LP3952

SNVS518A – JULY 2007 – REVISED MARCH 2013

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Symbol

Symbol explanation

Value

Unit

Type

100

nF

Ceramic, X7R

100

nF

Ceramic, X7R

5.6

k

Ω

±1%

82

k

Ω

±1%

Rectifying Diode (Vf @ maxload)

0.3

V

Schottky diode

C between Audio input and ASE

100

nF

Ceramic, X7R / X5R

LEDs

User defined

Application Examples

EXAMPLE 1

There may be cases where the audio input signal going into the LP3952 is too weak for audio synchronization. This

figure presents a single-supply inverting amplifier connected to the ASE input for audio signal amplification. The

amplification is +20 dB, which is well enough for 20 mVp-p audio signal. Because the amplifier (LMV321) is operating

in single supply voltage, a voltage divider using R3 and R4 is implemented to bias the amplifier so the input signal is

within the input common-mode voltage range of the amplifier. The capacitor C1 is placed between the inverting input

and resistor R1 to block the DC signal going into the audio signal source. The values of R1 and C1 affect the cutoff

frequency, fc = 1/(2

π*R1*C1), in this case it is around 160 Hz. As a result, the LMV321 output signal is centered

voltage system

30

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