SPX1117M3-L-1-5 Exar Corporation, SPX1117M3-L-1-5 Datasheet - Page 7

• Manufacturer Part Number: SPX1117M3-L-1-5
• Description: IC REG LDO 1.5V 800MA SOT223-3
• Manufacturer: Exar Corporation

Specifications of SPX1117M3-L-1-5

• Regulator Topology: Positive Fixed
• Voltage - Output: 1.5V
• Voltage - Input: 2.6 ~ 15 V
• Voltage - Dropout (typical): 1.1V @ 800mA
• Number Of Regulators: 1
• Current - Output: 800mA
• Current - Limit (min): 1A
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SOT-223 (3 leads + Tab), SC-73, TO-261
• Primary Input Voltage: 3V
• Output Voltage Fixed: 1.5V
• Dropout Voltage Vdo: 1.1V
• No. Of Pins: 3
• Output Current: 800mA
• Operating Temperature Range: -40°C To +125°C
• Termination Type: SMD
• Mounting Style: SMD/SMT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Lead free / RoHS Compliant
• Other names: 1016-1236

layer on the backside of the substrate. Refer
to table 1 for the results of the experiment.
The
components in the application can affect the
thermal resistance of the SPX1117. The actual
thermal resistance can be determined with
experimentation.
SPX1117 power dissipation is calculated as
follows:
Maximum Junction Temperature
Maximum
exceed 125°C.
R
Ripple rejection can be improved by adding a
capacitor between the ADJ pin and ground as
shown in Figure 23. When ADJ pin bypassing
is used, the value of the output capacitor
required increases to its maximum. If the ADJ
pin is not bypassed, the value of the output
capacitor can be lowered to 10μF for an
electrolytic aluminum capacitor or 2.2μF for a
ceramic or solid tantalum capacitor (Fig 22).
However
capacitor should be chosen with respect to the
following equation:
© 2010 Exar Corporation
IPPLE
thermal
Fig. 19: Substrate Layout for SOT-223
R
EJECTION
the
junction
value
interaction
6.28
temperature
1
of
the
from
ADJ-bypass
must
other
not
.
8
8
7/11
0
0
0
0
m
m
Where
C: value of capacitor in Farads
F
R1: value of resistor R1 in ohms
If an ADJ-bypass capacitor is used, the
amplitude
independent of the output voltage. If an ADJ-
bypass capacitor is not used, the output ripple
will be proportional to the ratio of the output
voltage to the reference voltage:
Where M=multiplier for the ripple seen when
the ADJ pin is optimally bypassed.
Ripple rejection for the adjustable version is
shown in Figure 20.
O
The output of the adjustable regulator can be
set to any voltage between 1.25V and 15V.
The value of V
using the formula
A small correction to this formula is required
depending on the values of resistors R1 and
R2, since the adjustable pin current (approx
50μA) flows through R2. When IADJ is taken
into account, the formula becomes
Where V
R
: ripple frequency in Hz
UTPUT
A
A
L
L
o
o
REF
V
w
w
IN
=1.25V
V
=3.3V, V
OLTAGE
D
D
of
r
r
Fig. 20: Ripple Rejection
o
o
OUT
p
p
the
OUT
o
o
V
can be quickly approximated
=1.8V(adj), I
REF
u
u
1.25
t
t
=1.25V
output
V
V
o
o
l
l
t
t
a
a
LOAD
g
g
ripple
e
e
=200mA
S
S
R
R
P
P
e
e
X
X
g
g
Rev. 2.0.0
u
will
1
u
1
l
l
1
1
a
a
1
t
1
t
o
o
be
7
7
r
r