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 ����������������������������������������������������������������� Maxim Integrated Products 2 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) ����������������������������������������������������������������� Maxim Integrated Products 4 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) ����������������������������������������������������������������� Maxim Integrated Products 5 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 ����������������������������������������������������������������� Maxim Integrated Products 6 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 ����������������������������������������������������������������� Maxim Integrated Products 7 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.