LT1761IS5-2.5#PBF Linear Technology, LT1761IS5-2.5#PBF Datasheet - Page 18

• Manufacturer Part Number: LT1761IS5-2.5#PBF
• Description: IC, LDO VOLT REG, 2.5V, 0.1A, 5-TSOT-23
• Manufacturer: Linear Technology

Specifications of LT1761IS5-2.5#PBF

• Primary Input Voltage: 3.5V
• Output Voltage Fixed: 2.5V
• Dropout Voltage Vdo: 300mV
• No. Of Pins: 5
• Output Current: 100mA
• Operating Temperature Range: -40°C To +125°C
• Termination Type: SMD
• Msl: MSL 1 - Unlimited
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LT1761 Series
APPLICATIONS INFORMATION
and a maximum ambient temperature of 50°C, what will
the maximum junction temperature be?
The power dissipated by the device will be equal to:
where,
So,
The thermal resistance will be in the range of 125°C/W to
150°C/W depending on the copper area. So the junction
temperature rise above ambient will be approximately
equal to:
The maximum junction temperature will then be equal to
the maximum junction temperature rise above ambient
plus the maximum ambient temperature or:
Protection Features
The LT1761 regulators incorporate several protection
features which make them ideal for use in battery-pow-
ered circuits. In addition to the normal protection features
associated with monolithic regulators, such as current
limiting and thermal limiting, the devices are protected
against reverse input voltages, reverse output voltages
and reverse voltages from output to input.
18
I
I
V
I
P = 50mA(6V – 3.3V) + 1mA(6V) = 0.14W
0.14W(150°C/W) = 21.2°C
T
OUT(MAX)
OUT(MAX)
GND
JMAX
IN(MAX)
at (I
= 50°C + 21.2°C = 71.2°C
= 6V
OUT
(V
= 50mA
IN(MAX)
= 50mA, V
– V
OUT
IN
) + I
= 6V) = 1mA
GND
(V
IN(MAX)
)
Current limit protection and thermal overload protection
are intended to protect the device against current overload
conditions at the output of the device. For normal operation,
the junction temperature should not exceed 125°C.
The input of the device will withstand reverse voltages
of 20V. Current fl ow into the device will be limited to less
than 1mA (typically less than 100μA) and no negative
voltage will appear at the output. The device will protect
both itself and the load. This provides protection against
batteries which can be plugged in backward.
The output of the LT1761-X can be pulled below ground
without damaging the device. If the input is left open circuit
or grounded, the output can be pulled below ground by
20V. For fi xed voltage versions, the output will act like a
large resistor, typically 500k or higher, limiting current fl ow
to typically less than 100μA. For adjustable versions, the
output will act like an open circuit; no current will fl ow out
of the pin. If the input is powered by a voltage source, the
output will source the short-circuit current of the device
and will protect itself by thermal limiting. In this case,
grounding the SHDN pin will turn off the device and stop
the output from sourcing the short-circuit current.
The ADJ pin of the adjustable device can be pulled above
or below ground by as much as 7V without damaging the
device. If the input is left open circuit or grounded, the
ADJ pin will act like an open circuit when pulled below
ground and like a large resistor (typically 100k) in series
with a diode when pulled above ground.
1761sff