Datasheet

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General Description

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 volt-

age for maximum lamp brightness.

The MAX4990 utilizes an inductor-based boost convert-

er 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 con-

nected from SW to GND and an external resistor con-

nected 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 connect-

ed from EL to GND and an external resistor connected

from SLEW to GND.

The MAX4990 uses a proprietary acoustic noise-reduction

circuit that controls the slew rate of the AC voltage, reduc-

ing 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.

Features

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 250V

P-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

MAX4990

High-Voltage, ±15kV ESD-Protected

Electroluminescent Lamp Driver

________________________________________________________________

Maxim Integrated Products

19-0886; Rev 1; 11/07

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.

Ordering Information

Note: The device operates over the -40°C to +85°C operating

temperature range.

Denotes a lead-free package.

EP = Exposed paddle.

PART PIN-PACKAGE

TOP

MARK

PKG

CODE

±15kV

PROTECTION

DIM CONTROL

SLEW-RATE

CONTROL

MAX4990ETD+ 14 TDFN-EP (3mm x 3mm) ADL T1433-2 Yes Yes Yes

Keypad Backlighting

MP3 Players

LCD Backlighting

PDAs/Smartphones

Automotive Instrument

Clusters

MAX4990

TDFN-EP

TOP VIEW

245

13 11 10

N.C.

SLEW

DIM

N.C.V

LXGND

*EP = EXPOSED PAD. CONNECT EP TO GND OR LEAVE UNCONNECTED.

*EP

Pin Configuration

Typical Application Circuits appear at end of data sheet.

Summary of content (16 pages)

PAGE 1
9-0886; 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.
PAGE 2
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.
PAGE 3
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.
PAGE 4
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.
PAGE 5
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.
PAGE 6
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.
PAGE 7
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.
PAGE 8
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.
PAGE 9
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.
PAGE 10
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.
PAGE 11
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.
PAGE 12
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.
PAGE 13
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.
PAGE 14
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.
PAGE 15
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.
PAGE 16
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.