MAX1599ETA+T Maxim Integrated Products, MAX1599ETA+T Datasheet - Page 7

• Manufacturer Part Number: MAX1599ETA+T
• Description: IC LED DRIVR WHITE BCKLGT 8-TDFN
• Manufacturer: Maxim Integrated Products
• Type: Backlight, White LEDr

Specifications of MAX1599ETA+T

• Constant Current: Yes
• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 1
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 400kHz ~ 600kHz
• Voltage - Supply: 2.6 V ~ 5.5 V
• Voltage - Output: 26V
• Mounting Type: Surface Mount
• Package / Case: 8-TDFN Exposed Pad
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 700mA
• Internal Switch(s): Yes
• Efficiency: 87%
• Number Of Segments: 6
• Operating Supply Voltage: 2.6 V to 5.5 V
• Maximum Power Dissipation: 1950 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Figure 1. Functional Diagram
Adjusting the MAX1561/MAX1599s’ output current
changes the brightness of the LEDs. An analog input
(CTRL) and the sense-resistor value set the output cur-
rent. Output current is given by:
The V
0.24V to 1.62V. To set the maximum current, calculate
R
SENSE
CTRL
when V
PWM OR
ANALOG
DIMING
voltage range for adjusting output current is
R
SENSE
I
CTRL
LED
_______________________________________________________________________________________
High-Efficiency, 26V Step-Up Converters
=
is at its maximum as follows:
=
f
CTRL
OSC
170mV
10
10
×
2.6V TO 5.5V
V
×
CTRL
Adjusting LED Current
R
1 62
I
Design Procedure
LED MAX
450kΩ
.
SENSE
INPUT
V
(
PWM CONTROL
50kΩ
)
SHUTDOWN TIMER
GND
IN
g
m
SLOPE COMP
CURRENT SENSE
for Two to Six White LEDs
Power dissipation in R
making a standard chip resistor sufficient.
CTRL is also used as a digital input allowing LED bright-
ness control with a logic-level PWM signal applied direct-
ly to CTRL. The frequency range is from 200Hz to
200kHz, while 0% duty cycle corresponds to zero cur-
rent and 100% duty cycle corresponds to full current.
The error amplifier and compensation capacitor form a
lowpass filter so PWM dimming results in DC current to
the LEDs without the need for any additional RC filters;
see the Typical Operating Characteristics.
The exact values of input and output capacitors are not
critical. The typical value for the input capacitor is
2.2µF and the typical value for the output capacitor is
0.1µF. Larger value capacitors can be used to reduce
OVERVOLTAGE
PROTECTION
SHUTDOWN
MAX1561
MAX1599
2.2µF
COMP
PGND
OUT
CS
LX
SENSE
L1
C
0.1µF
COMP
PWM Dimming Control
2 TO 6 LEDS
is typically less than 5mW,
Capacitor Selection
UP TO 26V
C
0.1µF
OUT
R
7.5Ω
SENSE
7