Datasheet SPX1084AT, SPX1084AT-1.5, SPX1084AT-2.5, SPX1084AT-3.3, SPX1084AT-5.0 Datasheet (Sipex Corporation)

5A Low Dropout Voltage Regulator

Adjustable & Fixed Output,

SPX1084

Fast Response

FEATURES

Adjustable Output Down To 1.2V

•

Fixed Output Voltages 1.5, 2.5, 3.3 & 5.0V

•

Output Current Of 5A

•

Low Dropout Voltage 1.1V Typ.

•

Extremely Tight Load And Line Regulation

•

Current & Thermal Limiting

•

Standard 3-Terminal Low Cost TO-220 & TO-263

•

Similar To Industry Standard LT1085/LT1585

•

PRODUCT DESCRIPTION

The SPX1084 are low power 5A adjustable and fixed voltage regulators with 30V maximum VIN. They are very easy to use. It
requires only 2 external resistors to set the output voltage for adjustable version. The SPX1084 are designed for low voltage
applications that offers lower dropout voltage and faster transient response. This device is an excellent choice for use in powering low
voltage microprocessor that require a lower dropout, faster transient response to regulate from +2.5V to 3.8V supplies and as a post
regulator for switching supplies applications. The SPX1084 features low dropout of a maximum of 1.2 volts.

The SPX1084 offers full protection against over-current faults, reversed input polarity, reversed load insertion, and positive and
negative transient voltage. On-Chip trimming adjusts the reference voltage to 1%. The I
increases efficiency.

The SPX1084 are offered in 3-pin TO-220 and TO-263 packages compatible with other 3 terminal regulators. For a similar 5A low
dropout voltage regulator refer to the SPX1084 datasheet. Also for higher current requirements, refer to the SPX1084 datasheet.

PIN CONNECTIONS

TO-263-3 (T)

ADJ/GND

SPX1084

1

2

V

OUT

Top View

3

V

IN

ADJ/GND

TO-220-3 (U)

Front View

APPLICATIONS

Powering VGA & Sound Card

•

Power PC Supplies

•

SMPS Post-Regulator

•

High Efficiency “Green” Computer Systems

•

High Efficiency Linear Power Supplies

•

Portable Instrumentation

•

Constant Current Regulators

•

Adjustable Power Supplies

•

Battery charger

•

SPX1084

1

23

V

V

IN

OUT

of this device flows into load, which

Q

Rev. 10/23/00

SPX1084

ABSOLUTE MAXIMUM RATINGS

Lead Temp. (Soldering, 10 Seconds) .............................. 300°C Input Voltage........................................................ 30V

Storage Temperature Range ............................ -65° to +150°C Input to Output Voltage Differential .................... 30V

Operating Junction Temperature Range

SPX1084 Control Section.......................... -45°C +125°C

SPX1084 Power Transistor.........................-45°C +150°C

ELECTRICAL CHARACTERISTICS

PARAMETER CONDITIONS Typ SPX1084A SPX1084 UNITS

Min Max Min Max

1.5V Version

3.3V<V

2.5V Version

4.0V<V

3.3V Version

4.8V<V

5.0V Version

SPX1084-5.0V, 0 ≤ I

6.5V≤V

Adjustable Version

Reference Voltage (V

All Voltage Options

Min. Load Current (Note 3)

Line Regulation (∆V

Load Regulation(∆V

Dropout Voltage

Long Term Stability TA=125ºC, 1000 Hrs. 0.3

Thermal Regulation(∆V

Temperature Stability (∆V

Output Noise, RMS 10Hz to 10kHz TA=25ºC 0.003 % VO

Thermal Resistance TO-220 Junction to Tab

The Bold specifications apply to the full operating temperature range.
Note 1: Changes in output voltage due to heating effects are covered under the specification for thermal regulation.
Note 2: Fixed Version Only
Note 3: Adjustable Version Only

OUT

) 1.250 1.238 1.262 1.225 1.270 V

REF

1.5V≤ (V

1.5V≤ (V

(Vin)) 2.75V≤VIN ≤25V, I

REF

(Note 3)

≤25V, I

V

IN

REF(IOUT

))

10mA≤I
(Note 3)

0≤I

≤5A, VIN=7V, TJ=25ºC (Note 2)

OUT

=1% I

V

∆

REF

I

(MAX)

VIN=7V 6 5.2 5.2 A Current Limit I

1.4V ≤ (V

T

OUT

(Pwr))

(T))

OUT

=25ºC, 20 ms pulse 0.01 0.020 0.020 %/W

A

Junction to Ambient
DD Package Junction to Tab
Junction to Ambient

(NOTE 1) at I

<25V

IN

<25V

IN

<25V

IN

25V

≤

IN

-V

IN

–V

IN

OUT

≤5A, (VIN-V

OUT

– V

IN

OUT

OUT

OUT

OUT

)≤25V, 10mA≤I

OUT

)≤25V

OUT

=10mA, TJ=25ºC

OUT

=0mA, TJ=25ºC (Note 2)

) (Note3)

OUT

= 10mA, Ta=25°C, unless otherwise specified.

OUT

< 5A,

< 5A,

< 5A,

≤ 5A,

1.5

2.5

3.3

5 4.950 5.050 4.9 5.1 V Output Voltage (Note 2)

5A

≤

OUT

1.250 1.225 1.270 1.212 1.288

5 10 10

0.005 0.2 0.2

0.005 0.2 0.2

)=3V, TJ=25ºC

OUT

0.05 0.7 0.7

0.05 0.3 0.3

= 5A (Note 3)

OUT

< 5A (Note 2)

OUT

1.2 1.5 1.5

(Note 2)

0.25 %

3.0
60

3.0
60

1.485 1.515 1.47 1.53 V Output Voltage (Note 2) SPX1084-1.5V, 0 < I

1.47 1.53 1.455 1.545

2.475 2.525 2.45 2.55 V Output Voltage (Note 2) SPX1084-2.5V, 0 < I

2.45 2.55 2.425 2.575

3.267 3.333 3.234 3.366 V Output Voltage (Note 2) SPX1084-3.3V, 0 < I

3.234 3.366 3.069 3.399

4.900 5.100 4.65 5.15

V

%

%

1 1 %

3.0
60

3.0
60

3.0
60

3.0
60

ºC/W

Rev. 10/23/00

SPX1084

APPLICATION HINTS

The SPX1084 incorporates protection against over-current
faults, reversed load insertion, over temperature operation, and
positive and negative transient voltage. However, the use of
an output capacitor is required in order to insure the stability
and the performances.

Stability

The output capacitor is part of the regulator’s frequency
compensation system. Either a 220µF aluminum electrolytic
capacitor or a 47µF solid tantalum capacitor between the
output terminal and ground guarantees stable operation for all
operating conditions.
However, in order to minimize overshoot and undershoot, and
therefore optimize the design, please refer to the section
‘Ripple Rejection’.

Ripple Rejection

Ripple rejection can be improved by adding a capacitor
between the ADJ pin and ground. When ADJ pin bypassing is
used, the value of the output capacitor required increases to its
maximum (220µF for an aluminum electrolytic capacitor, or
47µF for a solid tantalum capacitor). If the ADJ pin is not
bypass, the value of the output capacitor can be lowered to
100µF for an electrolytic aluminum capacitor or 15µF for a
solid tantalum capacitor.
However the value of the ADJ-bypass capacitor should be
chosen with respect to the following equation:
C = 1 / ( 6.28 * F

Where C = value of the capacitor in Farads (select an
equal or larger standard value),
F
R

= ripple frequency in Hz,

R

= value of resistor R1 in Ohms.

1

If an ADJ-bypass capacitor is use, the amplitude of the output
ripple will be independent of the output voltage. If an ADJ­bypass capacitor is not used, the output ripple will be
proportional to the ratio of the output voltage to the reference
voltage:
M = V

OUT

/ V
Where M = multiplier for the ripple seen when the ADJ pin
is optimally bypassed.
V

REF

* R1 )

R

REF

= Reference Voltage

Reducing parasitic resistance and inductance

One solution to minimize parasitic resistance and inductance is
to connect in parallel capacitors. This arrangement will
improve the transient response of the power supply if your
system requires rapidly changing current load condition.

Thermal Consideration

Although the SPX1084 offers some limiting circuitry for
overload conditions, it is necessary not to exceed the
maximum junction temperature, and therefore to be careful
about thermal resistance. The heat flow will follow the lowest
resistance path, which is the Junction-to-case thermal
resistance. In order to insure the best thermal flow of the
component, a proper mounting is required. Note that the case
of the device is electrically connected to the output. In case
the case has to be electrically isolated, a thermally conductive
spacer can be used. However do not forget to consider its
contribution to thermal resistance.

Assuming:
V

= 7V, V

IN

θ

Heatsink Case

= 5V, I

OUT

= 6°C/W,

= 1.5A, TA = 50°C/W,

OUT

θ

Heatsink Case

= 0.5°C/W, θ JC = 3°C/W

Power dissipation under this condition
P

= (VIN – V

D

OUT

) * I

= 7.5W

OUT

Junction Temperature
T

= TA + PD * (

J

θ

Case- HS

+ θ

+ θ JC)

HS

For the Control Sections
T

= 50 + 7.5*(0.5+6=3) = 121.25°C

J

121.25°C < T

for the Control & Power Sections.

J(max)

In both case reliable operation is insured by adequate junction
temperature.

Rev. 10/23/00

SPX1084

Basic Adjustable Regulator

V

IN

SPX1084

I

ADJ

50µA

V

REF

V

= V

OUT

* ( 1 + R2/R1) + I

REF

ADJ

* R

2

V

OUT

R

1

R

2

Fig.2 Basic Adjustable Regulator

Output Voltage

Consider Figure 2. The resistance R
go through the resistance R

to set the overall output voltage. The current I

2

generates a constant current flow, normally the specified load current of 10mA. This current will

1

is very small and constant. Therefore its contribution to

ADJ

the overall output voltage is very small and can generally be ignored

Load Regulation

Parasitic line resistance can degrade load regulation. In order not to affect the behavior of the regulator, it is best to connect directly
the R

resistance from the resistor divider to the case, and not to the load. For the same reason, it is best to connect the resistor R2 to

1

the Negative side of the load.

R

Parasitic Line

P

V

IN

SPX1084

Resistance

Connect R1 to

Case of Regulator

R

1

R

R

2

L

Connect R2 to Load

Fig.3 Basic Adjustable Regulator

Rev. 10/23/00

TYPICAL APPLICATIONS

V

IN

IN

C

1

SPX1084

ADJ

Fig. 4 5A Current output Regulator

(Note A)

V

IN

10µF

IN OUT

+

SPX1084

ADJ

*C1 improves ripple rejection. Xc

should be ~ R

at ripple frequency.

1

Note A: V

= (Intended V

IN(MIN)

OUT

) + (V

DROPOUT (MAX)

Fig. 6 Improving Ripple Rejection

365Ω

)

OUT

R

1%

SPX1084

V

LOAD

IN

R

1

V

= V

OUT

IN

C

1

(1 + R2 ) + I

REF

R

1

SPX1084

ADJ

ADJ R2

Fig. 5 Typical Adjustable Regulator

5V

R

1

121Ω

1%

2

+

10µF*

V

OUT

150µF

C

1

V

IN

(Note A)

TTL

Input

Note A: V

IN OUT

SPX1084

+

10µF

1k

IN(MIN)

ADJ

1k

= (Intended V

2N3904

OUT

OUT

) + (V

R

1

R

2

121Ω

1%

365Ω

1%

DROPOUT (MAX)

C

2

5V

+

100µF

)

V

OUT

Fig.7 5V Regulator with Shutdown

Rev. 10/23/00

SPX1084

ORDERING INFORMATION

Ordering No. Precision Output Voltage Packages

SPX1084U
SPX1084U-1.5
SPX1084U-2.5
SPX1084U-3.3
SPX1084U-5.0
SPX1084AU
SPX1084AU-1.5
SPX1084AU-2.5
SPX1084AU-3.3
SPX1084AU-5.0
SPX1084T
SPX1084T-1.5
SPX1084T-2.5
SPX1084T-3.3
SPX1084T-5.0
SPX1084AT
SPX1084AT-1.5
SPX1084AT-2.5
SPX1084AT-3.3
SPX1084AT-5.0

2% Adj 3 Lead TO-220
2% 1.5V 3 Lead TO-220
2% 2.5V 3 Lead TO-220
2% 3.3V 3 Lead TO-220
2% 5.0V 3 Lead TO-220
1% Adj 3 Lead TO-220
1% 1.5V 3 Lead TO-220
1% 2.5V 3 Lead TO-220
1% 3.3V 3 Lead TO-220
1% 5.0V 3 Lead TO-220
2% Adj 3 Lead TO-263
2% 1.5V 3 Lead TO-263
2% 2.5V 3 Lead TO-263
2% 3.3V 3 Lead TO-263
2% 5.0V 3 Lead TO-263
1% Adj 3 Lead TO-263
1% 1.5V 3 Lead TO-263
1% 2.5V 3 Lead TO-263
1% 3.3V 3 Lead TO-263
1% 5.0V 3 Lead TO-263

SIGNAL PROCESSING EXCELLENCE

Corporation

Sipex Corporation

Headquarters and Main Offices:

22 Linnell Circle
Billerica, MA 01821
TEL: [phone]
FAX: [phone]
e-mail: [e-mail]

233 South Hillview Drive
Milpitas, CA 95035
TEL: [phone]
FAX: [phone]

Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described
hereing; neither does it convey any license under its patent rights nor the rights of others.

Rev. 10/23/00