19-4536; Rev 0; 3/09
Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
General Description
The MAX9875 combines a high-efficiency Class D
audio power amplifier with a stereo Class AB capacitor-
less DirectDrive
®
headphone amplifier. Maxim’s 3rd
generation, filterless Class D amplifier with active emis-
sions limiting technology provides Class AB perfor-
mance with Class D efficiency.
The MAX9875 delivers up to 725mW from a 3.7V supply
into an 8Ω load with 87% efficiency to extend battery life.
The filterless modulation scheme combined with active
emissions limiting circuitry and spread-spectrum modu-
lation greatly reduces EMI while eliminating the need for
output filtering used in traditional Class D devices.
The stereo Class AB headphone amplifier in the
MAX9875 uses Maxim’s DirectDrive architecture, that
produces a ground-referenced output from a single sup-
ply, eliminating the need for large DC-blocking capaci-
tors, saving cost, space, and component height.
The device utilizes a user-defined input architecture,
three preamplifier gain settings, an input mixer, volume
control, comprehensive click-and-pop suppression, and
I
2
C control.
The MAX9875 is available in a thermally efficient,
space-saving 20-bump WLP package.
KIT
ATION
EVALU
BLE
AVAILA
Features
♦
Low Emissions, Filterless Class D Amplifier
Achieves Better than 10dB Margin Under EN55022
Class B Limits
♦
Low RF Susceptibility Design Rejects TDMA
Noise from GSM Radios
♦
Input Mixer with User-Defined Input Mode
♦
725mW Speaker Output (R
SPK
= 8Ω, PVDD = 3.7V)
♦
53mW Headphone Output (R
HP
= 16Ω, V
DD
= 3.7V)
♦
Low 0.05% THD+N at 1kHz (Class D Power
Amplifier)
♦
Low 0.016% THD+N at 1kHz (Headphone
Amplifier)
♦
87% Efficiency (R
SPK
= 8Ω, P
OUT
= 750mW)
♦
High Speaker Amplifier PSRR (72dB at 217Hz)
♦
High Headphone Amplifier PSRR (84dB at 217Hz)
♦
I
2
C Control
♦
Hardware and Software Shutdown Mode
♦
Click-and-Pop Suppression
♦
Current-Limit and Thermal Protection
♦
Available in a Space-Saving, 2.5mm x 2.0mm WLP
Package
MAX9875
Ordering Information
PART
MAX9875ERP+TG45
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
20 WLP (5x4)
Applications
Cell Phones
Portable Multimedia Players
DirectDrive is a registered trademark of Maxim Integrated
Products, Inc.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
G45 indicates protective die coating.
Simplified Block Diagram
SINGLE SUPPLY
2.7V TO 5.25V
Pin Configuration
TOP VIEW
(BUMP SIDE DOWN)
1
2
3
4
5
PREAMPLIFIER
VOLUME
CONTROL
A
HPR
B
V
DD
BIAS
SDA
N.C.
OUT+
HPL
V
SS
C1N
C1P
MIXER/MUX
I
2
C
INTERFACE
VOLUME
CONTROL
C
INB2
D
INA2
INA1
GND
N.C.
INB1
SCL
PGND
PVDD
MAX9875
OUT-
WLP
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
MAX9875
ABSOLUTE MAXIMUM RATINGS
V
DD
, PVDD to PGND .............................................-0.3V to +5.5V
V
DD
to PVDD .........................................................-0.3V to +0.3V
V
SS
to PGND .........................................................-5.5V to +0.3V
C1N to PGND..............................................(V
SS
- 0.3V) to +0.3V
C1P to PGND...........................................-0.3V to (PVDD + 0.3V)
HPL, HPR to V
SS
(Note 1)......-0.3V to the lower of (PVDD - (V
SS
+ 0.3V)) or +9V
HPL, HPR to PVDD
(Note 2) .....+0.3V to the higher of (V
SS
- (PVDD - 0.3V)) or -9V
GND to PGND.....................................................................±0.3V
INA1, INA2, INB1, INB2, BIAS..................................-0.3V to +4V
SDA, SCL...............................................................-0.3V to +5.5V
All Other Pins to GND..............................-0.3V to (PVDD + 0.3V)
Continuous Current In/Out of PVDD, PGND, OUT_........±800mA
Continuous Current In/Out of HPR and HPL .....................140mA
Continuous Input Current V
SS
...........................................100mA
Continuous Input Current (all other pins) .........................±20mA
Duration of OUT_ Short Circuit to GND or PVDD .......Continuous
Duration of Short Circuit Between OUT+ and OUT- ..Continuous
Duration of HP_ Short Circuit to GND or PVDD..........Continuous
Continuous Power Dissipation (T
A
= +70°C)
20-Bump WLP, 5 x 4, Multilayer Board
(derate 13.0mW/°C above +70°C) ..................................1.04W
Junction Temperature ......................................................+150°C
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
HPR and HPL should be limited to no more than 9V above V
SS
, or above PVDD + 0.3V, whichever limits first.
Note 2:
HPR and HPL should be limited to no more than 9V below PVDD, or below V
SS
- 0.3V, whichever limits first.
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS
(V
DD
= V
PVDD
= 3.7V, V
GND
= V
PGND
= 0V. Single-ended inputs, preamp gain = 0dB, volume controls = 0dB, OSC = 00,
SHDN
= 1.
Speaker loads (Z
SPK
) connected between OUT+ and OUT-. Headphone loads (R
HP
) connected from HPL or HPR to GND. SDA and
SCL pullup voltage = 3.3V. Z
SPK
=
∞,
R
HP
=
∞.
C1 = C2 = C
BIAS
= 1µF. T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 3)
PARAMETER
Supply Voltage Range
SYMBOL
CONDITIONS
OSC = 00
OSC = 10
OSC = 00
OSC = 10
OSC = 00
OSC = 10
MIN
2.7
5.6
5.5
6.6
5.7
10.4
9.3
10
10
10
17.5
25
11
3
21
5.5
2.30
0.820
0.230
V
P-P
80
31
8
ms
kΩ
ms
22
µA
16.0
11.0
mA
TYP
MAX
5.25
9.0
UNITS
V
V
DD
, PVDD Guaranteed by PSRR test
HP mode,
OUTMODE = 2
Quiescent Current
I
DD
SPK mode,
OUTMODE = 7
SPK + HP mode,
OUTMODE = 9
Shutdown Current
I
SHDN
I
SHDN
= I
VDD
+ I
PVDD
;
SHDN
= 0; V
SDA
=
V
SCL
= logic-high; T
A
= +25°C
OSC = 00
Time from shutdown to
full operation
OSC = 01
OSC = 10
Turn-On Time
t
ON
BIAS Release Time
Input Resistance
t
BR
R
IN
After forcing BIAS low, time from BIAS
released to I
2
C reset
T
A
= +25°C, preamp gain = 0dB or +9dB
T
A
= +25°C, preamp gain = +20dB
Preamp = 0dB
Preamp = +9dB
Preamp = +20dB
Maximum Input Signal Swing
2
_______________________________________________________________________________________
Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= V
PVDD
= 3.7V, V
GND
= V
PGND
= 0V. Single-ended inputs, preamp gain = 0dB, volume controls = 0dB, OSC = 00,
SHDN
= 1.
Speaker loads (Z
SPK
) connected between OUT+ and OUT-. Headphone loads (R
HP
) connected from HPL or HPR to GND. SDA and
SCL pullup voltage = 3.3V. Z
SPK
=
∞,
R
HP
=
∞.
C1 = C2 = C
BIAS
= 1µF. T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 3)
PARAMETER
Common-Mode Rejection Ratio
Input DC Voltage
Bias Voltage
V
BIAS
T
A
= +25°C (volume at mute)
Output Offset Voltage
V
OS
T
A
= +25°C (volume at 0dB,
OUTMODE = 1,
∆IN_
= 0)
Peak voltage, T
A
=
+25°C, A-weighted, 32
samples per second,
volume at mute (Note 4)
Into shutdown
Out of shutdown
PVDD = V
DD
=
2.7V to 5.5V
f = 217Hz,
100mV
P-P
ripple
f = 1kHz,
100mV
P-P
ripple
f = 20kHz,
100mV
P-P
ripple
Z
SPK
= 8Ω +
68µH, V
DD
= 3.7V
Z
SPK
= 8Ω +
68µH, V
DD
= 3.3V
Output Power (Note 5)
P
OUT
THD+N
≤
1%
Z
SPK
= 8Ω +
68µH, V
DD
= 3.0V
Z
SPK
= 4Ω +
33µH, V
DD
= 3.7V
Z
SPK
= 4Ω +
33µH, V
DD
= 3.0V
Total Harmonic Distortion Plus
Noise
THD+N
f = 1kHz, P
OUT
= 350mW, T
A
= +25°C,
Z
SPK
= 8Ω + 68µH
A-weighted,
OUTMODE = 1, 3,
4, 6
Signal-to-Noise Ratio
SNR
A-weighted,
OUTMODE = 7, 9
∆IN_
= 0
(single-ended)
∆IN_
= 1 (differential)
∆IN_
= 0
(single-ended)
∆IN_
= 1 (differential)
50
SPEAKER AMPLIFIER (OUTMODE = 1)
±0.5
±1.5
-70
dBV
-70
76
72
dB
68
55
725
560
465
825
770
0.05
92
94
88
92
dB
%
mW
±4
mV
SYMBOL
CMRR
CONDITIONS
Preamp = 0dB
f
IN
= 1kHz (differential
input mode)
IN__ inputs
Preamp = +9dB
Preamp = +20dB
1.22
1.13
MIN
TYP
47
49
42
1.3
1.2
1.38
1.27
V
V
dB
MAX
UNITS
MAX9875
Click-and-Pop Level
K
CP
Power-Supply Rejection Ratio
(Note 4)
PSRR
T
A
= +25°C, PVDD =
V
DD
_______________________________________________________________________________________
3
Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
MAX9875
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= V
PVDD
= 3.7V, V
GND
= V
PGND
= 0V. Single-ended inputs, preamp gain = 0dB, volume controls = 0dB, OSC = 00,
SHDN
= 1.
Speaker loads (Z
SPK
) connected between OUT+ and OUT-. Headphone loads (R
HP
) connected from HPL or HPR to GND. SDA and
SCL pullup voltage = 3.3V. Z
SPK
=
∞,
R
HP
=
∞.
C1 = C2 = C
BIAS
= 1µF. T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 3)
PARAMETER
SYMBOL
CONDITIONS
Spread-spectrum modulation mode,
OSC = 00
Output Frequency
Fixed-frequency mode, OSC = 01
Fixed-frequency mode, OSC = 10
Current Limit
Efficiency
Speaker Gain
Output Noise
HEADPHONE AMPLIFIERS (OUTMODE = 2)
Output Offset Voltage
V
OS
T
A
= +25°C (volume at mute)
T
A
= +25°C (volume at 0dB)
Peak voltage, T
A
=
+25°C, A-weighted,
32 samples per
second. volume at
mute (Note 4)
Into shutdown
Out of shutdown
PVDD = V
DD
= 2.7V
to 5.25V
f = 217Hz,
V
RIPPLE
= 100mV
P-P
f = 1kHz,
V
RIPPLE
= 100mV
P-P
f = 20kHz,
V
RIPPLE
= 100mV
P-P
Output Power
Headphone Gain
Channel-to-Channel Gain
Tracking
Total Harmonic Distortion Plus
Noise
THD+N
P
OUT
A
V
T
A
= +25°C, HPL to HPR, volume at 0dB,
OUTMODE = 2, 5;
∆IN_
= 0
R
HP
= 32Ω (P
OUT
= 10mW, f = 1kHz)
R
HP
= 16Ω (P
OUT
= 10mW, f = 1kHz),
T
A
= +25°C
A-weighted,
OUTMODE = 2, 3,
5, 6; R
HP
= 16Ω
Signal-to-Noise Ratio
SNR
A-weighted, R
HP
=
16Ω, OUTMODE =
8, 9
∆IN_
= 0
(single-ended)
∆IN_
= 1 (differential)
∆IN_
= 0
(single-ended)
∆IN_
= 1 (differential)
THD+N
≤
1%
R
HP
= 16Ω
R
HP
= 32Ω
-0.4
70
±0.15
±1.6
-80
dBV
-80
85
84
dB
80
62
53
27
0
±0.3
0.016
0.03
98
98
96
96
dB
%
+0.4
±2.5
mW
dB
%
±0.6
mV
η
A
V
A-weighted, OUTMODE = 1,
∆IN_
= 0
(Note 4)
P
OUT
= 600mW, f = 1kHz
11.5
MIN
TYP
1176
±60
1100
700
1.5
87
12.0
63
12.5
A
%
dB
µV
RMS
kHz
MAX
UNITS
Click-and-Pop Level
K
CP
Power-Supply Rejection Ratio
(Note 4)
PSRR
T
A
= +25°C, PVDD =
V
DD
4
_______________________________________________________________________________________
Low RF Susceptibility, Mono Audio
Subsystem with DirectDrive Headphone Amplifier
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= V
PVDD
= 3.7V, V
GND
= V
PGND
= 0V. Single-ended inputs, preamp gain = 0dB, volume controls = 0dB, OSC = 00,
SHDN
= 1.
Speaker loads (Z
SPK
) connected between OUT+ and OUT-. Headphone loads (R
HP
) connected from HPL or HPR to GND. SDA and
SCL pullup voltage = 3.3V. Z
SPK
=
∞,
R
HP
=
∞.
C1 = C2 = C
BIAS
= 1µF. T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 3)
PARAMETER
Slew Rate
Capacitive Drive
Crosstalk
SYMBOL
SR
C
L
HPL to HPR, HPR to HPL, f = 20Hz to 20kHz
Spread-spectrum modulation mode,
OSC = 00
Charge-Pump Frequency
Fixed-frequency mode, OSC = 01
Fixed-frequency mode, OSC = 10
VOLUME CONTROL
Minimum Setting
Maximum Setting
Preamp Gain
_VOL = 1
_VOL = 31
PGAIN_ = 00
Input A or B
PGAIN_ = 01
PGAIN_ = 10
Mute Attenuation
Zero-Crossing Detection Timeout
DIGITAL INPUTS
Input-Voltage High (SDA, SCL)
Input-Voltage Low (SDA, SCL)
Input-Voltage Low (BIAS)
Input Hysteresis (SDA, SCL)
SDA, SCL Input Capacitance
Input Leakage Current
BIAS Pullup Current
Output Low Voltage SDA
Output Fall Time SDA
2-WIRE INTERFACE TIMING
External Pullup Voltage Range:
SDA and SCL
Serial Clock Frequency
Bus Free Time Between STOP
and START Conditions
START Condition Hold
START Condition Setup Time
Clock Low Period
Clock High Period
f
SCL
t
BUF
t
HD:STA
t
SU:STA
t
LOW
t
HIGH
1.7
DC
1.3
0.6
0.6
1.3
0.6
3.6
400
V
kHz
µs
µs
µs
µs
µs
DIGITAL OUTPUTS (SDA Open Drain)
V
OL
t
OF
I
SINK
= 3mA
V
H(MIN)
to V
L(MAX)
bus capacitance = 10pF
to 400pF, I
SINK
= 3mA
0.4
250
V
ns
V
H
V
L
V
BL
V
HYS
C
IN
I
IN
I
BIAS
SDA, SCL; T
A
= +25°C
94
80
4
±1.0
1.4
0.4
0.15
V
V
V
mV
pF
µA
µA
f = 1kHz, _VOL = 0
ZCD = 1
Speaker
Headphone
-75
0
0
9
20
100
110
60
dB
ms
dB
dB
dB
430
220
CONDITIONS
MIN
TYP
0.35
100
65
588
±30
550
350
670
500
kHz
MAX
UNITS
V/µs
pF
dB
MAX9875
_______________________________________________________________________________________
5
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