MAX8901A MAXIM [Maxim Integrated Products], MAX8901A Datasheet
MAX8901A
Available stocks
Related parts for MAX8901A
MAX8901A Summary of contents
Page 1
... Li+/Li-Poly battery range. These converters use a single input (ON) to enable the IC and to control WLED intensity. The MAX8901A requires a direct PWM input to regulate WLED intensity with the WLED current proportional to the PWM duty cycle ...
Page 2
... V rising IN V falling IN V rising IN V falling +25° SHDN +85°C A MAX8901A V = 0.55V load (not Q MAX8901B switching external boost diode voltage drop OUT DIODE V 6 LEDs with 25V OVP option OVP = 20V dimming CS Time V ...
Page 3
... FULL SOFT-START 32/33 I LED_ SHUTDOWN Figure 1. MAX8901B Timing Diagram _______________________________________________________________________________________ = 0V, COMP, CS, and LX are unconnected, T CONDITIONS T = +25° 24.75mA A LED (MAX8901B -40°C to +85° MAX8901A PWM t SOFT 0.022µF (Figure 1) COMP START 0.4V MAX +25° 27V LXLKG +85° ...
Page 4
Highest Efficiency Supply for Series WLEDs in a 2mm x 2mm TDFN Package (Circuit of Figure 24.75mA, V LED IN LED EFFICIENCY vs. INPUT VOLTAGE WLEDs 80 6 WLEDs 75 INDUCTOR: ...
Page 5
... IN CURRENT ( vs. SUPPLY VOLTAGE MAX8901B MAX8901A SUPPLY VOLTAGE (V) INPUT OVERVOLTAGE PROTECTION RESPONSE MAX8901A/B toc10 6.4V 1V/div (AC-COUPLED) 5.4V 10V/div 0V 20mA/div 0mA 20mA/div 0V 20ms/div STARTUP AND SHUTDOWN RESPONSE (MAX8901B) MAX8901A/B toc12 2V/div 0V 10V/div 0V 100mA/div 0mA 20mA/div 0mA 10ms/div 5 ...
Page 6
... PWM 499.4 80 100 0 5 MINIMUM LED CURRENT vs. TEMPERATURE (MAX8901B) 750 745 740 735 730 -40 - +25°C, unless otherwise noted.) RESPONSE (MAX8901B) MAX8901A/B toc14 2V/div 0V 50mV/div (AC-COUPLED) 1V/div 0V 20mV/div 0V 20mA/div 0mA 10ms/div vs. LED CURRENT STEP (MAX8901B) = 24.75mA I = 0.75mA LED 10 15 ...
Page 7
... COMP discharges to GND when in COMP shutdown. WLED Current Sense Input. For the MAX8901A, connect a current-sense resistor from CS to GND. Voltage sensed at CS regulates the WLED current. For the MAX8901B, do not connect a sense 8 CS resistor from CS to GND ...
Page 8
... These converters use a single input (ON) to enable the IC and to control WLED intensity. The MAX8901A requires a direct PWM input to modulate WLED intensity, with WLED current proportional to the PWM duty cycle. The MAX8901B uses single-wire, serial-pulse dimming that reduces the WLED intensity in 32 equal steps ...
Page 9
... Shutdown mode that reduces current to 0.01µA (typ). No WLED current is present in shutdown or during an overvoltage condition if the WLED forward voltage is greater than the input supply voltage. Figures 2 and 3 show the block diagrams for the MAX8901A and MAX8901B, respectively. _______________________________________________________________________________________ MAX8901B REF THERMAL ...
Page 10
... Typical shutdown timing characteristics are shown in the Typical Operating Characteristics section. A PWM signal (MAX8901A) or serial pulses (MAX8901B) are applied to dim the WLEDs. See the PWM Dimming Control (MAX8901A) and Serial-Pulse Dimming Control (MAX8901B) sections for more details. ...
Page 11
... Current-Sense Resistor (MAX8901A Only) The MAX8901A uses a sense resistor (R from CS to GND to program the maximum WLED cur- rent for 100% PWM duty cycle. The MAX8901A regu- lates (in ohms) using the following equation: CS ...
Page 12
... Highest Efficiency Supply for Series WLEDs in a 2mm x 2mm TDFN Package INPUT 2.6V TO 5.5V C1 1μF C3 0.022μF PWM DIMMING CONTROL Figure 4. MAX8901A Application Circuit INPUT 2.6V TO 5.5V C1 1μF R1 0Ω C3 0.022μF SERIAL-PULSE DIMMING CONTROL Figure 5. MAX8901B Application Circuit 12 ______________________________________________________________________________________ L1 22μH ...
Page 13
Highest Efficiency Supply for Series WLEDs in a 2mm x 2mm TDFN Package Pin Configuration TOP VIEW CS COMP GND PGND MAX8901 * OVP TDFN-EP ...
Page 14
Highest Efficiency Supply for Series WLEDs in a 2mm x 2mm TDFN Package (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.) 14 ...
Page 15
Highest Efficiency Supply for Series WLEDs in a 2mm x 2mm TDFN Package (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.) COMMON ...