19-4466; Rev 0; 2/09 KIT ATION EVALU E L B A IL AVA Dual Electroluminescent Lamp Driver ♦ Resistor Adjustable Slew-Rate Control ♦ Resistor Adjustable Lamp and Switching Converter Frequencies ♦ DIM Input for Controlling Output Voltage Through DC Analog Voltage, PWM, or Resistor to GND ♦ Capacitor Adjustable Soft Turn-On/-Off ♦ Low 150nA Shutdown Current ♦ Thermal Shutdown ♦ Space Saving, 14-Pin, 3mm x 3mm TDFN Package Ordering Information PART MAX14514ETD+ TEMP RANGE PIN-PACKAGE -40°C to +85°C 14 TDFN-EP* +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. CS LX TOP VIEW COM Pin Configuration V2 Applications ♦ +2.7V to +5.5V Input Voltage Range V1 The MAX14514 enters a low-power shutdown mode when the EN and DIM_ inputs are connected to GND. The device also features thermal shutdown if the die temperature exceeds +158°C (typ). The MAX14514 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. ♦ 300VP-P Maximum Output for Highest Brightness EN The MAX14514 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 panels. An external resistor controls the slewrate of the rising and falling edges of the AC drive waveform to reduce audible noise output. The high-voltage outputs are ESD protected up to ±15kV Human Body Model, ±4kV IEC 61000-4-2 Air Gap Discharge, and ±4kV IEC 61000-4-2 Contact Discharge. The MAX14514 features dimming/enable controls (DIM1, DIM2) for each output to allow the user to set the peak-to-peak output voltage with a PWM signal, a DC analog voltage, or a resistor connected from DIM_ to GND. The MAX14514 also provides a slow turn-on/off feature that slowly ramps the output voltage applied to the lamp when enabled or disabled. ♦ Dual ±15kV ESD-Protected EL Lamp Outputs SLEW The MAX14514 is a high-voltage DC-AC converter ideal for driving two electroluminescent (EL) lamps. The MAX14514 features a +2.7V to +5.5V input range that allows the device to accept a wide variety of voltage sources, including single-cell lithium-ion (Li+) batteries. The lamp outputs of the device generate up to 300VP-P for maximum lamp brightness. The MAX14514 utilizes an inductor-based boost converter to generate the high voltage necessary to drive EL lamps and allows the use of a 220µH inductor to effectively drive total combined lamp sizes of up to 20nF. Features 14 13 12 11 10 9 8 Keypad Backlighting LCD Backlighting PDAs/Smartphones MAX14514 Automotive Instrument Clusters *EP 4 5 6 7 SW VDD GND DIM2 3 EL 2 CAP 1 DIM1 + TDFN-EP (3mm x 3mm) *EP = EXPOSED PAD. CONNECT EP TO GND OR LEAVE UNCONNECTED. ________________________________________________________________ Maxim Integrated Products For information on other Maxim products, visit Maxim’s website at www.maxim-ic.com. 1 MAX14514 General Description Dual Electroluminescent Lamp Driver MAX14514 Typical Application Circuit RSLEW BASEBAND/PMIC DIM1 SLEW DIM2 EN CCAP V1 CAP MAX14514 CEL EL V2 CSW SW COM VDD CS GND LX EL LAMP CLAMP = 10nF EL LAMP CLAMP = 10nF VDD 0.1µF VBAT CCS = 3.3nF LX = 220µH 4.7µF 2 _______________________________________________________________________________________ Dual Electroluminescent Lamp Driver Junction-to-Ambient Thermal Resistance (θJA) (Note 1) 14-Pin TDFN .................................................................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 Note 1: 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 www.maxim-ic.com/thermal-tutorial. 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 = +2.7V to +5.5V, CLAMP_TOTAL = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), TA = -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +3.0V, TA = +25°C.) (Note 2) PARAMETER Input Supply Voltage Input Supply Current SYMBOL VDD IIN Shutdown Supply Current ISHDN Shutdown Inductor Supply Current ILX_SHDN Undervoltage Lockout Undervoltage Lockout Hysteresis CONDITIONS VUV MIN TYP 2.7 RSLEW = 375kΩ, FEL = 200Hz, (V1,V2) - VCOM = 300VP-P EN = GND TA = +25°C 40 TA = -40°C to +85°C UNITS 5.5 V 700 µA 150 400 EN = GND, LX = VDD, CS = VDD VDD falling MAX 1.5 1.8 VUV_HYST 2.1 2.3 125 nA µA V mV EL OUTPUTS (V1, V2, COM) Peak-to-Peak Output Voltage V_ - VCOM VDD = +3V VDIM_ = +0.5V 105 130 VDIM_ = +1V 210 260 162 310 VDIM_ = +1.3V 250 300 350 V V1, V2 High-Side Switch OnResistance RONHS_VN ISOURCE = 1mA 1.5 3.0 kΩ V1, V2 Low-Side Switch OnResistance RONLS_VN ISINK = 1mA 0.7 2.0 kΩ COM High-Side Switch OnResistance RONHS_COM ISOURCE = 1mA 0.7 1.5 kΩ COM Low-Side Switch OnResistance RONLS_COM ISINK = 1mA 0.4 1.0 kΩ High-Side Switch Off-Leakage RONHS_LEAK V1, V2, VCOM = 0, VCS = 150V -1 +1 µA Low-Side Switch Off-Leakage RONLS_LEAK V1, V2, VCOM = 150V, VCS = 150V -1 +1 µA 290 Hz EL Lamp Switching Frequency ESD Protection (COM, V1, V2 Only) fEL CEL = 872pF, RSLEW = 375kΩ 210 250 Human Body Model ±15 IEC 61000-4-2 Contact Discharge ±4 IEC 61000-4-2 Air-Gap Discharge ±4 kV _______________________________________________________________________________________ 3 MAX14514 ABSOLUTE MAXIMUM RATINGS (Voltages referenced to GND.) VDD ........................................................................-0.3V to +6.0V CS, LX...................................................................-0.3V to +160V V1, V2, COM................................................-0.3V to (VCS + 0.3V) SW, EL, DIM_, SLEW, CAP, EN ..................-0.3V to (VDD + 0.3V) Continuous Power Dissipation (TA = +70°C) 14-Pin TDFN (derate 24.4mW/°C above +70°C) .......1951mW Junction-to-Case Thermal Resistance (θJC) (Note 1) 14-Pin TDFN ...................................................................8°C/W MAX14514 Dual Electroluminescent Lamp Driver ELECTRICAL CHARACTERISTICS (continued) (VDD = +2.7V to +5.5V, CLAMP_TOTAL = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), TA = -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +3.0V, TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS BOOST CONVERTER Output Regulation Voltage VCS VDD = +3V VDIM_ = +0.5V 52 65 81 VDIM_ = +1V 105 130 155 VDIM_ = +1.3V 125 150 175 80 100 120 Boost Switching Frequency fSW CSW = 96pF, RSLEW = 375kΩ Switch On-Resistance RLX ISINK = 25mA, VDD = +3V LX Leakage Current ILX VLX = +150V CS Input Current ICS No load, VCS = +150V, VEN = 0, VDIM_ = 0 -1 V kHz 20 Ω +1 µA 50 µA CONTROL INPUT (SW) Input-Voltage High Threshold VIH_CSW RSLEW = 375kΩ 0.9 0.98 1.06 V Input-Voltage Low Threshold VIL_CSW RSLEW = 375kΩ 0.43 0.49 0.55 V Input Low Current IIL_CSW RSLEW = 375kΩ, VCS = +78V, CEL = VDD, VDIM_ = VDD 43 79 µA Input High Current IIH_CSW RSLEW = 375kΩ, VCS = +78V, CEL = VDD, VDIM_ = VDD 5 7.5 µA 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 1.3 1.88 µA Input High Current IIH_CEL RSLEW = 375kΩ 1.3 1.88 µA fCAP RSLEW = 375kΩ, CCAP = 1.25nF 180 410 Hz Slow Turn-On Time tSLOW_ON RSLEW = 375kΩ, CCAP = 1.25nF Fast Turn-On CAP Threshold VFAST_CAP RSLEW = 375kΩ CONTROL INPUT (EL) CONTROL INPUT (CAP) CAP Switching Frequency Nonfast Turn-On CAP Threshold Input Leakage Current VNONFAST_CAP 300 0.3 V RSLEW = 375kΩ IIH_CAP CAP = VDD, RSLEW = 375kΩ VFORCE RSLEW = 375kΩ s VDD - 0.35 1.4 V Normal operation 0.3 1 µA Shutdown mode -100 100 nA CONTROL INPUT (SLEW) Force Voltage High-Voltage Output Slew Rate 0.9 RSLEW = 375kΩ 0.98 1.05 32 V V/100µs CONTROL INPUTS (DIM1, DIM2) Input High Voltage VIH_DIM__ Max output voltage Input Low Voltage VIL_DIM__ Min output voltage 1.3 Input Low Current IIL_DIM__ VDIM_ = 0, RSLEW = 375kΩ 2.2 Input High Current IIH_DIM__ VDIM_ = VDD -1 PWM Frequency Range 2.6 V 3.0 µA +1 0.2 to 1 Low-Peak Detector Threshold VLPD Low-Peak Detector Hysteresis VLPD_HYST 4 V 0.15 0.13 0.35 100 _______________________________________________________________________________________ µA MHz V mV Dual Electroluminescent Lamp Driver (VDD = +2.7V to +5.5V, CLAMP_TOTAL = 10nF, CCS = 3.3nF, LX = 220µH (ISAT = 170mA, RS = 5.5Ω), TA = -40°C to +85°C, unless otherwise noted. Typical values are at VDD = +3.0V, TA = +25°C.) (Note 2) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0.3 V CONTROL INPUT (EN) Input Logic-High Voltage VIH_EN Input Logic-Low Voltage VIL_EN 1.4 V THERMAL SHUTDOWN Thermal Shutdown Thermal Shutdown Hysteresis 158 °C 8 °C MAX14514 ELECTRICAL CHARACTERISTICS (continued) Note 2: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design. Typical Operating Characteristics (VDD = +3.6V, TA = +25°C, unless otherwise noted.) 5 10 5 0 0 3.4 4.1 4.8 5.5 225 40 150 20 75 -15 10 35 60 85 0 40 80 120 160 SUPPLY VOLTAGE (V) TEMPERATURE (°C) BOOST CONVERTER FREQUENCY (kHz) SHUTDOWN CURRENT vs. SUPPLY VOLTAGE SHUTDOWN CURRENT vs. TEMPERATURE PEAK-TO-PEAK OUTPUT VOLTAGE vs. SUPPLY VOLTAGE 0.35 0.3 0.25 0.2 0.15 0.1 100 DIM1 = DIM2 = EN = 0V 10 1 0.1 0.01 0.05 3.4 4.1 SUPPLY VOLTAGE (V) 4.8 5.5 DIM = 1V 200 150 DIM_ = 0.7V 100 DIM_ = 0.4V DIM = 0.5V 50 0 0.001 0 200 250 PEAK-TO-PEAK OUTPUT VOLTAGE (V) DIM1 = DIM2 = EN = 0V MAX14514 toc05 MAX14514 toc04 0.4 2.7 60 0 -40 SHUTDOWN CURRENT (nA) 2.7 SHUTDOWN CURRENT (nA) 15 300 PEAK-TO-PEAK OUTPUT 90% DUTY CYCLE MAX14514 toc06 10 20 MAX14514 toc03 80 TOTAL INPUT CURRENT (mA) 15 INPUT CURRENT AND PEAK-TO-PEAK OUTPUT VOLTAGE vs. BOOST CONVERTER FREQUENCY MAX14514 toc02 20 25 TOTAL INPUT CURRENT (mA) MAX14514 toc01 TOTAL INPUT CURRENT (mA) 25 TOTAL INPUT CURRENT vs. TEMPERATURE -40 -15 10 35 TEMPERATURE (°C) 60 85 2.7 3.4 4.1 4.8 5.5 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 5 PEAK-TO-PEAK OUTPUT VOLTAGE (V) TOTAL INPUT CURRENT vs. SUPPLY VOLTAGE Typical Operating Characteristics (continued) (VDD = +3.6V, TA = +25°C, unless otherwise noted.) 150 100 50 200 VDD = 4.6V 150 VDD = 3.6V 100 VDD = 2.7V 50 -15 10 35 60 0.35 85 50 0.85 20 1.35 40 60 80 RMS OUTPUT VOLTAGE vs. SUPPLY VOLTAGE AVERAGE OUTPUT VOLTAGE vs. SUPPLY VOLTAGE AVERAGE OUTPUT VOLTAGE vs. TEMPERATURE 50 40 30 20 500 400 300 200 4.1 4.8 2.7 5.5 500 400 300 200 0 0 3.4 600 100 100 0 MAX14514 toc12 600 700 AVERAGE OUTPUT VOLTAGE (mV) 60 MAX14514 toc11 MAX14514 toc10 70 700 10 3.4 4.1 4.8 -40 5.5 -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 300 200 100 233 232 231 230 229 228 227 225 1 1.5 CEL (nF) 2 2.5 260 250 240 230 220 210 200 190 226 0 270 85 MAX14514 toc15 234 EL SWITCHING FREQUENCY (Hz) 400 MAX14514 toc14 500 235 EL SWITCHING FREQUENCY (Hz) MAX14514 toc13 600 6 100 DUTY CYCLE (%) 80 0.5 fDIM = 200kHz 150 DIM VOLTAGE (V) 90 2.7 fDIM = 1MHz 200 TEMPERATURE (°C) AVERAGE OUTPUT VOLTAGE (mV) -40 DIM1 = DIM2 VDD = 5.5V 0 0 0 RMS OUTPUT VOLTAGE (V) VDD = 5.5V 250 MAX14514 toc09 DIM1 = DIM2 PEAK-TO-PEAK OUTPUT VOLTAGE (V) 200 250 PEAK-TO-PEAK OUTPUT VOLTAGE (V) MAX14514 toc07 PEAK-TO-PEAK OUTPUT VOLTAGE (V) 250 PEAK-TO-PEAK OUTPUT VOLTAGE vs. DIM DUTY CYCLE PEAK-TO-PEAK OUTPUT VOLTAGE vs. DIM VOLTAGE MAX14514 toc08 PEAK-TO-PEAK OUTPUT VOLTAGE vs. TEMPERATURE EL SWITCHING FREQUENCY (Hz) MAX14514 Dual Electroluminescent Lamp Driver 180 2.7 3.4 4.1 4.8 SUPPLY VOLTAGE (V) 5.5 -40 -15 10 35 TEMPERATURE (°C) _______________________________________________________________________________________ 60 85 Dual Electroluminescent Lamp Driver BOOST CONVERTER FREQUENCY vs. SUPPLY VOLTAGE 100 80 60 40 20 124 122 120 118 116 114 130 126 124 122 120 118 116 114 110 3.4 4.1 4.8 5.5 -40 -15 10 35 60 CSW (pF) SUPPLY VOLTAGE (V) TEMPERATURE (°C) OUTPUT VOLTAGE SLOPE vs. RSLEW OUTPUT VOLTAGE SLOPE vs. SUPPLY VOLTAGE OUTPUT VOLTAGE SLOPE vs. TEMPERATURE 30 25 20 15 34 33 32 31 30 29 28 10 27 5 26 400 500 600 700 800 900 1000 MAX14514 toc21 35 35 34 33 32 31 30 29 28 27 26 2.7 3.4 4.1 4.8 5.5 -40 -15 10 35 60 RSLEW (kΩ) SUPPLY VOLTAGE (V) TEMPERATURE (°C) SLOW TURN-ON/TURN-OFF TIME vs. CCAP NORMALIZED BRIGHTNESS LEVEL vs. SUPPLY VOLTAGE TYPICAL V_, VCOM, AND V_ - VCOM WAVEFORMS 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 MAX14514 toc24 2 1.8 1.6 V_ - VCOM 50V/div 1.4 1.2 1 0.8 0.6 0.4 V_, VCOM 25V/div 0.2 0.1 85 MAX14514 toc23 VDD = 5.5V DIM1 = 0V to VDD DIM2 = GND NORMALIZED BRIGHTNESS LEVEL MAX14514 toc22 1 85 36 OUTPUT VOLTAGE SLOPE (V/100μs) 35 MAX14514 toc20 40 36 OUTPUT VOLTAGE SLOPE (V/100μs) MAX14514 toc19 45 300 128 112 2.7 180 MAX14514 toc18 126 130 110 80 OUTPUT VOLTAGE SLOPE (V/100μs) 128 112 0 SLOW TURN-ON/TURN-OFF TIME (s) MAX14514 toc17 120 130 BOOST CONVERTER FREQUENCY (kHz) MAX14514 toc16 BOOST CONVERTER FREQUENCY (Hz) 140 BOOST CONVERTER FREQUENCY vs. TEMPERATURE BOOST CONVERTER FREQUENCY (kHz) BOOST CONVERTER FREQUENCY vs. CSW 0 0 0 2 4 6 CCAP (nF) 8 10 MAX14514 Typical Operating Characteristics (continued) (VDD = +3.6V, TA = +25°C, unless otherwise noted.) 2.7 3.4 4.1 4.8 5.5 1ms/div SUPPLY VOLTAGE _______________________________________________________________________________________ 7 Dual Electroluminescent Lamp Driver MAX14514 Pin Description PIN NAME 1 DIM1 High-Voltage Output 1 Dimming Control. Apply a PWM signal, DC analog control signal, or connect a resistor from DIM1 to GND to adjust V1 peak-to-peak output voltage. Drive DIM1 high or leave DIM1 unconnected to set V1 to full brightness level. 2 DIM2 High-Voltage Output 2 Dimming Control. Apply a PWM signal, DC analog control signal, or connect a resistor from DIM2 to GND to adjust V2 peak-to-peak output voltage. Drive DIM2 high or leave DIM2 unconnected to set V2 to full brightness level. 3 CAP Turn-On Time Input. For fast turn-on mode, connect CAP to VDD. For slow turn-on/-off mode, connect a capacitor from CAP to GND to set the turn-on/-off time. tON/OFF = 0.27 x CCAP x RSLEW. 4 EL EL Voltage Switching Frequency. Connect an external capacitor, CEL, from EL to GND or drive EL with an external oscillator to set the switching frequency of the V1 and V2 high-voltage outputs. Connect EL to GND to shut off the EL oscillator. SW Boost Converter Switching Frequency. Connect an external capacitor, CSW, from SW 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. To avoid LX shorting to GND and causing an increase in internal die temperature, do not keep SW high. The MAX14514 is protected by entering a thermal-shutdown state. (See the Thermal Short-Circuit Protection section.) 6 VDD Input Supply Voltage 7 GND Ground 8 LX Internal Switching DMOS Drain Connection. Connect LX to a switching inductor and an anode of a rectifying diode. High-Voltage Feedback Connection. Connect CS to output of boost converter (cathode of rectifying diode). 5 8 FUNCTION 9 CS 10 COM 11 V2 High-Voltage EL Panel Output 2. Connect V2 to non-COM side of EL lamp 2. 12 V1 High-Voltage EL Panel Output 1. Connect V1 to non-COM side of EL lamp 1. 13 EN Enable Input. Drive EN > VIH_EN to turn on the device. Drive EN < VIL_EN to turn off the device (see the Shutdown section). 14 SLEW ⎯ EP High-Voltage EL Panel Common Output. Connect COM to common side of EL lamp. High-Voltage Slew-Rate Control. Connect an external resistor, RSLEW, from SLEW to GND to set the slew rate of the high-voltage outputs V1 and V2. Exposed Pad. Connect EP to GND. _______________________________________________________________________________________ Dual Electroluminescent Lamp Driver VDD LX SW EL SWITCH OSCILLATOR EL OSCILLATOR N REF VSENSE SLEW V-I CONVERTER EL LOW-POWER SHUTDOWN DIM1 DIM2 DMOS DRIVER PWM CONVERTER CAP LOW PEAK DETECTOR THERMAL SHUTDOWN GND H-BRIDGE CS HIGH ESD PROTECTION V1 HIGH ESD PROTECTION V2 HIGH ESD PROTECTION COM NO-OPERATION SIGNAL UVLO MAX14514 LOW-POWER SHUTDOWN _______________________________________________________________________________________ 9 MAX14514 Functional Diagram MAX14514 Dual Electroluminescent Lamp Driver Detailed Description The MAX14514 high-voltage DC-AC converter is designed to drive two EL lamps. The MAX14514 features a +2.7V to 5.5V input range that allows the device to accept a wide variety of voltage sources, including single-cell Li+ batteries. The lamp outputs of the device generate up to 300VP-P for maximum lamp brightness. The slew rate, frequency, and peak-to-peak voltage of the MAX14514 EL lamp outputs are programmed through a combination of external components and/or logic inputs. Output Slew Rate The MAX14514 uses the resistor RSLEW to set a reference current for the 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.) Output Frequency The MAX14514 uses an internal oscillator to set the desired output 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 EL lamp output voltage is related to VDIM_ (for VDIM_ > VIL_DIM_) or PWM duty cycle by the following equation: V_ - VCOM = 260 x (VDIM_) = 260 x (%duty cycle) x (VIH_DIM_) Slow Turn-On, Slow Turn-Off The MAX14514 provides a slow turn-on and slow turnoff time feature that is enabled by connecting a capacitor from CAP to GND (see the Typical Application Circuit and the CCAP Capacitor Selection section). This slow turn-on/-off feature causes the peak-to-peak voltage of the EL outputs to slowly rise or fall any time the outputs are enabled or disabled, either through EN or DIM_ (see Table 1). The slow rise and fall of the peakto-peak EL output voltage creates a soft fade-on and fade-off of the EL lamp, rather than an abrupt change in brightness. To disable the slow turn-on/turn-off feature, connect CAP to VDD. Table 1. Slow Turn-On, Slow Turn-Off LOGIC INPUT EL OUTPUTS* EN DIM1 DIM2 V1 V2 1≥0 1 1 Slow Turn-Off Slow Turn-Off Slow Turn-On 0≥1 1 1 Slow Turn-On 1 1≥0 X Slow Turn-Off X 1 0≥1 X Slow Turn-On X Dimming Control 1 X 1≥0 X Slow Turn-Off The MAX14514 features dimming control inputs, DIM1 and DIM2, to control the peak-to-peak voltages on lamp outputs V1, V2, and COM. DIM_ is controlled by either a DC voltage, a PWM signal, or a resistor from DIM_ to GND. (See the RDIM Resistor Selection section.) 1 X 0≥1 X Slow Turn-On Applying a DC voltage to DIM_ ranging from VLPD to VIH_DIM_ linearly varies the corresponding output voltage from 130V to 300V. Increasing the voltage on DIM_ increases the peak-to-peak output, and decreasing the voltage on DIM_ decreases the peak-to-peak output voltage. Note that when VDIM_ goes below VIL_DIM_, the corresponding output turns off. DIM_ features an internal lowpass filter to allow a PWM signal to control the output voltage. Voltages on DIM_ are internally level translated down to VIH_DIM_, so that the equivalent voltage on DIM_ is (%duty cycle) x VIH_DIM_. The DIM_ inputs accept the 200kHz to 1MHz frequency range. Note that for PWM signals, the logic voltage applied to DIM__ must be greater than or equal to VIH_DIM_. 10 *With capacitor from CAP to GND (CAP is not connected to VDD). X = Don’t Care. Boost Converter The MAX14514 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 lamps, CLAMP1 and CLAMP2, 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 lamps. Note: Keeping SW high shorts LX to GND and causes the internal die temperature to increase. The MAX14514 is protected by entering a thermal-shutdown state (see the Thermal Short-Circuit Protection section). ______________________________________________________________________________________ Dual Electroluminescent Lamp Driver Shutdown The MAX14514 features a shutdown mode to disable the device and reduce supply current. Entering and exiting shutdown mode depends on if slow turn-on/turnoff is enabled or disabled. When slow turn-on/turn-off is enabled, shut down the device by driving EN low. Enable the device by driving EN high. When slow turn-on/turn-off is disabled, shut down the device by driving EN low and both DIM1 and DIM2 below VIL_DIM_. Enable the device by driving EN high and either DIM1 or DIM2 above VLPD_. Undervoltage Lockout (UVLO) The MAX14514 has a UVLO threshold of +2.1V (typ). When VDD falls below this threshold, the device enters a nonoperative mode. Thermal Short-Circuit Protection The MAX14514 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 (typ). ±15kV ESD Protection 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 MAX14514 (V1, V2, and COM) have extra protection against static electricity. Maxim’s engineers have developed state-ofthe-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 MAX14514 keeps working without latchup or damage. ESD protection can be tested in various ways. The transmitter EL lamp outputs of the MAX14514 are characterized for protection to the following limits: • ±15kV using the Human Body Model • • ±4kV IEC 61000-4-2 Contact Discharge ±4kV 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 MAX14514 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 61000-4-2 ESD Contact Discharge test. 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. ______________________________________________________________________________________ 11 MAX14514 The MAX14514 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.) MAX14514 Dual Electroluminescent Lamp Driver RC 1MΩ CHARGE-CURRENTLIMIT RESISTOR HIGHVOLTAGE DC SOURCE Cs 100pF RD 1500Ω RC 50MΩ TO 100MΩ DISCHARGE RESISTANCE CHARGE-CURRENTLIMIT RESISTOR DEVICE UNDER TEST STORAGE CAPACITOR DEVICE UNDER TEST STORAGE CAPACITOR I 100% 90% PEAK-TO-PEAK RINGING (NOT DRAWN TO SCALE) IPEAK Ir Cs 150pF DISCHARGE RESISTANCE Figure 1c. IEC 61000-4-2 ESD Test Model Figure 1a. Human Body ESD Test Model IP 100% 90% HIGHVOLTAGE DC SOURCE RD 330Ω 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 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. Table 2. Inductor Vendors 12 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 ______________________________________________________________________________________ Dual Electroluminescent Lamp Driver larger than 220µH, it may be necessary to increase CCS. For a 470µH inductor and CLAMP_TOTAL = 20nF, a CCS ranging from 3.3nF to 6.8nF is recommended. SlewRate(V/100µs) = 12/RSLEW(MΩ) fEL = 0.08175/(RSLEW x CEL) 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 1.2MΩ to 600kΩ. For example, if the desired slew rate is 20(V/100µs), this leads to an RSLEW value of 12/20(V/100µs) = 600kΩ. Note: Connecting RSLEW to GND does 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 section), the frequency of the EL lamp (see the CEL Capacitor Selection section), and the peak-to-peak voltage of the EL lamp. For example, an RSLEW = 375kΩ and a CEL capacitor value of 872pF equals an EL lamp output frequency of fEL = 250Hz. CCAP Capacitor Selection 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 MAX14514 is protected by entering a thermal-shutdown state. (See the Thermal Short-Circuit Protection section.) The MAX14514 provides a slow turn-on/-off feature that is enabled by connecting a capacitor from CAP to GND. For fast turn-on/-off, connect CAP to VDD. Slow turn-on/-off time is related by the following equation: tON/OFF = 0.27 x CCAP x RSLEW CEL Capacitor Selection The MAX14514 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. The EL lamp output frequency is related to the CEL capacitor by the following equation: 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 = 3.6/(RSLEW x CSW) RDIM Resistor Selection The MAX14514 features dimming control inputs, DIM1 and DIM2, to control the peak-to-peak voltages on the lamp outputs V1, V2, and COM. DIM_ is controlled by a PWM signal, DC voltage, or by a resistor connected from DIM_ to GND. When using a resistor, the output voltage is related by the following equation: 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. V_ - VCOM = 260 x RDIM/RSLEW 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. 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 EL lamps have a capacitance of approximately 2.5nF to 3.5nF per square inch. The MAX14514 effectively charges capacitance ranging from 2nF to 20nF. Bypass Capacitor Selection Diode Selection EL Lamp Selection ______________________________________________________________________________________ 13 MAX14514 RSLEW Resistor Selection To help reduce audible noise emission by the EL lamps, the MAX14514 features a slew-rate control input (SLEW) that allows the user to set the slew rate of high-voltage outputs, V1, V2, and COM, by connecting a resistor, R SLEW , from the SLEW input to GND. Decreasing the value of RSLEW increases the slew rate at the EL lamp output. Increasing the value of RSLEW decreases the slew rate at the EL lamp outputs. The output slew rate is related to RSLEW by the following equation: MAX14514 Dual Electroluminescent Lamp Driver Applications Information PCB Layout Chip Information PROCESS: BiCMOS-DMOS 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. Package Information For the latest package outline information and land patterns, go to www.maxim-ic.com/packages. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. 14 TDFN-EP T1433-2 21-0137 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. 14 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2009 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.