Datasheet SPX1585AT, SPX1585AT-1.5, SPX1585AT-2.5, SPX1585AT-3.3, SPX1585AT-5.0 Datasheet (Sipex Corporation)

SPX1585

5A Low Dropout Voltage Regulator

Adjustable & Fixed Output,

Fast Response

FEATURES

Adjustable Output Down To 1.2V

•

Fixed Output Voltages 1.5V, 2.5V, 3.3V & 5.0V

•

Output Current Of 5A

•

Low Dropout Voltage 1.1V Typ @ 5A.

•

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 SPX1585 are low power 5A adjustable and fixed voltage regulators that are very easy to use. It requires only 2 external resistors
to set the output voltage for adjustable version. The SPX1585 are designed for low voltage applications that offer 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 SPX1585 features low dropout of a maximum 1.2 volts.

The SPX1585 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 SPX1585 are offered in a 3-pin TO-220 and TO-263 package compatible with other 3 terminal regulators. For a 8A low dropout
regulator refer to the SPX1585 data sheet.

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

•

of this device flows into the load, which

Q

PIN CONNECTIONS

TO-263-3 (T)

3

SPX1585

Top View

2

1

V

IN

V

OUT

ADJ/GND

TO-220-3 (U)

SPX1585

Front View

3

2

1

V

IN

V

OUT

ADJ/GND

Rev. 10/23/00

SPX1585

ABSOLUTE MAXIMUM RATINGS

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

Storage Temperature Range ............................ -65° to +150°C Input to Output Voltage Differential .................... 10V

Operating Junction Temperature Range

SPX1585 Control Section.......................... -45°C +125°C

SPX1585 Power Transistor.........................-45°C +150°C

ELECTRICAL CHARACTERISTICS

PARAMETER CONDITIONS Typ SPX1585A SPX1585 UNITS

Min Max Min Max

1.5V Version

2.5V Version

3.3V Version

5.0V Version

SPX1585-5.0V, 0 ≤ I

All Voltage Options

Reference Voltage (Vref)

Min. Load Current (Note 3)

Line Regulation (∆Vref(Vin)) 2.75V≤VIN ≤7V, Iout=10mA, TJ=25ºC

Load Regulation(∆Vref(Iout))

Dropout Voltage

Iout(MAX)

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

Thermal Regulation
(∆Vout(Pwr))
Temperature Stability
(∆Vout(T))
Output Noise, RMS 10Hz to 10kHz TA=25ºC 0.003 % Vo

Thermal Resistance

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

V

7V, P≤ P

≤

IN

1.5V≤ (V

1.5V≤ (V

(Note 3)
V

≤7V, I

IN

10mA≤I

OUT

0≤I

≤5A, VIN=7V, TJ=25ºC (Note 2)

OUT

V

=1% I

∆

REF

I
VIN=7V 6 5.2 5.2 A Current Limit

1.4V ≤ (V

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

Junction to Ambient

DD Package Junction to Tab
Junction to Ambient

(NOTE 1)

< 5A, 3.3V<VIN<10V 1.5

OUT

< 5A, 4.0V<VIN<10V 2.5

OUT

< 5A, 4.8V<VIN<10V 3.3

OUT

≤ 5A, 6.5V≤V

OUT

MAX

-V

)≤5.75V, 10mA≤I

IN

OUT

–V

)≤5.75V

IN

OUT

=0mA, TJ=25ºC (Note 2)

OUT

≤5A, (VIN-V

- V

IN

OUT

OUT

) (Note3)

at I

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

OUT

12V

≤

IN

5A

≤

OUT

)=3V, TJ=25ºC (Note 3)

= 5A (Note 3)

OUT

< 5A (Note 2)

OUT

1.485 1.515 1.47 1.53 V Output Voltage (Note 2) SPX1585-1.5V, 0 < I

1.47 1.53 1.455 1.545

2.475 2.525 2.45 2.55 V Output Voltage (Note 2) SPX1585-2.5V, 0 < I

2.45 2.55 2.425 2.575

3.267 3.333 3.234 3.366 V Output Voltage (Note 2) SPX1585-3.3V, 0 < I

3.234 3.366 3.069 3.399

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

4.900 5.100 4.65 5.15

1.250 1.225 1.270 1.225 1.270

5 10 10

0.005 0.2 0.2

0.005 0.2 0.2

0.05 0.3 0.3

0.05 0.3 0.3

1.1 1.2 1.2

(Note 2)

0.25 %

3.0 3.0 TO-220 Junction to Tab

60 60

3.0 3.0

60 60

1 1 %

V

V

%

%

ºC/W

Rev. 10/23/00

SPX1585

APPLICATION HINTS

The SPX1585 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 22µF aluminum electrolytic
capacitor or a 10µF 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
10µF for an electrolytic aluminum capacitor or 4.7µF 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 SPX1585 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

= 10V, 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

= 3°C/W

JC

Power dissipation under this condition
P

= (VIN – V

D

OUT

) * I

= 7.5W

OUT

Junction Temperature
T

= TA + PD * (

J

θ

Case – HS

+ θ

HS

)

θ

JC

For the Control Section
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

SPX1585

Basic Adjustable Regulator

V

IN

V

OUT

= V

REF

SPX1585

ADJ

I

ADJ

50uA

* ( 1 + R2/R1) + I

ADJ

* R

V

REF

2

V

OUT

R

1

R

2

Fig.2 Basic Adjustable Regulator

Output Voltage

Consider Figure 2. The resistance R

generates a constant

1

current flow, normally the specified load current of 10mA.
This current will go through the resistance R
output voltage. The current I

is very small and constant.

ADJ

to set the overall

2

Therefore its contribution to the overall output voltage is very
small and can generally be ignored

R

V

IN

SPX1585

ADJ

Parasitic Line

P

Resistance

Connect R1 to

Case of Regulator

V

OUT

R

1

R

2

R

L

Connect R2 to Load

Fig.3 Basic Adjustable Regulator

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,

1

and not to the load. For the same reason, it is best to connect
the resistor R

to the Negative side of the load.

2

V

5V

IN

SPX1585

C1

10uF

V

OUT

3.3V

C2

10uF

Basic Fixed Regulator

Output Voltage

The fixed voltage LDO voltage regulators are simple to use
regulators since the V

is preset to the specifications. It is

OUT

important however, to provide the proper output capacitance
for stability and improvement. For most operating conditions
a capacitance of 22uF tantalum or 100uF electrolytic will
ensure stability and prevent oscillation.

Rev. 10/23/00

SPX1585

TYPICAL APPLICATIONS

V

IN

C

1

Fig. 4 5A Current output Regulator

(Note A)

V

IN

*C1 improves ripple rejection. Xc

should be ~ R

Note A: V

IN(MIN)

+

10µF

at ripple frequency.

1

= (Intended V

Fig. 6 Improving Ripple Rejection

V

IN

SPX1585

ADJ

OUT

LOAD

R

1

IN

V

OUT

= V

IN

C

1

(1 + R2 ) + I

REF

R

1

SPX1585

ADJ

ADJ R2

OUT

R

1

R

2

Fig. 5 Typical Adjustable Regulator

IN OUT

SPX1585

ADJ

) + (V

OUT

DROPOUT (MAX)

365Ω

)

R

1%

5V

R

1

121Ω

1%

2

+

10µF*

V

OUT

150µF

C

1

V

IN

(Note A)

TTL

Input

Note A: V

IN OUT

SPX1585

+

10µF

1k

IN(MIN)

ADJ

1k

= (Intended V

2N3904

OUT

) + (V

121Ω

1%

365Ω

1%

DROPOUT (MAX)

Fig.7 5V Regulator with Shutdown

V

OUT

C

2

5V

+

100µF

)

Rev. 10/23/00

SPX1585

TYPICAL CHARACTERISTICS

Rev. 10/23/00

SPX1585

ORDERING INFORMATION

Ordering No. Precision Output Voltage Packages

SPX1585U
SPX1585U-1.5
SPX1585U-2.5
SPX1585U-3.3
SPX1585U-5.0
SPX1585AU
SPX1585AU-1.5
SPX1585AU-2.5
SPX1585AU-3.3
SPX1585AU-5.0
SPX1585T
SPX1585T-1.5
SPX1585T-2.5
SPX1585T-3.3
SPX1585T-5.0
SPX1585AT
SPX1585AT-1.5
SPX1585AT-2.5
SPX1585AT-3.3
SPX1585AT-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

Rev. 10/23/00