MAX6956ATL-T Maxim Integrated Products, MAX6956ATL-T Datasheet - Page 17

• Manufacturer Part Number: MAX6956ATL-T
• Description: LED Drivers LED Static Display D river and I-O Port,
• Manufacturer: Maxim Integrated Products

Specifications of MAX6956ATL-T

• Number Of Segments: 28
• Low Level Output Current: 18000 uA
• Operating Supply Voltage: 2.5 V to 5.5 V
• Maximum Supply Current: 230 uA
• Maximum Power Dissipation: 2105 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Package / Case: TQFN EP
• Minimum Operating Temperature: - 40 C
• Dc: 03+

Table 11. Global Segment Current Register Format
X = Don’t care bit.
with the M bit clear, or a transition is detected. The INT
status bit (transition detection mask register bit D7)
goes low. Port P31 (if enabled as INT output) also goes
low, if it was not already low.
Once transition detection is enabled, the MAX6956
continuously compares the snapshot register against
the changing states of P24 through P31. If a change on
any of the monitored ports is detected, even for a short
time (like a pulse), the INT status bit (transition detec-
tion mask register bit D7) is set. Port P31 (if enabled as
INT output) also goes high. The INT output and INT sta-
tus bit are not cleared if more changes occur or if the
data pattern returns to its original snapshot condition.
The only way to clear INT is to access (read or write)
the transition detection mask register (Table 15). So if
the transition detection mask register is read twice in
succession after a transition event, the first time reads
with bit D7 set (identifying the event), and the second
time reads with bit D7 clear.
Transition detection is a one-shot event. When INT has
been cleared after responding to a transition event,
transition detection is automatically disabled, even
though the M bit in the configuration register remains
set (unless cleared by the user). Reenable transition
detection by writing the configuration register with the
LED DRIVE
FRACTION
10/16
11/16
12/16
13/16
14/16
15/16
16/16
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
28-Port LED Display Driver and I/O Expander
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
TYPICAL SEGMENT
______________________________________________________________________________________
CURRENT (mA)
10.5
13.5
16.5
19.5
22.5
1.5
4.5
7.5
12
15
18
21
24
3
6
9
CODE (HEX)
ADDRESS
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
0x02
D7
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
M bit set, to take a new snapshot of the seven ports
P24 to P30.
Display test mode turns on all ports configured as LED
drivers by overriding, but not altering, all controls and
port registers, except the port configuration register
(Table 16). Only ports configured as LED drivers are
affected. Ports configured as GPIO push-pull outputs
do not change state. In display test mode, each port’s
current is temporarily set to 1/2 the maximum current
limit as controlled by R
The MAX6956 uses an external resistor R
maximum segment current. The recommended value,
39kΩ, sets the maximum current to 24mA, which makes
the segment current adjustable from 1.5mA to 24mA in
1.5mA steps.
To set a different segment current, use the formula:
where I
D6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
SEG
D5
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
is the desired maximum segment current.
D4
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Selecting External Component R
R
ISET
to Set Maximum Segment Current
D3
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Display Test Register
ISET
= 936kΩ / I
D2
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
.
D1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
SEG
D0
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
ISET
HEX CODE
to set the
0xXA
0xXB
0xXC
0xXD
0xXE
0xX0
0xX1
0xX2
0xX3
0xX4
0xX5
0xX6
0xX7
0xX8
0xX9
0xXF
ISET
17