LM5007
Pin Descriptions
Pin
1
2
Name
SW
BST
Switching Node
Boost Boot–strap capacitor input
Description
Application Information
Power switching node. Connect to the LC output filter.
An external capacitor is required between the BST
and the SW pins. A 0.01uF ceramic capacitor is
recommended. An internal diode between Vcc and
BST completes the Buck gate drive bias network.
A resistor between this pin and RTN determines the
variation of off time, along with the FB pin voltage, per
cycle while in current limit. The off time is preset to
17uS if FB =0V and decreases as the FB pin voltage
increases.
This pin is connected to the inverting input of the
internal regulation comparator. The regulation
threshold is 2.5V.
A resistor between this pin and Vin sets the switch on
time as a function of Vin. The minimum recommended
on time is 300ns at the maximum input voltage.
3
R
CL
Current Limit OFF time programming pin
Toff = 10
-5
/ (0.59 + (FB / 7.22 x 10
− 6
x R
CL
))
4
5
RTN
FB
Circuit Ground
Feedback Signal from Regulated Output
6
R
ON
On time set pin
Ton = 1.42 x 10
-10
R
ON
/ Vin
7
Vcc
Output from the internal high voltage bias regulator. If an auxiliary voltage is available to raise the voltage
V
CC
is nominally regulated to 7 Volts
on this pin, above the regulation setpoint (7V), the
internal series pass regulator will shutdown, reducing
the IC power dissipation. Do not exceed 14V. This
output provides gate drive power for the internal Buck
switch. An internal diode is provided between this pin
and the BST pin. A local 0.1uF decoupling capacitor
is recommended. Series pass regulator is current
limited to 10mA.
Input supply voltage
Exposed PAD, underside of the LLP package
option
Recommended operating range: 9V to 75V.
Internally bonded to the die substrate. Connect to
GND potential for low thermal impedance.
8
-
Vin
EP
3
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