SM72485/NOPB National Semiconductor, SM72485/NOPB Datasheet - Page 2

• Manufacturer Part Number: SM72485/NOPB
• Description: IC BUCK SWITCH 100V REG 8-LLP
• Manufacturer: National Semiconductor
• Series: SolarMagic™r
• Type: Step-Down (Buck)r

Specifications of SM72485/NOPB

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: Adj to 2.5V
• Current - Output: 150mA
• Frequency - Switching: 50kHz ~ 1.1MHz
• Voltage - Input: 6 V ~ 95 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: *
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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Connection Diagram
Ordering Information
Pin Descriptions
Pin
1
2
3
4
5
6
7
8
Order Number
SM72485E
SM72485X
SM72485
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
Description
Package Type
LLP-8
LLP-8
LLP-8
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.
IN
. The minimum recommended on time is 400 ns at the maximum input
8-Lead LLP
Top View
SDC08A
SDC08A
SDC08A
2
CC
during each off-time.
Application Information
30142302
Package Marking
S2485
S2485
S2485
1000 Units on Tape and
4500 Units on Tape and
250 Units on Tape and
Supplied As
Reel
Reel
Reel