TS487 STMICROELECTRONICS [STMicroelectronics], TS487 Datasheet - Page 28

• Manufacturer Part Number: TS487
• Description: 100mW STEREO HEADPHONE AMPLIFIER WITH STANDBY MODE
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

TS486-TS487
and for various values of the input resistor R
The input resistance of the fixed gain version is
typically 20k .
The following curve shows the limits of the roll off
frequency depending on the min. and max. values
of Rin:
LOW FREQUENCY ROLL OFF WITH OUTPUT
CAPACITORS
The DC voltage on the outputs of the TS486/487
is blocked by the output capacitors C
C
the resistance of the load R
order high pass filter.
Assuming that F
amplified (with a 3dB attenuation), the minimum
value of C
C
The following curve gives directly the low roll-off
28/31
OUT2
OUT
1000
100
> 1 / (2* *F
10
. Each output capacitor C
1
0.01
Rin = 100k
OUT
is:
Rin = 20k
fixed gain versions
min
min
0.1
is the lowest frequency to be
Rin = 10k
*R
and
L
Cin (µF)
)
L
is equivalent to a first
1
OUT
in series with
Rin = 1k
OUT1
10
IN
and
.
frequency versus the output capacitor C
and for the two typical 16 and 32 impedances:
DECOUPLING CAPACITOR C
The internal bias voltage at Vcc/2 is decoupled
with the external capacitor C
The TS486 and TS487 have a specified Power
Supply Rejection Ratio parameter with C
A higher value of C
example, a 4.7µF improves the PSRR by 15dB at
200Hz (please, refer to fig. 76 "PSRR vs Bypass
Capacitor").
POP PRECAUTIONS
Generally headphones are connected using a
connector as a jack. To prevent a pop in the
headphones when plugged in the jack, a resistor
should be connected in parallel with each
headphone output. This allows the capacitors
Cout to be charged even when no headphone is
plugged.
A resistor of 1 k is high enough to be a negligible
load, and low enough to charge the capacitors
Cout in less than one second.
1000
100
10
1
10
RL = 32
100
B
C
improves the PSRR, for
OUT
( F)
B
.
1000
B
RL = 16
OUT
B
10000
= 1µF.
in µF