SM72485MM NSC [National Semiconductor], SM72485MM Datasheet - Page 2

• Manufacturer Part Number: SM72485MM
• Description: SolarMagic 100V, 150 mA Constant On-Time Buck Switching Regulator
• Manufacturer: NSC [National Semiconductor]

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Connection Diagrams
Ordering Information
Pin Descriptions
Pin
1
2
3
4
5
6
7
8
Order Number
SM72485MME
SM72485MMX
SM72485SDE
SM72485SDX
SM72485MM
SM72485SD
RT/SD
Name
RTN
VCC
BST
RCL
SW
VIN
EP
FB
Switching Node
Boost Pin (Boot–strap capacitor
input)
Current Limit OFF time set pin
Ground pin
Feedback input from Regulated
Output
On time set pin
Output from the internal high
voltage series pass regulator.
Input voltage
Exposed Pad
8-Lead LLP
Top View
Package Type
Description
MSOP-8
LLP-8
30142302
NSC Package Drawing
Power switching node. Connect to the output inductor, re-circulating diode,
and bootstrap capacitor.
An external capacitor is required between the BST and the SW pins. A 0.01
µF ceramic capacitor is recommended. An internal diode charges the
capacitor from V
A resistor between this pin and RTN sets the off-time when current limit is
detected. The off-time is preset to 35 µs if FB = 0V.
Ground for the entire circuit.
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
V
voltage. This pin can be used for remote shutdown.
This regulated voltage provides gate drive power for the internal Buck
switch. An internal diode is provided between this pin and the BST pin. A
local 0.47 µF decoupling capacitor is required. The series pass regulator is
current limited to 9 mA.
Input operating range: 6V to 95V.
The exposed pad has no electrical contact. Connect to system ground plane
for reduced thermal resistance.
MUA08A
SDC08A
IN
. The minimum recommended on time is 400 ns at the maximum input
2
CC
during each off-time.
Package Marking
Application Information
S2485
2485
8-Lead MSOP
Top View
1000 Units on Tape and Reel
4500 Units on Tape and Reel
1000 Units on Tape and Reel
3500 Units on Tape and Reel
250 Units on Tape and Reel
250 Units on Tape and Reel
Supplied As
30142303