MAX9723
Stereo DirectDrive Headphone Amplifier
with BassMax, Volume Control, and I2C
_______________________________________________________________________________________
7
CROSSTALK
vs. FREQUENCY
-100
-80
-60
-40
-20
0
-120
MAX9723
toc16
FREQUENCY (Hz)
CROSSTALK
(dB)
10k
1k
100
10
100k
VIN = 1VP-P
RL = 32
Ω
A = 0dB
LEFT TO RIGHT
A = 0dB
RIGHT TO LEFT
A = 0dB
CROSSTALK
vs. FREQUENCY
-100
-80
-60
-40
-20
0
-120
MAX9723
toc17
FREQUENCY (Hz)
CROSSTALK
(dB)
10k
1k
100
10
100k
VIN = 1VP-P
RL = 32
Ω
A = -10dB
LEFT TO RIGHT
A = -10dB
RIGHT TO LEFT
A = -10dB
BASS BOOST FREQUENCY
RESPONSE
-5
0
5
10
15
20
-10
MAX9723
toc18
FREQUENCY (Hz)
AMPLITUDE
(dB)
10k
1k
100
10
100k
NO LOAD
R1 = 47k
Ω
BassMax DISABLED
R2 = 36k
Ω
C3 = 0.068
μF
R2 = 22k
Ω
C3 = 0.1
μF
R2 = 10k
Ω
C3 = 0.22
μF
GAIN FLATNESS
vs. FREQUENCY
-6
-5
-4
-3
-2
-1
0
1
-7
MAX9723
toc19
FREQUENCY (Hz)
AMPLITUDE
(dB)
10k
1k
100
10
100k
OUTPUT SPECTRUM
vs. FREQUENCY
MAX9723
toc20
FREQUENCY (kHz)
AMPLITUDE
(dBV)
15
10
5
-130
-120
-110
-100
-90
-80
-70
-60
-50
-40
-140
020
RL = 32
Ω
VDD = 3V
fIN = 1kHz
CHARGE-PUMP OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX9723
toc21
OUTPUT CURRENT (mA)
OUTPUT
VOLTAGE
(V)
175
150
125
100
75
50
25
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0
-3.5
0200
NO HEADPHONE LOAD
CHARGE-PUMP LOAD
CONNECTED
BETWEEN PVSS AND PGND
Typical Operating Characteristics (continued)
(VDD = SHDN = 3V, PGND = SGND = 0V, C1 = C2 = 1F, BB_ = 0V, gain = 0dB, maximum volume, BassMax disabled. Load con-
nected between OUT_ and SGND where specified. Outputs in phase, both channels loaded. TA = +25°C, unless otherwise noted.)
(See Functional Diagram/Typical Operating Circuit)