MIC2845 Datasheet, PDF (5/21 Pages) Micrel Semiconductor – 6 Channel High Side Current Source WLED driver

Micrel Inc.
MIC2845/46
WLED Current Sinks
V_IN = V_DC (2846) V_END (2845) = 3.8V, V_EN1 = V_EN2 = 0V; R_SET = 20.5kΩ; V_DROP = 0.6V;
T_J = 25°C, bold values indicate –40°C ≤ T_J ≤ 125°C; unless noted.
Parameter
Conditions
Min
Typ
Max Units
Current Accuracy⁽⁵⁾
V_DROPNOM = 0.6V
-5
+5
%
Matching⁽⁶⁾
V_DROPNOM = 0.6V
-3.6
+3.6
%
-5.5
+5.5
%
Drop-out
Ground/Supply Bias Current
Shutdown Current
(current source leakage)
Where I_LED = 90% of LED current seen at
V_DROPNOM = 0.6V, 100% brightness level
I_OUT = 20mA
V_END = 0V or V_DC = 0V > 1260µs, V_ENLDO1,2 = 0V
50
100
mV
1.0
mA
0.01
1
µA
MIC2845- PWM Dimming
Enable Input Voltage V_END
Enable Input Current
Minimum Pulse Width
Current Source Delay
(50% levels)
Current Source Transient Time
(10%-90%)
Stand-by to shutdown time
Logic Low
Logic High
V_IH > 1.0V
Shutdown to on⁽⁵⁾
Standby to on; V_DROP = 0.1V
Standby to on; V_DROP = 0.6V
On to Standby; V_DROP = 0.1V
On to Standby; V_DROP = 0.6V
R_SET = 20.5k
T_RISE, V_DROP = 0.1V
T_RISE, V_DROP = 0.6V
T_FALL; V_DROP = 0.1V
T_FALL, V_DROP = 0.6V
V_END = 0V
0.2
V
1.2
V
0.01
1
µA
10
µs
125
µs
1
µs
0.5
µs
1
µs
1
µs
1
µs
1
µs
0.3
µs
0.3
µs
20
TBD
40
ms
MIC2846- Digital Dimming
V_DC Input Voltage V_DC
Logic Low
0.2
V
Logic High
1.2
V
VDC Enable Input Current
V_IH > 1.2V
0.01
1
µA
t_SHUTDOWN
Time DC pin is low to put into shutdown
1260
µs
t_{MODE_UP}
Time DC pin is low to change to Count Up Mode
100
160
µs
t_{MODE_DOWN}
Time DC pin is low to change to Count Down Mode
420
500
µs
t_{PROG_HIGH}, t_{PROG_LOW}
Time for valid edge count; Ignored if outside limit range
1
32
µs
t_DELAY
Time DC pin must remain high before a mode change
140
µs
can occur
t_{PROG_SETUP}
First down edge must occur in this window during
35
presetting brightness
50
µs
t_{START_UP}
Delay from DC is high to start up
140
µs
Notes:
5. As determined by average current of all channels in use and all channels loaded.
6. The current through each LED meet the stated limits from the average current of all LEDs.
7. Maximum differential in forward voltage anticipated from the LED with the highest forward voltage to the LED with the lowest forward voltage at
nominal current.
8. Current accuracy guaranteed for V_DROP current source 100mV to V_IN-1.2V.
9. Dropout voltage is defined as the input-output differential at which the output voltage drops 2% below its nominal value measured at 1V differential.
January 2008
5
M9999-010808-A