µ
19-0509; Rev 0; 4/06
Stereo 3W Audio Power Amplifiers with
Headphone Drive and Input Mux
General Description
The MAX9777/MAX9778 combine a stereo 3W bridge-
tied load (BTL) audio power amplifier, stereo single-
ended (SE) headphone amplifier, headphone sensing,
and a 2:1 input multiplexer all in a tiny 28-pin thin QFN
package. These devices operate from a single 4.5V to
5.5V supply and feature an industry-leading 100dB
PSRR, allowing these devices to operate from noisy
supplies without the addition of a linear regulator. An
ultra-low 0.002% THD+N ensures clean, low-distortion
amplification of the audio signal. Click-and-pop sup-
pression minimizes audible transients on power and
shutdown cycles. Power-saving features include low
4mV V
OS
(minimizes DC current drain through the
speakers), low 13mA supply current, and a 10µA shut-
down mode. A MUTE function allows the outputs to be
quickly enabled or disabled.
A headphone sense input detects the presence of a
headphone jack and automatically configures the
amplifiers for either speaker or headphone mode. In
speaker mode, the amplifiers can deliver up to 3W of
continuous average power into a 3Ω load. In head-
phone mode, the amplifier can deliver up to 200mW of
continuous average power into a 16Ω load. The gain of
the amplifiers is externally set, allowing maximum flexi-
bility in optimizing output levels for a given load. The
amplifiers also feature a 2:1 input multiplexer, allowing
multiple audio sources to be selected. The multiplexer
can also be used to compensate for limitations in the
frequency response of the loud speakers by selecting
an external equalizer network. The various functions are
controlled by either an I
2
C-compatible (MAX9777) or
simple parallel control interface (MAX9778).
The MAX9777/MAX9778 are available in a thermally
efficient 28-pin thin QFN package (5mm x 5mm x
0.8mm). These devices have thermal-overload protec-
tion (OVP) and are specified over the extended -40°C
to +85°C temperature range.
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
♦
Features
Industry-Leading, Ultra-High 100dB PSRR
3W BTL Stereo Speaker Amplifier
200mW Stereo Headphone Amplifier
Low 0.002% THD+N
Click-and-Pop Suppression
ESD-Protected Outputs
Low Quiescent Current: 13mA
Low-Power Shutdown Mode: 10µA
MUTE Function
Headphone Sense Input
Stereo 2:1 Input Multiplexer
Optional 2-Wire, I
2
C-Compatible or Parallel
Interface
♦
Tiny 28-Pin Thin QFN (5mm
x
5mm
x
0.8mm)
Package
MAX9777/MAX9778
Ordering Information
PART
MAX9777ETI+
MAX9778ETI+
CONTROL
INTERFACE
I
2
C Compatible
Parallel
PIN-
PACKAGE
PKG
CODE
28 Thin QFN-EP* T2855-6
28 Thin QFN-EP* T2855-6
Note: All devices are specified over the -40°C to +85°C operat-
ing temperature range.
+Denotes lead-free package.
*EP = Exposed paddle.
Pin Configurations and Functional Diagrams appear at end
of data sheet.
Simplified Block Diagram
SINGLE SUPPLY
4.5V TO 5.5V
LEFT IN
1
Applications
Notebooks
Portable DVD Players
Tablet PCs
PC Audio Peripherals
Camcorders
Multimedia Monitor
LEFT IN
2
SE/
BTL
RIGHT IN
1
RIGHT IN
2
CONTROL
I
2
C-
COMPATIBLE
MAX9777
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Stereo 3W Audio Power Amplifiers with
Headphone Drive and Input Mux
MAX9777/MAX9778
ABSOLUTE MAXIMUM RATINGS
V
DD
to GND ...........................................................................+6V
PV
DD
to V
DD
.......................................................................±0.3V
PGND to GND.....................................................................±0.3V
All Other Pins to GND.................................-0.3V to (V
DD
+ 0.3V)
Continuous Input Current (into any pin except power-supply
and output pins) ...............................................................±20mA
OUT__ Short Circuit to GND, V
DD
..........................................10s
Short Circuit Between OUT_+ and OUT_- .................Continuous
Continuous Power Dissipation (T
A
= +70°C)
28-Pin TQFN, Multilayer Board
(derate 34.5mW/°C above +70°C) ..........................2758.6mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
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
= PV
DD
= 5.0V, GND = PGND = 0V, V
SHDN
= 5V, C
BIAS
= 1µF, R
IN
= R
F
= 15kΩ, R
L
=
∞.
T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
Quiescent Supply Current
(I
VDD
+ I
PVDD
)
Shutdown Current
Switching Time
Turn-On Time
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
OUTPUT AMPLIFIERS (SPEAKER MODE, HPS = GND)
Output Offset Voltage
Power-Supply Rejection Ratio
(Note 2)
V
OS
PSRR
OUT_+ - OUT_-, A
V
= 1V/V
V
DD
= 4.5V to 5.5V
f = 1kHz, V
RIPPLE
= 200mV
P-P
f = 20kHz, V
RIPPLE
= 200mV
P-P
Output Power
Total Harmonic Distortion Plus
Noise
Signal-to-Noise Ratio
Slew Rate
Maximum Capacitive Load Drive
Crosstalk
Click/Pop Level
K
CP
P
OUT
f
IN
= 1kHz,
THD+N < 1%,
T
A
= +25°C
f
IN
= 1kHz, BW =
22Hz to 22kHz
R
L
= 8Ω
R
L
= 4Ω
R
L
= 3Ω
P
OUT
= 1W, R
L
= 8Ω
P
OUT
= 2W, R
L
= 4Ω
75
±4
100
82
70
1.4
2.6
3
0.005
0.01
95
1.6
No sustained oscillations
f
IN
= 10kHz
Peak voltage, A-weighted,
32 samples per second
(Notes 2, 6)
Into shutdown
Out of shutdown
1
73
-50
dBV
-65
%
dB
V/µs
nF
dB
W
dB
±32
mV
SYMBOL
V
DD
/PV
DD
I
DD
I
SHDN
t
SW
t
ON
CONDITIONS
Inferred from PSRR test
BTL mode, HPS = 0V, MAX9777/MAX9778
Single-ended mode, HPS = V
DD
SHDN
= GND
Gain or input switching
C
BIAS
= 1µF
C
BIAS
= 0.1µF
MIN
4.5
13
7
10
10
300
30
+160
15
TYP
MAX
5.5
32
18
50
µA
µs
ms
o
o
UNITS
V
mA
C
C
THD+N
SNR
SR
C
L
R
L
= 8Ω, P
OUT
= 1W, BW = 22Hz to 22kHz
2
_______________________________________________________________________________________
Stereo 3W Audio Power Amplifiers with
Headphone Drive and Input Mux
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= 5.0V, GND = PGND = 0V, V
SHDN
= 5V, C
BIAS
= 1µF, R
IN
= R
F
= 15kΩ, R
L
=
∞.
T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
V
DD
= 4.5V to 5.5V
PSRR
f = 1kHz, V
RIPPLE
= 200mV
P-P
f = 20kHz, V
RIPPLE
= 200mV
P-P
Output Power
P
OUT
f
IN
= 1kHz, THD+N < R
L
= 32Ω
1%, T
A
= +25°C
R
L
= 16Ω
f
IN
= 1kHz,
BW = 22Hz to 22kHz
P
OUT
= 60mW,
R
L
= 32Ω
P
OUT
= 125mW,
R
L
= 16Ω
MIN
75
TYP
106
88
76
88
200
0.002
%
0.002
92
1.8
No sustained oscillations
f
IN
= 10kHz
V
BIAS
R
BIAS
V
IH
V
IL
I
IN
0.9 x
V
DD
0.7 x
V
DD
±1
Peak voltage, A-weighted,
32 samples per second
(Notes 2, 4)
Into shutdown
Out of shutdown
-70
dBV
-52
2
0.8
±1
2.35
2
78
2.5
50
2.65
dB
V/µs
nF
dB
V
kΩ
V
V
µA
mW
dB
MAX
UNITS
OUTPUT AMPLIFIERS (HEADPHONE MODE, HPS = V
DD
)
Power-Supply Rejection Ratio
(Note 2)
MAX9777/MAX9778
Total Harmonic Distortion Plus
Noise
THD+N
Signal-to-Noise Ratio
Slew Rate
Maximum Capacitive Load Drive
Crosstalk
BIAS VOLTAGE (BIAS)
BIAS Voltage
Output Resistance
Input-Voltage High
Input-Voltage Low
Input Leakage Current
HEADPHONE SENSE INPUT (HPS)
Input-Voltage High
Input-Voltage Low
Input Leakage Current
Click/Pop Level
SNR
SR
C
L
R
L
= 32Ω, BW = 22Hz to 22kHz,
V
OUT
= 1V
RMS
1
DIGITAL INPUTS (MUTE,
SHDN,
HPS_EN, GAINA/B, IN1/2)
V
IH
V
IL
I
IN
K
CP
V
V
µA
_______________________________________________________________________________________
3
Stereo 3W Audio Power Amplifiers with
Headphone Drive and Input Mux
MAX9777/MAX9778
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= PV
DD
= 5.0V, GND = PGND = 0V, V
SHDN
= 5V, C
BIAS
= 1µF, R
IN
= R
F
= 15kΩ, R
L
=
∞.
T
A
= T
MIN
to T
MAX
, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Input-Voltage High
Input-Voltage Low
Input Hysteresis
Input High Leakage Current
Input Low Leakage Current
Input Capacitance
Output-Voltage Low
Output Current High
Serial Clock Frequency
Bus Free Time Between STOP
and START Conditions
START Condition Hold Time
START Condition Setup Time
Clock Period Low
Clock Period High
Data Setup Time
Data Hold Time
Receive SCL/SDA Rise Time
Receive SCL/SDA Fall Time
Transmit SDA Fall Time
Pulse Width of Suppressed
Spike
I
IH
I
IL
C
IN
V
OL
I
OH
f
SCL
t
BUF
t
HD:STA
t
SU:STA
t
LOW
t
HIGH
t
SU:DAT
t
HD:DAT
t
r
t
f
t
f
t
SP
(Note 3)
(Note 4)
(Note 4)
(Note 4)
(Note 5)
1.3
0.6
0.6
1.3
0.6
100
0
20 +
0.1C
B
20 +
0.1C
B
20 +
0.1C
B
50
0.9
300
300
250
I
OL
= 3mA
V
OH
= 5V
V
IN
= 5V
V
IN
= 0V
10
0.4
1
400
SYMBOL
V
IH
V
IL
0.2
±1
±1
CONDITIONS
MIN
2.6
0.8
TYP
MAX
UNITS
V
V
V
µA
µA
pF
V
µA
kHz
µs
µs
µs
µs
µs
ns
µs
ns
ns
ns
ns
2-WIRE SERIAL INTERFACE (SCL, SDA, ADD,
INT)
(MAX9777)
TIMING CHARACTERISTICS (MAX9777)
Note 1:
All devices are 100% production tested at +25°C. All temperature limits are guaranteed by design.
Note 2:
Inputs AC-coupled to GND.
Note 3:
A master device must provide a hold time of at least 300ns for the SDA signal to bridge the undefined region of SCL’s
falling edge.
Note 4:
C
B
= total capacitance of one of the bus lines in picofarads. Device tested with C
B
= 400pF. 1kΩ pullup resistors connected
from SDA/SCL to V
DD
.
Note 5:
Input filters on SDA, SCL, and ADD suppress noise spikes of less than 50ns.
Note 6:
Headphone mode testing performed with 32Ω resistive load connected to GND. Speaker mode testing performed with 8Ω
resistive load connected to GND. Mode transitions are controlled by
SHDN.
KCP level is calculated as 20log[(peak voltage
during mode transition, no input signal)/1V
RMS
]. Units are expressed in dBV.
4
_______________________________________________________________________________________
Stereo 3W Audio Power Amplifiers with
Headphone Drive and Input Mux
Typical Operating Characteristics
(V
DD
= PV
DD
= 5V, GND = PGND = 0V, V
SHDN
= 5V, C
BIAS
= 1µF, T
A
= +25°C, unless otherwise noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
MAX9777/78 toc01
MAX9777/MAX9778
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
R
L
= 3Ω
A
V
= 4V/V
MAX9777/78 toc02
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
R
L
= 4Ω
A
V
= 2V/V
MAX9777/78 toc03
1
R
L
= 3Ω
A
V
= 2V/V
0.1
THD+N (%)
1
1
0.1
THD+N (%)
P
OUT
= 500mW
P
OUT
= 1W
P
OUT
= 500mW P
OUT
= 1W
THD+N (%)
0.1
P
OUT
= 250mW P
OUT
= 500mW
0.01
P
OUT
= 2W
P
OUT
= 2.5W
P
OUT
= 1W
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
10
100
1k
FREQUENCY (Hz)
10k
100k
P
OUT
= 2W
0.01
P
OUT
= 2W
P
OUT
= 2.5W
0.01
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
MAX9777/78 toc04
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
MAX9777/78 toc05
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY (SPEAKER MODE)
R
L
= 8Ω
A
V
= 4V/V
MAX9777/78 toc06
1
R
L
= 4Ω
A
V
= 4V/V
1
R
L
= 8Ω
A
V
= 2V/V
1
0.1
THD+N (%)
THD+N (%)
P
OUT
= 250mW P
OUT
= 500mW
0.1
THD+N (%)
0.1
P
OUT
= 250mW
0.01
P
OUT
= 1.2W
P
OUT
= 500mW
P
OUT
= 250mW P
OUT
= 500mW
0.01
0.01
P
OUT
= 1W
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
P
OUT
= 2W
P
OUT
= 1W P
OUT
= 1.2W
0.001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.001
10
P
OUT
= 1W
100
1k
FREQUENCY (Hz)
10k
100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
MAX9777/78 toc07
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
A
V
= 4V/V
R
L
= 3Ω
10
MAX9777/78 toc08
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (SPEAKER MODE)
A
V
= 2V/V
R
L
= 4Ω
10
MAX9777/78 toc09
100
A
V
= 2V/V
R
L
= 3Ω
10
100
100
THD+N (%)
THD+N (%)
THD+N (%)
1
f = 10kHz
f = 20Hz
1
f = 1kHz
0.1
f = 10kHz
1
0.1
0.1
f = 1kHz
f = 10kHz
0.01
f = 1kHz
0.01
f = 20Hz
0.001
0.01
f = 20Hz
0.001
0
1
2
OUTPUT POWER (W)
3
4
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
OUTPUT POWER (W)
0.001
0
1
2
OUTPUT POWER (W)
3
4
_______________________________________________________________________________________
5
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