Datasheet
10-Port Constant-Current LED Drivers and I/O
Expanders with PWM Intensity Control
The ramp-down register sets the hold-off and fade-off
times and allows hold-off and fade-off to be disabled
(zero delay), if desired (Table 9). The ramp-up register
sets the ramp-up time and allows ramp-up to be dis-
abled (zero delay), if desired (Table 10). The configura-
tion register contains 3 status bits that identify whether
the MAX6966/MAX6967 are in hold-off, fade-off, or ramp-
up condition (Table 4). The configuration register also
enables or disables ramp-up. One write to the configura-
tion register can put the MAX6966/MAX6967 into shut-
down (using hold-off and fade-off settings in the fade
register) and determine whether CS run is enabled for
restart, and whether ramp-up is to be used for restart.
REGISTER DATA
REGISTER
R/W
ADDRESS
CODE
(HEX)
D7 D6 D5 D4 D3 D2 D1
D0
Write ramp-down 0
XX
Read ramp-down 1
00
Hold-off Fade-off
Fade-off time (f
PWM
= 32768Hz)
Instant going into shutdown after hold-off delay X
XXXXX00
0
1/16s ramp-down from full current before shutdown after
hold-off delay
X
XXXXX00
1
1/8s ramp-down from full current before shutdown after
hold-off delay
X
XXXXX01
0
1/4s ramp-down from full current before shutdown after
hold-off delay
X
XXXXX01
1
1/2s ramp-down from full current before shutdown after
hold-off delay
X
XXXXX10
0
1s ramp-down from full current before shutdown after
hold-off delay
X
XXXXX10
1
2s ramp-down from full current before shutdown after
hold-off delay
X
XXXXX11
0
4s ramp-down from full current before shutdown after
hold-off delay
X
XXXXX11
1
Hold-off time (f
PWM
= 32768Hz)
Zero hold-off delay before fade-off going into shutdown X
XX000XX
X
1/16s hold-off delay before fade-off going into shutdown X
XX001XX
X
1/8s hold-off delay before fade-off going into shutdown X
XX010XX
X
1/4s hold-off delay before fade-off going into shutdown X
XX011XX
X
1/2s hold-off delay before fade-off going into shutdown X
XX100XX
X
1s hold-off delay before fade-off going into shutdown X
XX101XX
X
2s hold-off delay before fade-off going into shutdown X
XX110XX
X
4s hold-off delay before fade-off going into shutdown X
0x11
XX111XX
X
Table 9. Ramp-Down Register Format
MAX6966/MAX6967
Maxim Integrated
19