TC1240 Ver la hoja de datos (PDF) - TelCom Semiconductor Inc => Microchip

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Fabricante

TC1240

Positive Doubling Charge Pump with Shutdown in SOT Package

TelCom Semiconductor Inc => Microchip 

Positive Doubling Charge Pump with

Shutdown in SOT Package

TC1240

ROUT =

R

OUT

OF

SINGLE

DEVICE

NUMBER OF DEVICES

VIN

...

VIN

C1A

3

TC1240

2

1

C1B

1

3

TC1240

2

6

"1"

5

4

SHDN

6

"n"

4 SHDN

5

VOUT

...

Shutdown

Control

C2

VOUT = 2 x VIN

Figure 5. Paralleling Multiple Devices to Reduce Output Resistance

PARALLELING DEVICES

To reduce the value of ROUT, multiple TC1240s can be

connected in parallel (Figure 5). The output resistance will

be reduced by a factor of N where N is the number of

TC1240s. Each device will require its own pump capacitor

(C1x), but all devices may share one resevoir capacitor (C2).

However, to preserve ripple performance the value of C2

should be scaled according to the number of paralleled

TC1240s.

LAYOUT CONSIDERATIONS

As with any switching power supply circuit good layout

practice is recommended. Mount components as close

together as possible to minimize stray inductance and

capacitance. Also use a large ground plane to minimize

noise leakage into other circuitry.

TC1240 DEMO CARD

The TC1240 Demo Card is a 1.25” x 1.0” card contain-

ing a TC1240 and all of the necessary external components

that allow the user to evaluate the device’s ability to gener-

ate a 2X non-regulated output voltage. The demo card is

fully assembled with the required external capacitors along

with a variable load resistor that allows the user to vary the

output load current of the output stage. For convenience,

several test points and jumpers are available for measuring

various voltages and currents on the circuit board.

TC1240-1 7/7/00

Figure 6. TC1240 Demo Card Schematic

5

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