MAX6957AAX+ Maxim Integrated Products, MAX6957AAX+ Datasheet - Page 20

• Manufacturer Part Number: MAX6957AAX+
• Description: IC DRVR DSPL LED 36-SSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6957AAX+

• Display Type: LED
• Configuration: 7, 16, 20 Segment
• Interface: 4-Wire Serial
• Current - Supply: 180µA
• Voltage - Supply: 2.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 36-SSOP
• Number Of Digits: 7
• 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: 941 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• No. Of Segments: 28
• Supply Voltage Range: 2.5V To 5.5V
• Driver Case Style: SSOP
• No. Of Pins: 36
• Operating Temperature Range: -40°C To +125°C
• Device Type: LED
• Termination Type: SMD
• Rohs Compliant: Yes
• Filter Terminals: SMD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Digits Or Characters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port LED Display Driver and I/O Expander
The MAX6957’s SPI interface is guaranteed to operate at
26Mbps on a 2.5V supply, and on a 5V supply typically
operates at 50Mbps. This means that the transmission
line issues should be considered when the interface con-
nections are longer that 100mm, particularly with higher
supply voltages. Ringing manifests itself as communica-
tion issues, often intermittent, typically due to double
clocking due to ringing at the SCLK input. Fit a 1kΩ to
10kΩ parallel termination resistor to either GND or V+ at
the DIN, SCLK, and CS input to damp ringing for moder-
ately long interface runs. Use line impedance matching
terminations when making connections between boards.
Ensure that all the MAX6957 GND connections are
used. A ground plane is not necessary, but may be
20
______________________________________________________________________________________
TOP VIEW
PC Board Layout Considerations
DOUT
GND
GND
ISET
P12
P13
P10
P11
P15
P16
P17
P18
P19
P20
P21
P14
P8
P9
SPI Routing Considerations
10
11
12
13
14
15
16
17
18
1
2
3
4
5
6
7
8
9
MAX6957
SSOP
36
35
34
33
32
31
30
29
28
27
26
25
24
23
22
21
19
20
V+
CS
DIN
SCLK
P4
P31
P5
P30
P6
P29
P7
P28
P27
P26
P25
P24
P23
P22
useful to reduce supply impedance if the MAX6957
outputs are to be heavily loaded. Keep the track length
from the ISET pin to the R
sible, and take the GND end of the resistor either to the
ground plane or directly to the GND pins.
The MAX6957 operates with power-supply voltages of
2.5V to 5.5V. Bypass the power supply to GND with a
0.047µF capacitor as close to the device as possible.
Add a 1µF capacitor if the MAX6957 is far away from
the board's input bulk decoupling capacitor.
TRANSISTOR COUNT: 30,316
PROCESS: CMOS
P12
P13
P10
P14
P11
P15
P16
P17
P8
P9
Pin Configurations (continued)
10
1
2
3
4
5
6
7
8
9
Power-Supply Considerations
MAX6957
TQFN
ISET
Chip Information
resistor as short as pos-
30
29
28
27
26
25
24
23
22
21
P4
P31
P5
P30
P6
P29
P7
P28
P27
P26