MAX4990ETD+T

19-0886; Rev 1; 11/07 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver Features The MAX4990 high-voltage DC-AC converter is ideal for driving electroluminescent (EL) lamps. The MAX4990 features a wide +2.4V to +5.5V input range that allows the device to accept a wide variety of voltage sources such as single-cell lithium-ion (Li+) batteries and higher voltage battery chargers. The lamp outputs of the device generate up to 250V peak-to-peak output voltage for maximum lamp brightness. The MAX4990 utilizes an inductor-based boost converter to generate the high voltage necessary to drive an EL lamp. The boost-converter switching frequency is set with the combination of an external capacitor connected from SW to GND and an external resistor connected from SLEW to GND. The MAX4990 uses a high-voltage full-bridge output stage to convert the high voltage generated by the boost converter to an AC waveform suitable for driving the EL panel. The EL output switching frequency is set with the combination of an external capacitor connected from EL to GND and an external resistor connected from SLEW to GND. o ESD-Protected EL Lamp Outputs ±15kV Human Body Model ±4kV IEC 61000-4-2 Contact Discharge ±15kV IEC 61000-4-2 Air-Gap Discharge o 250VP-P (MAX) Output for Highest Brightness o Wide +2.4V to +5.5V Input Voltage Range o Resistor-Adjustable Slew-Rate Control for Audible Noise Reduction o Externally Driven Lamp and Switching Converter Frequencies o Capacitor-Adjustable Lamp and Switching Converter Frequencies o Low 100nA Shutdown Current o DIM Input for Controlling Output Voltage Through DC Analog Voltage, PWM, or Resistor to GND o Capacitor Adjustable for Slow Turn-On/-Off o Space-Saving Packages 14-Pin, 3mm x 3mm TDFN Applications Keypad Backlighting MP3 Players The MAX4990 uses a proprietary acoustic noise-reduction circuit that controls the slew rate of the AC voltage, reducing audible noise from the EL panel. The slew rate is set with an external resistor connected from SLEW to GND. The MAX4990 features an EL lamp dimming control (DIM) that allows the user to set the EL output voltage with a PWM signal, a DC analog voltage, or a resistor connected from the DIM input to GND. A capacitor placed in parallel to the resistor on DIM allows the user to program a slow turn-on/-off time that generates a soft fade-on/fade-off effect of the EL lamp. The MAX4990 enters a low-power shutdown mode (100nA max) when the EN and DIM inputs are connected to GND. The MAX4990 also enters thermal shutdown if the die temperature rises above +158°C. The MAX4990 is available in a space-saving, 14-pin, 3mm x 3mm TDFN package and is specified over the extended -40°C to +85°C operating temperature range. PDAs/Smartphones Automotive Instrument Clusters LCD Backlighting Pin Configuration VA N.C. VB N.C. CS N.C. LX TOP VIEW 14 13 12 11 10 9 8 MAX4990 *EP DIM 5 6 7 GND EN 4 SW 3 VDD 2 EL 1 SLEW + TDFN-EP *EP = EXPOSED PAD. CONNECT EP TO GND OR LEAVE UNCONNECTED. Typical Application Circuits appear at end of data sheet. Ordering Information PART MAX4990ETD+ PIN-PACKAGE 14 TDFN-EP (3mm x 3mm) TOP MARK PKG CODE ±15kV PROTECTION DIM CONTROL SLEW-RATE CONTROL ADL T1433-2 Yes Yes Yes Note: The device operates over the -40°C to +85°C operating temperature range. +Denotes a lead-free package. EP = Exposed paddle. ________________________________________________________________ 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. MAX4990 General Description MAX4990 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver ABSOLUTE MAXIMUM RATINGS (All voltages referenced to GND.) VDD ...........................................................................-0.3V to +7V CS, LX...................................................................-0.3V to +160V VA, VB .........................................................-0.3V to (VCS + 0.3V) EN, EL, SLEW, DIM, SW .............................-0.3V to (VDD + 0.3V) Continuous Power Dissipation (TA = +70°C) 14-Pin TDFN (derate 24.4mW/°C above +70°C) ...... 1951mW JA .................................................................................41°C/W 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 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 (VDD = +2.4V to +5.5V, CLAMP = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +3.0V and TA = +25°C.) (Note 1) PARAMETER SYMBOL Power-Supply Voltage VDD Power-Supply Current IDD Shutdown Supply Current ISHDN Shutdown Inductor Supply Current ILXSHDN Undervoltage Lockout UVLO Hysteresis VLO CONDITIONS MIN TYP 2.4 RSLEW = 375kΩ, slope = 30V/100µs; fEL = 200Hz, VA - VB = 250VP-P EN = 0V, DIM = 0V, TA = +25°C 25 MAX UNITS 5.5 V 350 µA 100 nA EN = 0V, DIM = 0V, TA = -40°C to +85°C 300 EN = 0V, DIM = 0V, LX = VDD, CS = VDD 1500 nA 2.3 V VDD rising 1.8 VHYST 2.1 125 mV EL OUTPUTS (VA - VB) VDD = +3V, DIM = +0.5V Peak-to-Peak Output Voltage VA - VB 84 100 122 VDD = +3V, DIM = +1V 170 200 230 VDD = +3V, DIM = +1.3V 210 250 280 V Pulldown Switch On-Resistance RONPD ISINK = 1mA, VCS = +10V, VA, VB < +0.6V, VDD = +3V 50 165 500 Ω Pullup Switch On-Resistance RONPU VCS = +125V, ISOURCE = 1mA 700 1500 2200 Ω ILKG_NMOS Switch Off-Leakage VA = +125V, VB = +125V, shutdown mode, VCS = +125V V = 0V, VB = unconnected, shutdown ILKG_PMOS A mode, VCS = +125V VA, VB Differential Resistor EL Lamp Switching Frequency ESD Protection (VA, VB Only) 2 VAB_RES fEL VA = +0.1V, VB = 0V, shutdown mode, CS = unconnected CEL = 872pF, RSLEW = 375kΩ -1 +1 µA -60 +60 2 7 MΩ 290 Hz 210 250 Human Body Model ±15 IEC 61000-4-2 Contact Discharge ±4 IEC 61000-4-2 Air-Gap Discharge ±15 _______________________________________________________________________________________ kV High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver (VDD = +2.4V to +5.5V, CLAMP = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +3.0V and TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS BOOST CONVERTER VDD = +3V, DIM = +0.5V forced externally 42 50 61 VDD = +3V, DIM = +1V forced externally 85 100 115 VDD = +3V, DIM = +1.3V forced externally 105 125 140 CSW = 96pF, RSLEW = 375kΩ 80 100 120 kHz 20 Ω +1 µA 50 µA Output Peak Voltage VCS Boost Switching Frequency fSW Switch On-Resistance RLX ISINK = 25mA, VDD = +3V LX Leakage Current ILX VLX = +125V CS Input Current ICS No load, VCS = +125V, EN = 0V, DIM = 0V -1 V CONTROL INPUT SW Input Voltage-High Threshold VIH_SW RSLEW = 375kΩ 0.9 0.98 1.06 V Input Voltage-Low Threshold VIL_SW RSLEW = 375kΩ 0.43 0.49 0.55 V Input Low Current IIL_SW RSLEW = 375kΩ, CS = +40V, EL = VDD, DIM = VDD 43 77 µA Input High Current IIH_SW RSLEW = 375kΩ, CS = +40V, EL = VDD, DIM = VDD 5.0 7.5 µA CONTROL INPUT EL Input Voltage-High Threshold VIH_CEL RSLEW = 375kΩ 1.08 1.32 V Input Voltage-Low Threshold VIL_CEL RSLEW = 375kΩ 0.22 0.39 V Input Low Current IIL_CEL RSLEW = 375kΩ 1.2 1.87 µA Input High Current IIH_CEL RSLEW = 375kΩ 1.2 1.87 µA ISOURCE = 20µA 0.89 CONTROL INPUT SLEW Force Voltage VFORCE High-Voltage Output Slew Rate RSLEW = 375kΩ 0.95 1.04 30 V V/100µs CONTROL INPUT DIM Input Logic-High Voltage VIH_DIM Output voltage (max) Input Logic-Low Voltage VIL_DIM Output voltage (off) Input Low Current IIL_DIM VDIM = 0V, RSLEW = 375kΩ Input High Current IIH_DIM VDIM = VDD 1.3 V 0.15 2.22 3.0 µA -1 +1 µA PWM Frequency Range 0.2 to 1 Low-Peak Detector Threshold VLPD Low-Peak Detector Hysteresis VLPD_HYST V 0.15 MHz 0.35 100 V mV CONTROL INPUT EN Input Voltage-High Threshold VIH_EN Input Voltage-Low Threshold VIL_EN Input Low Current IIL_EN Input High Current IIH_EN 1.2 V 0.2 V -1 +1 µA -1 +1 µA _______________________________________________________________________________________ 3 MAX4990 ELECTRICAL CHARACTERISTICS (continued) ELECTRICAL CHARACTERISTICS (continued) (VDD = +2.4V to +5.5V, CLAMP = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), TA = TMIN to TMAX, unless otherwise noted. Typical values are at VDD = +3.0V and TA = +25°C.) (Note 1) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS THERMAL SHUTDOWN Thermal Shutdown 158 °C 8 °C Thermal Shutdown Hysteresis Note 1: Specifications at TA = -40°C are guaranteed by design and not production. Typical Operating Characteristics (VDD = +3.6V, CLAMP = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), RSLEW = 390kΩ, DIM = VDD, CSW = 100pF, CEL = 1.2nF, TA = +25°C, unless otherwise noted.) 12 10 8 6 4 16 12 8 4 60 225 CCS = 2.2nF 40 150 CCS = 4.7nF CCS = 4.7nF 20 2 0 3.6 4.2 4.8 5.4 -15 10 35 60 80 120 160 TEMPERATURE (°C) BOOST CONVERTER FREQUENCY (kHz) SHUTDOWN CURRENT vs. SUPPLY VOLTAGE SHUTDOWN CURRENT vs. TEMPERATURE PEAK-TO-PEAK OUTPUT VOLTAGE vs. SUPPLY VOLTAGE 100 SHUTDOWN CURRENT (nA) 0.8 0.6 0.4 0 DIM = EN = 0V 10 1 0.1 0.01 3.0 3.6 4.2 SUPPLY VOLTAGE (V) 4.8 5.4 0 200 300 PEAK-TO-PEAK OUTPUT VOLTAGE (V) DIM = EN = 0V 2.4 40 85 SUPPLY VOLTAGE (V) 0.2 4 -40 MAX4990 toc05 1.0 3.0 MAX4990 toc04 2.4 CCS = 2.2nF 0 0 75 DIM = 1.3V 250 DIM = 1.0V 200 DIM = 0.8V 150 DIM = 0.6V 100 50 0 -40 -15 10 35 TEMPERATURE (°C) 60 85 2.4 3.0 3.6 4.2 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 4.8 5.4 PEAK-TO-PEAK OUTPUT VOLTAGE (V) 14 300 - - - - PEAK-TO-PEAK OUTPUT VOLTAGE 90% DUTY CYCLE MAX4990 toc06 TOTAL INPUT CURRENT (mA) 16 TOTAL INPUT CURRENT (mA) 18 MAX4990 toc03 80 MAX4990 toc02 20 MAX4990 toc01 20 TOTAL INPUT CURRENT (mA) TOTAL INPUT CURRENT AND PEAK-TO-PEAK OUTPUT VOLTAGE vs. BOOST CONVERTER FREQUENCY TOTAL INPUT CURRENT vs. TEMPERATURE TOTAL INPUT CURRENT vs. SUPPLY VOLTAGE SHUTDOWN CURRENT (nA) MAX4990 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver 200 195 190 185 180 -15 10 35 60 200 150 100 50 300 150 100 fDIM = 1MHz 50 0 0.54 0.73 0.92 1.11 20 1.30 40 60 80 RMS OUTPUT VOLTAGE vs. SUPPLY VOLTAGE AVERAGE OUTPUT VOLTAGE vs. SUPPLY VOLTAGE AVERAGE OUTPUT VOLTAGE vs. TEMPERATURE -200 -300 -400 -500 -600 -700 -800 -100 -200 -300 -400 -500 -600 -700 -800 -900 0 -900 -1000 3.0 3.6 4.2 4.8 -1000 2.4 5.4 MAX4990 toc12 -100 0 AVERAGE OUTPUT VOLTAGE (mV) MAX4990 toc11 0 AVERAGE OUTPUT VOLTAGE (mV) MAX4990 toc10 40 20 3.0 3.6 4.2 4.8 5.4 -40 -15 10 35 60 SUPPLY VOLTAGE (V) SUPPLY VOLTAGE (V) TEMPERATURE (°C) EL SWITCHING FREQUENCY vs.CEL EL SWITCHING FREQUENCY vs. SUPPLY VOLTAGE EL SWITCHING FREQUENCY vs. TEMPERATURE 300 200 100 185 180 175 170 0 1.0 1.5 CEL (nF) 2.0 2.5 2.4 3.0 3.6 4.2 SUPPLY VOLTAGE (V) 4.8 5.4 85 MAX4990 toc15 190 EL SWITCHING FREQUENCY (Hz) 400 190 MAX4990 toc14 RSLEW = 390kΩ EL SWITCHING FREQUENCY (Hz) MAX4990 toc13 EL SWITCHING FREQUENCY (Hz) fDIM = 200kHz DIM DUTY CYCLE (%) 60 0.5 200 DIM VOLTAGE (V) 80 500 250 TEMPERATURE (°C) 100 2.4 MAX4990 toc09 250 0 0.35 85 120 RMS OUTPUT VOLTAGE (V) VDD = 4.5V PEAK-TO-PEAK OUTPUT VOLTAGE (V) 205 300 PEAK-TO-PEAK OUTPUT VOLTAGE (V) MAX4990 toc07 PEAK-TO-PEAK OUTPUT VOLTAGE (V) 210 -40 PEAK-TO-PEAK OUTPUT VOLTAGE vs. DIM DUTY CYCLE PEAK-TO-PEAK OUTPUT VOLTAGE vs. DIM VOLTAGE MAX4990 toc08 PEAK-TO-PEAK OUTPUT VOLTAGE vs. TEMPERATURE 185 180 175 170 -40 -15 10 35 60 85 TEMPERATURE (°C) _______________________________________________________________________________________ 5 MAX4990 Typical Operating Characteristics (continued) (VDD = +3.6V, CLAMP = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), RSLEW = 390kΩ, DIM = VDD, CSW = 100pF, CEL = 1.2nF, TA = +25°C, unless otherwise noted.) Typical Operating Characteristics (continued) (VDD = +3.6V, CLAMP = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), RSLEW = 390kΩ, DIM = VDD, CSW = 100pF, CEL = 1.2nF, TA = +25°C, unless otherwise noted.) 80 40 80 115 150 185 100 95 MAX4990 toc18 95 3.0 3.6 4.2 4.8 -40 5.4 -15 -10 35 TEMPERATURE (°C) OUTPUT VOLTAGE SLOPE vs. RSLEW OUTPUT VOLTAGE SLOPE vs. SUPPLY VOLTAGE OUTPUT VOLTAGE SLOPE vs. TEMPERATURE 15 10 5 0 28 26 24 22 500 600 700 RSLEW (kΩ) 800 2.4 3.5 3.0 BRIGHTNESS (cd/m2) tON 2.5 2.0 1.5 1.0 0.5 26 24 3.0 3.6 4.2 4.8 5.4 -40 -15 10 35 TEMPERATURE (°C) BRIGHTNESS AND TOTAL INPUT CURRENT vs. SUPPLY VOLTAGE TYPICAL VA, VB, AND VA - VB WAVEFORMS MAX4990 toc23 - - - - SUPPLY CURRENT CLAMP = 20nF 20 26 15 22 10 18 5 14 0 0.6 1.2 1.8 CDIM (μF) 2.4 3.0 3.6 VA - V B 100V/div VA 50V/div VB 50V/div 10 2.4 3.0 3.6 4.2 4.8 SUPPLY VOLTAGE (V) 85 MAX4990 toc24 30 tOFF 0 80 SUPPLY VOLTAGE (V) 25 MAX4990 toc22 RDIM = 390kΩ 28 22 900 1000 SLOW TURN-ON/-OFF TIME vs. CDIM 30 TOTAL INPUT CURRENT (mA) 400 MAX4990 toc21 MAX4990 toc20 30 85 32 OUTPUT VOLTAGE SLOPE (V/100μs) 20 32 OUTPUT VOLTAGE SLOPE (V/100μs) MAX4990 toc19 25 0 60 SUPPLY VOLTAGE (V) 30 4.0 100 CSW (pF) 35 300 105 90 2.4 220 40 OUTPUT VOLTAGE SLOPE (V/100μs) 105 90 0 6 110 BOOST CONVERTER FREQUENCY (kHz) 120 110 MAX4990 toc17 RSLEW = 390kΩ BOOST CONVERTER FREQUENCY (kHz) MAX4990 toc16 BOOST CONVERTER FREQUENCY (kHz) 160 BOOST CONVERTER FREQUENCY vs. TEMPERATURE BOOST CONVERTER FREQUENCY vs. SUPPLY VOLTAGE BOOST CONVERTER FREQUENCY vs. CSW SLOW TURN ON/OFF TIME (s) MAX4990 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver 5.4 _______________________________________________________________________________________ 1ms/div High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver PIN NAME FUNCTION 1 SLEW 2 EN Enable Input. Drive EN > +1.2V and DIM > +0.35V to turn on the device. Drive EN < +0.2V and DIM < +0.15V to turn off the device. 3 DIM EL Panel Dimming Control. Apply a PWM signal or DC analog control signal, or connect a resistor to GND to adjust peak-to-peak output voltage. Use DIM together with EN to control device shutdown (see Shutdown section). 4 EL EL Voltage Switching Frequency. Connect an external capacitor, CEL, to GND or drive with an external oscillator to set the switching frequency of the VA and VB high-voltage outputs. Connect EL to GND to shut off the EL oscillator. Drive EL high to keep alternatively VA or VB output high. 5 SW Boost-Converter Switching Frequency. Connect an external capacitor, CSW, to GND or drive with an external oscillator to set the switching frequency of the boost converter. Connect SW to GND to shut off the boost oscillator. Do not keep SW high to avoid LX shorting to GND, which causes the internal die temperature to increase. The MAX4990 is protected by entering a themal-shutdown state. (See the Thermal Short-Circuit Protection section.) 6 7 VDD GND 8 LX 9, 11, 13 N.C. 10 CS High-Voltage Supply. Connect CS to output capacitor of boost converter. 12 VB High-Voltage EL Panel Output. Connect to non-VA side of EL lamp. 14 VA High-Voltage EL Panel Output. Connect to non-VB side of EL lamp. EP EP Exposed Pad. Connect exposed pad to GND. High-Voltage Slew-Rate Control. Connect an external resistor, RSLEW, to GND to set the slew rate of the VA and VB high-voltage outputs. Power-Supply Voltage Ground Internal Switching DMOS Drain Connection. Connect LX to a switching inductor and an anode of a rectifying diode. No Connection. Leave N.C. unconnected. Detailed Description The MAX4990 high-voltage DC-AC converter is ideal for driving EL lamps. The MAX4990 features a wide +2.4V to +5.5V input range that allows the device to accept a wide variety of voltage sources such as single cell Li+ batteries and higher voltage battery chargers. The lamp outputs of the device generate up to 250V peak-to-peak output voltage for maximum lamp brightness. The MAX4990 utilizes an inductor-based boost converter that allows for the use of a 220µH inductor to generate the high voltage necessary to drive an EL lamp. The boost converter switching frequency is set with the combination of an external capacitor connected from the SW input to GND and an external resistor connected from SLEW to GND. Applying a PWM signal to the SW input allows the switching frequency of the boost converter to take the frequency of the PWM signal. The MAX4990 uses a high-voltage full-bridge output stage to convert the high voltage generated by the boost converter to an AC waveform suitable for driving the EL panel. The EL output switching frequency is set with the combination of an external capacitor connected from EL to GND and an external resistor connected from SLEW to GND. The MAX4990 allows programmability of the EL Lamp output frequency by applying a clock signal to the EL input. Applying a clock signal to the EL input allows the switching frequency of the lamp to take the frequency of the clock signal divided by 4 to switch at the EL input frequency divided by 4. The MAX4990 uses a proprietary acoustic noise-reduction circuit to control the slew rate of the AC voltage, reducing audible noise from the EL panel. The slew rate is set with an external resistor connected from SLEW to GND. The MAX4990 enters a low-power shutdown mode (100nA max) when EN and DIM inputs are connected _______________________________________________________________________________________ 7 MAX4990 Pin Description High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver MAX4990 Functional Diagram VDD SW LX SWITCH OSCILLATOR N TIMEOUT + EL SLEW EL OSCILLATOR - VSENSE V-I CONVERTER - EN LOW-POWER SHUTDOWN DIM PWM CONVERTER CS REF HIGH ESD PROTECTION VA HIGH ESD PROTECTION VB + H-BRIDGE DMOS DRIVER LOW PEAK DETECTOR SHUTDOWN THERMAL SHUTDOWN NO-OPERATION SIGNAL GND MAX4990 UVLO TIMEOUT LOW-POWER SHUTDOWN to GND. The MAX4990 also enters thermal shutdown if the die temperature rises above +158°C. The MAX4990 features an EL lamp dimming control (DIM) that allows the user to set the EL output voltage with a PWM, DC analog voltage, or a resistor connected to GND. A capacitor placed in parallel to the resistor on the DIM input allows the user to program a slow turn-on/-off time of the MAX4990’s outputs to generate a soft fade-on/fade-off effect of the EL lamp. The high-voltage outputs are ESD protected up to ±15kV Human Body Model, ±15kV Air-Gap Discharge, and ±4kV Contact Discharge, as specified in the IEC 61000-4-2 specification. EL Output Voltage The slew rate, frequency, and peak-to-peak voltage of the MAX4990 EL lamp outputs are programmed through a combination of external components and/or DC inputs. 8 The device uses resistor RSLEW to set the bias current used as a reference current for the MAX4990 internal circuitry. The reference current directly affects the slew rate of the EL lamp output. Increasing the value of RSLEW decreases the slew rate, and decreasing the value of RSLEW increases the slew rate. (See the RSLEW Resistor Selection section on how to select RSLEW.) The MAX4990 EL lamp output frequency uses an internal EL oscillator to set the desired frequency. The output frequency is adjusted by either 1) the combination of a resistor from SLEW to GND and an external capacitor from the EL input to GND, or 2) by driving a clock signal directly into the EL input. (See the CEL Capacitor Selection section for choosing the CEL capacitor value.) The peak-to-peak voltage of the EL lamp output is varied from 70VP-P to 250VP-P by applying an external DC voltage ranging from +0.35V to +1.3V to the DIM input. _______________________________________________________________________________________ High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver Boost Converter The MAX4990 boost converter consists of an external inductor from VDD to the LX input, an internal DMOS switch, an external diode from LX to the CS output, an external capacitor from the CS output to GND, and the EL lamp, CLAMP, connected to the EL lamp outputs. When the DMOS switch is turned on, LX is connected to GND, and the inductor is charged. When the DMOS switch is turned off, the energy stored in the inductor is transferred to the capacitor CCS and the EL lamp. Note: Keeping SW high shorts LX to GND, causing the internal die temperature to increase. The MAX4990 is protected by entering a thermal-shutdown state (See the Thermal Short-Circuit Protection section.) The MAX4990 boost converter frequency uses an internal switch oscillator to set the desired frequency of the boost converter. The boost converter frequency is adjusted by either 1) the combination of a resistor from SLEW to GND and an external capacitor from SW to GND, or 2) by driving a PWM signal directly into the SW input. When SW is driven with an external PWM signal at a suggested 90% duty cycle, the boost converter frequency is changed to the frequency of the external PWM signal. (See the CSW Capacitor Selection section for choosing the CSW capacitor value.) Dimming Control The MAX4990 features a dimming control input, DIM, that controls the peak-to-peak voltage on the lamp outputs VA and VB. DIM is controlled by a resistor con- nected from the DIM input to GND, a PWM signal applied to the DIM input, or a DC voltage applied to the DIM input. (See the RDIM Resistor and CDIM Capacitor Selection section.) The duty cycle of a PWM signal to the DIM input is internally translated into a DC voltage with the 0 to +1.22V range. The DIM input accepts the frequency range of 200kHz to 1MHz. As the duty cycle increases, the peak-to-peak voltage of the output increases, and as the duty cycle decreases, the peak-to-peak voltage of the output decreases. The peak-to-peak voltage is adjusted by applying a DC voltage to the DIM input. Increasing the voltage on DIM increases the peak-to-peak output, and decreasing the voltage on DIM decreases the peak-to-peak output voltage. The DIM input, in combination with the EN input, controls the shutdown mode of the MAX4990 shutdown. (See the Shutdown section.) Slow Turn-On, Slow Turn-Off The MAX4990 provides a slow turn-on/-off feature by connecting a resistor in parallel with a capacitor connected from the DIM input to GND (see the R DIM Resistor and CDIM Capacitor Selection section). When EN is driven high, the reference current I B (set by RSLEW) is used to charge capacitor CDIM. When EN is driven to GND, IB is removed, and the voltage on the capacitor CDIM and resistor decays with a time constant of RDIM x CDIM. A slow turn-on effect is seen by driving EN high. The slow rise and fall of the voltage on DIM during transitions on the EN input modulates the peak-to-peak voltage of the EL outputs, creating a soft fade-on/-off effect at the EL lamp. Shutdown The MAX4990 features an enable logic input, EN, to enable and disable the device. To enable the device, apply +1.2V or greater to the EN input and +0.35V or greater to the DIM input. To place the device in shutdown, apply +0.2V or less to the EN input, and +0.15V or less to the DIM input. Undervoltage Lockout (UVL0) The MAX4990 has a UVLO threshold of +2.1V (typ). When VDD falls below +2.1V (typ), the device enters a nonoperative mode. Thermal Short-Circuit Protection The MAX4990 enters a nonoperative mode if the internal die temperature of the device reaches or exceeds +158°C (typ). The device turns back on when the internal die temperature cools to +150°C. _______________________________________________________________________________________ 9 MAX4990 Increasing the voltage on the DIM input increases the peak-to-peak voltage, and decreasing the voltage on the input decreases the peak-to-peak voltage. The EL lamp peak-to-peak voltage is also adjusted by applying a PWM signal to the DIM input. The duty cycle of the PWM determines the EL lamp output peak-to-peak voltage. As the duty cycle is increased, the peak-to-peak output voltage is increased, and as the duty cycle is decreased, the peak-to-peak voltage is decreased. The MAX4990 also features a slow turn-on and slow turn-off time feature that is enabled by connecting a resistor and capacitor from DIM to GND (see the Typical Application Circuits and the R DIM Resistor and C DIM Capacitor Selection section). This slow turn-on/-off feature causes the peak-to-peak voltage of the EL outputs to slowly rise from zero to the maximum set value when the device is enabled. This feature also causes the peak-to-peak voltage of the EL outputs to fall from the maximum set value to zero when the device is placed into shutdown. The slow rise and fall of the peak-to-peak EL output voltage creates a soft fade-on and fade-off of the EL lamp, rather than an abrupt change in brightness. MAX4990 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver ±15kV ESD Protection Machine Model As with all Maxim devices, ESD-protection structures are incorporated on all pins to protect against electrostatic discharges encountered during handling and assembly. The EL lamp driver outputs of the MAX4990 have extra protection against static electricity. Maxim’s engineers have developed state-of-the-art structures to protect these pins against ESD of ±15kV without damage. The ESD structures withstand high ESD in all states: normal operation, shutdown, and powered down. After an ESD event, the MAX4990 keep working without latchup or damage. ESD protection can be tested in various ways. The transmitter EL lamp outputs of the MAX4990 are characterized for protection to the following limits: • ±15kV using the Human Body Model The machine model for ESD tests all pins using a 200pF storage capacitor and zero discharge resistance. • ±4kV IEC 61000-4-2 Contact Discharge • ±15kV IEC 61000-4-2 Air-Gap Discharge 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. Human Body Model Figure 1a shows the Human Body Model, and Figure 1b shows the current waveform it generates when discharged into a low impedance. This model consists of a 100pF capacitor charged to the ESD voltage of interest, which is then discharged into the test device through a 1.5kΩ resistor. IEC 61000-4-2 The IEC 61000-4-2 standard covers ESD testing and performance of finished equipment. However, it does not specifically refer to integrated circuits. The MAX4990 assists in designing equipment to meet IEC 61000-4-2 without the need for additional ESD-protection components. The major difference between tests done using the Human Body Model and IEC 61000-4-2 is higher peak current in IEC 61000-4-2 because series resistance is lower in the IEC 61000-4-2 model. Hence, the ESD withstand voltage measured to IEC 61000-4-2 is generally lower than that measured using the Human Body Model. Figure 1c shows the IEC 61000-4-2 model, and Figure 1d shows the current waveform for IEC 61000-42 ESD Contact Discharge test. 10 The objective is to emulate the stress caused when I/O pins are contacted by handling equipment during test and assembly. Of course, all pins require this protection. The Air-Gap test involves approaching the device with a charged probe. The Contact Discharge method connects the probe to the device before the probe is energized. Design Procedure LX Inductor Selection The recommended inductor values are 220µH/330µH. For most applications, series resistance (DCR) should be below 8Ω for reasonable efficiency. Do not exceed the inductor’s saturation current. RSLEW Resistor Selection To help reduce audible noise emission by the EL lamp, the MAX4990 features a slew-rate control input (SLEW) that allows the user to set the slew-rate of the high-voltage outputs, V A and V B, by connecting a resistor, RSLEW, from the SLEW input to GND. RSLEW precisely sets the reference current IB that is used to charge and discharge the capacitances at the SW input and EL input, and is used as a reference current for internal circuitry. The reference current is related to RSLEW by the following equation: I B = 1V/R SLEW . Decreasing the value of RSLEW increases IB and increases the slew rate at the EL lamp output. Increasing the value of RSLEW decreases IB and decreases the slew rate at the EL lamp output. The output slew rate is related to RSLEW by the following equation: ⎛ V ⎞ 11.25 SlewRate ⎜ ⎟= 100 μ s R ⎝ ⎠ SLEW (MΩ) The ideal value for a given design varies depending on lamp size and mechanical enclosure. Typically, the best slew rate for minimizing audible noise is between 10V/100µs and 20V/100µs. This results in RSLEW values ranging from 1.125MΩ to 0.5625MΩ. For example, if the desired slew rate is 20 (V/100µs), this leads to an RSLEW resistor value in MΩ of RSLEW = 11.25/20V = 0.5625MΩ. Note: Connecting RSLEW to GND will not damage the device. However, for the device to operate correctly, RSLEW should be in the 100kΩ to 2.2MΩ range. RSLEW also affects the frequency of the boost converter (see the CSW Capacitor Selection), the frequency of the EL lamp (see the CEL Capacitor Selection section), and the peak-to-peak voltage of the EL lamp. ______________________________________________________________________________________ High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF RC 50MΩ TO 100MΩ RD 1500Ω CHARGE-CURRENTLIMIT RESISTOR DISCHARGE RESISTANCE DEVICE UNDER TEST STORAGE CAPACITOR DISCHARGE RESISTANCE DEVICE UNDER TEST STORAGE CAPACITOR I 100% 90% PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) IPEAK Ir Cs 150pF RD 330Ω Figure 1c. IEC 61000-4-2 ESD Test Model Figure 1a. Human Body ESD Test Model IP 100% 90% HIGHVOLTAGE DC SOURCE MAX4990 RC 1MΩ AMPS 36.8% 10% 0 10% 0 tRL TIME tr = 0.7ns TO 1ns tDL CURRENT WAVEFORM t 30ns 60ns Figure 1d. IEC 61000-4-2 ESD Generator Current Waveform Figure 1b. Human Body Current Waveform Table 1. Inductor Vendors INDUCTOR VALUE (µH) VENDOR WEBSITE PART 220 TOKO www.tokoam.com D312C 1001BS-221M 330 Coilcraft www.coilcraft.com DO1608C-334ML 470 Coilcraft www.coilcraft.com DO1608C-474ML 220 Coilcraft www.coilcraft.com LPS4018-224ML 330 Coilcraft www.coilcraft.com LPS4018-334ML 470 Coilcraft www.coilcraft.com LPS4018-474ML 220 Cooper Bussmann www.cooperet.com SDH3812-221-R 220 Cooper Bussmann www.cooperet.com SD3110-221-R The peak-to-peak voltage is adjusted by connecting a resistor from the SLEW input to GND together with a resistor from the DIM input to GND. The equation relating the peak-to-peak voltage to the resistors is the following: VP-P = 200 × RDIM RSLEW RDIM Resistor and CDIM Capacitor Selection The MAX4990 provides a slow turn-on/-off feature by connecting a resistor in parallel with a capacitor connected from the DIM input to GND. The reference current IB is used to charge the resistor and capacitor. When EN is driven to GND, IB is removed, and the voltage across the capacitor and resistor decay with a time constant of RC that provides a slow turn off of the EL ______________________________________________________________________________________ 11 MAX4990 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver lamp outputs. A slow turn-on effect is produced by driving EN high. Slow turn-on/-off time is related by the following equation: tON = 2.6 x RDIM x CDIM tOFF = 1.2 x RDIM x CDIM For this equation to be valid, R DIM /R SLEW must be ≤ 1.3. CCS Capacitor Selection CCS is the output of the boost converter and provides the high-voltage source for the EL lamp. Connect a 3.3nF capacitor from CS to GND and place as close to the CS input as possible. When using an inductor value larger than 220µH, it may be necessary to increase the C CS . For a L X = 470µH and C LAMP = 20nF, a C CS ranging from 3.3nF to 6.8nF is recommended. CEL Capacitor Selection The MAX4990 EL lamp output frequency is set by connecting a capacitor from the EL input to GND together with a resistor from SLEW to GND or by driving the EL input with an external clock (0 to +1.5V). The EL lamp output frequency is related to the CEL capacitor by the following equation: Connect the SW input to GND to turn the switch oscillator of the boost converter off. Although the optimal fSW depends on the inductor value, the suggested f SW range is 20kHz to 150kHz. Note: Driving SW with a logic-high causes LX to be driven to GND. Keeping SW high shorts LX to GND, causing the internal die temperature to increase. The MAX4990 is protected by entering a thermal-shutdown state. (See the Thermal Short-Circuit Protection section.) CB Capacitor Selection Bypass VDD with a 0.1µF ceramic capacitor as close to the IC as possible and a 4.7µF ceramic capacitor as close to the inductor as possible Diode Selection Connect a diode, D1, from the LX node to CS to rectify the boost voltage on CS. The diode should be a fastrecovery diode that is tolerant to +150V. EL Lamp Selection EL lamps have a capacitance of approximately 2.5nF to 3.5nF per square inch. The MAX4990 effectively charges capacitance ranging from 2nF to 20nF. Applications Information 0.0817 fEL = RSLEW × CEL For example, an RSLEW = 375kΩ and a CEL capacitor value of 1000pF equals an EL lamp output frequency of FEL = 217Hz. CSW Capacitor Selection The boost converter switching frequency is set by connecting a capacitor from the SW input to GND, together with the resistance from the SLEW input to GND, or driving the SW input with an external clock (0 to +1.5V). The switching frequency of the boost converter is related to the capacitor from SW to GND by the following equation: fSW = 12 PCB Layout Keep PCB traces as short as possible. Ensure that bypass capacitors are as close to the device as possible. Use large ground planes where possible. Chip Information PROCESS: BiCMOS-DMOS 3.61 RSLEW × CSW ______________________________________________________________________________________ High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver RSLEW 1 2 DIGITAL OUTPUT 3 PWM OR VBIAS μC OR ASIC CEL 4 CSW 5 6 CB = 0.1μF 7 VA SLEW EN N.C. VB DIM EL MAX4990 N.C. SW CS VDD N.C. LX GND 14 13 EL LAMP CLAMP = 10nF 12 11 10 9 D1 CCS = 3.3nF 8 VDD LX = 220μH 4.7μF RSLEW 1 2 DIGITAL OUTPUT CDIM μC OR ASIC 3 CEL RDIM CSW VA EN N.C. VB DIM MAX4990 4 5 6 CB = 0.1μF SLEW 7 EL N.C. CS SW N.C. VDD LX GND 14 13 EL LAMP CLAMP = 10nF 12 11 10 9 D1 CCS = 3.3nF 8 VDD LX = 220μH 4.7μF ______________________________________________________________________________________ 13 MAX4990 Typical Application Circuits 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.) 6, 8, &10L, DFN THIN.EPS MAX4990 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver 14 ______________________________________________________________________________________ High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver COMMON DIMENSIONS PACKAGE VARIATIONS SYMBOL MIN. MAX. PKG. CODE N D2 E2 e JEDEC SPEC b [(N/2)-1] x e A 0.70 0.80 T633-2 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF D 2.90 3.10 T833-2 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF E 2.90 3.10 T833-3 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF A1 0.00 0.05 T1033-1 10 1.50±0.10 2.30±0.10 0.50 BSC MO229 / WEED-3 0.25±0.05 2.00 REF L 0.20 0.40 T1033-2 10 1.50±0.10 2.30±0.10 0.50 BSC MO229 / WEED-3 0.25±0.05 2.00 REF k 0.25 MIN. T1433-1 14 1.70±0.10 2.30±0.10 0.40 BSC ---- 0.20±0.05 2.40 REF A2 0.20 REF. T1433-2 14 1.70±0.10 2.30±0.10 0.40 BSC ---- 0.20±0.05 2.40 REF ______________________________________________________________________________________ 15 MAX4990 Package Information (continued) (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.) MAX4990 High-Voltage, ±15kV ESD-Protected Electroluminescent Lamp Driver Revision History REVISION NUMBER REVISION DATE DESCRIPTION 0 8/07 Initial release 1 11/07 Revise lead–free part number from MAX4990E to MAX4990 PAGES CHANGED — 1-13 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. 16 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2007 Maxim Integrated Products SPRINGER is a registered trademark of Maxim Integrated Products, Inc.