High-Efficiency, 36V Step-Up Converters with T Derating Option for 2 to 9 White LEDs

The MAX8595X/MAX8596X drive up to nine white LEDs with constant current and high efficiency to provide LCD backlighting in cell phones, PDAs, and other handheld devices. The series connection allows the LED currents to be identical for uniform brightness and minimizes the number of traces to the LEDs. The MAX8595X regulates constant LED current over the entire temperature range. The MAX8596X features an ambient-temperature derating function to avoid over-driving the white LEDs during high ambient temperatures, enabling higher drive current below +42°C.

A single Dual Mode™ input provides a simple means of brightness adjustment and on/off control. Fast 1MHz current-mode PWM operation allows for small input and output capacitors and a small inductor while minimizing ripple on the input supply/battery. Soft-start eliminates inrush current during startup.

The MAX8595X/MAX8596X are available in a space-saving, 8-pin, 3mm x 3mm TDFN package.

Applications

* Cell Phones/Smartphones * e-Books and Subnotebooks * PDAs, Palmtops, and Wireless Handhelds * White LED Display Backlighting

* Up to Nine LEDs at 25mA

* Temperature Derating Function to Allow Fewer LEDs for Same Light (MAX8596X)

* 86% Efficiency (PLEDs / PIN)

* 1.7% Current-Regulation Accuracy

* Output Overvoltage Protection

* Flexible Dimming Control

* Analog

* Direct-PWM Internal Filter

* 1MHz PWM Switching Frequency

* 0.1µF Output Capacitor

* 12mVP-P Low Input Ripple

* Soft-Start Eliminates Inrush Current

* 2.6V to 6V Input Range

* 0.3µA Shutdown Current

* Pin Compatible with the MAX1561 and MAX1599

* TDFN 3mm x 3mm x 0.8mm Package with Exposed Paddle