LT1763CS8-1.8 Linear Technology, LT1763CS8-1.8 Datasheet - Page 17

• Manufacturer Part Number: LT1763CS8-1.8
• Description: IC REG LDO 1.8V 500MA LN 8SOIC
• Manufacturer: Linear Technology

Specifications of LT1763CS8-1.8

• Regulator Topology: Positive Fixed
• Voltage - Output: 1.8V
• Voltage - Input: Up to 20V
• Voltage - Dropout (typical): 0.3V @ 500mA
• Number Of Regulators: 1
• Current - Output: 500mA
• Current - Limit (min): 520mA
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

APPLICATIONS INFORMATION
Y5V and Z5U capacitors, but can still be signifi cant enough
to drop capacitor values below appropriate levels. Capacitor
DC bias characteristics tend to improve as component
case size increases, but expected capacitance at operating
voltage should be verifi ed.
Voltage and temperature coeffi cients are not the only
sources of problems. Some ceramic capacitors have a
piezoelectric response. A piezoelectric device generates
voltage across its terminals due to mechanical stress,
similar to the way a piezoelectric accelerometer or
microphone works. For a ceramic capacitor, the stress
can be induced by vibrations in the system or thermal
transients. The resulting voltages produced can cause
appreciable amounts of noise, especially when a ceramic
capacitor is used for noise bypassing. A ceramic capacitor
produced Figure 6’s trace in response to light tapping from a
pencil. Similar vibration induced behavior can masquerade
as increased output voltage noise.
500μV/DIV
V
OUT
Figure 6. Noise Resulting from
Tapping on a Ceramic Capacitor
LT1763-5
C
C
I
LOAD
OUT
BYP
= 0.01μF
= 10μF
= 100mA
100ms/DIV
1763 F06
Thermal Considerations
The power handling capability of the device will be limited
by the maximum rated junction temperature (125°C). The
power dissipated by the device will be made up of two
components:
1. Output current multiplied by the input/output voltage
2. GND pin current multiplied by the input voltage:
The GND pin current can be found by examining the GND
Pin Current curves in the Typical Performance Character-
istics section. Power dissipation will be equal to the sum
of the two components listed above.
The LT1763 series regulators have internal thermal limiting
designed to protect the device during overload conditions.
For continuous normal conditions, the maximum junction
temperature rating of 125°C must not be exceeded. It is
important to give careful consideration to all sources of
thermal resistance from junction-to-ambient. Additional
heat sources mounted nearby must also be considered.
For surface mount devices, heat sinking is accomplished
by using the heat spreading capabilities of the PC board
and its copper traces. Copper board stiffeners and plated
through-holes can also be used to spread the heat gener-
ated by power devices.
The following tables list thermal resistance for several
different board sizes and copper areas. All measurements
were taken in still air on 3/32" FR-4 board with one ounce
copper.
Table 1. DE Package, 12-Lead DFN
* Device is mounted on topside
TOPSIDE*
2500mm
1000mm
225mm
100mm
differential: (I
(I
GND
COPPER AREA
2
2
)(V
2
2
IN
BACKSIDE
2500mm
2500mm
2500mm
2500mm
).
OUT
2
2
2
2
)(V
BOARD AREA
IN
2500mm
2500mm
2500mm
2500mm
– V
OUT
LT1763 Series
2
2
2
2
), and
(JUNCTION-TO-AMBIENT)
THERMAL RESISTANCE
40°C/W
45°C/W
50°C/W
60°C/W
17
1763fg