MIC2860-2DYD6 TR Micrel Inc, MIC2860-2DYD6 TR Datasheet - Page 6

• Manufacturer Part Number: MIC2860-2DYD6 TR
• Description: IC WHITE LED DRIVER 2CH SOT-23-6
• Manufacturer: Micrel Inc
• Series: -r

Specifications of MIC2860-2DYD6 TR

• Constant Current: -
• Constant Voltage: -
• Topology: Linear (LDO)
• Number Of Outputs: 2
• Internal Driver: Yes
• Type - Primary: Backlight
• Type - Secondary: White LED
• Frequency: -
• Voltage - Supply: 3 V ~ 5.5 V
• Voltage - Output: 0 V ~ 5.5 V
• Mounting Type: Surface Mount
• Package / Case: SOT-23-6
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 576-3939-2

Functional Diagram
Functional Description
The MIC2860-2D is a 2 channel WLED driver. The
WLED driver is designed to maintain proper current
regulation with LED current accuracy of 1.0% while the
typical matching between the 2 channels is 0.5% at
room temperature. The WLEDs are driven independently
from the input supply and will maintain regulation with a
dropout of 52mV at 30.2mA. The low dropout of the
linear drivers allows the WLEDs to be driven directly
from the battery voltage and eliminates the need for
large and inefficient charge pumps. The maximum
WLED current for each channel is set via an external
resistor.
Block Diagram
As shown in Figure 1, the MIC2860-2D consists of 2
current mirrors set to copy a master current determined
by R
block for enabling and dimming of the WLEDs. The
MIC2860-2D dimming is controlled by an internal Digital
Control Interface.
V
The input supply (V
drivers and the control circuitry. The V
is 3V to 5.5V. Due to wire inductance a minimum bypass
capacitor of 1µF should be placed close to the input (V
pin and the ground (GND) pin. Refer to the layout
recommendations section for details on placing the input
capacitor (C1).
SC
The SC pin is equivalent to the enable pin for the linear
drivers on the MIC2860-2D. It can also be used for
dimming using a single wire digital interface. See the
MIC2860-2D Digital Dimming Interface in the Application
Information section for details. Do not leave control pins
floating.
Micrel Inc.
July 2010
IN
SET
. The linear drivers have a designated control
IN
) provides power to the linear
Figure 1. MIC2860-2D Functional Block Diagram
IN
operating range
IN
)
6
R
The R
ground to set the peak current of the linear drivers. The
maximum LED current set by the R
in the table below:
A plot of maximum I
Table 1. Maximum LED Current vs. R
SET
SET
R
pin is used by connecting an R
SET
Figure 2. Peak LED current vs. R
9.53
11.5
14.3
15.8
19.1
28.7
(kΩ)
35
30
25
20
15
10
5
0
8
LED
12
Peak LED Current
versus R
16
vs. R
R
SET
20
(kΩ)
SET
SET
24
SET
is shown in Figure 2.
SET
resistor is shown
28
I
LED
M9999-072010-A
SET
Resistor Values
30.2
25.0
20.1
18.2
15.1
10.0
MIC2860-2D
(mA)
SET
32
resistor to