High-Voltage Switch for Wireless Power

Transcription

1 General Description The MAX20304 is a DPST switch intended for wirelesspower-circuit applications. The new application for the portable device is the magnetic card reader. There has been a method to use the wireless transmit emulation of credit card swiping to the terminal. However, the transmitting loop couples to the wireless charging input, causing an unwanted induced voltage. Therefore, there is a need to either isolate the two circuits or combine the two loops into a single-loop architecture. The current wireless-receiver loop circuit also consists of a small series capacitor that impedes the lower-frequency magnetic pulse transmission. This capacitor is an essential part of the wireless charging, but has to be eliminated from the circuit during the magnetic card pulse transmitting mode. The device should stay open during the wireless-charging mode and should close during the magnetic card pulse transmitting mode. Though V CC powers the device, however, the device can isolate the magnetic secure transmission ports from the wireless charger inputs even without V CC. The MAX20304 offers a low on-resistance (R ON ) necessary for transmitting mode and is capable of blocking a high-frequency wireless charging signal. The device operates from a 2.7V to 5.5V V CC supply. The device is available in a 25-bump (2.02mm x 2.07mm) wafer-level package (WLP) and operates over the -40 C to +85 C extended temperature range. Typical Application Circuit MST EN = 1 Benefits and Features High-Voltage Blocking Switch for Common Loop Off Isolation Signal Range: -36V to +36V R ON : 100mΩ (typ) Signal Bandwidth 40MHz Flexible System Design EN Controls to Turn-On for Transmitting Mode Block 36V PP Signal at WP1/WP2 Without V CC Supply Low Supply Current During AC Blocking 25-Bump WLP (2.02mm x 2.07mm) Package -40 C to +85 C Operating Temperature Range Robust and Safety ±2kV Human Body Model ESD Protection Thermal-Shutdown Protection Fault Flag Output Applications Smart Phones Phablets Tablets Ordering Information appears at end of data sheet. MST1 MST2 AP EN MAX20304 WP1 WP2 MST ONLY TAP WIRELESS CHARGER PMIC EN = 0 COMMON LOOP ; Rev 0; 11/15

2 Absolute Maximum Ratings (All voltages referenced to GND.) V CC, EN, FLAG V to +6V WP1, WP2 (EN V IL )...-40V to +40V WP1, WP2 (EN V IH ) V to V CC + 0.3V MST1, MST V to V CC + 0.3V WP_ - MST_...-40V to +40V WP_ - WP_...-40V to +40V WP_ (AC Signal)... 40V PP CAP1, CAP2 (Note 1)...Internally Driven Package Thermal Characteristics (Note 4) WLP Junction-to-Ambient Thermal Resistance (θ JA ) C/W Continuous Current for Switch (Note 2)...±4.5A Pulse Current for Switch (Note 3)...±9A Continuous Power Dissipation (T A = +70 C) WLP (derate 19.07mW/ºC above +70 C) mW Operating Temperature Range C to +85 C Junction Temperature C Storage Temperature Range C to +150 C Soldering Temperature (reflow) C Note 1: CAP1 and CAP2 are internally driven. Do not connect anything but the recommended capacitors to CAP1 and CAP2 pins. Note 2: Maximum reliable current the part can stand until thermal shutdown intervention. The application must limit the DC continuous current based on power dissipation on both channels, ambient temperature and system thermal design. 4.5A rating is for the silicon temperature (T J ) below 85 C. (Please note this is not the ambient temperature T A.) Note 3: Pulse current rating is for a pulse period < 10ms and duty cycle < 10% (maximum pulse length 1ms). 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. Note 4: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board. For detailed information on package thermal considerations, refer to Electrical Characteristics (V CC = 2.7V to 5.5V, C CAP1 = C CAP2 = 10nF, T A = -40 C to +85 C, unless otherwise noted. Typical values are at V CC = 4.3V, T A = +25 C) (Note 5) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS SUPPLY OPERATION Operating Voltage V CC V Supply Current I CC EN V IH µa Supply Current During AC Blocking I CC_BLOCK V WP1 - V WP2 = 20V PP, signal frequency = 100kHz, V EN = 0V 5 µa Supply EN Shutdown Current I CC_SDN EN V IL µa WP1, WP2, MST1, MST2 WP_ Off Leakage Current I WP_LEAK V WPy = 0V, V CC = 0V, 5.5V, V WPx = 36V, 0V, -36V, V MST_ = 0V, switch open MST_ Off Leakage Current I MST_OFFLEAK V CC = 4.3V, V MST_ = 0V, V CC, V WP_ = 0V, switch open MST_ On Leakage Current I MST_ONLEAK V CC = 4.3V, V MST_ = 0V, V CC, WP_ = hi-z, switch closed µa -1 1 µa µa Maxim Integrated 2

3 Electrical Characteristics (continued) (V CC = 2.7V to 5.5V, C CAP1 = C CAP2 = 10nF, T A = -40 C to +85 C, unless otherwise noted. Typical values are at V CC = 4.3V, T A = +25 C) (Note 5) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS WP1 to MST1, WP2 to MST2 (SWITCH) Analog Signal Pass-Through V Range MST_PASS 0 V CC V DC Analog Signal-Blocking Range AC Analog Signal-Blocking Range V WP_STOPDC V CC = 0V to 5.5V V V WP_STOPAC V CC = 0V to 5.5V +36 V PP On-Resistance R ON V CC = 4.3V, I MST_ = 100mA, T A = +25 C On-Resistance Match Between Channels ΔR ON V CC = 4.3V, V MST_ = 4.3V, I MST_ = 100mA (Note 6) On-Resistance Flatness R ONFLAT V CC = 4.3V, I MST_ = 100mA, V MST_ = 0V to V CC (Note 7) mω mω 2 15 mω Turn-On Time (Figure 2) t ON V MST_ = V CC = 4.3V, R L = 50Ω 625 µs Turn-Off Time (Figure 2) t OFF V MST_ = V CC = 4.3V, R L = 50Ω 700 µs WP_ Off Capacitance C WP_OFF V WP_ = 20V PP, DC bias = 0V, f = 300kHz (Note 8) MST_ Off Capacitance C MST_OFF V MST_ = 4.3V PP, DC bias = 2.15V, f = 300kHz (Note 8) MST_ On Capacitance C MST_ON V MST_ = 4.3V PP, DC bias = 2.15V, f = 300kHz (Note 8) pf pf pf DIGITAL SIGNAL (FLAG, EN) FLAG Output Voltage Low V FLAG I FLAG = 1mA 0.4 V FLAG Output Leakage I FLAGLEAK V FLAG = 5V -1 1 µa Input Voltage High V IH EN 1.4 V Input Voltage Low V IL EN 0.4 V Input Leakage I LEAK EN = 5.5V or GND -1 1 µa AC CHARACTERISTICS -3dB Bandwidth BW V WP_ = 0dBm, R S = 50Ω, Figure 3 40 MHz Off Isolation On Crosstalk (Note 9) Off Crosstalk f = 100kHz to 300kHz, V WP_ = 20V PP, R S = 50Ω, R L = 50Ω, CAP1 = CAP2 = 10nF, Figure 3 f = 100kHz, V MST_ = 4.3V PP, DC bias = 2.15V, R L = 50Ω, Figure 3 f = 100kHz, V WP_ = 20V PP, R L = 50Ω, Figure 3-65 db -65 db -65 db Maxim Integrated 3

4 Electrical Characteristics (continued) (V CC = 2.7V to 5.5V, C CAP1 = C CAP2 = 10nF, T A = -40 C to +85 C, unless otherwise noted. Typical values are at V CC = 4.3V, T A = +25 C) (Note 5) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS THERMAL PROTECTION Thermal Shutdown T SHDN 150 C Thermal Hysteresis T HYST 20 C ESD PROTECTION Human Body Model All Pins ±2 kv Note 5: All devices are 100% production tested at T A = +25 C. Specifications over the operating temperature range are guaranteed by design. Note 6: ΔR ON(MAX) = R ON(CH1) R ON(CH2) Note 7: Flatness is defined as the difference between the maximum and minimum value of on-resistance, as measured over specified analog signal ranges. Note 8: Guaranteed by design. Note 9: Between two switches. ton toff WP1 WP2 MST1 MST2 MST1 MST2 EN FLAG VIH VIO THERMAL SHUTDOWN Figure 1. Timing Diagram Maxim Integrated 4

5 VIN = VCC MST_ VCC VCC WP_ VOUT LOGIC INPUT VIH VIL 50% tr < 5ns tf < 5ns LOGIC INPUT CONTROL MAX20304 GND RL CL SWITCH INPUT 0V VOUT ton 0.9 x VOUT toff 0.1 x VOUT CL INCLUDES FIXTURE AND STRAY CAPACITANCE. RL VOUT = VIN RL + RON CONTROL DEPENDS ON SWITCH CONFIGURATION; INPUT POLARITY DETERMINED BY SENSE OF SWITCH. Figure 2. Switching Timing Diagram VCC 0.1µF VCC NETWORK ANALYSER OFF-ISOLATION = 20log VOUT VIN MST2 WP1 VIN 50Ω 50Ω ON-LOSS = 20log VOUT VIN 50Ω MAX20304 CROSSTALK = 20log VOUT VIN MST1* VOUT MEAS REF GND 50Ω 50Ω *FOR CROSSTALK THIS PIN IS MST2. MEASUREMENTS ARE STANDARDIZED AGAINST SHORTS AT IC TERMINALS. OFF-ISOLATION IS MEASURED BETWEEN WP_ AND "OFF" MST_ TERMINAL ON EACH SWITCH. ON-LOSS IS MEASURED BETWEEN WP_ AND "ON" MST_ TERMINAL ON EACH SWITCH. CROSSTALK IS MEASURED FROM ONE CHANNEL TO THE OTHER CHANNEL. SIGNAL DIRECTION THROUGH SWITCH IS REVERSED; WORST VALUES ARE RECORDED. Figure 3. On-Loss, Off-Isolation, and Crosstalk Maxim Integrated 5

6 Typical Operating Characteristics (V CC = 4.3V, C CAP1 = C CAP2 = 10nF, T A = +25 C, unless otherwise noted.) SUPPLY CURRENT (µa) V CC SUPPLY CURRENT vs. SUPPLY VOLTAGE V MST_ = 0V, T A = 25 C V MST_ = V CC, T A = 25ºC V MST_ = OPEN, T A = 25ºC V MST_ = OPEN, T A = 85 C SUPPLY VOLTAGE (V) toc01 V EN = 3V, V WP_ = OPEN V MST_ = 0V, T A = 85 C V MST_ = V CC, T A = 85 C V MST_ = 0V, T A = -40 C V MST_ = V CC, T A = -40 C V MST_ = OPEN, T A = -40 C SUPPLY SHUTDOWN CURRENT (µa) V CC SUPPLY SHUTDOWN CURRENT vs. SUPPLY VOLTAGE toc T A = 85 C 6 T 5 A = 25ºC 4 3 T A = -40ºC 2 1 V EN = 0V, V MST_ = 0V, V WP_ = 0V SUPPLY VOLTAGE (V) 8 V CC SUPPLY SHUTDOWN CURRENT vs. SUPPLY VOLTAGE toc03 MST1 TO WP1 NORMALIZED ON-RESISTANCE vs. TEMPERATURE toc SUPPLY SHUTDOWN CURRENT (µa) 7 6 T A = 85 C 5 T A = 25 C 4 3 T A = -40 C 2 1 V EN = 0V, V MST_ = 0V, V WP_ = 40V SUPPLY VOLTAGE (V) NORMALIZED ON-RESISTANCE V CC = 2.7V V CC = 5.5V V CC = 4.3V 0.4 V MST1 = V CC 0.2 I MST1 = 100mA NORMALIZED TO V CC = 4.3V, T A = +25ºC TEMPERATURE (ºC) NORMALIZED ON-RESISTANCE MST2 TO WP2 NORMALIZED ON-RESISTANCE vs. TEMPERATURE toc05 V CC = 2.7V V CC = 5.5V V CC = 4.3V 0.4 V MST2 = V CC 0.2 I MST2 = 100mA NORMALIZED TO V CC = 4.3V, T A = +25ºC TEMPERATURE (ºC) NORMALIZED ON-RESISTANCE MST_ TO WP_ NORMALIZED ON-RESISTANCE vs. CURRENT toc V CC = 2.7V 1.2 V CC = 4.3V 1.0 V CC = 5.5V V MST_ = V CC NORMALIZED TO V CC = 4.3V, I MST_ = 0.1A LOAD CURRENT (A) Maxim Integrated 6

7 Typical Operating Characteristics (continued) (V CC = 4.3V, C CAP1 = C CAP2 = 10nF, T A = +25 C, unless otherwise noted.) MST_ ON LEAKAGE CURRENT (µa) MST_ ON LEAKAGE CURRENT vs. TEMPERATURE V CC = 4.3V, V MST_ = V CC V CC = 5.5V, V MST_ = V CC V CC = 2.7V, V MST_ = V CC V CC = 2.7V, V MST_ = 0V V -2.5 CC = 5.5V, V MST_ = 0V V EN = 1.8V TEMPERATURE (ºC) V CC = 4.3V, V MST_ = 0V toc07 EN TURN-ON TIME (µs) EN TURN-ON TIME vs. SUPPLY VOLTAGE 560 V MST_ = V CC 555 EN = 0V TO 1.8V 550 R L = 50Ω V CC VOLTAGE (V) toc08 EN TURN-OFF TIME (µs) EN TURN-OFF TIME vs. SUPPLY VOLTAGE 500 V MST_ = V CC 450 EN = 1.8V TO 0V R L = 50Ω V CC VOLTAGE (V) toc09 MAGNITUDE (db) 10 FREQUENCY RESPONSE toc10 0 ON LOSS OFF ISOLATION CROSSTALK FREQUENCY (MHz) ISOLATION WP_ vs. MST_ WAVEFPRM toc11 ISOLATION WP_ vs. MST_ WAVEFPRM toc12 V WP1 20V/div V WP1 20V/div V WP2 20V/div V WP2 20V/div V MST1 500mV/div V MST1 500mV/div V MST2 500mV/div V MST2 500mV/div 10µs/div V EN = 0V, V CC = 0V R MST1 =R MST2 =1MΩ 10µs/div V EN = 0V, V CC = 4.3V R MST1 = R MST2 = 1MΩ Maxim Integrated 7

8 Bump Configurations TOP VIEW (BUMP SIDE DOWN) MAX20304 A VCC GND CAP1 EN FLAG B WP1 WP1 CAP1 WP2 WP2 C WP1 MST1 CAP1 MST2 WP2 D WP1 MST1 CAP2 MST2 WP2 E MST1 MST1 CAP2 MST2 MST2 Bump Description BUMP NAME FUNCTION A1 V CC Battery Power Supply Input. Bypass V CC with a 0.1µF ceramic capacitor as close to the device as possible. A2 GND Ground A3, B3, C3 CAP1 A4 EN Connect CAP1 with a 10nF, 50V ceramic capacitor to ground. Connect all CAP1 pins together for proper operation. Active-High Enable Input. When EN is high, WP1 is connected to MST1 and WP2 is connected to MST2. When EN is low, both switches are open. A5 FLAG Open-Drain Flag Output. FLAG is driven low when thermal shutdown occurs. B1, B2, C1, D1 WP1 Wireless Power Input 1. Connect all WP1 pins together for proper operation. B4, B5, C5, D5 WP2 Wireless Power Input 2. Connect all WP2 pins together for proper operation. C2, D2, E1, E2 MST1 Magnetic Secure Transmission Input 1. Connect all MST1 pins together for proper operation. C4, D4, E4, E5 MST2 Magnetic Secure Transmission Input 2. Connect all MST2 pins together for proper operation. D3, E3 CAP2 Connect CAP2 with a 10nF, 50V ceramic capacitor to ground. Connect all CAP2 pins together for proper operation. Maxim Integrated 8

9 Functional Diagram WP1 MST1 TEMPERATURE FAULTS CHARGE-PUMP CONTROL LOGIC CONTROL EN FLAG WP2 MAX20304 MST2 VCC VBG REFERENCE GND CAP1 CAP2 Detailed Description The MAX20304 is an ESD-protected DPST switch that operates from a 2.7V to 5.5V supply and is designed to block high-voltage wireless signals when disabled. The switch combines the high-voltage isolation and low on-resistance (R ON ) necessary for high-performance switching applications. Switch Signal The device blocks wireless charger ports (WP_) from magnetic secure transmission ports (MST_) when the device is either disabled, or when V CC is absent. The device blocks WP_ AC signal range up to 36V PP or DC signal up to ±36V. When the device is enabled, MST_ is connected to WP_ and magnetic pulse can be transmitted with range up to V CC voltage. The WP_ and MST_ are protected against ESD up to ±2kV (Human Body Model). Switch Control When EN is high, WP1 is connected to MST1 and WP2 is connected to MST2. When EN is low, both switches are open and the device enters a low-current shutdown mode. FLAG Output The FLAG is an open-drain output. It asserts low when thermal-shutdown protection is active (thermalshutdown protection intervention is latched after a thermalshutdown fault. See the Thermal-Shutdown Protection section for details.) Thermal-Shutdown Protection The device features thermal-shutdown protection to protect the device from overheating. Thermal-shutdown protection latches when the junction temperature exceeds +150 C (typ). After a thermal-shutdown fault, the EN pin needs to be cycled to bring the device back to the normal operating state. If EN is cycled while a thermal-shutdown fault is still present, the part returns to normal operation right after the junction temperature falls below the thermal hysteresis threshold (20 C, typ). During thermal shutdown, the switches are open and FLAG is asserted. Maxim Integrated 9

10 Ordering Information PART TEMP RANGE PIN-PACKAGE MAX20304EWA+T -40 C TO +85 C 25 WLP +Denotes a lead(pb)-free/rohs-compliant package. T = Tape and reel. Chip Information PROCESS: BiCMOS Package Information For the latest package outline information and land patterns (footprints), go to 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. 25 WLP W252P LAND PATTERN NO. Refer to Application Note Maxim Integrated 10

11 Revision History REVISION NUMBER REVISION DATE DESCRIPTION PAGES CHANGED 0 11/15 Initial release For pricing, delivery, and ordering information, please contact Maxim Direct at , or visit Maxim Integrated s website at Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses are implied. Maxim Integrated 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 and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc Maxim Integrated Products, Inc. 11