LP3966ES-2.5 National Semiconductor, LP3966ES-2.5 Datasheet - Page 13

• Manufacturer Part Number: LP3966ES-2.5
• Description: IC, LDO VOLT REG, 2.5V, 3A, TO-263-5
• Manufacturer: National Semiconductor

Specifications of LP3966ES-2.5

• Primary Input Voltage: 7V
• Output Voltage Fixed: 2.5V
• Dropout Voltage Vdo: 800mV
• No. Of Pins: 5
• Output Current: 3A
• Operating Temperature Range: -40°C To +125°C
• Termination Type: SMD
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Application Hints
Once the power pass element shuts down, the control loop
will rapidly cycle the output on and off until the average
power dissipation causes the thermal shutdown circuit to
respond to servo the on/off cycling to a lower frequency.
Please refer to the section on thermal information for power
dissipation calculations.
ERROR FLAG OPERATION
The LP3963/LP3966 produces a logic low signal at the Error
Flag pin when the output drops out of regulation due to low
input voltage, current limiting, or thermal limiting. This flag
has a built in hysteresis. The timing diagram in Figure 1
SENSE PIN
In applications where the regulator output is not very close to
the load, LP3966 can provide better remote load regulation
using the SENSE pin. Figure 2 depicts the advantage of the
SENSE option. LP3963 regulates the voltage at the output
pin. Hence, the voltage at the remote load will be the regu-
lator output voltage minus the drop across the trace resis-
(Continued)
FIGURE 1. Error Flag Operation
13
shows the relationship between the ERROR flag and the
output voltage. In this example, the input voltage is changed
to demonstrate the functionality of the Error Flag.
The internal Error flag comparator has an open drain output
stage. Hence, the ERROR pin should be pulled high through
a pull up resistor. Although the ERROR flag pin can sink
current of 1mA, this current is energy drain from the input
supply. Hence, the value of the pull up resistor should be in
the range of 10kΩ to 1MΩ. The ERROR pin must be
connected to ground if this function is not used. It should
also be noted that when the shutdown pin is pulled low, the
ERROR pin is forced to be invalid for reasons of saving
power in shutdown mode.
tance. For example, in the case of a 3.3V output, if the trace
resistance is 100mΩ, the voltage at the remote load will be
3V with 3A of load current, I
voltage at the sense pin. Connecting the sense pin to the
remote load will provide regulation at the remote load, as
shown in Figure 2. If the sense option pin is not required, the
sense pin must be connected to the V
LOAD
10126707
. The LP3966 regulates the
OUT
pin.
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