19-3377; Rev 0; 7/04
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
The MAX4855 dual, single-pole/double-throw (SPDT)
switch operates from a single +2V to +5.5V supply and
features rail-to-rail signal handling. The MAX4855 has
low on-resistance (0.75Ω) with a +3V supply making it
ideal for audio switching applications in portable
devices. The device also integrates two internal comparators that can be used for headphone detection or
mute/send key functions.
The MAX4855 is available in the space-saving (3mm x
3mm), 16-pin thin QFN package and operates over the
extended temperature range of -40°C to +85°C.
Applications
Features
♦ Audio Signal Routing
♦ 0.75Ω On-Resistance
♦ 0.18Ω On-Resistance Flatness
♦ 0.07Ω Channel-to-Channel Matching
♦ Rail-to-Rail Signal Handling
♦ 2 Integrated Comparators
♦ 1.8V Logic Compatible
♦ 2V to 5.5V Supply Range
♦ Available in a Space-Saving (3mm x 3mm),
16-Pin TQFN Package
Speaker Headset Switching
Audio-Signal Routing
Ordering Information
Cellular Phones
Notebook Computers
PART
TEMP RANGE
PINPACKAGE
MAX4855ETE
-40°C to +85°C
16 TQFN-EP*
PDAs and Other Handheld Devices
TOP
MARK
ABY
*EP = Exposed paddle.
Pin Configuration
Block Diagram/Truth Table
ON
1
ON
OFF
SWITCHES SHOWN FOR
LOGIC 0 INPUT
IN2
NC2
16
15
14
13
N.C.
1
12 NO2
CIN1
2
11 COUT1
CIN2
3
10 COM2
COM1
4
9
MAX4855
COM2
0.75Ω
NO2
TOP VIEW
COUT2
OFF
VCC
0
VCC
3
COUT1
5
NO1
CIN1
VCC
3
6
7
8
N.C.
IN1
NC_
NC2
NO1
NO_
IN1
COM1
0.75Ω
IN_
GND
NC1
NC1
MAX4855
MAX4855
IN2
THIN QFN
COUT2
CONNECT EXPOSED PADDLE TO GROUND.
CIN2
________________________________________________________________ Maxim Integrated Products
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.
1
MAX4855
General Description
MAX4855
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
ABSOLUTE MAXIMUM RATINGS
VCC, IN_, CIN_ to GND ..............................................-0.3V to +6.0V
NO_, NC_, COM_, COUT_ (Note 1) ...............-0.3V to (VCC + 0.3V)
COUT_ Continuous Current...................................................±20mA
Closed Switch Continuous Current COM_, NO_, NC_.......±300mA
Peak Current COM_, NO_, NC_
(pulsed at 1ms, 50% duty cycle) ....................................±400mA
Peak Current COM_, NO_, NC_
(pulsed at 1ms, 10% duty cycle) ....................................±500mA
Continuous Power Dissipation (TA = +70°C)
16-Pin Thin QFN (derate 20.8mW/°C above +70°C) .....1667mW
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
Note 1: Signals on NO, NC, or COM exceeding VCC or GND are clamped by internal diodes. Signals on IN exceeding GND are
clamped by an internal diode. Limit forward-diode current to maximum current rating.
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
(VCC = +2.7V to +5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = +3.0V, TA = +25°C, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
Supply Voltage
VCC
Supply Current
ICC
CONDITIONS
MIN
TYP
2
VCC = 5.5V, VIN_ = 0V or VCC
5
MAX
UNITS
5.5
V
10
µA
VCC
V
ANALOG SWITCH
Analog Signal Range
On-Resistance (Note 3)
VNO_,
VNC_,
VCOM_
RON
On-Resistance Match
Between Channels
(Notes 3, 4)
∆RON
On-Resistance Flatness
(Note 5)
RFLAT
NO_/NC_ Off-Leakage
Current (Note 2)
IOFF
COM_ On-Leakage
Current (Note 2)
ION
0
VCC = 2.7V, ICOM_ =
100mA, VNC_ or VNO_ = 0V
to VCC
VCC = 2.7V, ICOM = 100mA,
VNC_ or VNO_ = 1.5V
VCC = 2.7V, ICOM_ =
100mA, VNC_ or VNO_ =
0.75V, 1.5V, 1.75V
TA = +25°C
0.75
Ω
TA = -40°C to +85°C
1.1
TA = +25°C
0.075
0.135
TA = +25°C
0.18
0.275
Ω
TA = -40°C to +85°C
VCC = 5.5V; VNC_ or VNO_ = TA = +25°C
1V, 4.5V, or floating; VCOM_
TA = -40°C to +85°C
= 1V, 4.5V, or floating
0.120
Ω
TA = -40°C to +85°C
VCC = 5.5V, VNC_ or VNO_ = TA = +25°C
1V or 4.5V, VCOM_ = 4.5V or
TA = -40°C to +85°C
1V
1
0.3
-2
+2
-10
+10
-2
+2
-15
+15
nA
nA
DYNAMIC CHARACTERISTICS
Turn-On Time
2
tON
VCC = 2.7V, VNO_ or VNC_ = TA = +25°C
1.5V, RL = 300Ω, CL = 50pF
TA = -40°C to +85°C
(Figure 1)
40
_______________________________________________________________________________________
60
ns
100
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
(VCC = +2.7V to +5.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at VCC = +3.0V, TA = +25°C, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
Turn-Off Time
tOFF
Break-Before-Make Time
Delay (Note 3)
tD
Charge Injection
Q
CONDITIONS
MIN
TYP
MAX
VCC = 2.7V, VNO_ or VNC_ = TA = +25°C
1.5V, RL = 300Ω, CL = 50pF
TA = -40°C to +85°C
(Figure 1)
30
40
VCC = 2.7V, VNO_ or VNC_ = TA = +25°C
1.5V, RL = 50Ω, CL = 50pF
TA = -40°C to +85°C
(Figure 2)
15
UNITS
ns
60
ns
2
VCOM_ = 1.5V, RS = 0Ω, CL = 1.0nF (Figure 3)
170
pC
f = 100kHz, VCOM_= 1VRMS, RL = 50Ω, CL = 5pF
(Figure 4)
-75
dB
VCT
f = 100kHz, VCOM_= 1VRMS, RL = 50Ω, CL = 5pF
(Figure 4)
-93
dB
-3dB Bandwidth
BW
Signal = 0dBm, RL = 50Ω, CL = 5pF (Figure 4)
Total Harmonic Distortion
THD
f = 20Hz to 20kHz, VCOM_ = 1V + 2VP-P, RL = 32Ω
NO_/NC_ OffCapacitance
COFF
COM On-Capacitance
CON
Off-Isolation (Note 6)
Crosstalk
38
MHz
0.07
%
f = 1MHz (Figure 5)
50
pF
f = 1MHz (Figure 5)
150
pF
DIGITAL I/O (IN_)
Input-Logic High Voltage
VIH
Input-Logic Low Voltage
VIL
Input Leakage Current
IIN
VCC = 2V to 3.6V
1.4
VCC = 3.6V to 5.5V
1.8
V
VCC = 2V to 3.6V
0.5
VCC = 3.6V to 5.5V
0.8
VIN_ = 0 or 5.5V
V
-0.5
+0.5
µA
0
5.5
V
0.36 x
VCC
V
COMPARATOR
Comparator Range
Comparator Threshold
VCC = 2V to 5.5V, falling input
Comparator Hysteresis
VCC = 2V to 5.5V
Comparator Output High
Voltage
ISOURCE = 1mA
Comparator Output Low
Voltage
ISINK = 1mA
Comparator Switching
Time
Note 2:
Note 3:
Note 4:
Note 5:
Note 6:
0.3 x
VCC
0.33 x
VCC
50
mV
VCC 0.4V
V
0.4
Rising input (Figure 6)
2.5
Falling input (Figure 6)
0.5
V
µs
Specifications are 100% tested at TA = +85°C only, and guaranteed by design and characterization over the specified
temperature range.
Guaranteed by design and characterization; not production tested.
∆RON = RON(MAX) - RON(MIN).
Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the
specified analog signal ranges.
Off-Isolation = 20log10 (VCOM_ / VNO_), VCOM_ = output, VNO_ = input to off switch.
_______________________________________________________________________________________
3
MAX4855
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(VCC = 3.0V, TA = +25°C, unless otherwise noted.)
MAX4855 toc01
2.0
VCC = 2.0V
1.5
VCC = 2.3V
1.0
VCC = 2.5V
VCC = 3.0V
VCC = 3.0V
0.8
TA = +25°C
TA = +85°C
0.6
0.4
VCC = 5.0V
0.8
ON-RESISTANCE (Ω)
VCC = 1.8V
2.5
ON-RESISTANCE (Ω)
TA = +85°C
0.4
TA = -40°C
VCC = 5.0V
0.2
0.2
TA = -40°C
0.5
0
2
4
0
6
0.5
1.0
1.5
2.0
2.5
0
3.0
1
2
3
4
COM VOLTAGE (V)
COM VOLTAGE (V)
COM VOLTAGE (V)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
TURN-ON/TURN-OFF TIME
vs. SUPPLY VOLTAGE
TURN-ON/TURN-OFF TIME
vs. TEMPERATURE
TA = +25°C
4
TA = +85°C
50
tON
40
30
20
tOFF
36
10
3.5
4.5
2.5
tOFF
26
3.5
4.5
5.5
-40
-15
MAX4855 toc07
200
160
CHARGE INJECTION (pC)
VIN RISING
1.2
1.0
VIN FALLING
VCC = 3V
180
35
60
85
LEAKAGE CURRENT vs. TEMPERATURE
0.8
VCC = 5V
140
120
100
80
60
0.6
COM ON-LEAKAGE
0.4
0.2
COM OFF-LEAKAGE
40
0.8
10
TEMPERATURE (°C)
CHARGE INJECTION vs. COM VOLTAGE
LOGIC THRESHOLD vs. SUPPLY VOLTAGE
1.4
28
SUPPLY VOLTAGE (V)
SUPPLY VOLTAGE (V)
1.6
30
22
1.5
5.5
LEAKAGE CURRENT (nA)
2.5
MAX4855 toc08
1.5
32
24
0
2
tON
34
MAX4855 toc09
3
60
5
38
TURN-ON/TURN-OFF TIME (ns)
5
MAX4855 toc05
TA = -40°C
70
TURN-ON/TURN-OFF TIME (ns)
MAX4855 toc04
6
SUPPLY CURRENT (µA)
0
0
0
TA = +25°C
0.6
MAX4855 toc06
ON-RESISTANCE (Ω)
3.0
ON-RESISTANCE vs. COM VOLTAGE
1.0
MAX4855 toc03
ON-RESISTANCE vs. COM VOLTAGE
1.0
MAX4855 toc02
ON-RESISTANCE vs. COM VOLTAGE
3.5
LOGIC THRESHOLD (V)
MAX4855
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
20
1.5
2.5
3.5
SUPPLY VOLTAGE (V)
4
0
0
0.6
4.5
5.5
0
1
2
3
COM VOLTAGE (V)
4
5
-40
-15
10
35
TEMPERATURE (°C)
_______________________________________________________________________________________
60
85
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
TOTAL HARMONIC DISTORTION
vs. FREQUENCY
FREQUENCY RESPONSE
ON-RESPONSE
0
THD (%)
-20
-40
OFF-RESPONSE
RL = 32Ω
0.1
-60
RL = 600Ω
CROSSTALK
-80
-100
0.01
0.1
1
10
100
100
1k
10k
FREQUENCY (Hz)
COMPARATOR THRESHOLD
vs. TEMPERATURE
COMPARATOR THRESHOLD
vs. TEMPERATURE
VCMPI_ RISING
1.06
1.04
VCMPI_ FALLING
VCC = 5.0V
VCMPI_ RISING
1.725
100k
MAX4855 toc13
1.08
1.750
COMPARATOR THRESHOLD (V)
MAX4855 toc12
VCC = 3.0V
1.02
10
FREQUENCY (MHz)
1.10
COMPARATOR THRESHOLD (V)
MAX4855 toc11
1
MAX4855 toc10
FREQUENCY RESPONSE (dB)
20
1.700
VCMPI_ FALLING
1.675
1.650
1.625
1.00
1.600
-40
-15
10
35
TEMPERATURE (°C)
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
_______________________________________________________________________________________
5
MAX4855
Typical Operating Characteristics (continued)
(VCC = 3.0V, TA = +25°C, unless otherwise noted.)
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
MAX4855
Pin Description
PIN
NAME
FUNCTION
1, 8
N.C.
No Connection. Not internally connected.
2
CIN1
Inverting Input for Comparator 1
3
CIN2
Inverting Input for Comparator 2
4
COM1
5
NO1
Normally Open Terminal for Analog Switch 1
6
GND
Ground
7
NC2
Normally Closed Terminal for Analog Switch 2
9
IN2
Digital Control Input for Analog Switch 2. A logic LOW on IN2 connects COM2 to NC2 and a logic
HIGH connects COM2 to NO2.
Common Terminal for Analog Switch 1
10
COM2
Common Terminal for Analog Switch 2
11
COUT1
Output for Comparator 1
12
NO2
13
COUT2
Normally Open Terminal for Analog Switch 2
14
VCC
Supply Voltage. Bypass to GND with a 0.01µF capacitor as close to the pin as possible.
15
IN1
Digital Control Input for Analog Switch 1. A logic LOW on IN1 connects COM1 to NC1 and a logic
HIGH connects COM1 to NO1.
16
NC1
Normally Closed Terminal for Analog Switch 1
EP
—
Output for Comparator 2
Exposed Paddle. Connect to PC board ground plane.
Detailed Description
The MAX4855 dual SPDT, low on-resistance, low-voltage,
analog switch operates from a +2V to +5.5V supply and
can handle signals up to the power rails. In addition, the
MAX4855 integrates two internal comparators that can
be used for headphone or mute detection. The comparator threshold is internally generated to be approximately
1/3 of VCC.
Applications Information
Digital Control Inputs
The logic inputs (IN_) accept up to +5.5V even if the
supply voltages are below this level. For example, with
a +3.3V VCC supply, IN_ can be driven low to GND and
high to +5.5V allowing for mixing of logic levels in a
system. Driving IN_ rail-to-rail minimizes power consumption. For a +2V supply voltage, the logic thresholds
are 0.5V (low) and 1.4V (high); for a +5V supply voltage,
the logic thresholds are 0.8V (low) and 1.8V (high).
6
Analog Signal Levels
The on-resistance of these switches changes very little
for analog input signals across the entire supply voltage
range (see the Typical Operating Characteristics). The
switches are bidirectional, so the NO_, NC_, and COM_
pins can be either inputs or outputs.
Comparator
The positive terminal of the comparator is internally set to
VCC/3. When the negative terminal (CIN_) is below the
threshold (VCC/3), the comparator output (COUT_) is
high. When CIN_ rises above VCC/3, COUT_ is low.
The comparator threshold allows for detection of headphones since headphone audio signals are typically
biased to VCC/2.
Power-Supply Sequencing
Caution: Do not exceed the absolute maximum ratings because stresses beyond the listed ratings
may cause permanent damage to the device.
Proper power-supply sequencing is recommended for
all CMOS devices. Always apply VCC before applying
analog signals, especially if the analog signal is not
current-limited.
_______________________________________________________________________________________
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
MAX4855
VCC
t R < 20ns
t F < 20ns
V CC
VNO
COM_
NO_
VOUT
RL
VCC
50%
0V
t OFF
CL
SWITCH
OUTPUT
IN_
GND
LOGIC
INPUT
LOGIC
INPUT
VOUT
0.9 x V0UT
0.9 x VOUT
0V
t ON
CL INCLUDES FIXTURE AND STRAY CAPACITANCE.
RL
RL + RON
VOUT = VNO
(
)
Figure 1. Switching Time
V CC
MAX4855
LOGIC
INPUT
V CC
VN_
50%
0V
NC_
VOUT
COM_
NO_
RL
IN_
LOGIC
INPUT
VCC
CL
GND
0.9 x VOUT
VOUT
tBBM
CL INCLUDES FIXTURE AND STRAY CAPACITANCE.
Figure 2. Break-Before-Make Interval
_______________________________________________________________________________________
7
MAX4855
Test Circuits/Timing Diagrams
MAX4855
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
V CC
∆VOUT
MAX4855
VCC
RGEN
VOUT
COM_
NC_
OR NO_
VOUT
IN
OFF
CL
V GEN
GND
ON
OFF
IN_
VIL TO VIH
OFF
IN
ON
OFF
Q = (∆V OUT )(C L )
LOGIC-INPUT WAVEFORMS INVERTED FOR SWITCHES
THAT HAVE THE OPPOSITE LOGIC SENSE.
Figure 3. Charge Injection
+5V 10nF
V
OFF-ISOLATION = 20log OUT
VIN
NETWORK
ANALYZER
VCC
0V OR VCC
50Ω
VIN
COM1
IN_
V
ON-LOSS = 20log OUT
VIN
50Ω
MAX4855
VOUT
NO1*
NC1
GND
50Ω
MEAS
50Ω
MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS.
OFF-ISOLATION IS MEASURED BETWEEN COM_ AND "OFF", NO_ OR NC_ TERMINAL ON EACH SWITCH.
ON-LOSS IS MEASURED BETWEEN COM_ AND "ON", NO_ OR NC_ TERMINAL ON EACH SWITCH.
CROSSTALK IS MEASURED FROM ONE CHANNEL TO THE OTHER CHANNEL.
SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED.
REF
V
CROSSTALK = 20log OUT
VIN
50Ω
*FOR CROSSTALK THIS PIN IS NO2.
NC2 AND COM2 ARE OPEN.
Figure 4. On-Loss, Off-Isolation, and Crosstalk
10nF
V CC
VCC
COM_
MAX4855
IN
CAPACITANCE
METER
f = 1MHz
VIL OR VIH
NC_ OR
NO_
GND
Figure 5. Channel Off-/On-Capacitance
8
_______________________________________________________________________________________
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
VTH + 100mV
VCC
NO_
VCC
3
COMPARATOR
INPUT (VCIN_)
VCC
VCIN_
50%
50%
VTH - 100mV
COUT_
VOUT
VCOUT_
CIN_
COMPARATOR
OUTPUT (VCOUT_)
GND
MAX4855
tR < 20ns
tF < 20ns
MAX4855
tCOMP
tCOMP
50%
50%
0V
VTH = VCC/3
Figure 6. Comparator Switching Time
Typical Operating Circuit
Chip Information
TRANSISTOR COUNT: 735
PROCESS: CMOS
OUT+ NC1
AUDIO
SOURCE 1
MAX4855
OUT-
COM1
NO1
IN1
INPUT
SELECT
8Ω
SPEAKER
IN2
NC2
COM2
OUT+
AUDIO
SOURCE 2
OUT-
NO2
MUTE
VCC
VCC
3
COUT
CIN
MUTE
BUTTON
_______________________________________________________________________________________
9
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information
go to www.maxim-ic.com/packages.)
12x16L QFN THIN.EPS
MAX4855
0.75Ω, Dual SPDT Audio Switch with
Integrated Comparators
D2
0.10 M C A B
b
D
D2/2
D/2
E/2
E2/2
CL
(NE - 1) X e
E
E2
L
k
e
CL
(ND - 1) X e
CL
CL
0.10 C
0.08 C
A
A2
A1
L
L
e
e
PACKAGE OUTLINE
12, 16L, THIN QFN, 3x3x0.8mm
E
21-0136
1
2
EXPOSED PAD VARIATIONS
DOWN
BONDS
ALLOWED
NOTES:
1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994.
2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.
3. N IS THE TOTAL NUMBER OF TERMINALS.
4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO
JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED
WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR
MARKED FEATURE.
5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.20 mm AND 0.25 mm
FROM TERMINAL TIP.
6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.
7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.
8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.
9. DRAWING CONFORMS TO JEDEC MO220 REVISION C.
PACKAGE OUTLINE
12, 16L, THIN QFN, 3x3x0.8mm
21-0136
E
2
2
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
10 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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