CAT3644HV3-GT2 ON Semiconductor, CAT3644HV3-GT2 Datasheet - Page 12

• Manufacturer Part Number: CAT3644HV3-GT2
• Description: IC LED DVR 4CH QUAD MODE 16TQFN
• Manufacturer: ON Semiconductor
• Series: QUAD-Mode®r
• Type: Backlight, White LEDr

Specifications of CAT3644HV3-GT2

• Topology: Linear (LDO), Switched Capacitor (Charge Pump)
• Number Of Outputs: 4
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: 800kHz ~ 1.6MHz
• Voltage - Supply: 2.5 V ~ 5.5 V
• Voltage - Output: 7V
• Mounting Type: Surface Mount
• Package / Case: 16-TFQFN Exposed Pad
• Operating Temperature: -40°C ~ 85°C
• Current - Output / Channel: 25mA
• Internal Switch(s): Yes
• Efficiency: 92%
• Number Of Digits: 4
• Low Level Output Current: 25 mA
• High Level Output Current: 100 mA
• Operating Supply Voltage: 2.5 V to 5.5 V
• Maximum Supply Current: 30 mA
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Unused LED Channels
recommended the unused LED pins be tied directly to V
(see Figure 27).
Protection Mode
automatically ignores that channel. When all LEDs are
disconnected, the driver goes to 1x mode where the output
is equal to the input voltage.
itself and reevaluate the mode.
enter a thermal protection shutdown mode. When the device
temperature drops by about 20°C, the device will resume
normal operation.
ENABLE
DIMMING
R
V
SET
For applications not requiring all the channels, it is
If an LED is disconnected, the driver senses that and
As soon as the output exceeds about 6 V, the driver resets
If the die temperature exceeds +150°C, the driver will
C
IN
1 mF
IN
Figure 27. Application with 3 LEDs
V
EN/DIM
RSET
C1+
IN
C1−
CAT3644
1 mF
GND
C2+
V
LED1
LED2
LED3
LED4
RSET
GND
OUT
1 mF
C2−
Figure 28. Recommended Layout
EN/DIM
COUT
C
1 mF
Pin1
http://onsemi.com
OUT
OUT
12
GND
LED Selection
4.3 V may be used. Selecting LEDs with lower V
recommended in order to improve the efficiency by keeping
the driver in 1x mode longer as the battery voltage decreases.
over one with V
lower supply voltage of 0.2 V. This helps improve the
efficiency and extends battery life.
External Components
for decoupling input, output, and for the charge pump. Both
capacitors type X5R and X7R are recommended for the
LED driver application. In all charge pump modes, the input
current ripple is kept very low by design and an input bypass
capacitor of 1 mF is sufficient.
not introduce switching noise back onto the supply.
Recommended Layout
high frequency. It is recommended to minimize trace length
to all four capacitors. A ground plane should cover the area
under the driver IC as well as the bypass capacitors. Short
connection to ground on capacitors C
implemented with the use of multiple via. A copper area
matching the TQFN exposed pad (TAB) must be connected
to the ground plane underneath. The use of multiple via
improves the package heat dissipation.
GND
LEDs with forward voltages (V
For example, if a white LED with a V
The driver requires four external 1 mF ceramic capacitors
In 1x mode, the device operates in linear mode and does
In charge pump mode, the driver switches internally at a
CIN
F
of 3.5 V, the driver will stay in 1x mode for
C2
C1
VIN
F
) ranging from 1.3 V to
IN
F
of 3.3 V is selected
and C
OUT
can be
F
is