MAX8614A

The MAX8614A dual-output step-up DC-DC converters generate both a positive and negative supply voltage that are each independently regulated. The positive output delivers up to 50mA while the inverter supplies up to 100mA with input voltages between 2.7V and 5.5V. The MAX8614A is ideal for powering CCD imaging devices and displays in digital cameras and other portable equipment.

Features of the MAX8614A are:(1)dual output voltages (+ and -); (2)adjustable up to +24V and Down to -10V at 5.5VIN; (3)output short/overload protection; (4)true shutdown on both outputs; (5)controlled inrush current during soft-start; (6)selectable power-on sequencing; (7)up to 90% efficiency; (8)1A Shutdown current; (9)1MHz fixed-frequency PWM operation; (10)fault-condition flag; (11)thermal shutdown; (12)small, 3mm x 3mm, 14-Pin TDFN package.Additional features include pin-selectable power-on sequencing for use with a wide variety of CCDs, True Shutdown, overload protection, fault flag, and internal soft-start with controlled inrush current.

The absolute maximum ratings of the MAX8614A can be summarized as:(1)operating temp:-40 to 85;(2)VCC, AVCC to GND:-0.3V to +6V;(3)LXN to VCC:-18V to +0.3V;(4)LXP to:-0.3V to +33V;(5)AVCC to VCC:-0.3V to +0.3V;(6)storage temp:-65 to 150;(7)lead temperature (soldering, 10s):+300.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.Both converters MAX8614A use a fixed-frequency, PWM currentmode control-scheme. The heart of the current-mode PWM controllers is a comparator that compares the error-amp voltage-feedback signal against the sum of the amplified current-sense signal and a slope-compensation ramp. At the beginning of each clock cycle,the internal power switch turns on until the PWM comparator trips. During this time the current in the inductor ramps up, storing energy in the inductor's magnetic field. When the power switch of MAX8614A turns off, the inductor releases the stored energy while the current ramps down, providing current to the output.