SPX29300T-L-1-8/TR Exar Corporation, SPX29300T-L-1-8/TR Datasheet - Page 6

• Manufacturer Part Number: SPX29300T-L-1-8/TR
• Description: 3A Low Dropout Voltage Regulator
• Manufacturer: Exar Corporation

Specifications of SPX29300T-L-1-8/TR

• Regulator Topology: Positive Fixed
• Voltage - Output: 1.8V
• Voltage - Input: 2.8 V ~ 16 V
• Number Of Regulators: 1
• Current - Output: 3A
• Current - Limit (min): 3A
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: TO-263-4, D²Pak (3 leads + Tab), TO-263AA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

THEORY OF OPERATION
The SPX29300/01/02 incorporates protection
against over-current faults, reversed load
insertion, over temperature operation, and
positive and negative transient voltage.
T
Although the SPX29300/01/02 offers limiting
circuitry for overload conditions, it is still
necessary
junction temperature is not exceeded in the
application. Heat will flow through the lowest
resistance path, the junction-to-case path. In
order to insure the best thermal flow of the
component, proper mounting is required.
TO-220 D
Assume
I
2°C/W, and θ
T
θ
θ
θ
The power calculated under these conditions
is:
And the junction temperature is calculated as
or
Reliable
Requirements
C
The output capacitor is needed to insure
stability and minimize the output noise. The
value of the capacitor varies with the load.
However, a minimum value of 10μF aluminum
© 2010 Exar Corporation
OUT
A
HA
CH
JC
HERMAL
APACITOR
= ambient temperature,
= heatsink to ambient thermal resistance
= case to heatsink thermal resistance
= junction to case thermal resistance
= 1.5A, T
that
C
ESIGN
operation
ONSIDERATIONS
to
50
R
JC
EQUIREMENTS
= 3C°/W, where:
A
insure
V
7.5
= 50°C, θ
IN
E
XAMPLE
=
1
is
that
10V,
2
:
HA
insured.Capacitor
3
= 1°C/W, θ
the
V
7.5
95°
OUT
maximum
=
CH
5V,
=
6/10
capacitor will guarantee stability over all load
conditions.
A tantalum capacitor is recommended if a
faster load transient response is needed. If the
power source has high AC impedance, a 0.1μF
ceramic capacitor between input & ground is
recommended.
M
To ensure a proper behavior of the regulator
under light load, a minimum load of 5mA for
SPX29300/01/02 is required.
A
The
regulator that can be programmed to any
value between 1.25V and 16V using 2 external
resistors, R1 and R2. The relationship between
the resistors and the output voltage is:
E
The SPX29301 features an error flag that
indicates either an over current or under
current voltage condition. The flag output goes
low, sinking 10mA when either conditions
occurs.
E
The SPX29301/02 has an Enable function that
switches the regulator on and off. Their
thresholds are TTL compatible. When the
regulator is active, approximately 20µA flows
through the Enable pin.
T
Figure 1 represents the typical implementation
for an adjustable output regulator. The values
of R1 and R2 set the output voltage value as
follows:
A minimum value of 10kohms is recommended
for R2 with a range between 10kΩ and 47kΩ.
3
3
RROR
NABLE
YPICAL
DJUSTABLE
INIMUM
A
A
L
L
o
o
SPX29300/01/02
F
w
w
I
LAG
A
NPUT
L
PPLICATION
D
D
OAD
r
r
R
o
o
EGULATOR
p
p
C
o
o
URRENT
S
u
S
u
t
t
P
P
V
V
X
X
1.240
C
o
o
2
2
IRCUITS
l
l
is
D
1
t
t
9
9
a
a
ESIGN
3
3
g
g
1
an
0
0
e
e
0
0
R
R
/
/
e
e
adjustable
0
0
g
g
Rev. 2.1.0
u
u
1
1
l
l
/
/
a
a
0
t
0
t
o
o
2
2
r
r