MAXIM MAX14627

19-6310; Rev 0; 5/12
EVALUATION KIT AVAILABLE
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
General Description
The MAX14627/MAX14628 provide a simple solution for
detecting the insertion and managing the operation of a
3.5mm stereo headset with a microphone. These devices
integrate all circuitry needed to detect SEND/END button
press events and generate required microphone bias voltages, and are fully compatible with Windows Mobile 7.
The devices need only three GPIOs from the host controller to select between call mode and standby mode, and
monitor the SEND/END and jack insertion status. In call
mode, the low-noise LDO is enabled to provide DC bias to
the externally preamplified microphone. In standby mode,
microphone low-power pulsing is enabled to reduce supply current while waiting for a SEND/END button press
event. Two open-drain outputs signal the host controller
when an insertion/removal or SEND/END button press
event occurs. If a 3P headset without a microphone is
inserted, the low-power pulsing can be disabled by setting
the MODE input to high impedance.
The MAX14627 operates from a 2.5V to 5.5V input voltage
supply and features an internal 2.2V LDO output, while the
MAX14628 operates from a 3.1V to 5.5V voltage supply
and features an internal 2.8V LDO output voltage. Both
devices control jack insertion detection by monitoring a
3.5mm socket with a normally open jack insertion switch.
Additionally, the MAX14628 features open microphone
detection.
The MAX14627/MAX14628 are available in an 8-pin TDFN
package, and are fully specified over the -40NC to +85NC
extended temperature range.
Benefits and Features
SVersatile Jack Detection and Control
MODE Three-State Microphone Bias Control
MIC Switch Ground Detection (MAX14627)
MIC Switch Open and Ground Detection (MAX14628)
SCompatible with Windows Mobile 7 and Google
Android
Microphone Button Press Detection
SHigh-Performance MIC Bias and Power Savings
No Pop-Up Noises
Ultra-Low Noise, High-PSRR MIC Bias
Low-Power MIC Idle Mode
Automatic Ultra-Low-Power Mode When Microphone Is Disabled
SPCB Space and Cost Savings
Integrated ±15kV ESD Protection (HBM) on DETIN and MIC Input Terminals
Small 8-Pin (2mm x 2mm) TDFN Package
Applications
Cell Phones
Portable Media Players
Tablet/Laptop PCs
Ordering Information appears at end of data sheet.
For related parts and recommended products to use with this part,
refer to www.maxim-ic.com/MAX14627.related.
Windows Mobile is a registered trademark of Microsoft Corporation.
Typical Operating Circuits
Typical Operating Circuits continued
at end of data sheet.
VCC
MIC
1µF
MODE
VCC
AUDIO DIRECT
DRIVE
CAP
1µF
VIO
RES
1MI
SWD
PROCESSOR
MAX14628
VIO
2.2kI
MIC
MIC
MICROPHONE
LEFT
1MI
DET
DET
EP/GND
DETIN
RIGHT
SEND/
END
GND
����������������������������������������������������������������� 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.
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
ABSOLUTE MAXIMUM RATINGS
(Voltages referenced to GND.)
VCC, MODE, SWD, DET...........................................-0.3V to +6V
CAP, MIC, RES.......................................... -0.3V to (VCC + 0.3V)
DETIN..........................................................................-6V to +6V
Continuous Current into Any Terminal........................... Q100mA
Continuous Power Dissipation (TA = +70NC)
TDFN (derate 11.9mW/NC above +70NC)..................953.5mW
Operating Temperature Range........................... -40NC to +85NC
Junction Temperature......................................................+150NC
Storage Temperature Range............................. -65NC to +150NC
Lead Temperature (soldering, 10s) ................................+300NC
Soldering Temperature (reflow).......................................+260NC
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.
PACKAGE THERMAL CHARACTERISTICS (Note 1)
TDFN
Junction-to-Ambient Thermal Resistance (qJA)........83.9°C/W
Junction-to-Case Thermal Resistance (qJC)....................37°C/W
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial.
ELECTRICAL CHARACTERISTICS
(VCC = 2.5V to 5.5V for MAX14627, VCC = 3.1V to 5.5V for MAX14628, CDETIN < 100pF, TA = -40NC to +85NC, unless otherwise noted.
Typical values are at VCC = +3.6V, TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
DC CHARACTERISTICS
Supply Voltage Range
VCC Undervoltage-Lockout
Threshold
VCC
VCCUVLO
MAX14627
2.5
5.5
MAX14628
3.1
5.5
VCC rising
0.9
MAX14627,
VCC = 2.8V
VCC Supply Current
ICC
MAX14628,
VCC = 3.3V
1.7
2.45
MODE = low,
DETIN = high
1.3
MODE = low,
DETIN = low, IMIC = 300FA
11.7
MODE = high,
DETIN = low, IMIC = 300FA
800
MODE = high-Z,
DETIN = low
6.0
MODE = low,
DETIN = high
1.9
MODE = low,
DETIN = low, IMIC = 300FA
13.2
MODE = high,
DETIN = low, IMIC = 300FA
800
MODE = high-Z,
DETIN = low
7.0
V
V
FA
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MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
ELECTRICAL CHARACTERISTICS (continued)
(VCC = 2.5V to 5.5V for MAX14627, VCC = 3.1V to 5.5V for MAX14628, CDETIN < 100pF, TA = -40NC to +85NC, unless otherwise noted.
Typical values are at VCC = +3.6V, TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
DETIN Pullup Resistance
RDETIN
DETIN Series Resistance
RDETININT
Negative Current from DETIN
MIC SEND/END Detection
Threshold
INDETIN
CONDITIONS
MIN
TYP
MAX
1000
kI
100
VDETIN = -2V
VMICTH_LOW
UNITS
kI
31
FA
0.20 x
VBIAS
0.22 x
VBIAS
0.24 x
VBIAS
V
MIC Open Switch Detection
Threshold
VMICTH_HI
MAX14628
0.90 x
VBIAS
0.94 x
VBIAS
0.98 x
VBIAS
V
DETIN Detection Threshold
VDETINTH
Falling edge
1/3 x
VCC
1/2 x
VCC
2/3 x
VCC
V
MODE Pullup Resistance for
High-Z Detection
RMODE_HI
200
kI
MODE Pulldown Resistance for
High-Z Detection
RMODE_LO
200
kI
LINEAR REGULATOR (CAP)
Output Current Limit
ICAP
LDO Output Voltage
VLDO
LDO PSRR
PSRRLDO
LDO Noise
NLDO
LDO Turn-Off Time
Minimum Bypass Capacitance
tLDO_OFF
COUT
VCAP = 0V
4
mA
MAX14627, VCC = 2.8V
2.0
2.2
2.45
MAX14628, VCC = 3.3V
2.55
2.8
3.1
V
Noise from VCC to CAP, f = 217Hz,
VCC = 2.8V ±0.1V, ICAP = 300FA,
MODE = high
100
dB
VCC = 2.8V, IMIC = 300FA,
f = 100Hz to 4000Hz
11
FVRMS
MAX14627, VCC = 2.8V, RL = 2kI,
VCAP from 90% to 10%
60
MAX14628, VCC = 3.3V, RL = 2kI,
VCAP from 90% to 10%
60
(Note 3)
Fs
0.22
FF
1.4
V
DIGITAL SIGNALS (MODE, SWD, DET)
Input Logic-High Voltage
VIH
Input Logic-Low Voltage
VIL
MODE Average Current
IMODE_LOW
MODE Input Resistance
RMODE_HI
When MODE = high, DETIN = low
MODE External Maximum
Leakage
IMODE_LKG
When MODE = high-Z (Note 3)
Output Logic-High Leakage
Current (Open Drain)
IOH_LKG
Pulsing with 1/64 duty cycle from MODE
terminal when MODE = low, DETIN = low
(Note 4)
VOH = 5V
120
-1
220
0.4
V
1
FA
380
kI
+1
FA
1
FA
����������������������������������������������������������������� Maxim Integrated Products 3
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
ELECTRICAL CHARACTERISTICS (continued)
(VCC = 2.5V to 5.5V for MAX14627, VCC = 3.1V to 5.5V for MAX14628, CDETIN < 100pF, TA = -40NC to +85NC, unless otherwise noted.
Typical values are at VCC = +3.6V, TA = +25NC.) (Note 2)
PARAMETER
SYMBOL
Output Logic-Low Voltage
VOL
MAX
UNITS
ISINK = 1mA
CONDITIONS
MIN
TYP
0.4
V
(Note 3)
200
pF
DYNAMIC CHARACTERISTICS
MODE Maximum Load
Capacitance
CMODE
MIC Low-Power Mode On-Time
tMICLPO
MIC Low-Power Mode Period
High-Z Detection Time
MODE 0 → 1 Detection Time
MODE 1 → 0 Detection Time
120
Fs
tMICLPP
8
ms
tHIZDET
16
ms
tMODE0-1
4
ms
tMODE1-0
DETIN Debounce Time
tDIDEB
SEND/END Debounce Time
tSEDEB
Falling edge
16
ms
300
ms
30
ms
ESD PROTECTION
MIC, DETIN
Human Body Model
±15
kV
All Other Pins
Human Body Model
±2
kV
Note 2: All devices are production tested at TA = +25°C. Specifications over temperature are guaranteed by design.
Note 3: External specification requirements.
Note 4: Guaranteed by design.
Typical Operating Characteristics
(VCC = 3.3V, TA = +25NC, CDETIN < 100pF, unless otherwise noted.)
9
8
7
TA = -40°C
2.5
ICC (µA)
ICC (µA)
3.0
2.0
160
TA = +25°C
6
TA = +85°C
5
4
1.5
3
1.0
TA = +85°C
0.5
MPLP MODE, IMIC = 0µA
VMODE = VDETIN = LOW
1
0
3.0
3.5
4.0
VCC (V)
4.5
5.0
5.5
TA = +25°C
120
TA = -40°C
CALL MODE, IMIC = 0µA
VMODE = HIGH, VDETIN = LOW
80
0
2.5
140
100
TA = -40°C
2
TA = +85°C
180
ICC (µA)
TA = +25°C
VCC SUPPLY CURRENT vs. VOLTAGE
200
MAX14627 toc02
3.5
MAX14627 toc01
SHUTDOWN MODE,
VMODE = LOW,
VDETIN = HIGH
4.0
VCC SUPPLY CURRENT vs. VOLTAGE
10
MAX14627 toc03
VCC SUPPLY CURRENT vs. VOLTAGE
4.5
60
2.5
3.0
3.5
4.0
VCC (V)
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
VCC (V)
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MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Typical Operating Characteristics (continued)
(VCC = 3.3V, TA = +25NC, CDETIN < 100pF, unless otherwise noted.)
MAX14627 CAP VOLTAGE vs. VCC
2.9
VCAP (V)
2.3
2.2
MAX14627 toc05
2.4
VCAP (V)
MAX14628 CAP VOLTAGE vs. VCC
3.0
MAX14627 toc04
2.5
2.1
2.8
2.7
2.6
ICAP = 0mA
ICAP = 0mA
2.0
2.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
3.1
3.5
3.9
VCC (V)
MAX14627 CAP VOLTAGE vs. CURRENT
5.1
5.5
MAX14628 CAP VOLTAGE vs. CURRENT
MAX14627 toc07
2.5
2.5
2.0
VCAP (V)
2.0
1.5
1.0
1.5
1.0
VCC = 3.3V
0.5
VCC = 3.3V
0.5
0
0
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
ICAP (mA)
ICAP (mA)
MAX14627 CAP VOLTAGE
vs. TEMPERATURE
MAX14628 CAP VOLTAGE
vs. TEMPERATURE
3.0
MAX14627 toc08
2.5
2.4
2.9
VCAP (V)
2.3
2.2
2.1
2.8
2.7
2.6
VCC = 3.3V
ICAP = 0mA
2.0
7
MAX14627 toc09
VCAP (V)
4.7
3.0
MAX14627 toc06
3.0
VCAP (V)
4.3
VCC (V)
VCC = 3.3V
ICAP = 0mA
2.5
-40
-15
10
35
TA (°C)
60
85
-40
-15
10
35
60
85
TA (°C)
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MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Typical Operating Characteristics (continued)
(VCC = 3.3V, TA = +25NC, CDETIN < 100pF, unless otherwise noted.)
MAX14627 CAP DROPOUT VOLTAGE
vs. CAP CURRENT
MAX14628 CAP DROPOUT VOLTAGE
vs. CAP CURRENT
500
400
300
200
VCC = 3.8V
700
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
600
100
600
500
400
300
200
100
0
0
0
1
2
3
5
4
0
1
ICAP (mA)
-40
-60
-80
-100
-120
1k
5
4
10k
100k
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
MAX14627 toc13
NOISE SPECTRAL DENSITY (µV/√Hz)
VCC = 2.8V ± 0.1V
-20
100
3
CAP NOISE DENSITY vs. FREQUENCY
MAX14627 toc12
0
10
2
ICAP (mA)
CAP POWER SUPPLY REJECTION RATIO
vs. FREQUENCY
PSRR TO CAP (dB)
MAX14627 toc11
VCC = 3.2V
700
800
MAX14627 toc10
800
100
1k
10k
FREQUENCY (Hz)
FREQUENCY (Hz)
MICROPHONE LOW-POWER MODE
OPERATION (4kI FROM MIC TO GND)
DETIN DEBOUNCE TIMING
(VMODE = LOW)
MAX14627 toc14
MAX14627 toc15
VDETIN
(2V/div)
VMIC
(1V/div)
VRES
(2V/div)
1ms/div
100ms/div
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MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Typical Operating Characteristics (continued)
(VCC = 3.3V, TA = +25NC, CDETIN < 100pF, unless otherwise noted.)
SWD DEBOUNCE TIMING
(MODE = L)
MIC vs. MODE
(TRANSITIONS FROM HIGH TO HIGH-Z)
MAX14627 toc16
MIC vs. MODE
(TRANSITIONS FROM LOW TO HIGH-Z)
MAX14627 toc17
MAX14627 toc18
VDETIN = LOW,
4kI FROM MIC TO GND
VDETIN = LOW,
4kI FROM MIC TO GND
3.3V
VMIC
(2V/div)
0V
VMODE
(1V/div)
VMODE
(1V/div)
3.3V
VSWD
(2V/div)
0V
VMIC
(1V/div)
40ms /div
VMIC
(1V/div)
4ms/div
MODE PULSING IN HIGH-Z
(VDETIN = LOW)
4ms/div
VCAP DISCHARGE TIMING
MAX14627 toc19
MAX14627 toc20
VMODE
(1V/div)
VDETIN
(1V/div)
VCAP
(1V/div)
2ms/div
40µs/div
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MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Pin Configuration
TOP VIEW
MIC DENTIN VCC
8
7
6
CAP
5
MAX14627
MAX14628
*EP/GND
+
1
2
3
RES MODE SWD
4
DET
TDFN
*CONNECT THE EXPOSED PAD (EP/GND) TO THE GROUND PLANE.
Pin Description
PIN
NAME
FUNCTION
Resistor Connection. Connect an external 2.2kI resistor from RES to MIC for microphone
biasing.
1
RES
2
MODE
3
SWD
SEND/END Button Detection Output. SWD is an active-low, open-drain output.
4
DET
Jack Insertion Detection Output. DET is asserted when there is a 3.5mm jack inserted into the
socket. DET is an active-low open-drain output.
5
CAP
Internal LDO Output. Connect a 1FF ceramic (X5R, X7R, or better) capacitor between CAP
and ground as close as possible to the device.
6
VCC
Supply Voltage Input. Bypass VCC to ground with a 1FF ceramic capacitor as close as
possible to the device.
7
DETIN
8
MIC
—
EP/GND
Microphone Mode Selection Three-State Input. MODE selects the operating mode. See the
MODE Control Input section for more information.
Jack Insertion Detection Input. An internal comparator monitors DETIN for jack insertion/
removal events.
Microphone Connection Input. An internal comparator monitors MIC for SEND/END button
press events.
Exposed Pad. The exposed pad is the ground connection for the device. Connect EP/GND to
the ground plane.
����������������������������������������������������������������� Maxim Integrated Products 8
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
MAX14627 Functional Diagram
VCC
VCC
MAX14627
CAP
LOW NOISE
2.2V LDO
VBIAS
200kI
MODE
HIGH-Z
DETECTION
MODEINT
HIGH-Z
CONTROL AND
LOW DUTY
CYCLE
PULSING
200kI
RES
MIC
SWD
10kI
SEND/END
DETECTION
(30ms DEBOUNCE)
0.22VBIAS
HIGH-Z
MODEINT
DET
VCC
1MI
DEB_DET
JACK INSERT
DETECTION
(300ms DEBOUNCE)
100kI
DETIN
GND
����������������������������������������������������������������� Maxim Integrated Products 9
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
MAX14628 Functional Diagram
VCC
VCC
MAX14628
LOW NOISE
2.8V LDO
CAP
VBIAS
200kI
MODE
HIGH-Z
DETECTION
MODEINT
HIGH-Z
CONTROL AND
LOW DUTY
CYCLE
PULSING
200kI
RES
MIC
SWD
10kI
SEND/END
DETECTION
(30ms DEBOUNCE)
0.94VBIAS
MODEINT
HIGH-Z
0.22VBIAS
VCC
DET
DEB_DET
JACK INSERT
DETECTION
(300ms DEBOUNCE)
100kI
1MI
DETIN
GND
���������������������������������������������������������������� Maxim Integrated Products 10
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Detailed Description
The MAX14627/MAX14628 manage headsets by integrating 3.5mm jack insertion detection, microphone bias
generation, and SEND/END button press detection. Both
devices feature a low-power microphone mode to reduce
the high bias current required for microphone operation
while it is not in use. These devices require only a single
three-state input (MODE) to select between call mode
and two different low-power modes. See the Internal
LDO Regulator and SEND/END Button Press Detection
sections for details about the differences between these
two devices.
Internal LDO Regulator
The devices integrate a low-noise, low-dropout regulator
(LDO) for biasing the microphone connected to MIC. The
LDO output voltage is set at 2.2V for the MAX14627 and
2.8V for the MAX14628. The LDO is enabled and enters
low-noise mode (LNM) when the MODE input is logichigh and a jack is detected (DETIN is low). Pull the MODE
input low or leave it open to put the LDO in low-power
shutdown mode (SDM).
Connect a 1FF capacitor from CAP to ground as close as
possible to the pin.
Microphone Operation
and Bias Voltage Generation
An externally preamplified microphone is connected to
MIC. Connect MIC to RES through an external 2.2kI
resistor to bias the microphone.
The devices generate a bias voltage (VBIAS) at RES.
VBIAS is connected to the internal LDO when the LDO is
on or connected to VCC when the LDO is off.
Microphone Low-Power Mode (MPLP)
A microphone draws a large amount of current due to the
2.2kI required bias resistor when it is connected. This
current is dissipated even when the microphone is not
in use for audio input. This allows the SEND/END button
detection to operate. The devices feature internal circuitry
to reduce this current while simultaneously detecting
SEND/END button press events.
When a jack is inserted (DETIN is low and DET is asserted low) and if MODE is pulled low, these devices enter
the microphone low-power mode (MPLP). In this mode,
MIC is periodically connected to VBIAS (= VCC) through
the 2.2kI resistor to RES only for a short duration (120Fs
pulse over an 8ms period) to check for the SEND/END
button press event (switch to GND in both MAX14627/
MAX14628 and switch open in the MAX14628 only).
The devices exit MPLP when the MODE input transitions
to logic-high or to high-Z state.
Note that VBIAS is disconnected from RES when no jack is
inserted and microphone low-power mode is not entered.
Jack Insertion Detection
The devices monitor the DETIN input to detect jack insertion/removal events. Debounce circuitry ensures that
transient voltages do not force the device to enter or exit
microphone low-power mode due to false jack insertion/
removal detection. DETIN input is capable of handling
±15kV HBM ESD event.
The devices are designed for sockets with a normally
open pin. Without the 3.5mm jack inserted at DETIN, the
input is pulled high by a large internal pullup resistor
(1MI). When the jack is plugged in, DETIN is pulled to
ground through the detection pin of the jack. DET is then
asserted (after 300ms debounce time) and MIC is biased
according to the logic state of the MODE input as follows:
• If MODE is low, the external 2.2kI resistor connects
MIC to VCC in pulsing mode (MPLP) waiting for a
SEND/END button press event.
• If MODE is high, the external 2.2kI resistor connects
MIC to LDO output continuously.
• If MODE is high-Z, MIC is internally pulled down.
The devices feature an internal series 100kI resistor
at DETIN and do not require a series resistor between
DETIN and the jack even when a direct drive audio output is connected to DETIN through the detection pin of
the jack. DETIN withstands input voltages down to -2V.
Ensure that the total capacitance on DETIN is less than
100pF.
SEND/END Button Press Detection
The devices monitor the MIC input to detect SEND/END
button press events. The SEND/END button press with
the 4P microphone headset is detected and pulls the
SWD output low if the voltage at MIC falls below the
MIC switch to GND detection threshold (0.22 O VBIAS) for
longer than 30ms.
���������������������������������������������������������������� Maxim Integrated Products 11
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
The MAX14628 also features an additional SEND/END
detection mechanism through an additional MIC switch
open detection threshold (0.94 O VBIAS). If there is an
open switch, then MIC is pulled up to VBIAS in pulsing
mode. If this happens for longer than 30ms, then the
output SWD is pulled low.
The debounce period built into the SEND/END button
press detection allows the mechanical SEND/END button
to reach steady-state before applying the microphone
bias. This mitigates click-and-pop noise.
The SEND/END detection circuitry is active whenever a
jack is inserted (DETIN is low and DET is low).
MODE High-Z State
If a 3P headset without a microphone is inserted, the
SWD output is asserted low continuously. The user can
turn off the microphone low-power mode by placing the
MODE input to high-Z state after the recognition of a 3P
jack. When in high-Z state, MODE is internally driven in
pulsed mode.
MODE Control Input
An external host processor controls the MODE input.
Table 1 shows the behavior of these devices based on
the MODE input and jack insertion status. The device
enters call mode when the MODE pin is logic-high and
a jack is detected, enabling the LDO immediately in lownoise mode (LNM). The LDO output powers VBIAS and is
connected to the microphone (MIC) through the external
2.2kI bias resistor.
Drive MODE low to put the devices in standby mode. In
standby mode, VCC powers VBIAS, the LDO enters shutdown mode (SDM), and the microphone bias connection
either turns off permanently if no jack is inserted or enters
MPLP if a jack is inserted.
When MODE is set to high-Z, both the LDO and MPLP
turn off. Also, the SWD output returns to a high-Z state,
which can be used as a feedback of the device.
The MODE input is designed to be compatible with 1.8V
logic when the VCC is up to 5.5V. The MODE pin must be
properly controlled based on DETIN status to avoid the
click-and-pop noise due to a headset insertion.
Applications Information
Typical Connections for 3.5mm Jacks
There are two typical 3.5mm jacks: tip-ring-ring-sleeve
(TRRS) with four conductors (Figure 1a) and tip-ringsleeve (TRS) with three conductors (Figure 1b). The most
common configuration of the TRRS jack is to use rings 1
and 2 for audio signals, ring 3 for ground, and ring 4 for
a microphone. The TRS jack typically uses rings 1 and 2
for audio signals and rings 3 and 4 as ground.
Supported Accessories
All the devices support all standard configurations of
headsets with a microphone and SEND/END button on a
TRS or TRRS 3.5mm jack. Figure 2 shows the supported
connections of the speakers, SEND/END button, and
microphone to the jack.
1
2
3
4
(a)
1
2
3
4
(b)
Figure 1. Typical 3.5mm Jacks
Table 1. Operating Modes
MODE
DETIN
LOW
Low
LDO Mode
HIGH-Z
High
Low
Off
Off*
SDM
MIC Bias Mode
MPLP
HIGH
High
Low
High
LNM
SDM
Off
2.2kI
Off
SDM
*MIC is internally pulled down.
���������������������������������������������������������������� Maxim Integrated Products 12
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Headset with No Microphone
When the 3.5mm jack in Figure 2a is inserted, the MIC
input is pulled low permanently by the ground connection
on the sleeve and the SWD output is logic-low permanently. This type of headset is supported by implementing a timeout period in software to recognize that the
permanent SWD logic-low state is not due to a very long
SEND/END button press event. In this case, the MODE
input pin can be placed in high-Z state to disable the
pulsing on the MIC pin (MPLP) and set the SWD output
in high-Z state.
Headset with Microphone and Normally Open
SEND/END Button in Parallel
When the 3.5mm jack in Figure 2b is inserted, the MIC
input is pulled below the threshold only during a SEND/
END button press event. The SWD output is logic-low
when the SEND/END button is pressed for more than the
30ms (typ) debounce time.
Headset with Normally Open SEND/END
Button and Resistive Remote Control
The devices support the 3.5mm jack with a microphone
and two buttons in Figure 2c that is the standard Windows
Mobile configuration. The threshold is set to detect a button press, regardless of which button is pressed.
1
2
3
4
SPEAKER
SPEAKER
(a)
1
2
3
4
MICROPHONE
SPEAKER
SEND/
END
SPEAKER
(b)
1
2
3
Headset with Microphone and Normally
Closed SEND/END Button in Series
The MAX14628 supports the 3.5mm jack with a microphone and a normally closed series switch. When the
switch opens for more than the 30ms (typ) debounce
time (SEND/END button press event), the SWD output
asserts low.
4
SPEAKER
SEND/
END
600Ω
200Ω
MICROPHONE
SPEAKER
(c)
High-ESD Protection
Electrostatic discharge (ESD)-protection structures are
incorporated on all pins to protect against electrostatic
discharges up to ±2kV Human Body Model (HBM)
encountered during handling and assembly. DETIN
and MIC are further protected against ESD up to ±15kV
(HBM) without damage. After an ESD event, all the
devices continue to function without latchup.
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
1
2
3
4
SEND/
END
SPEAKER
MICROPHONE
SPEAKER
(d)
Figure 2. Supported 3.5mm Accessory Configurations
���������������������������������������������������������������� Maxim Integrated Products 13
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Typical Operating Circuits (continued)
VCC
MIC
1µF
MODE
VCC
AUDIO DIRECT
DRIVE
CAP
1µF
VIO
RES
1MI
SWD
PROCESSOR
MAX14627
VIO
2.2kI
MIC
MIC
MICROPHONE
LEFT
1MI
DET
DET
EP/GND
DETIN
RIGHT
SEND/
END
GND
���������������������������������������������������������������� Maxim Integrated Products 14
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Package Information
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX14627ETA+T
-40NC to +85NC
8 TDFN-EP*
MAX14628ETA+T
-40NC to +85NC
8 TDFN-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*EP = Exposed pad.
Chip Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
8 TDFN-EP
T822+2
21-0168
90-0065
PROCESS: BiCMOS
���������������������������������������������������������������� Maxim Integrated Products 15
MAX14627/MAX14628
Low-Power Headset Detectors with
SEND/END Button Support
Revision History
REVISION
NUMBER
REVISION
DATE
0
5/12
DESCRIPTION
Initial release
PAGES
CHANGED
—
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. The parametric values (min and max limits) shown in the Electrical
Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2012
Maxim Integrated Products 16
Maxim is a registered trademark of Maxim Integrated Products, Inc.