LM3691TL-0.9 NSC [National Semiconductor], LM3691TL-0.9 Datasheet - Page 14

• Manufacturer Part Number: LM3691TL-0.9
• Description: High Accuracy, Miniature 1A, Step-Down DC-DC Converter for Portable Applications
• Manufacturer: NSC [National Semiconductor]

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FORCED PWM MODE
Setting Mode pin high (>1.2V) places the LM3691 in Forced
PWM. The part is in forced PWM regardless of the load.
SHUTDOWN MODE
Setting the EN input pin low (<0.4V) places the LM3691 in
shutdown mode. During shutdown the PFET switch, NFET
FIGURE 5. Typical ECO Operation
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switch, reference, control and bias circuitry of the LM3691 are
turned off. Setting EN high (>1.2V) enables normal operation.
When turning on the device with EN soft-start is activated. EN
pin should be set low to turn off the LM3691 during system
power up and under-voltage conditions when the supply is
less than 2.3V. Do not leave the EN pin floating.
SOFT-START
The LM3691 has a soft-start circuit that limits in-rush current
during start-up. Output voltage increase rate is 30 mV/µsec
(at V
THERMAL SHUTDOWN PROTECTION
The LM3691 has a thermal overload protection function that
operates to protect itself from short-term misuse and overload
conditions. When the junction temperature exceeds around
150°C, the device inhibits operation. Both the PFET and the
NFET are turned off. When the temperature drops below 130°
C, normal operation resumes. Prolonged operation in thermal
overload conditions may damage the device and is consid-
ered bad practice.
OUT
= 1.8V typ.) during soft-start.