19-4295; Rev 0; 10/08
Shunt Mode Audio Click-and-Pop Eliminator
General Description
The MAX9892 is an audio click-and-pop eliminator for
portable multimedia devices. Operating from a 1.7V to
3.6V supply, the MAX9892 connects to the output of the
existing system amplifier and provides a low-imped-
ance path to ground during startup and shutdown. The
inputs INL and INR accept voltage swings from V
DD
to
5.5V below V
DD
. See the
Setting the Supply Voltage
section for more information. The power-up and power-
down transients are shunted to ground to prevent clicks
and pops from becoming audible.
The MAX9892 features two low-impedance analog
switches controlled by
MUTE
that opens and closes the
switches. The switches are open during normal opera-
tion and have no impact on the output signal. During
startup and shutdown of the amplifier, the MAX9892
can be activated to short the outputs to ground and
prevent clicks and pops from pulling current through
the headphones.
The MAX9892 is available in 6-bump UCSP (1mm x
1.52mm x 0.6mm) and 6-pin µDFN (2mm x 2mm x
0.75mm) packages. The MAX9892 is specified over the
-40°C to +85°C temperature range.
♦
Less than 1µA Supply Current
♦
1.7V to 3.6V Single-Supply Operation
♦
Tiny Packages
6-Bump UCSP (1mm x 1.52mm x 0.6mm)
6-Pin µDFN (2mm x 2mm x 0.75mm)
Features
♦
Distortion-Free, Click-and-Pop Elimination
MAX9892
Ordering Information
PART
MAX9892ERT+
MAX9892ELT+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
6 UCSP
6 µDFN
+Denotes
a lead-free/RoHS-compliant package.
Pin Configurations
TOP VIEW
(BUMPS ON BOTTOM)
1
2
3
Applications
Mobile Phones
Smart Phones
Mobile Internet Devices
Portable Gaming Consoles
Portable Media Players
Notebook Computers
A
INL
GND
INR
MAX9892
V
DD
B
MUTE
SET
Typical Operating Circuit
R
SERIES
HEADPHONE
AMPLIFIER
UCSP
TOP VIEW
R
SERIES
MUTE
6
V
DD
5
SET
4
INL
1.7V TO 3.6V
INR
MAX9892
MAX9892
V
DD
MUTE
0.1μF
+
SET
GND
C SET
1
INL
2
GND
3
INR
μDFN
________________________________________________________________
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.
Shunt Mode Audio Click-and-Pop Eliminator
MAX9892
ABSOLUTE MAXIMUM RATINGS
V
DD
,
MUTE,
SET to GND..........................................-0.3V to +6V
INL, INR to GND .................................(V
DD
- 6V) to (V
DD
+ 0.3V)
Continuous Current In/Out of V
DD
......................................30mA
Continuous Current In/Out of
MUTE
...................................30mA
Continuous Current In/Out of SET.......................................30mA
Continuous Current In/Out of INL, INR and GND .............390mA
Continuous Power Dissipation (T
A
= +70°C)
6-Bump UCSP (derate 3.9mW/°C above +70°C) .....308.3mW
6-Pin µDFN (derate 4.5mW/°C above +70°C) ..........357.8mW
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
Bump Temperature (soldering)
Reflow ..........................................................................+235°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
= 3.0V, V
GND
= 0, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
Recommended Supply Voltage
Range
Supply Current
Input Voltage Range
Turn-On Time (Figure 1)
SYMBOL
V
DD
V
DD
I
DD
V
IN
t
ON
CONDITIONS
Guaranteed by R
ON
test
(Note 2)
V
DD
= 5.5V, T
A
= +25°C (Note 3)
Guaranteed by input leakage current test
Measured from
MUTE
= GND and input
voltage settled to 90% of its final value
C
SET
= 500pF
Turn-Off Time (Figure 1)
Turn-On Time Resistor
Switch On-Resistance
Click-and-Pop Reduction
Input Leakage Current
MUTE
Leakage Current
MUTE
Input-Voltage High
MUTE
Input-Voltage Low
I
IN
I
MUTE
V
IH
V
IL
t
OFF
R
SET
R
ON
C
SET
= 50pF
C
SET
= 50nF
C
SET
= 500pF
V
DD
= 3.0V
V
DD
= 1.7V
V
DD
= 5.5V
R
SERIES
= 30Ω, R
LOAD
= 16Ω
T
A
= +25°C
V
IN
= V
DD
- 5.5V, V
DD
= 1.7V
V
IN
= V
DD
, V
DD
= 5.5V
1.5
0.4
35
±1
±1
±1
350
4
V
DD
-
5.5V
130
10
1
1000
800
0.3
2
1
dB
µA
µA
V
V
Ω
1300
kΩ
17
ms
MIN
1.7
1.7
0.6
TYP
MAX
5.5
3.6
1
V
DD
UNITS
V
V
µA
V
ns
V
DD
= 5.5V, V
MUTE
= 0 or 5.5V, T
A
= +25°C
Note 1:
All devices are 100% production tested at T
A
= +25°C. All temperature limits are guaranteed by design.
Note 2:
Operating within the recommended supply voltage range ensures that negative audio signals are not limited by the device.
Supply voltages above the recommended supply voltage range may limit the headphone amplifier’s maximum output voltage.
Note 3:
Supply current is measured when switches are off.
2
_______________________________________________________________________________________
Shunt Mode Audio Click-and-Pop Eliminator
Typical Operating Characteristics
(V
DD
= 3.0V, V
GND
= 0, T
A
= +25°C, unless otherwise noted.)
MAX9892
CLICK AND POP vs. R
SERIES
MAX9892 toc01
t
OFF
vs. C
SET
MAX9892 toc02
R
ON
vs. SUPPLY VOLTAGE
0.7
0.6
MAX9892 toc03
0
-10
-20
CLICK AND POP (dBV)
-30
TESTED WITH THE MAX4338
1200
1000
800
t
OFF
(ms)
0.8
-40
-50
-60
-70
-80
-90
0
10
20 30 40 50 60 70 80 90 100
R
SERIES
(Ω)
OUT OF SHUTDOWN
R
ON
(Ω)
0.5
0.4
0.3
0.2
600
400
200
INTO SHUTDOWN
0
0
5
10 15 20 25 30 35 40 45 50
C
SET
(nF)
0.1
0
1.5
2.5
3.5
V
DD
(V)
4.5
5.5
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
MAX9892 toc04
CLICK AND POP vs. V
DD
MAX9892 toc05
SWITCH TURN-OFF/ON TIME
MAX9892 toc06
1.0
0
TESTED WITH THE MAX4338
-20
CLICK AND POP (dBV)
C
SET
= 500pF
MUTE
2V/div
0.8
I
DD
(μA)
0.6
-40
0.4
-60
OUT OF SHUTDOWN
-80
INTO SHUTDOWN
IN_
2V/div
0.2
0
1.5
2.5
3.5
V
DD
(V)
4.5
5.5
-100
1.5
2.5
3.5
V
DD
(V)
4.5
5.5
2ms/div
CROSSTALK vs. FREQUENCY
MAX9892 toc07
0
-20
CROSSTALK (dB)
-40
-60
-80
-100
-120
0.01
0.1
1
FREQUENCY (kHz)
10
100
_______________________________________________________________________________________
3
Shunt Mode Audio Click-and-Pop Eliminator
MAX9892
Pin Description
UCSP
BUMP
A1
A2
A3
B1
B2
B3
µDFN
PIN
1
2
3
6
5
4
NAME
FUNCTION
Left-Channel Input. Connect INL in between the output coupling capacitor and the headphone
jack.
Ground
Right-Channel Input. Connect INR in between the output coupling capacitor and the
headphone jack.
Active-Low Enable
Power Supply
Turn-Off Time Set. Connect an external capacitor in between SET and GND to set the switch
open delay; see the
Setting the Turn-Off Time
section for more information.
INL
GND
INR
MUTE
V
DD
SET
Timing Diagram
MUTE
GND
V
DD
IN_
V
DD
- 5.5V
GND
t
OFF
R
ON
t
ON
0.5Ω
Figure 1. Turn-On/Off Time
4
_______________________________________________________________________________________
Shunt Mode Audio Click-and-Pop Eliminator
Detailed Description
The MAX9892 is the second-generation click-and-pop
eliminator designed to be used with conventional head-
phone amplifiers. The MAX9892 works by adding a low-
impedance current path from the headphone side of
the DC-blocking capacitor to ground. Drive
MUTE
low
when turning off the amplifier, and high when enabling
the amplifier. A short turn-on time allows the switches in
the MAX9892 to close before the DC-blocking capaci-
tors have significantly discharged, eliminating clicks
and pops at amplifier turn-off. An adjustable turn-off
time allows the delay to be set to mask all clicks and
pops during amplifier turn-on.
where V
AMP
is the supply voltage of the amplifier, and
I
2
is the current through R
2
. For a signal of ±2V in refer-
ence to GND, the MAX9892 supply can be set from 2V
to 3.5V.
MAX9892
Selecting Series Resistors
A series resistor (R
SERIES
), as shown in the
Typical
Operating Circuit,
is necessary to achieve optimal click-
and-pop reduction. See the Click and Pop vs. R
SERIES
graph in the
Typical Operating Characteristics
for
details on how much click-and-pop reduction to expect
for a given series resistor.
Layout Considerations
Bypass V
DD
to GND with a 0.1µF capacitor. The 0.1µF
bypass capacitor should be positioned as close as
possible to V
DD
. Minimize trace length from GND to
solid system ground plane to ensure optimum perfor-
mance.
Refer to the MAX9892 Evaluation Kit for a proven PCB
layout.
Setting the Turn-Off Time
The MAX9892 features a SET input that allows the turn-
off time to be adjusted from 1ms to 1000ms to match
the click-and-pop profile of the amplifier startup. The
value of an external capacitor sets the switch open
delay, as shown in the following equation:
t
ON
(ms) = 0.02 x C
SET
(pF)
When the headphone amplifier is enabled, the
MAX9892 automatically waits the set delay time before
opening the analog switches. This allows amplifier turn-
on click and pop to be eliminated.
A
V
DD
Applications Information
Setting the Supply Voltage
The MAX9892 operates from 1.7V to 3.6V supply volt-
age. The inputs, INL and INR, accept voltage swings
from V
DD
to V
DD
- 5.5V. The audio signal applied to a
headphone is ground biased, meaning that the signal
swings just as much negative as positive. Since the
MAX9892 input voltage is limited to V
DD
- 5.5V on the
negative side, the voltage on V
DD
must be set properly
to pass the audio signal when the switch is open
(Figure 2).
A voltage-divider can be used to scale down an avail-
able supply voltage as shown in Figure 3. The voltage-
divider allows the creation of a supply voltage for the
MAX9892 that is low enough to allow the negative por-
tion of the audio signal to pass. When using large resis-
tances for the voltage-divider, the supply current
affects what resistors to use. Select R
2
between 10kΩ
to 1MΩ for a given supply voltage. Use the following
equation to calculate the R
1
:
R
1
=
(V
AMP
−
V
DD
)
I
2
+
I
DD
IN_
GND
V
DD
- 5.5V
B
V
DD
IN_
V
DD
- 5.5V
GND
Figure 2. Proper Supply Selected for a Given Input Signal.
A: Supply Voltage with a Large Signal;
B: Supply Voltage with a Small Signal
_______________________________________________________________________________________
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