MAX8790ETP+T Maxim Integrated Products, MAX8790ETP+T Datasheet - Page 16

• Manufacturer Part Number: MAX8790ETP+T
• Description: IC LED DRVR WHITE BCKLGT 20-TQFN
• Manufacturer: Maxim Integrated Products
• Type: Backlight, White LEDr

Specifications of MAX8790ETP+T

• Topology: PWM, Step-Up (Boost)
• Number Of Outputs: 6
• Internal Driver: No
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 1MHz
• Voltage - Supply: 4.5 V ~ 5.5 V, 5.5 V ~ 26 V
• Voltage - Output: 5V
• Mounting Type: Surface Mount
• Package / Case: 20-TQFN Exposed Pad
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 25mA
• Internal Switch(s): Yes
• Low Level Output Current: 1 A
• High Level Output Current: 1 A
• Operating Supply Voltage: 4.5 V to 26 V
• Maximum Power Dissipation: 1349 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Efficiency: -
• Lead Free Status / Rohs Status: Details

Six-String White LED Driver with Active
Current Balancing for LCD Panel Applications
adequate for oscillator frequencies in the 166Hz < f
< 500Hz range. The PLL frequency capture window is
0.6 x f
The PLL is disabled in DPWM mode; consequently, the
BRT frequency is not limited by f
BRT frequency is determined by the minimum BRT on-
time of 50µs and the minimum acceptable dimming
factor. If a 1% dimming factor is needed, the maximum
BRT frequency is 200Hz. If a 10% dimming factor is
acceptable, the maximum BRT frequency is 2kHz.
In analog dimming mode, load-current transients can
occur when the BRT duty cycle abruptly changes on
the fly. Large regulation transients induce a flash on the
LED load that is observable with the naked eye and
should therefore be avoided. Such annoying flashes
can be eliminated by dynamically changing the ENA
Table 3. Component List
16
Switching
Frequency
White LED
Number of
White LEDs
Input Voltage 4.5V to 5.5V, V
Inductor L1
Input
Capacitors
C
Capacitor
MOSFET N1
Diode
Rectifier D1
Sense
Resistor
OUT
CIRCUIT
______________________________________________________________________________________
PLL
Output
to f
PLL
1MHz
3.2V (typ), 3.5V (max) at
20mA
Nichia NSSW008C
6 series x 6 parallel,
20mA (max)
2.2µH , 2.5A p ow er i nd uctor
Sumida CDRH5D16-2R2
10µF ±10%, 10V X5R
ceramic capacitor (1206)
Murata GRM31MR61A106K
2.2µF ±10%, 50V X7R
ceramic capacitor (1x)
Murata GRM31CR71H225K
30V, 3A n-channel MOSFET
(6-pin SC70)
Vishay Si1402DH
2A, 30V Schottky diode
Nihon EC21QS03L
50mΩ ±1%, 1/2W
IRC LRC-LRF-1206LF-01-
R050-F
.
FIGURE 1
CC
= IN
PLL
. The maximum
750kHz
3.2V (typ), 3.5V (max) at
20mA
Nichia NSSW008C
8 series x 6 parallel,
20mA (max)
7V to 21V
4.7µH , 2.05A p ow er i nd uctor
Sumida CDRH5D16-4R7
10µF ±10%, 25V X5R
ceramic capacitor (1206)
M ur ata GRM 31C R61E 106KA
2.2µF ±10%, 50V X7R
ceramic capacitor (1206)
(1x)
Murata GRM31CR71H225K
60V, 2.8A n-channel
MOSFET (6-pin TSOP)
Fairchild Semiconductor
FDC5612
Sanyo Semiconductor
CPH6424
2A, 40V Schottky diode
Toshiba CMS11
Nihon EC21QS04
56mΩ ±1%, 1/2W
IRC LRC-LRF-1206LF-01-
R056-F
FIGURE 1
PLL
pin setting. When a capacitor is connected to the CPLL
pin and the ENA pin is grounded, the PLL continues to
run but does not affect the dimming. When fast PLL
lockup transitions are required, the ENA pin can be
momentarily pulled to ground; after the PLL is locked
up, ENA can be pulled high to reenable PLL in dim-
ming control.
The MAX8790 includes a thermal-protection circuit.
When the local IC temperature exceeds +170°C (typ),
the controller and current sources shut down and do
not restart until the die temperature drops by 15°C.
All MAX8790 designs should be prototyped and tested
prior to production. Table 3 provides a list of power
500kHz
3.2V (typ), 3.5V (max) at
20mA
Nichia NSSW008C
10 series x 6 parallel,
25mA (max)
7V to 21V
4.7µH , 3.6A p ow er i nd uctor
Sumida CDRH8D28-4R7
10µF ±10%, 25V X5R
ceramic capacitor (1206)
M ur ata GRM 31C R61E 106KA
4.7µF ±10%, 50V X7R
ceramic capacitor (1210)
(1x)
Murata GRM32ER71H475K
60V , 6A n- channel M O S FE T
( P ow er P AK 1212- 8)
Vishay Si7308DN
3A, 60V Schottky diode
Nihon EC31QS06
40mΩ ±1%, 1/2W
IRC LRC-LRF-1206LF-01-
R040-F
FIGURE 1
Design Procedure
750kHz
3.2V (typ), 3.5V (max) at
20mA
Nichia NSSW008C
6 series x 6 parallel,
20mA (max)
2.8V to 5.5V, V
0.9µH , 4.7A p ow er i nd uctor
Sumida CDRH5D16-0R9
10µF ±10%, 10V X5R
ceramic capacitor (1206)
M ur ata GRM 31M R61A106K
2.2µF ±10%, 50V X7R
ceramic capacitor (1x)
Murata GRM31CR71H225K
30V, 4.9A n-channel
MOSFET (6-pin TSOP)
Vishay Si3456BDV
3A, 30V Schottky diode
Nihon EC31QS03L
30mΩ ±1%, 1/2W
IRC LRC-LRF-1206LF-01-
R030-F
Thermal Shutdown
FIGURE 3
CC
= 5V