MAX6956ATL+T Maxim Integrated Products, MAX6956ATL+T Datasheet - Page 19

• Manufacturer Part Number: MAX6956ATL+T
• Description: IC DRVR DSPL LED 40-TQFN
• Manufacturer: Maxim Integrated Products

Specifications of MAX6956ATL+T

• Display Type: LED
• Interface: I²C
• Current - Supply: 180µA
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 40-TQFN Exposed Pad
• Number Of Segments: 28
• Low Level Output Current: 18 mA
• 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
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Configuration: -
• Digits Or Characters: -
• Lead Free Status / Rohs Status: Details

Table 14. Odd Individual Segment Current Format
The recommended value of R
The recommended value of R
allowed value, since it sets the display driver to the
maximum allowed segment current. R
higher value to set the segment current to a lower maxi-
mum value where desired. The user must also ensure
that the maximum current specifications of the LEDs
connected to the driver are not exceeded.
The drive current for each segment can be controlled
through programming either the Global Current register
(Table 11) or Individual Segment Current registers
(Tables 12, 13, and 14), according to the setting of the
Current Control bit of the Configuration register (Table 9).
These registers select the LED’s constant-current drive
from 16 equal fractions of the maximum segment cur-
rent. The current difference between successive current
steps, I
If I
FRACTION
SEG
DRIVE
10/16
11/16
12/16
13/16
14/16
15/16
16/16
LED
1/16
2/16
3/16
4/16
5/16
6/16
7/16
8/16
9/16
STEP
= 24mA, then I
28-Port LED Display Driver and I/O Expander
, is therefore determined by the formula:
2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
R
CURRENT WITH
ISET
______________________________________________________________________________________
I
CONSTANT
STEP
SEGMENT
STEP
= 39kΩ (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
= I
= 24mA / 16 = 1.5mA.
SEG
ISET
/ 16
ISET
is 39kΩ.
is the minimum
CODE (HEX)
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
0x12 to 0x1F
ISET
ADDRESS
can be a
D7
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
Bicolor digits group a red and a green die together for
each display element, so that the element can be lit
red, green (or orange), depending on which die (or
both) is lit. The MAX6956 allows each segment’s cur-
rent to be set individually from 1/16th (minimum current
and LED intensity) to 16/16th (maximum current and
LED intensity), as well as off (zero current). Thus, a
bicolor (red-green) segment pair can be set to 289
color/intensity combinations. A discrete or CA tricolor
(red-green-yellow or red-green-blue) segment triad can
be set to 4913 color/intensity combinations.
Each MAX6956 port can sink a current of 24mA into an
LED with a 2.4V forward-voltage drop when operated
from a supply voltage of at least 3.0V. The minimum
voltage drop across the internal LED drivers is there-
fore (3.0V - 2.4V) = 0.6V. The MAX6956 can sink 28 x
24mA = 672mA when all outputs are operating as LED
D6
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
D5
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Driving Bicolor and Tricolor LEDs
D4
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
Applications Information
D3
Power Dissipation Issues
See Table 13.
D2
D1
D0
HEX CODE
0xAX
0xBX
0xCX
0xDX
0x0X
0x1X
0x2X
0x3X
0x4X
0x5X
0x6X
0x7X
0x8X
0x9X
0xEX
0xFX
19