is
10mA, R1 is typically selected to be a 121V resistor so
that it automatically satisfies this condition. Notice that
since the IADJ is typically in the range of 50mA, it adds a
small error to the output voltage and should be consid­ered when very precise output voltage setting is required.

Load Regulation

Since the IRU1160 has separate pins for the output (VOUT)
and the sense (V SENSE), it is ideal for providing true re­mote sensing of the output voltage at the load. This
means that the voltage drops due to parasitic resistance
such as PCB traces between the regulator and the load
are compensated for using remote sensing. Figure 4
shows a typical application of the IRU1160 with remote
sensing.

V

V

CTRL

VIN

IN

IRU1160

VCTRL

Adj

VOUT

VSENSE

R1

R L

R2

4

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Figure 4 - Schematic showing connection

for best load regulation.

Rev. 1.4

08/20/02

IRU1160

Stability

The IRU1160 requires the use of an output capacitor as
part of the frequency compensation in order to make the
regulator stable. Typical designs for the microproces­sor applications use standard electrolytic capacitors with
typical ESR in the range of 50 to 100mV and an output
capacitance of 500 to 1000mF. Fortunately as the ca­pacitance increases, the ESR decreases resulting in a
fixed RC time constant. The IRU1160 takes advantage
of this phenomena in making the overall regulator loop
stable.

For most applications a minimum of 100mF aluminum
electrolytic capacitor such as Sanyo, MVGX series,
Panasonic FA series as well as the Nichicon PL series
insures both stability and good transient response.

Thermal Design

The IRU1160 incorporates an internal thermal shutdown
that protects the device when the junction temperature
exceeds the allowable maximum junction temperature.
Although this device can operate with junction tempera­tures in the range of 1508C, it is recommended that the
selected heat sink be chosen such that during maxi­mum continuous load operation the junction tempera­ture is kept below this number. The example below
shows the steps in selecting the proper surface mount
package.

Assuming, the following conditions:

VOUT = 2.8V
VIN = 3.3V
VCTRL = 5V
IOUT = 3A (DC Avg)

Calculate the maximum power dissipation using the fol­lowing equation:

PD = IOUT3(VIN - VOUT)+ 3(VCTRL - VOUT)

PD = 13(3.3 - 2.8)+ 3(5 - 2.8) = 1.61W

Using table below select the proper package and the
amount of copper board needed.

Pkg Copper θJA(°C/W) Max Pd Max Pd

Area (TA=25°C) (TA=45°C)
TO-263 1.4"X1.4" 25 4.4W 3.6W
TO-263 1.0"X1.0" 30 3.7W 3.0W
TO-263 0.7"X0.7" 35 3.1W 2.6W
TO-263 Pad Size 45 2.4W 2.0W

Note: Above table is based on the maximum junction
temperature of 1358C.

( )

3

( )

60

IOUT

60

Rev. 1.4
08/20/02

IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: [phone]

TAC Fax: [phone]

Visit us at www.irf.com for sales contact information

Data and specifications subject to change without notice. 02/01

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5

IRU1160

(M) TO-263 Package

5-Pin

A E

K

S

B

H

G D

C

C

L

U

V

M

L

P

N

R

SYMBOL

A
B
C
D
E
G
H
K

L
M
N
P
R
S
U

V

MIN

10.05

8.28

4.31

0.66

1.14

1.575

14.605

1.143

0.00

2.49

0.33

2.286
08

1.143

6.50 REF

7.75 REF

MAX

10.668

9.169

4.597

0.91

1.40

1.829

15.875

1.68

0.305

2.74

0.58

2.794
88

2.67

NOTE: ALL MEASUREMENTS

ARE IN MILLIMETERS.

6

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Rev. 1.4

08/20/02

IRU1160

(P) Ultra Thin-Pak

TM

5-Pin

A

A1

K

H

B

G

C

L

D

C

E

V

M

L

P

N

R

U

SYMBOL

A

A1

B
C
D

E
G
H

K

L
M
N

P
R
U

V

MIN

9.27

8.89

7.87

1.78

0.63

0.25 NOM

1.72

10.41

0.76

0.03

0.89

0.25

0.79
38

5.59 NOM

7.49 NOM

MAX

9.52

9.14

8.13

2.03

0.79

10.67

1.27

0.13

1.14

1.04
68

NOTE: ALL MEASUREMENTS

ARE IN MILLIMETERS.

Rev. 1.4
08/20/02

www.irf.com

7

IRU1160

PACKAGE SHIPMENT METHOD

PKG

DESIG

M

P

PACKAGE

DESCRIPTION

TO-263
Ultra Thin-Pak

1 1 1

Feed Direction

TM

Figure A

PIN

COUNT

5
5

PARTS

PER TUBE

50
75

PARTS

PER REEL

750

2500

11 1

Feed Direction

Figure B

T & R

Orientation

Fig A
Fig B

8

IR WORLD HEADQUARTERS: 233 Kansas St., El Segundo, California 90245, USA Tel: [phone]

TAC Fax: [phone]

Visit us at www.irf.com for sales contact information

Data and specifications subject to change without notice. 02/01

www.irf.com

Rev. 1.4

08/20/02