MIC2860-P
High Efficiency 2 Channel WLED Driver
with PWM Control
General Description
The MIC2860-2P 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 MIC2860-2P
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 typical matching of
≤
±0.5%, which
ensures uniform display illumination under all conditions.
The WLEDs brightness is externally preset by a resistor
and dimmed using PWM interface operating down to less
than 1% duty cycle.
The MIC2860-2P 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)
PWM frequency as low as 250Hz
Input voltage range: 3.0V to 5.5V
Linear 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 packages
Applications
•
Mobile handsets
•
Digital cameras
•
Portable media/MP3 players
•
Portable navigation devices (GPS)
•
Portable applications
____________________________________________________________________________________________________________
Typical Application
LCD Display Backlight with 2 WLEDs
MLF and
MicroLeadFrame
are registered trademark Amkor Technology Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 •
http://www.micrel.com
September 2010
M9999-092710-A
Micrel Inc.
MIC2860-2P
Ordering Information
Part Number
MIC2860-2PYC6
MIC2860-2PYD6
Notes:
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)
62P
602P
Junction Temperature Range
–40°C to +125°C
–40°C to +125°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
MIC2860-2P
1
2
3
4
5
6
Pin Name
EN
GND
VIN
D2
RSET
D1
Pin Function
PWM Control Pin. This pin is used as a PWM input for dimming of WLEDs. 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.
An internal 1.27V reference sets the nominal maximum WLED current. Example, apply a 9.53kΩ
resistor between RSET and GND to set LED current to 30.2mA at 100% duty cycle.
LED1 driver. Connect LED anode to VIN and cathode to this pin. Do not leave floating.
September 2010
2
M9999-092710-A
Micrel Inc.
MIC2860-2P
Absolute Maximum Ratings
(1)
Main Input Voltage (V
IN
) .................................. –0.3V to +6V
Enable Input Voltage (V
EN
)................................ –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.................................................................... 2KV
Operating Ratings
(2)
Supply Voltage (V
IN
)..................................... +3.0V to +5.5V
Enable Input Voltage (V
EN
) .................................... 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
WLED Linear Drivers
V
IN
= V
EN
= 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
(3)
Matching
(4)
Drop-Out
(V
D1,D2
)
Ground/Supply Bias Current
Shutdown Current (current source leakage)
PWM Dimming
Enable Input Voltage (V
EN
)
Enable Input Current
Current-Source Delay (50% levels)
Logic Low
Logic High
V
EN
≥1.4
Shutdown to On
Standby to On
On to Standby
T
RISE
T
FALL
V
EN
= 0V
4
1.4
0.01
32
1.5
0.3
0.7
0.2
5.8
10
1
80
4
0.4
V
V
µA
µs
Where I
LED
= 90% of LED current seen at
V
DROPNOM
= 0.6V, 100% brightness level
I
OUT
= 30.2mA
V
EN
= 0V
Conditions
Min.
27.18
Typ.
30.2
±0.5
52
0.7
0.01
Max.
33.22
±3
125
1.5
1
Units
mA
%
mV
mA
µA
Current-Source Transient Time (10%−90%)
On-to-Shutdown Time
Notes:
1.
2.
3.
4.
µs
ms
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
As determined by average current of all channels in use and all channels loaded.
The current through each LED meets the stated limits from the average current of all LEDs.
September 2010
3
M9999-092710-A
Micrel Inc.
MIC2860-2P
Typical Characteristics
Peak LED Current
vs. R
SET
CURRENT SINK DROPOUT (mV)
35
30
70
60
50
40
Dropout Voltage
vs. R
SET
70
60
Dropout Voltage
vs. Temperature
LED CURRENT (mA)
25
20
15
10
5
0
5
10
15
20
25
30
35
LED DROPOUT (mV)
LED1
50
40
LED1
30
20
10
0
0
10
20
30
40
LED2
LED2
30
20
10
0
-40
-20
0
20
40
60
80
100
120
R
SET
= 9.53KΩ
R
SET
(KΩ)
R
SET
(KΩ)
TEMPERATURE (°C)
Dropout Voltage
vs. Temperature
35
30
LED Current
vs. Temperature
32
31.5
16
15.5
15
14.5
14
13.5
LED Current
vs.Temperature
LED CURRENT (mA)
LED DROPOUT (mV)
LED CURRENT (mA)
LED2
25
20
15
10
5
0
-40
-20
0
20
40
60
80
100
120
31
30.5
30
29.5
29
28.5
28
-40
-20
0
20
40
60
80
100 120
ILED1
ILED2
LED1
LED1
LED2
R
SET
= 19.1KΩ
R
SET
= 9.53KΩ
13
-40
-20
0
20
40
R
SET
= 19.1KΩ
60
80
100
120
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
Matching
vs. Temperature
0.4
0.35
0.3
MATCHING (%)
0.25
0.2
0.15
0.1
0.05
0
-40
-20
0
20
40
60
80
100
120
R
SET
= 9.53KΩ
R
SET
= 19.1KΩ
TEMPERATURE (°C)
September 2010
4
M9999-092710-A
Micrel Inc.
MIC2860-2P
Functional Characteristics
September 2010
5
M9999-092710-A
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