SC4501 Semtech Corporation, SC4501 Datasheet - Page 4

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

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POWER MANAGEMENT
Pin Descriptions (MSOP-8)
Block Diagram
Block Diagram
2005 Semtech Corp.
Pin
2
3
4
5
6
7
8
1
Exposed Pad
Pin Name
COMP
ROSC
SHDN
SHDN
COMP
ROSC
GND
SW
FB
SS
REG_GOOD
SS
IN
ENABLE
FB
3
IN
6
2
1
8
7
1.1V
4.6 A
1.242V
REFERENCE
+
-
Power Supply Pin. Bypassed with capacitors close to the pin.
VOLTAGE
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 to the ground plane.
Collector of the internal power transistor. Connect to the boost inductor and the rectifying diode.
Soft-Start Pin. A capacitor from this pin to the ground lengthens the start-up time and reduces start-
up current.
CMP
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
Figure 2. SC4501 (MSOP-8) Block Diagram.
SHUTDOW N
THERMAL
REG
CLK
1.5 A
ENABLE
4
CLK
OSCILLATOR
-
+
PWM
INTERNAL
SUPPLY
SLOP E COMP
R
S
REG
Q
+
+
ILIM
+
-
I-LIMIT
ISEN
+
-
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GND
SC4501
SW
5
4
R
SENSE