GND

OUT

LM2664

CAP-

CAP+

V+

SD

LM2664

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SNVS005E – NOVEMBER 1999 – REVISED DECEMBER 2014

10 Power Supply Recommendations

The LM2664 is designed to operate from as an inverter over an input voltage supply range between 1.8 V and

5.5 V when the LV pin is grounded. This input supply must be well regulated and capable to supply the required

input current. If the input supply is located far from the LM2664 additional bulk capacitance may be required in

addition to the ceramic bypass capacitors.

11 Layout

11.1 Layout Guidelines

The high switching frequency and large switching currents of the LM2664 make the choice of layout important.

The following steps should be used as a reference to ensure the device is stable and maintains proper LED

current regulation across its intended operating voltage and current range

•

Place CIN on the top layer (same layer as the LM2664) and as close to the device as possible. Connecting

the input capacitor through short, wide traces to both the V+ and GND pins reduces the inductive voltage

spikes that occur during switching which can corrupt the V+ line

•

Place COUT on the top layer (same layer as the LM2664) and as close as possible to the OUT and GND pin.

The returns for both CIN and COUT should come together at one point, as close to the GND pin as possible.

Connecting COUT through short, wide traces reduce the series inductance on the OUT and GND pins that can

corrupt the VOUT and GND lines and cause excessive noise in the device and surrounding circuitry.

•

Place C1 on the top layer (same layer as the LM2664) and as close to the device as possible. Connect the

flying capacitor through short, wide traces to both the CAP+ and CAP– pins.

11.2 Layout Example

Figure 17. LM2664 Layout Example

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Product Folder Links: LM2664