PAM2811 Datasheet, PDF (7/12 Pages) Power Analog Micoelectronics – 4-Channel Single-Wire Dimming LED Drive with Ultra Low Dropout Current Sink

PAM2811
4-Channel Single-Wire Dimming LED Drive with
Ultra Low Dropout Current Sink
Application Information
The PAM2811 is a 4-channel programmable
white-LED driver. It is capable of supplying 20mA
per channel with a total of 80mA output current
available. LED brightness control of PAM2811 can
be achieved with a Pulses signal.
Enable Input
The EN input is used to enable or disable the
PAM2811. Pulling the EN pin higher than 1.5V will
enable the device. For producing constant, non-
pulsating output current compare to conventional
pulse width modulation(PWM) dimming scheme.
The PAM2811 incorporates a 4-bit DAC for
brightness control to program the output current
at 16 continuous steps:20~1.25mA. Table1 shows
details for current setting.
Table 1 Current Setting
Data
16
15
14
13
12
11
10
9
Current(mA)
20
18.75
17.5
16.25
15
13.75
12.5
11.25
Data
8
7
6
5
4
3
2
1
Current(mA)
10
8.75
7.5
6.25
5
3.75
2.5
1.25
Page2 shows the detail operation of 16-steps
brightness control. When Single-wire pulse
counting dimming is used, the ready time is
recommended to be greater than 30us for
enabling the device, the pulse high time THI
recommended to be greater than 0.5us, and the
pulse low time TLO is recommended to be greater
than0.5us and less than 500us. A constant current
is sourced as long as the EN signal remains high.
The shutdown feature reduces quiescent current
to less than 0.1uA.
LED connection
The PAM2811 supports up to 4 white LEDs. The
four LEDs are connected from VIN to LEDx
respectively. If the LED is not used, it should be
connected to GND or open.
Over Temperature Protection
The PAM2811 equips over temperature
protection. When the junction temperature (T_J)
exceeds +150°C, the current source turns off
automatically. The device will turn on again after
the IC’s T_J cools down under +120°C. Operating
at absolute maximum temperature is not
recommended.
Power Analog Microelectronics,Inc
www.poweranalog.com
7
03/2010 Rev1.0