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MAX4295/MAX4297
Mono/Stereo 2W Switch-Mode (Class-D)
Audio Power Amplifiers
________________________________________________________________ Maxim Integrated Products
1
AOUTL
INL
AOUTR
INR
FS1
FS2
PGND
AGND
SS
V
PVCC
V
CC
V
PVCC
V
CC
OUT+L
OUT-L
OUT+R
OUT-R
1
2
12
11
22
14
15
24
10
17
13
8
20
5
3
4, 9,
16, 21
6, 7,
18, 19
INPUTL
INPUTR
V
CC
V
CC
RF
RF
RIN
RIN
CIN
CIN
L1A
L1B
L2A
L2B
CSS
C1A
C1B
C2A
C2B
VCM*
*DO NOT CONNECT.
SHDN
MAX4297
+
19-1746; Rev 1; 2/01
Ordering Information
16 QSOP
PIN-PACKAGE
TEMP. RANGE
-40C to +85C
MAX4295EEE
PART
16 Narrow SO
-40C to +85C
MAX4295ESE
24 SSOP
-40C to +85C
MAX4297EAG
24 Wide SO
-40C to +85C
MAX4297EWG
Palmtop/Notebook
Computers
PDA Audio
Sound Cards
Game Cards
Boom Boxes
AC Amplifiers
Battery-Powered Speakers
Cordless Phones
Portable Equipment
Pin Configurations appear at end of data sheet.
Typical Operating Circuit
General Description
The MAX4295/MAX4297 mono/stereo, switch-mode
(Class-D) audio power amplifiers operate from a single
+2.7V to +5.5V supply. They have >85% efficiency and
are capable of delivering 2W continuous power to a 4
load, making them ideal for portable multimedia and
general-purpose high-power audio applications.
The MAX4295/MAX4297 feature a total harmonic distor-
tion plus noise (THD+N) of 0.4% (f
OSC
= 125kHz), low
quiescent current of 2.8mA (MAX4295) or 4.6mA
(MAX4297), high efficiency, and clickless power-up and
shutdown. The SHDN input disables the device and lim-
its supply current to <1.5A (MAX4295) or <2.3A
(MAX4297). Other features include a 1A current limit,
thermal protection, and under-voltage lockout.
The MAX4295 (mono) and MAX4297 (stereo) reduce
the number of required external components. Both
devices have internal high-speed power-MOS transis-
tors, allowing operation as bridge-tied load (BTL) ampli-
fiers. The BTL configuration eliminates the need for
isolation capacitors on the output. The frequency-selec-
table pulse-width modulator (PWM) allows the user to
optimize the size and cost of the output filter.
The MAX4295 is offered in a space-saving 16-pin
QSOP package, and the MAX4297 is offered in a com-
pact 24-pin SSOP package.
Applications
Features
o +2.7V to +5.5V Single-Supply Operation
o 2W/Channel Output Power at 5V
0.7W/Channel Output Power at 3V
o 87% Efficiency (R
L
= 4
, P
O
= 2W, MAX4295)
o 0.4% THD+N (R
L
= 4
, f
OSC
= 125kHz)
o Logic-Programmable PWM Frequency Selection
(125kHz, 250kHz, 500kHz, 1MHz)
o Low-Power Shutdown Mode
o Clickless Transitions Into and Out of Shutdown
o 1A Current Limit and Thermal Protection
o Available in Space-Saving Packages
16-Pin QSOP (MAX4295)
24-Pin SSOP (MAX4297)
MAX4295/MAX4297
Mono/Stereo 2W Switch-Mode (Class-D)
Audio Power Amplifiers
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= PV
CC
= +5V, SHDN = V
CC
, FS1 = GND, FS2 = V
CC
(f
OSC
= 250kHz), input amplifier gain = -1V/V, T
A
= T
MIN
to T
MAX
, unless
otherwise noted. Typical values are T
A
= +25C.) (Note 1)
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.
V
CC
, PV
CC
to GND or PGND....................................-0.3V to +6V
PGND to GND.....................................................................0.3V
PV
CC
to V
CC
.......................................................................0.3V
VCM, SS, AOUT_, IN_ ................................-0.3V to (V
CC
+ 0.3V)
SHDN, FS1, FS2 .......................................................-0.3V to +6V
OUT_ _ .....................................................-0.3V to (PV
CC
+ 0.3V)
Op Amp Output Short-Circuit
Duration (AOUT_) .......Indefinite Short Circuit to Either Supply
H-Bridge Short-Circuit
Duration (OUT_ _) .............Continuous Short Circuit to PGND,
PV
CC
or between OUT+_ & OUT-_
Continuous Power Dissipation (T
A
= +70C)
16-Pin QSOP (derate 8.30mW/C above +70C)........667mW
24-Pin SSOP (derate 9.50mW/C above +70C) ........762mW
16-Pin Narrow SO
(derate 9.52mW/C above +70C) ..........................696mW
24-Pin Wide SO
(derate 11.76mW/C above +70C) ........................941mW
Operating Temperature Range
MAX4295E__/MAX4297E__ ............................-40C to +85C
Junction Temperature ......................................................+150C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
GENERAL
Supply Voltage Range
(Note 2)
2.7
5.5
V
MAX4295
2.8
4
Quiescent Supply Current
Output load not
connected
MAX4297
4.6
8
mA
MAX4295
1.5
8
Shutdown Supply Current
SHDN = GND
MAX4297
2.5
15
A
Voltage at VCM Pin
0.285
V
CC
0.3
V
CC
0.315
V
CC
V
FS1 = GND, FS2 = GND
105
125
145
FS1 = GND, FS2 = V
CC
210
250
290
FS1 = V
CC
, FS2 = GND
420
500
580
PWM Frequency
FS1 = V
CC
, FS2 = V
CC
840
1000
1160
kHz
PWM Frequency Change with
V
CC
V
CC
= 2.7V to 5.5V
1
3
kHz/V
V
IN
= 0.06
V
CC
10.2
12
13.8
V
IN
= 0.30
V
CC
49.2
50
50.8
Duty Cycle
V
IN
= 0.54
V
CC
86.2
88
89.8
%
Duty Cycle Change with V
CC
V
IN
= 0.3
V
CC
, V
CC
= 2.7V to 5.5V
0.02
0.15
%/V
V
CC
= 5V
0.25
0.5
Switch On-Resistance
(each power device)
I
OUT
= 150mA
V
CC
= 2.7V
0.35
1.0
H-Bridge Output Leakage
SHDN = GND
0
5
A
H-Bridge Current Limit
1
A
Soft-Start Capacitor Charging
Current
V
SS
= 0
0.75
1.35
1.95
A
Undervoltage Lockout
1.8
2.2
2.6
V
Thermal Shutdown Trip Point
145
C
MAX4295/MAX4297
Mono/Stereo 2W Switch-Mode (Class-D)
Audio Power Amplifiers
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= PV
CC
= +5V, SHDN = V
CC
, FS1 = GND, FS2 = V
CC
(f
OSC
= 250kHz), input amplifier gain = -1V/V, T
A
= T
MIN
to T
MAX
, unless
otherwise noted. Typical values are T
A
= +25C.)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
Input Voltage Range
0 to 0.6
x V
CC
V
R
L
= 8
0.4
V
CC
= +3V, f
IN
= 1kHz
R
L
= 4
0.7
R
L
= 8
1.2
Maximum Output Power
V
CC
= +5V, f
IN
= 1kHz
R
L
= 4
2
W
THD Plus Noise
R
L
= 4
, f
IN
= 1kHz, P
O
= 1W, f
OSC
= 125kHz
0.4
%
Efficiency
MAX4295, R
L
= 4
, f
IN
= 1kHz, P
O
= 2W
87
%
Channel Isolation
MAX4297, f
IN
= 1kHz, P
O
= 2W
45
dB
LOGIC INPUTS (SHDN, FS1, FS2)
Logic Input Current
V
LOGIC
= 0 to V
CC
1
100
nA
Logic Input High Voltage
0.7
V
CC
V
Logic Input Low Voltage
0.3
V
CC
V
INPUT AMPLIFIER
Input Offset Voltage
0.5
4
mV
VOS Temp Coefficient
5
V/
C
Input Bias Current
(Note 3)
0.05
25
nA
Input Noise Voltage Density
f = 10kHz
32
nV/
Hz
Input Capacitance
2.5
pF
Output Resistance
0.01
AOUT Disabled Mode Leakage
Current
SHDN = GND, V
AOUT
= 0 to V
CC
0.1
1
A
AOUT to GND
8
Short-Circuit Current
AOUT to V
CC
65
mA
Large-Signal Voltage Gain
V
OUT
= 0.2V to 4.6V, R
L(OPAMP)
= 10k
78
115
dB
V
CC
- V
OH
40
250
AOUT Voltage Swing
V
DIFF
10mV,
R
L(OPAMP)
= 10k
V
OL
40
100
mV
Gain Bandwidth Product
1.25
MHz
Power-Supply Rejection
V
CC
= +2.7V to +5.5V
66
90
dB
Maximum Capacitive Load
No sustained oscillations
200
pF
Note 1: All devices are 100% production tested at T
A
= 25C. All temperature limits are guaranteed by design.
Note 2: Supply Voltage Range guaranteed by PSRR of input amplifier, frequency, duty cycle, and H-bridge on-resistance.
Note 3: Guaranteed by design, not production tested.
MAX4295/MAX4297
Mono/Stereo 2W Switch-Mode (Class-D)
Audio Power Amplifiers
4
_______________________________________________________________________________________
Typical Operating Characteristics
(V
CC
= PV
CC
= +3V, input amplifier gain = -1, SHDN = V
CC
, T
A
= +25C, unless otherwise noted.)
10
1k
100k
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT FREQUENCY (V
IN
= 2.5Vp-p)
MAX4295/7-02
INPUT FREQUENCY (Hz)
THD + N (%)
10
1
0.01
0.1
V
CC
= +5V
R
L
= 8
1MHz
125kHz
250kHz
500kHz
0
0.3
0.6
1.2
0.9
1.5
1.8
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 1kHz)
MAX4295/7-05
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +5V
R
L
= 8
500kHz
250kHz
1MHz
125kHz
0
0.3
0.6
0.9
1.2
1.5 1.8
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 20kHz)
MAX4295/7-08
OUTPUT POWER (W)
THD + N (%)
10
1
0.01
0.1
V
CC
= +5V
R
L
= 8
1MHz
125kHz
250kHz
500kHz
10
1k
100k
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT FREQUENCY (V
IN
= 2.5Vp-p)
MAX4295/7-01
INPUT FREQUENCY (Hz)
THD + N (%)
10
1
0.01
0.1
1MHz
125kHz
250kHz
500kHz
V
CC
= +5V
R
L
= 4
0
0.5
1.0
1.5
2.0
2.5
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 1kHz)
MAX4295/7-04
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +5V
R
L
= 4
1MHz
250kHz
125kHz
500kHz
0
0.5
1.0
1.5
2.0
2.5
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 20kHz)
MAX4295/7-07
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +5V
R
L
= 4
250kHz
125kHz
500kHz
1MHz
10
1k
100k
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT FREQUENCY (V
IN
= 2.5Vp-p)
MAX4295/7-03
INPUT FREQUENCY (Hz)
THD + N (%)
10
1
0.01
0.1
V
CC
= +5V
R
L
= 32
1MHz
125kHz
250kHz
500kHz
0
0.1
0.2
0.3
0.4
0.5
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 1kHz)
MAX4295/7-06
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +5V
R
L
= 32
1MHz
500kHz
250kHz
125kHz
0
0.1
0.2
0.3
0.4
0.5
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 20kHz)
MAX4295/7-09
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +5V
R
L
= 32
500kHz
1MHz
125kHz
250kHz
MAX4295/MAX4297
Mono/Stereo 2W Switch-Mode (Class-D)
Audio Power Amplifiers
_______________________________________________________________________________________
5
Typical Operating Characteristics (continued)
(V
CC
= PV
CC
= +3V, input amplifier gain = -1, SHDN = V
CC
, T
A
= +25C, unless otherwise noted.)
10
1k
100k
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT FREQUENCY (V
IN
= 1.5Vp-p)
MAX4295/7-11
INPUT FREQUENCY (Hz)
THD + N (%)
10
1
0.01
0.1
V
CC
= +3V
R
L
= 8
1MHz
125kHz
250kHz
500kHz
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7 0.8
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 1kHz)
MAX4295/7-14
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +3V
R
L
= 8
250kHz
500kHz
125kHz
1MHz
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7 0.8
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 20kHz)
MAX4295/7-17
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +3V
R
L
= 8
125kHz
1MHz
500kHz
250kHz
10
1k
100k
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT FREQUENCY (V
IN
= 1.5Vp-p)
MAX4295/7-10
INPUT FREQUENCY (Hz)
THD + N (%)
10
1
0.01
0.1
V
CC
= +3V
R
L
= 4
1MHz
125kHz
250kHz
500kHz
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7 0.8
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 1kHz)
MAX4295/7-13
OUTPUT POWER (W)
THD + N (%)
100
10
0.1
1
V
CC
= +3V
R
L
= 4
1MHz
250kHz
500kHz
125kHz
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7 0.8
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 20kHz)
MAX4295/7-16
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +3V
R
L
= 4
125kHz
250kHz
500kHz
1MHz
10
1k
100k
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. INPUT FREQUENCY (V
IN
= 1.5Vp-p)
MAX4295/7-12
INPUT FREQUENCY (Hz)
THD + N (%)
10
1
0.01
0.1
V
CC
= +3V
R
L
= 32
1MHz
125kHz
250kHz
500kHz
0
0.05
0.10
0.15
0.20
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 1kHz)
MAX4295/7-15
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +3V
R
L
= 32
250kHz
125kHz
500kHz
1MHz
0
0.05
0.10
0.15
0.20
MAX4295
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT POWER (f
IN
= 20kHz)
MAX4295/7-18
OUTPUT POWER (W)
THD + N (%)
100
10
1
0.10
0.1
V
CC
= +3V
R
L
= 32
250kHz
500kHz
1MHz
125kHz
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