SC4501 Semtech Corporation, SC4501 Datasheet - Page 5

• Manufacturer Part Number: SC4501
• Description: 2MHz Step-Up Switching Regulator
• Manufacturer: Semtech Corporation

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POWER MANAGEMENT
Pin Descriptions (MLPD - 10)
Block Diagram
2005 Semtech Corp.
Pin
4,5
6,7
10
2
3
8
9
1
Exposed Pad
SHDN
COMP
ROSC
FB
SS
Pin Name
10
REG_GOOD
ENABL E
IN
3
8
2
1
9
COMP
ROSC
SHDN
GND
1.1V
SW
SS
FB
IN
4.6 A
1.242V
REFERENC E
+
-
VOLTAGE
CMP
Pin Function
Shutdown Pin. The accurate 1.1V shutdown threshold and the 4.6uA shutdown pin current
hysteresis allow the user to set the undervoltage lockout threshold and hysteresis for the switching
regulator. Pulling this pin below 0.1V causes the converter to shut down to low quiescent current.
Ground. Tie both pins to the ground plane. Pins 4 and 5 are not internally connected.
Collector of the internal power transistor. Connect to the boost inductor and the rectifying diode.
Power Supply Pin. Bypassed with capacitors close to the pin.
Soft-Start Pin. A capacitor from this pin to the ground lengthens the start-up time and reduces start-
up current.
The output of the internal transconductance error amplifier. This pin is used for loop compensation.
The inverting input of the error amplifier. Tie to an external resistive divider to set the output voltage.
Tie this pin to IN if the UVLO and the shutdown features are not used. This pin should not be left
floating.
A resistor from this pin to the ground sets the switching frequency.
The exposed pad must be soldered to the ground plane on the PCB for good thermal conduction.
+
-
EA
SHUTDOWN
THERMAL
Figure 3. SC4501 (MLPD-10) Block Diagram.
REG
CLK
1.5 A
ENABL E
CLK
OSCILLATOR
-
+
PWM
5
INTERNAL
SUPPLY
SLOPE COMP
R
S
REG
Q
+
+
ILIM
+
-
I-LIMIT
ISEN
+
-
GND
SW
6
4
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SC4501
SW
R
GND
7
SENSE
5