RT9301GJ8 Richtek USA Inc, RT9301GJ8 Datasheet - Page 6

• Manufacturer Part Number: RT9301GJ8
• Description: IC LED DVR 3CH RGB TSOT23-8
• Manufacturer: Richtek USA Inc

Specifications of RT9301GJ8

• Internal Driver: Yes
• Type - Primary: Backlight, Flash/Torch
• Type - Secondary: RGB, White LED
• Mounting Type: Surface Mount
• Number Of Outputs: 3
• Voltage - Supply: 2.8 V ~ 5.5 V
• Package / Case: SOT-23-8 Thin, TSOT-23-8
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Topology: -
• Frequency: -
• Voltage - Output: -

RT9301
Applications Information
The RT9301 is a 3-Channel current source driver for RGB
LED or white LEDs. The output current can be controlled
from 2mA to 50mA by adjusting the setting current from
external. It is easy to support a multi-color RGB LED.
Input UVLO
The input operating voltage range of the RT9301 is 2.8V to
5.5V. An input capacitor at the VIN pin could reduce ripple
voltage. It is recommended to use a ceramic 1uF or larger
capacitance as the input capacitor. This IC provides an
under voltage lockout (UVLO) function to prevent it from
unstable issue when startup. The UVLO threshold of input
falling voltage is set at 2.1V typically with a hysteresis
0.1V.
Output Current Setting
The LED current is setting by the current of ISET pin. The
LED current of the three channels (LED1, LED2, LED3)
could be set from the ISET (ISET1, ISET2, ISET3) pins
individually. The typical application circuit shows as
Figure 1.
The LED current can be controlled from an external voltage
(V
The voltage range of V
reference voltage at ISET pin is 0.9V typically. LED current
is set as 800 times the current flowing into ISET pin.
Therefore, the LED current can be calculated as the
following equation.
For example, R
of LED1 is equal to 16mA.
www.richtek.com
6
I
LED1
SET
) and a resistor (R
~
V
V
V
3
SET1
SET2
SET3
800
Figure 1. Typical Application Circuit
V
BAT
I x
R
SET1
R
R
SET2
SET1
SET1
SET3
= 45k and V
~
SET
1uF
3
SET
ISET1
ISET2
ISET3
is from 1.3V to 5.5V. The internal
800
) between VSET and ISET pin.
VIN
x
LED1
V
SET1
RT9301
SET1
R
GND
SET1
LED2
= 1.8V, the current
~
3
-
~
0.9V
3
LED3
The LED current of each channel can be controlled from
2mA to 50mA. It is easy to obtain a multi-color output
by changing the current of ISET1, ISET2, and ISET3
respectively.
Figure 2 shows the characteristics of I
R
V
enable the LED. For low LED current application, it is
recommended to use a higher resistance on RSET (for
example: R
To disable the LED current, the ISET pin should be
connected to ground or floating. For one LED or two LEDs
application, the unused ISET pin should be connected to
GND. In addition, don’ t short V
SET
SET
. The voltage of VSET must be higher than 1.3V to
60
50
40
30
20
10
is selected, the LED current could be controlled from
0
V
V
Figure 3. Application Circuit for Two LEDs
SET1
SET2
1
SET
1.5
V
Figure 2. LED Current Setting
BAT
= 360k ).
R
R
SET1
SET2
2
R
2.5
1uF
SET
ISET1
ISET2
ISET3
= 36k
VIN
V
3
SET
LED1
SETx
(V)
3.5
R
DS9301-04 June 2009
RT9301
SET
GND
to ISETx pin.
= 51k
LED2
4
LED
4.5
vs. V
R
R
R
SET
SET
SET
LED3
= 360k
= 75k
= 160k
SET
5
. If the
5.5