MAX8595Z/MAX8596Z
High-Efficiency, 32V Step-Up Converters
with T
A
Derating Option for 2 to 8 White LEDs
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(Circuit of Figure 1, V
IN
= 3.6V, I
LED
= 25mA, L = 22µH, C
IN
= 2.2µF, C
OUT
= 0.1µF, C
COMP
= 0.1µF, R
SENSE
= 13Ω, 4 LEDs,
T
A
= +25°C, unless otherwise noted.)
Pin Description
PIN NAME FUNCTION
1 OUT
Overvoltage Sense. When V
OUT
is greater than 34V (typ), the internal n-channel MOSFET turns off
until V
OUT
drops below 32V (typ), then the IC re-enters soft-start. Connect a 0.1µF ceramic capacitor
from OUT to ground. In shutdown, V
OUT
is one diode drop below V
IN
.
2IN
Input Voltage Supply. The input voltage range is 2.6V to 5.5V. Connect a 2.2µF ceramic capacitor
from IN to GND.
3 CTRL
Brightness Control Input. The voltage applied to CTRL controls LED brightness. Varying the voltage
from 0.24V to 1.65V (1.72V for the MAX8596Z) adjusts the brightness from dim to 100% brightness,
respectively. Any voltage above 1.65V (1.72V) does not increase brightness. Hold CTRL below
100mV to shut down the IC after an 8.2ms delay.
4CS
Current-Sense Feedback Input. Connect a resistor from CS to GND to set the LED bias current. The
voltage at CS regulates to V
CTRL
/ 5 or 0.330V (0.343V for the MAX8596Z), whichever is lower.
5 COMP
Compensation Input. Connect a 0.1µF ceramic capacitor (C
COMP
) from COMP to GND. C
COMP
stabilizes the converter, controls soft-start, and lowpass filters direct PWM dimming at CTRL. C
COMP
discharges to 0V through an internal 20kΩ resistor in shutdown.
6 GND Ground. Connect to PGND and the exposed pad directly under the IC.
7 PGND Power Ground. Connect to GND and the exposed pad directly under the IC.
8LX
Inductor Connection. Connect LX to the node between the inductor and the Schottky diode. LX is
high impedance in shutdown.
—EP
Exposed Pad. Connect to a large ground plane for maximum package heat dissipation. Connect
directly to GND and PGND under the IC.
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