MAX6957_14 Datasheet, PDF (1/23 Pages) Maxim Integrated Products – 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander

MAX6957
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port LED Display Driver and I/O Expander
General Description
The MAX6957 compact, serial-interfaced LED display
driver general-purpose I/O (GPIO) peripheral provides
microprocessors with up to 28 ports. Each port is indi-
vidually user configurable to either a logic input, logic
output, or common-anode (CA) LED constant-current
segment driver. Each port configured as an LED seg-
ment driver behaves as a digitally controlled constant-
current sink, with 16 equal current steps from 1.5mA to
24mA. The LED drivers are suitable for both discrete
LEDs and CA numeric and alphanumeric LED digits.
Each port configured as a GPIO can be either a push-
pull logic output capable of sinking 10mA and sourcing
4.5mA, or a Schmitt logic input with optional internal
pullup. Seven ports feature configurable transition
detection logic, which generates an interrupt upon
change of port logic level. The MAX6957 is controlled
through an SPI-compatible 4-wire serial interface.
The MAX6957AAX and MAX6957ATL have 28 ports and
are available in 36-pin SSOP and 40-pin TQFN (6mm x
6mm) packages, respectively. The MAX6957AAI and
MAX6957ANI have 20 ports and are available in 28-pin
SSOP and 28-pin DIP packages, respectively.
For a 2-wire interfaced version, refer to the MAX6956
data sheet.
For a lower cost pin-compatible port expander without
the constant-current LED drive capability, refer to the
MAX7301 data sheet.
Applications
●● Set-Top Boxes
●● Panel Meters
●● White Goods
●● Bar Graph Displays
●● Industrial Controllers
●● System Monitoring
Typical operating Circuit appears at end of data sheet.
QSPI is a trademark of Motorola, Inc.
MICROWIRE is a registered trademark of National
Semiconductor Corp.
Features
●● High-Speed 26MHz SPI-/QSPI™-/MICROWIRE^®-
Compatible Serial Interface
●● 2.5V to 5.5V Operation
●● -40°C to +125°C Temperature Range
●● 20 or 28 I/O Ports, Each Configurable as
Constant-Current LED Driver
Push-Pull Logic Output
Schmitt Logic Input
Schmitt Logic Input with Internal Pullup
●● 11µA (max) Shutdown Current
●● 16-Step Individually Programmable Current Control
for Each LED
●● Logic Transition Detection for Seven I/O Ports
Ordering Information
PART
TEMP RANGE
MAX6957ANI
MAX6957AAI
MAX6957AAX
MAX6957ATL
*Exposed pad.
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-
PACKAGE
28 DIP
28 SSOP
36 SSOP
40 TQFN-EP*
Pin Configurations
TOP VIEW
ISET 1
GND 2
GND 3
DOUT 4
P12 5
P13 6
P14 7
P15 8
P16 9
P17 10
P18 11
P19 12
P20 13
P21 14
MAX6957
28 V+
27 CS
26 DIN
25 SCLK
24 P31
23 P30
22 P29
21 P28
20 P27
19 P26
18 P25
17 P24
16 P23
15 P22
SSOP/DIP
Pin Configurations continued at end of data sheet.
19-2429; Rev 5; 7/14