Datasheet

MAX6978
8-Port, 5.5V Constant-Current LED Driver with
LED Fault Detection and Watchdog
_______________________________________________________________________________________ 5
0
3
9
6
12
15
3.0 4.03.5 4.5 5.0 5.5
MAX6978 toc04
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
SUPPLY CURRENT vs. SUPPLY VOLTAGE
(INTERFACE IDLE, ALL OUTPUTS
ON, R
SET
= 360Ω)
T
A
= +125°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
0
10
5
20
15
25
30
0 1.0 1.50.5 2.0 2.5 3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 720Ω, V+ = 3.3V)
MAX6978 toc05
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
0
20
10
40
30
50
60
0 1.0 1.50.5 2.0 2.5 3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 360Ω, V+ = 3.3V)
MAX6978 toc06
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
0
10
5
20
15
25
30
0 1.0 1.50.5 2.0 2.5 3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 720Ω, V+ = 5.0V)
MAX6978 toc07
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
0
20
10
40
30
50
60
0 1.0 1.50.5 2.0 2.5 3.0
PORT OUTPUT CURRENT vs. PORT OUTPUT
VOLTAGE (R
SET
= 360Ω, V+ = 5.0V)
MAX6978 toc08
PORT OUTPUT VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
26.0
25.5
25.0
24.5
24.0
3.0 4.0
3.5
4.5 5.0 5.5
PORT OUTPUT CURRENT vs. SUPPLY
VOLTAGE (R
SET
= 720Ω, V
OUT
= 2V)
MAX6978 toc09
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
52
51
50
49
48
3.0 4.0
3.5
4.5 5.0 5.5
PORT OUTPUT CURRENT vs. SUPPLY
VOLTAGE (R
SET
= 360Ω, V
OUT
= 2V)
MAX6978 toc10
SUPPLY VOLTAGE (V)
PORT OUTPUT CURRENT (mA)
T
A
= +125°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
0
10
30
20
40
50
0 40002000 6000 8000 10,000
PORT OUTPUT CURRENT
vs. R
SET
RESISTANCE (V+ = 5.0V)
MAX6978 toc11
R
SET
RESISTANCE (Ω)
PORT OUTPUT CURRENT (mA)
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)