LM2675M-3.3/NOPB National Semiconductor, LM2675M-3.3/NOPB Datasheet - Page 22

• Manufacturer Part Number: LM2675M-3.3/NOPB
• Description: IC REG SIMPLE SWITCHER 8-SOIC
• Manufacturer: National Semiconductor
• Series: SIMPLE SWITCHER®r
• Type: Step-Down (Buck)r

Specifications of LM2675M-3.3/NOPB

• Internal Switch(s): Yes
• Synchronous Rectifier: No
• Number Of Outputs: 1
• Voltage - Output: 3.3V
• Current - Output: 1A
• Frequency - Switching: 260kHz
• Voltage - Input: 6.5 ~ 40 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Package: 8SOIC N
• Minimum Input Voltage: 8 V
• Maximum Input Voltage: 40 V
• Switching Frequency: 260(Typ) KHz
• Operating Supply Voltage: 6.5 to 40 V
• Maximum Output Current: 1 A
• Output Type: Fixed
• Output Voltage: 3.3 V
• Efficiency: 86(Typ) %
• Primary Input Voltage: 12V
• No. Of Outputs: 1
• Output Current: 1A
• No. Of Pins: 8
• Operating Temperature Range: -40°C To +125°C
• Msl: MSL 1 - Unlimited
• Filter Terminals: SMD
• Rohs Compliant: Yes
• For Use With: LM2675-5.0EVAL - EVALUATION BOARD FOR LM2675-5.0
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Power - Output: -
• Other names: *LM2675M-3.3; *LM2675M-3.3/NOPB; LM2675M-3.3

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Application Information
TYPICAL SURFACE MOUNT PC BOARD LAYOUT,
FIXED OUTPUT (4X SIZE)
C
C
D1 - 1A, 40V Schottky Rectifier, Surface Mount
L1 - 33 µH, L23, Coilcraft DO3316
C
TYPICAL SURFACE MOUNT PC BOARD LAYOUT,
ADJUSTABLE OUTPUT (4X SIZE)
C
C
D1 - 1A, 40V Schottky Rectifier, Surface Mount
L1 - 68 µH, L30, Coilcraft DO3316
C
R1 - 1k, 1%
R2 - Use formula in Design Procedure
Layout is very important in switching regulator designs. Rap-
idly switching currents associated with wiring inductance can
generate voltage transients which can cause problems. For
minimal inductance and ground loops, the wires indicated by
heavy lines (in Figure 2 and Figure 3) should be wide
printed circuit traces and should be kept as short as
IN
OUT
B
IN
OUT
B
- 0.01 µF, 50V, Ceramic
- 0.01 µF, 50V, Ceramic
- 15 µF, 50V, Solid Tantalum Sprague, “594D series”
- 15 µF, 50V, Solid Tantalum Sprague, “594D series”
- 68 µF, 16V, Solid Tantalum Sprague, “594D series”
- 33 µF, 25V, Solid Tantalum Sprague, “594D series”
FIGURE 18. PC Board Layout
22
possible. For best results, external components should be
located as close to the switcher IC as possible using ground
plane construction or single point grounding.
If open core inductors are used, special care must be
taken as to the location and positioning of this type of induc-
tor. Allowing the inductor flux to intersect sensitive feedback,
IC ground path, and C
OUT
wiring can cause problems.
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