19-3860; Rev 0; 12/05
KIT
ATION
EVALU
BLE
AVAILA
Quad Audio Line Driver with 3V
RMS
Output
General Description
The MAX9727 quad audio line driver with 3V
RMS
output is
ideal for portable audio devices where board space and
cost is at a premium. The device uses Maxim’s
DirectDrive
TM
architecture that produces a ground-refer-
enced output from a single supply, eliminating the need
for large DC-blocking capacitors and saving cost, board
space, and component height. A high 100dB PSRR and
low 0.0005% THD+N ensures clean, low-distortion ampli-
fication of the audio signal. Each MAX9727 amplifier can
provide 3V
RMS
to a 1kΩ load with less than 0.003%
THD+N while operating from a single +5V supply. Each
MAX9727 amplifier can provide 2V
RMS
to a 1kΩ load with
less than 0.003% THD+N while operating from a single
+3.3V supply.
A shutdown input disables the amplifiers and reduces
quiescent current consumption to less than 100nA. The
MAX9727 features Maxim’s comprehensive click-and-
pop suppression circuitry that reduces audible clicks and
pops during startup and shutdown.
The MAX9727 operates from a single 2.7V to 5.5V sup-
ply, consumes only 3mA of supply current per channel,
and is specified over the -40°C to +85°C extended tem-
perature range.
Features
o
2.7V to 5.5V Single-Supply Operation
o
High 100dB PSRR
o
109dB Signal-to-Noise Ratio (SNR)
o
o
o
o
o
Ground-Referenced Outputs
No Audible Clicks or Pops at Power-Up/Down
Differential Inputs
3V
RMS
into 1kΩ Load at 5V
2V
RMS
into 1kΩ Load at 3.3V
MAX9727
o
3mA Supply Current Per Channel
o
Unity-Gain Stable
o
100nA Low-Power Shutdown Mode
o
C
LOAD
Drive > 220pF
o
±8kV HBM ESD-Protected Outputs
Ordering Information
PART
MAX9727EEP+
TEMP RANGE
-40°C to +85°C
PIN-
PACKAGE
20 QSOP
GAIN
Adjustable
Applications
Set-Top Boxes
Consumer and
Professional Audio
Equipment
A/V Receivers
CD and DVD Players
Soundcards
Portable Audio
Devices
+Denotes
lead-free package.
Simplified Block Diagram
OUTA
OUTD
INA-
IND-
Pin Configuration
INA+
IND+
INC+
TOP VIEW
OUTA 1
INA- 2
INA+ 3
V
DD
4
INB+ 5
INB- 6
OUTB 7
SHDN 8
PV
DD
9
C1P 10
+
20 OUTD
19 IND-
18 IND+
INB+
INB-
INC-
MAX9727
17 V
SS
16 INC+
15 INC-
14 OUTC
13 PV
SS
12 C1N
11 PGND
C1P
C1N
ON
OFF
SHDN
PV
DD
PV
SS
OUTB
OUTC
MAX9727
PGND
QSOP
________________________________________________________________
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.
Quad Audio Line Driver with 3V
RMS
Output
MAX9727
ABSOLUTE MAXIMUM RATINGS
V
DD
, PV
DD
to PGND .................................................-0.3V to +6V
V
SS
, PV
SS
to PGND ..................................................-6V to +0.3V
IN_ to PGND ..................................(V
SS
+ 0.3V) to (PV
DD
- 0.3V)
OUT_ to PGND...............................(V
SS
- 0.3V) to (PV
DD
+ 0.3V)
SHDN
to PGND..........................(PGND - 0.3V) to (PV
DD
+ 0.3V)
C1P to PGND.............................(PGND - 0.3V) to (PV
DD
+ 0.3V)
C1N to PGND .............................(PV
SS
- 0.3V) to (PGND + 0.3V)
Output Short Circuit to PGND or P
VDD
.......................Continuous
Continuous Power Dissipation (T
A
= +70°C)
20-Pin QSOP Single-Layer Board
(derate 9.1mW/°C above +70°C) ..................................727mW
20-Pin QSOP Multilayer Board
(derate 11mW/°C above +70°C) ...................................884mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature .....................................................+150°C
Storage Temperature Range .............................-65°C to +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
= 3.3V, PGND = 0V,
SHDN
= V
DD
, V
CM
= 0V, C1 = C2 = 1µF, R
IN
= R
F
= 5kΩ, R
L
=
∞,
T
A
= T
MIN
to T
MAX
. Typical val-
ues are at T
A
= +25°C.) (Note 1)
PARAMETER
GENERAL
Supply Voltage Range
Quiescent Current
Shutdown Current
AMPLIFIERS
Input Offset Voltage
Input Bias Current
Input Offset Current
Open-Loop Gain
Input Common-Mode Voltage
Range
V
OS
I
BIAS
I
OS
A
V
CMR
V
OUT
= -3V to +3V, R
L
= 1kΩ
V
DD
= 2.7V
V
DD
= 3V
V
DD
= 5V
V
DD
= 2.7V, V
CM
= ±1.6V
Common-Mode Rejection Ratio
CMRR
V
DD
= 3V, V
CM
= ±1.9V
V
DD
= 5V, V
CM
= ±3.5V
V
DD
= PV
DD
= 2.7V to 5.5V
Power-Supply Rejection Ratio
PSRR
f = 1kHz, V
DD
= PV
DD
= 5V + 100mV
P-P
ripple
R
L
= 1kΩ, V
DD
= 3.3V, THD+N = 1%
R
L
= 1kΩ, V
DD
= 5V, THD+N = 1%
R
L
= 1kΩ,
V
DD
= 3.3V
R
L
= 1kΩ,
V
DD
= 5V
Sinking
Sourcing
Positive
Negative
Positive
Negative
1.6
2.0
2.6
-2.6
3.5
-3.5
-1.6
-2.3
-3.5
80
80
80
80
100
100
100
100
60
2.0
3.0
3.0
-3.0
4.2
-4.1
40
5
mA
V
dB
dB
±0.5
1000
500
82
+1.6
+2.3
+3.5
V
±5
mV
nA
nA
dB
V
DD
I
DD
I
DD, SHDN
Inferred from PSRR test
Current into V
DD
and PV
DD
V
SHDN
= 0V
2.7
12
0.1
5.5
14
10
V
mA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Output Voltage
V
RMS
Output Voltage Swing
V
OUT
Output Short-Circuit Current
I
SC
2
_______________________________________________________________________________________
Quad Audio Line Driver with 3V
RMS
Output
ELECTRICAL CHARACTERISTICS
(V
DD
= PV
DD
= 3.3V, PGND = 0V,
SHDN
= V
DD
, V
CM
= 0V, C1 = C2 = 1µF, R
IN
= R
F
= 5kΩ, R
L
=
∞,
T
A
= T
MIN
to T
MAX
. Typical val-
ues are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
V
OUT
= 1.6V
RMS
, BW = 22Hz to 22kHz,
f = 1kHz, unweighted, R
L
= 10kΩ
Total Harmonic Distortion Plus
Noise
THD+N
V
OUT
= 2V
RMS
, BW = 22Hz to 22kHz,
f = 1kHz, unweighted, R
L
= 10kΩ
V
OUT
= 1.6V
RMS
, BW = 22Hz to 22kHz,
f = 1kHz, unweighted, R
L
= 1kΩ
V
OUT
= 1.6V
RMS,
R
L
= 1kΩ
V
OUT
= 2V
RMS
,
R
L
= 1kΩ
Click-and-Pop Level
Slew Rate
Turn-On Time
Turn-Off Time
Capacitive Drive
Crosstalk
Large-Signal Open-Loop Gain
Small-Signal Open-Loop Gain
Gain Bandwidth
Charge-Pump Switching
Frequency
Charge-Pump Output Impedance
ESD Protection
DIGITAL INPUTS (SHDN)
Input-Voltage High
Input-Voltage Low
Input Leakage Current
V
IH
V
IL
I
LEAK
2.0
0.8
±1
V
V
µA
ESD
A
VOL
A
VOS
GBW
f
OSC
Measured at PV
SS
HBM
150
t
ON
t
OFF
C
L
No sustained oscillations
f = 10kHz
V
OUT
= 2V
RMS
V
OUT
= 100mV
RMS
K
CP
Peak voltage,
A-weighted, 32
samples/s (Notes 2, 3)
R
L
= 1kΩ, C
L
= 100pF
22Hz to 22kHz
A-weighted
22Hz to 22kHz
A-weighted
Into shutdown
Out of shutdown
MIN
TYP
0.0005
0.0006
0.003
109
113.6
111
115.5
-62.2
dBV
-54.3
0.9
90
1
220
-70
82
95
3
300
20
±8
450
V/µs
µs
µs
pF
dB
dB
dB
MHz
kHz
Ω
kV
dB
%
MAX
UNITS
MAX9727
Signal-to-Noise Ratio
SNR
Note 1:
All devices are 100% tested at T
A
= +25°C. Specifications over temperature are guaranteed by design.
Note 2:
Inputs AC-coupled to PGND.
Note 3:
Click-and-pop testing performed with a 1kΩ resistive load connected to ground. Mode transitions are controlled by
SHDN.
K
CP
level is calculated as 20log[(peak voltage during mode transition, no input signal)/1V
RMS
]. Units are expressed in dBV.
_______________________________________________________________________________________
3
Quad Audio Line Driver with 3V
RMS
Output
MAX9727
Typical Operating Characteristics
(V
DD
= PV
DD
= 3.3V, V
CM
= 0V, R
IN
= R
F
= 5kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise
noted.)
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE
MAX9727 toc01
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE
MAX9727 toc02
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE
V
DD
= 3.3V
R
L
= 1kΩ
f = 10kHz
f = 1kHz
f = 100Hz
MAX9727 toc03
100
10
1
THD+N (%)
0.1
f = 100Hz
0.01
0.001
0.0001
0
1
2
3
4
OUTPUT VOLTAGE (V
RMS
)
V
DD
= 5V
R
L
= 1kΩ
f = 10kHz
100
10
1
THD+N (%)
0.1
0.01
0.001
0.0001
0
1
2
3
4
OUTPUT VOLTAGE (V
RMS
)
R
L
= 1kΩ
R
L
= 10kΩ
R
L
= 5kΩ
V
DD
= 5V
f
IN
= 1kHz
100
10
1
THD+N (%)
0.1
0.01
0.001
0.0001
0
1
2
3
OUTPUT VOLTAGE (V
RMS
)
f = 1kHz
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. OUTPUT VOLTAGE
MAX9727 toc04
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9727 toc05
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
V
DD
= 5V
R
L
= 10kΩ
MAX9727 toc06
100
10
1
THD+N (%)
V
DD
= 3.3V
f
IN
= 1kHz
0.1
V
DD
= 5V
R
L
= 1kΩ
V
OUT
= 2.5V
RMS
0.1
0.01
THD+N (%)
R
L
= 5kΩ
R
L
= 1kΩ
0.01
THD+N (%)
V
OUT
= 1V
RMS
V
OUT
= 2.5V
RMS
0.1
0.01
0.001
0.001
V
OUT
= 1V
RMS
0.001
R
L
= 10kΩ
0.0001
0
1
2
3
OUTPUT VOLTAGE (V
RMS
)
0.0001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.0001
10
100
1k
FREQUENCY (Hz)
10k
100k
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9727 toc07
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. FREQUENCY
MAX9727 toc08
TOTAL HARMONIC DISTORTION PLUS NOISE
vs. COMMON-MODE VOLTAGE
V
DD
= 5V
R
L
= 1kΩ
DIFFERENTIAL
CONFIGURATION
MAX9727 toc09
0.1
V
DD
= 3.3V
R
L
= 1kΩ
V
OUT
= 2V
RMS
0.1
V
DD
= 3.3V
R
L
= 10kΩ
0.1
f = 10kHz
0.01
THD+N (%)
0.01
THD+N (%)
V
OUT
= 1V
RMS
THD+N (%)
V
OUT
= 2V
RMS
0.01
f = 1kHz
0.001
f = 100Hz
0.001
V
OUT
= 1V
RMS
0.001
0.0001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.0001
10
100
1k
FREQUENCY (Hz)
10k
100k
0.0001
-4
-2
0
2
4
COMMON-MODE VOLTAGE (V)
4
_______________________________________________________________________________________
Quad Audio Line Driver with 3V
RMS
Output
Typical Operating Characteristics (continued)
(V
DD
= PV
DD
= 3.3V, V
CM
= 0V, R
IN
= R
F
= 5kΩ, THD+N measurement bandwidth = 22Hz to 22kHz, T
A
= +25°C, unless otherwise
noted.)
OUTPUT VOLTAGE
vs. SUPPLY VOLTAGE
MAX9727 toc10
MAX9727
OUTPUT VOLTAGE
vs. LOAD RESISTANCE
MAX9727 toc11
OUTPUT VOLTAGE
vs. LOAD RESISTANCE
V
DD
= 3.3V
2.5
OUTPUT VOLTAGE (V
RMS
)
2.0
THD+N = 10%
1.5
1.0
0.5
THD+N = 1%
MAX9727 toc12
4.0
3.5
OUTPUT VOLTAGE (V
RMS
)
3.0
2.5
2.0
THD+N = 1%
1.5
f
IN
= 1kHz
R
L
= 1kΩ
THD+N = 10%
4.5
4.0
OUTPUT VOLTAGE (V
RMS
)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
THD+N = 10%
THD+N = 1%
V
DD
= 5V
3.0
1.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
SUPPLY VOLTAGE (V)
0
0
2
4
6
8
10
LOAD RESISTANCE (kΩ)
0
0
2
4
6
8
10
LOAD RESISTANCE (kΩ)
CHARGE-PUMP OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX9727 toc13
CHARGE-PUMP OUTPUT VOLTAGE
vs. OUTPUT CURRENT
MAX9727 toc14
GAIN AND PHASE
vs. FREQUENCY
60
GAIN/PHASE (dB/DEGREES)
A
V
= 60dB
MAX9727 toc15
MAX9727 toc18
1.0
0.5
0
OUTPUT VOLTAGE (V)
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-3.5
0
20
40
C1 = C2 = C3 = 0.22µF
C1 = C2 = C3 = 0.1µF
60
80
100
C1 = C2 = C3 = 1µF
V
DD
= 3.3V
OUTPUTS UNLOADED,
CHARGE-PUMP LOAD
CONNECTED BETWEEN
PV
SS
AND PGND
3
2
1
OUTPUT VOLTAGE (V)
0
-1
-2
-3
-4
-5
C1 = C2 = C3 = 0.1µF
-6
C1 = C2 = C3 = 1µF
C1 = C2 = C3 = 0.22µF
V
DD
= 5V
OUTPUTS UNLOADED,
CHARGE-PUMP LOAD
CONNECTED BETWEEN
PV
SS
AND PGND
0
GAIN
-60
-120
PHASE
120
0
50
100
150
200
-180
0.1
1
10
100
1000
10,000
OUTPUT CURRENT (mA)
OUTPUT CURRENT (mA)
FREQUENCY (kHz)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX9727 toc16
CROSSTALK vs. FREQUENCY
V
DD
= 5V
V
OUT
= 3V
RMS
R
L
= 1kΩ
MAX9727 toc17
CROSSTALK vs. FREQUENCY
-80
-90
CROSSTALK (dB)
-100
-110
-120
-130
V
DD
= 3.3V
V
OUT
= 2V
RMS
R
L
= 1kΩ
Ch. D to Ch. A
0
-10
-20
R
L
= 1kΩ
-80
-90
CROSSTALK (dB)
-100
-110
PSRR (dB)
-30
-40
-50
-60
-70
-80
10
100
1k
FREQUENCY (Hz)
10k
100k
V
DD
= 5V + 100mV
P-P
Ch. D to Ch. C
Ch. D to Ch. A
-120
-130
Ch. D to Ch. B
V
DD
= 3.3V + 100mV
P-P
-140
10
100
Ch. D to Ch. C
-140
1k
FREQUENCY (Hz)
10k
100k
10
100
Ch. D to Ch. B
1k
FREQUENCY (Hz)
10k
100k
_______________________________________________________________________________________
5
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