MIC2860-D
High Efficiency 2 Channel WLED Driver
with Single Wire Digital Control
General Description
The MIC2860-2D is a high efficiency White LED (WLED)
driver designed to drive two WLEDs and greatly extend
battery life for portable display backlighting, and keypad
backlighting in low cost mobile devices. The MIC2860-2D
architecture provides the highest possible efficiency by
eliminating switching losses present in traditional charge
pumps or inductive boost circuits. It features a typical
dropout of 52mV at 30.2mA per channel. This allows the
WLEDs to be driven directly from the battery eliminating
switching noise and losses present with the use of boost
circuitry.
The two channels have better than ±0.5% matching, which
ensures uniform display illumination under all conditions.
The WLEDs brightness is externally preset by a resistor
and dimmed using a single wire digital control signal. The
MIC2860-2D single wire digital interface accepts digital
programming pulses providing 32 dimming steps.
The MIC2860-2D is available in Thin SOT-23 and SC-70
six pin packages with a junction temperature range of
-40°C to +125°C.
Datasheets and support documentation can be found on
Micrel’s web site at:
www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
High Efficiency (no switching losses)
No charge pumps
2 WLED driver channels
Single wire digital control
Input voltage range: 3.0V to 5.5V
WLED driver dropout of 52mV at 30.2mA
Matching better than ±0.5% (typical)
Current Accuracy better than ±1.0% (typical)
Available in Thin SOT-23 and SC-70 6 pin packages
Applications
•
Mobile handsets
•
Digital cameras
•
Portable media/MP3 players
•
Portable navigation devices (GPS)
•
Portable applications
____________________________________________________________________________________________________________
Typical Application
LCD Display Backlight with 2 WLEDs
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
July 2010
M9999-072010-A
Micrel Inc.
MIC2860-2D
Ordering Information
Part Number
MIC2860-2DYC6
MIC2860-2DYD6
Note:
1. Under bar symbol ( _ ) may not be to scale.
2. Package is GREEN RoHS compliant. Lead finish is NiPdAu. Mold compound is halogen free.
Mark Code
(1)
62D
602D
Temperature Range
–40°C to +85°C
–40°C to +85°C
Package
(2)
6-Pin SC-70
6-Pin Thin SOT-23
Pin Configuration
6-Pin SC-70 (C6)
(Top View)
6-Pin Thin SOT-23 (D6)
(Top View)
Pin Description
Pin Number
MIC2860-2D
1
2
3
4
5
Pin Name
SC
GND
VIN
D2
RSET
Pin Function
Serial Control Digital input. Do not leave floating.
Ground.
Voltage Input. Connect at least 1µF ceramic capacitor between VIN and GND.
LED2 driver. Connect LED anode to VIN and cathode to this pin. Do not leave floating.
(1)
Connect an external resistor from this pin to GND to set the maximum LED current. Example,
apply a 9.53kΩ resistor between RSET and GND to set LED current to 30mA at 100% duty
cycle.
LED1 driver. Connect LED anode to VIN and cathode to this pin. Do not leave floating.
(1)
6
D1
Note 1.
When driving only 1 LED, connect D1 and D2 in parallel to the LED cathode and adjust the RSET resistor for half the desired output.
July 2010
2
M9999-072010-A
Micrel Inc.
MIC2860-2D
Absolute Maximum Ratings
(1)
Main Input Voltage (V
IN
) ................................... -0.3V to +6V
Enable Input Voltage (V
SC
).................................-0.3V to V
IN
LED Driver Voltage (V
D1, D2
) ..............................-0.3V to V
IN
Power Dissipation .....................................Internally Limited
Lead Temperature (soldering, 10sec.)....................... 260°C
Storage Temperature (T
s
) ..........................-65°C to +150°C
ESD Rating
(3)
................................................. ESD Sensitive
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +3.0V to +5.5V
Enable Input Voltage (V
SC
) .................................... 0V to V
IN
LED Driver Voltage (V
D1, D2
) .................................. 0V to V
IN
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
SC-70 (θ
JA
).....................................................256 °C /W
SOT-23 (θ
JA
) ..................................................177 °C /W
Electrical Characteristics
V
IN
= V
SC
= 3.6V, C
IN
= 1µF, R
SET
= 9.53kΩ; V
D1, D2
= 0.6V; T
J
= 25°C,
bold
values indicate –40°C
≤
T
J
≤
85°C; unless
noted.
Parameter
Current Accuracy
Matching
(5)
(4)
Conditions
Min
27.18
Typ
30.2
±0.5
Max
33.22
±3
125
1.5
1
Units
mA
%
mV
mA
µA
Drop-out (V
D1, D2
)
Ground/Supply Bias Current
Shutdown Current
(current source leakage)
Digital Dimming
V
SC
Input Voltage
V
SC
Enable Input Current
t
SHUTDOWN
t
PROG_HIGH
, t
PROG_LOW
t
START_UP
Notes:
Where I
LED
= 90% of LED current seen at
V
DROPNOM
= 0.6V, 100% brightness level
I
OUT
= 30.2mA
V
SC
= 0V > 500µs
52
0.7
0.01
Logic Low
Logic High
V
SC
= 1.2V
Time SC pin is low to put into shutdown
Time for valid SC edge; Ignored if outside limit range
Delay from SC is high to start up
0.3
33
1.4
0.01
100
0.4
1
500
75
V
V
µA
µs
µs
µs
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5kΩ in series with 100pF.
4. As determined by average current of all channels in use and all channels loaded.
5. The current through each LED meets the stated limits from the average current of all LEDs.
July 2010
3
M9999-072010-A
Micrel Inc.
MIC2860-2D
Typical Characteristics
70
DROPOUT VOLTAGE (mV)
60
Dropout Voltage
vs. R
SET
35
30
LED CURRENT (mA)
25
20
15
10
5
0
5
10
15
20
R
SET
(kΩ)
25
30
35
Peak LED Current
vs. R
SET
DROPOUT VOLTAGE (mV)
125
100
75
Dropout Voltage
vs. Brightness Level
50
40
30
20
10
0
LED2
LED1
LED2
50
25
0
0
5
10
15
LED1
R
SET
= 9.53kΩ
20
25
30
35
8
12
16
20
R
SET
(kΩ)
24
28
32
BRIGHTNESS LEVEL
100
DROPOUT VOLTAGE (mV)
80
Dropout Voltage
vs. Temperature
0.50
0.45
0.40
MATCHING (%)
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
-40 -20
Matching
vs. Temperature
R
SET
= 9.53kΩ
BL-21
60
40
BL-31
BL-31
BL-11
BL-21
20
0
BL-0
BL-11
R
SET
= 9.53kΩ
-40 -20
0
20
40
60
80 100 120
0
20
40
60
80 100 120
TEMPERATURE (°C)
TEMPERATURE (°C)
32.0
31.5
LED CURRENT (mA)
LED Current
vs.Temperature
22.0
21.5
LED CURRENT (mA)
21.0
20.5
20.0
19.5
19.0
18.5
18.0
LED Current
vs. Temperature
11.0
10.9
LED CURRENT (mA)
10.8
10.7
10.6
10.5
10.4
10.3
10.2
10.1
10.0
-40 -20
LED Current
vs. Temperature
31.0
30.5
30.0
29.5
29.0
28.5
28.0
-40
-20
0
20
R
SET
= 9.53kΩ
40
60
80
100
LED2-BL31
LED1-BL31
LED1-BL21
LED2-BL11
LED1-BL11
LED2-BL21
R
SET
= 9.53kΩ
-40 -20
0
20
40
60
80 100 120
R
SET
= 9.53kΩ
0
20
40
60
80 100 120
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
Note: BL = Brightness Level
July 2010
4
M9999-072010-A
Micrel Inc.
MIC2860-2D
Functional Characteristics
July 2010
5
M9999-072010-A
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