LM5007MM National Semiconductor, LM5007MM Datasheet - Page 7

• Manufacturer Part Number: LM5007MM
• Description: IC BUCK ADJ .5A 8MSOP
• Manufacturer: National Semiconductor
• Type: Step-Down (Buck)r

Specifications of LM5007MM

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 2.5 ~ 73 V
• Current - Output: 500mA
• Frequency - Switching: 800kHz
• Voltage - Input: 9 ~ 75 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-MSOP, Micro8™, 8-uMAX, 8-uSOP,
• For Use With: LM5007EVAL - EVALUATION BOARD FOR LM5007
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -

Over-Voltage Comparator
The over-voltage comparator is provided to protect the output
from overvoltage conditions due to sudden input line voltage
changes or output loading changes. The over-voltage com-
parator monitors the FB pin versus an internal 2.875V refer-
ence (OV_REF). If the voltage at FB rises above OV_REF the
comparator immediately terminates the buck switch on time
pulse.
FIGURE 1. Low Ripple Output Configuration
FIGURE 2. Self Biased Configuration
7
ON Time generator and Shutdown
The on time of the LM5007 is set inversely proportional to the
input voltage by an external resistor connected between Ron
and Vin. The Ron terminal is a low impedance input biased at
approximately 1.5V. Thus the current through the resistor and
into the Ron terminal is approximately proportional to Vin and
used internally to control the on timer. This scheme of input
voltage feed-forward hysteretic operation achieves nearly
constant operational frequency over varying line and load
conditions. The on time equation for the LM5007 is :
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