MAX8630W

The MAX8630W charge pumps drive up to 5 white LEDs with regulated constant current up to 125mA total. By utilizing adaptive 1x/1.5x charge-pump modes and very low-dropout current regulators, they achieve high efficiency over the full 1-cell Li+ battery input voltage range. The 1MHz fixed-frequency switching of MAX8630W allows for tiny external components, and the regulation scheme is optimized to ensure low EMI and low input ripple. An integrated derating function protects the LEDs from overheating during high ambient temperatures.

Features of the MAX8630W are:(1)93% Max/85% avg. efficiency (PLED/PBATT) over Li+ battery discharge; (2)1% LED current accuracy; (3)125mA total drive capability; (4)adaptive 1x/1.5x mode switchover; (5)15, 18, 20, and 25mA full-scale versions; (6)low 0.1A shutdown current; (7)soft-start eliminates inrush current; (8)output overvoltage protection; (9)thermal-derating function protects LEDs; (10)14-Pin, 3mm x 3mm TDFN package.Ceramic capacitors are recommended due to their small size, low cost, and low ESR. Select ceramic capacitors that maintain their capacitance over temperature and DC bias. Capacitors with X5R or X7R temperature characteristics generally perform well. See Table 1 for a list of recommended components.

The absolute maximum ratings of the MAX8630W can be summarized as:(1)IN, OUT to GND:-0.3V to +6.0V;(2)storage temperature range:-65 to +150;(3)LED_ to GND:-0.3V to (VOUT + 0.3V);(4)junction temperature:+150;(5)continuous power dissipation:1454mW.Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied.Exposure to absolute maximum rating conditions for extended periods may affect device reliability.Dim the MAX8630W by applying a direct-PWM logiclevel signal to PWM. An internal resistor combined with the capacitor at CPWM forms a lowpass filter that converts the PWM signal to DC LED current that is proportional to the PWM signal's duty cycle. All five LEDS are controlled together on the MAX8630W. The PWM frequency range is 900Hz to 200kHz.If dimming control is not required, PWM works as a simple on/off control. Drive PWM high to enable the LEDs,or drive PWM low for shutdown.