UTC 3544
APPLICATION EXAMPLE
330μ
+
LINEAR INTEGRATED CIRCUIT
+
Vcc
+
Vcc
8
OUT2
7
BIA
S
6
47μ
IN2
5
1μ
V
IN
2
BIAS
6dB
TSD
+
6dB
90K
+
90K
MUTE
1
OUT1
+
VMUTE
100k
H:Active
L:Mute
1μ
2
MUTE
3
IN1
4
GND
1μ
V
IN
1
EXPLANATION OF EXTERNAL XOMPONENTS
(1)Input coupling capacitor(C3 and C5)
Determined by the low-band cut-off frequency.Since the input impedance for this IC is 180kΩ,it can be
determined by the formula below,but take into consideration the fluctuations,ambent temperature,etc.(a
multi-layered ceramic capacitor is recommended).
C3(C5)=1/(2π×180kΩ×f)
(2)BIAS capacitor(C6)
47μF when Vcc=5V,and 33μF when Vcc=3V.If the capacitance is lowered too much,the electrical
characteristics will be adversely affected and popping noise may occur.Therefore,take th sufficient considerations
before changing these values.
(3)MUTE pin for anti-pop measures(R2 and C2)
Possesses an impedance of 190kΩ with respect to GND,so if R2 is increased too much,the MUTE mode may
become unable to be released.
(4)Output coupling capacitor(C1 and C7)
Determined by the low-band cutoff frequency.As the output load resistance value R
L
(assuming that for output
protection or current limiting,a resistor Rx will be inserted),it can be determined by the formula below.
C1(C7)=1/(2π×(R
L
+Rx)
×f)
(5)Input gain adjustment resistor(R3 and R4)
Input gain adjustment can by performed by extemal resistors R3 and R4,The desired gain can be set by the
formula givev below.
Gvc=6+20log(90kΩ/(90kΩ+R3))［ dB
�½
UTC
UNISONIC TECHNOLOGIES
CO. LTD
6
QW-R107-040,A
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