SPX5205M5-L-1-2/TR Exar Corporation, SPX5205M5-L-1-2/TR Datasheet - Page 6

• Manufacturer Part Number: SPX5205M5-L-1-2/TR
• Description: 150mA, Low0Noise LDO Voltage Regulator
• Manufacturer: Exar Corporation

Specifications of SPX5205M5-L-1-2/TR

• Regulator Topology: Positive Fixed
• Voltage - Output: 1.2V
• Voltage - Input: 2.5 V ~ 16 V
• Number Of Regulators: 1
• Current - Output: 150mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: SC-74A, SOT-753
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

SPX5205
150mA, Low-Noise LDO Voltage Regulator
The SPX5205 requires an output capacitor for
device stability. Its value depends upon the
application circuit. In general, linear regulator
stability decreases with higher output currents.
In applications where the SPX5205 is putting
out less current, a lower output capacitance may
be sufficient. For example, a regulator sourcing
only 10mA, requires approximately half the
capacitance as the same regulator sourcing
150mA.
Bench testing is the best method for determining
the proper type and value of the capacitor since
the high frequency characteristics of electro-
lytic capacitors vary widely, depending on type
and manufacturer. A high quality 2.2μF alumi-
num electrolytic capacitor works in most appli-
cation circuits, but the same stability often can
be obtained with a 1μF tantalum electrolytic.
With the SPX5205 adjustable version, the mini-
mum value of output capacitance is a function of
the output voltage. The value decreases with
higher output voltages, since closed loop gain is
increased.
Typical Applications Circuits
A 10nF capacitor on BYP pin will significantly
reduce output noise but it may be left uncon-
nected if the output noise is not a major concern.
The SPX5205 start-up speed is inversely pro-
Figure 1. Typical Adjustable Output Voltage.
V
IN
+
GND
Hi-ON
Lo-OFF
EN
1
3
2
TOP View
SPX5205
6
(Optn)
BYP
5
portional to the size of the BYP capacitor. Ap-
plications requiring a slow ramp-up of the out-
put voltage should use a larger C
if a rapid turn-on is necessary, the BYP capaci-
tor can be omitted.
The SPX5205’s internal reference is available
through the BYP pin.
The Typical Application Circuit shown on page
1 represents a SPX5205 standard application
circuit. The EN (enable) pin is pulled high
(>2.0V) to enable the regulator. To disable the
regulator, EN < 0.4V.
The SPX5205 in Figure 1 illustrates a typical
adjustable output voltage configuration. Two
resistors (R1 and R2) set the output voltage. The
output voltage is calculated using the formula:
R2 must be > 10 k
should be between 22 k and 47k . A capacitor
placed between adjustable and ground will pro-
vide improved noise performance.
4
ADJ
V
OUT
APPLICATION INFORMATION
= 1.235V x ( 1 + R1/R2)
R2
R1
and for best results, R2
+
V
BYP
OUT
. However,
REV. H