MAX6957AAI+ Maxim Integrated Products, MAX6957AAI+ Datasheet - Page 7

• Manufacturer Part Number: MAX6957AAI+
• Description: IC DRIVER LED PORT 20/28 28-SSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX6957AAI+

• 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: 28-SSOP
• Number Of Digits: 7
• Number Of Segments: 7, 14, 16
• Low Level Output Current: 18000 uA
• Operating Supply Voltage: 2.5 V to 5.5 V
• Maximum Supply Current: 270 uA
• Maximum Power Dissipation: 727 mW
• Maximum Operating Temperature: + 125 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Digits Or Characters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

When the MAX6957 is in shutdown mode, all ports are
forced to inputs, and the pullup current sources are
turned off. Data in the port and control registers remain
unaltered so port configuration and output levels are
restored when the MAX6957 is taken out of shutdown.
The display driver can still be programmed while in
shutdown mode. For minimum supply current in shut-
down mode, logic inputs should be at GND or V+
potential. Shutdown mode is exited by setting the S bit
in the configuration register (Table 6). Shutdown mode
is temporarily overridden by the display test function.
The MAX6957 communicates through an SPI-compati-
ble 4-wire serial interface. The interface has three
inputs, Clock (SCLK), Chip Select (CS), and Data In
(DIN), and one output, Data Out (DOUT). CS must be
Figure 1. MAX6957 Functional Diagram
LED DRIVERS
P4 TO P31
28-Port LED Display Driver and I/O Expander
OR GPIO
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
SCLK
DIN
CS
_______________________________________________________________________________________
D0
D0
SEGMENT OR
GPIO DATA
LED DRIVERS AND GPIO
D1
D1
8
Serial Interface
D2
D2
CONFIGURATION
D3
D3
DATA BYTE
INTENSITY
R/W
8
TEST
D4
D4
Shutdown
D5
D5
D6
D6
D7
D7
low to clock data into or out of the device, and DIN
must be stable when sampled on the rising edge of
SCLK. DOUT provides a copy of the bit that was input
15.5 clocks earlier, or upon a query it outputs internal
register data, and is stable on the rising edge of SCLK.
Note that the SPI protocol expects DOUT to be high
impedance when the MAX6957 is not being
accessed; DOUT on the MAX6957 is never high
impedance. Go to www.maxim-ic.com/an1879 for
ways to convert DOUT to tri-state, if required.
SCLK and DIN may be used to transmit data to other
peripherals, so the MAX6957 ignores all activity on
SCLK and DIN except between the fall and subsequent
rise of CS.
PORT CHANGE
DETECTOR
D8
D8
D9
D9
D10
D10
COMMAND BYTE
D11
D11
D12
D12
REGISTER DECODE
DATA
INTENSITY REGISTERS
COMMAND
PORT REGISTERS
8
TEST REGISTER
MASK REGISTER
CONFIGURATION
D13
D13
8
REGISTERS
CE
D14
D14
R/W
D15
D15
DOUT
7