Datasheet

LTC3220/LTC3220-1
6
32201fc
PIN FUNCTIONS
TYPICAL PERFORMANCE CHARACTERISTICS
T
A
= 25°C unless otherwise noted.
18-LED ULED Display Effi ciency
vs V
IN
Voltage
ULED1-ULED18 (Pins 1-9,13-21): Current Source Outputs
for Driving LEDs. The LED current can be set from 0mA
to 20mA in 64 steps via software control and internal
6-bit linear DAC. Each output can be disabled by setting
the associated data register REG1 to REG18 low. ULED1
to ULED18 can also be used as I
2
C controlled open-drain
general purpose outputs. Connect unused outputs to
ground.
DV
CC
(Pin 10): Supply Voltage for All digital I/O lines. This
pin sets the logic reference level of the LTC3220/LTC3220-1.
DV
CC
will reset the data registers when set below the
undervoltage lockout threshold. A 0.1μF X5R or X7R
ceramic capacitor should be connected to ground.
SCL (Pin 11): I
2
C Clock Input. The logic level for SCL is
referenced to DV
CC
.
ULED Current vs Input Code
INPUT CODE (HEX)
009
0
ULED CURRENT (mA)
10
25
12
24
2D
3220 G16
5
20
15
1B
36
3F
V
IN
VOLTAGE (V)
2.9
ULED EFFICIENCY (PLED/PIN) (%)
100
10
90
70
50
30
80
60
40
20
0
4.5253.875 5.175
3220 G17
5.54.23.55 4.853.225
1.5x Mode V
IN
Current vs I
CPO
(I
VIN
– 1.5I
CPO
)
2x Mode V
IN
Current vs I
CPO
(I
VIN
– 2I
CPO
)
ULED Pin Current
vs ULED Pin Voltage
I
CPO
(mA)
0
V
IN
CURRENT (mA)
6
8
10
180
300
3220 G13
4
2
0
60 120 240
12
14
16
360
I
CPO
(mA)
0
14
12
10
8
6
4
2
0
180 300
3220 G14
60 120
240 360
V
IN
CURRENT (mA)
ULED PIN VOLTAGE (V)
0
ULED PIN CURRENT (mA)
10
15
0.2
3220 G15
5
0
0.05
0.1
0.15
25
20