Datasheet

ADM8843
Rev. C | Page 5 of 16
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
PIN 1
INDICATOR
1V
OUT
2C2+
3I
SET
4GND
NOTES
1. CONNECT THE EXPOSED PADDLE TO GND.
11 C2–
12 CTRL2
10 GND
9GND
5
FB1
6
FB2
7
F
B3
8
FB4
15
V
CC
16
C1+
14
C1–
13
CTRL1
TOP VIEW
(Not to Scale)
ADM8843
05050-003
Figure 2. Pin Configuration
Table 3. Pin Function Descriptions
Pin No. Mnemonic Description
1 V
OUT
Charge Pump Output. A 2.2 μF capacitor to ground is required on this pin. Connect V
OUT
to the anodes of all the LEDs.
2 C2+ Flying Capacitor 2 Positive Connection.
3 I
SET
Bias Current Set Input. The current flowing through the R
SET
resistor, I
SET
, is gained up by 120 to provide the I
LED
current. Connect a resistor, R
SET
, to GND to set the bias current as V
SET
/R
SET
. Note that V
SET
= 1.18 V.
4, 9, 10 GND Device Ground Pins.
5 to 8 FB1 to FB4
LED1 to LED4 Cathode Connection and Charge Pump Feedback. The current flowing in these LEDs is 120 times
the current flowing through R
SET
, I
SET
. When using fewer than four LEDs, this pin can be left unconnected or
connected to GND.
11 C2− Flying Capacitor 2 Negative Connection.
12 CTRL2 Digital Input. 3 V CMOS Logic. Used with CTRL1 to control the shutdown operation of the main and sub LEDs.
13 CTRL1 Digital Input. 3 V CMOS Logic. Used with CTRL2 to control the shutdown operation of the main and sub LEDs.
14 C1− Flying Capacitor 1 Negative Connection.
15 V
CC
Positive Supply Voltage Input. Connect this pin to a 2.6 V to 5.5 V supply with a 4.7 μF decoupling capacitor.
16 C1+ Flying Capacitor 1 Positive Connection.
– EP Expose Paddle. Connect the exposed paddle to GND.