General Description

The MAX14521E is a quad-output high-voltage DC-AC converter that drives four electroluminescent (EL) lamps. The device features a 2.7V to 5.5V input range that allows the device to accept a variety of voltage sources such as single-cell lithium-ion (Li+) batteries. The lamp outputs of the device generate up to 300VP-P for maximum lamp brightness. The high-voltage outputs are ESD protected up to ±15kV Human Body Model (HBM), ±6kV Contact Discharge, and ±8kV Air Gap Discharge, as specified in IEC 61000-4-2.

The MAX14521E uses a high-voltage full-bridge output stage to convert the high voltage generated by the boost converter to a sinusoidal output waveform. The MAX14521E utilizes a high-frequency spread-spectrum oscillator to reduce the amount of EMI/EFI generated by the boost-converter circuit.

The MAX14521E provides an I2C interface to set the boost converter and EL output switching frequencies through an 8-bit register and the peak output voltages with 5 bits of resolution. The MAX14521E also provides an adjustable automatic ramping feature that slowly increases or decreases the peak output voltage when a change is made to the output amplitude. The slew rate of the automatic ramp is set with 3 bits of resolution through the I2C interface and it is independent for each channel. The MAX14521E features an audio auxiliary input AUX that modulates the EL output voltage and frequency for dynamic lighting effects.

The MAX14521E is available in a small, 4mm x 4mm, 24-pin TQFN package, and specified over the extended -40°C to +85°C operating temperature range.

Features

♦ 300VP-P Maximum Output for Highest Brightness

♦ ESD-Protected EL Lamp Outputs

   ±15kV Human Body Model

   ±6kV IEC 61000-4-2 Contact ESD Protection

   ±8kV IEC 61000-4-2 Air Gap Discharge

♦ 2.7V to 5.5V Input Voltage Range

♦ I2C Interface for Control of Brightness, EL

   Frequency, Boost Frequency, Shape

♦ Sinusoidal Output for Low Audible Noise

♦ Individual Dimming Control

♦ Individually Adjustable Output Brightness Ramping Rate

♦ ±3 EL Output Frequency Accuracy for Truest EL Panel Color

♦ Audio Input for Dynamic Lighting Effects

♦ Spread-Spectrum Boost Converter

♦ 100nA Shutdown Current

♦ Space-Saving, 4mm x 4mm, 24-Pin TQFN Package

Applications

   Keypad Backlighting

   LCD Backlighting

   PDAs

   Smartphones

   Automotive Instruments Clusters