Datasheet

ManualsBrandsMAXIM INTEGRATED ManualsPMICsPMIC - display driver LED 7 segments, 16 segments, 20 segments 4-wire, Seriell 180 µA TQFN

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.

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

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

Pin Configurations continued at end of data sheet.

*Exposed pad.

PART TEMP RANGE

PIN-

PACKAGE

MAX6957ANI -40°C to +125°C 28 DIP

MAX6957AAI -40°C to +125°C 28 SSOP

MAX6957AAX -40°C to +125°C 36 SSOP

MAX6957ATL -40°C to +125°C 40 TQFN-EP*

V+

SCLK

DIN

P31

P30

P22

P29

P28

P27

P26

P25

P24

P23

P21

P20

P19

P18

P17

P16

P15

P14

P13

P12

DOUT

GND

ISET

SSOP/DIP

TOP VIEW

MAX6957

MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and

28-Port LED Display Driver and I/O Expander

19-2429; Rev 5; 7/14

Pin Congurations

Ordering Information

Summary of content (23 pages)

PAGE 1
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 individually user configurable to either a logic input, logic output, or common-anode (CA) LED constant-current segment driver.
PAGE 2
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Absolute Maximum Ratings Voltage (with Respect to GND) V+.............................................................................-0.3V to +6V All Other pins................................................-0.3V to (V+ + 0.3V) P4–P31 Current ...............................................................±30mA GND Current.....................................................................
PAGE 3
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Electrical Characteristics (continued) (Typical Operating Circuit, V+ = 2.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.
PAGE 4
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Typical Operating Characteristics (RISET = 39kΩ, TA = +25°C, unless otherwise noted.) 7 0.16 0.12 V+ = 3.3V 6 5 V+ = 2.5V 4 0.08 ALL PORTS LED (OFF) -40.0 -12.5 15.0 42.5 70.0 97.5 3 125.0 -40.0 -12.5 27 MAX6957 toc04 20 LED DROP = 2.4V 18 16 LED DROP = 1.8V 14 12 10 3.0 3.5 4.0 4.5 5.0 V+ = 5.5V 23 V+ = 3.3V 22 8 V+ = 5.5V 7 PULLUP CURRENT (A) VPORT = 1.4V V+ = 3.
PAGE 5
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Pin Description PIN NAME 28 SSOP 36 SSOP 40 TQFN 28 PDIP FUNCTION 1 1 36 ISET Segment Current Setting. Connect ISET to GND through a resistor (RISET) to set the maximum segment current. 2, 3 2, 3 37, 38, 39 GND Ground 4 4 40 DOUT 5–24 — — P12–P31 LED Segment Drivers and GPIO.
PAGE 6
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 1.
PAGE 7
MAX6957 4-Wire-Interfaced, 2.5V to 5.
PAGE 8
MAX6957 4-Wire-Interfaced, 2.5V to 5.
PAGE 9
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander MICROCONTROLLER SERIAL DATA INPUT SERIAL CS OUTPUT CS CS MAX6957 SCLK SCLK SERIAL CLOCK OUTPUT DOUT DIN SERIAL DATA OUTPUT CS MAX6957 MAX6957 SCLK DIN DOUT DIN DOUT Figure 4. Daisy-Chain Arrangement for Controlling Multiple MAX6957s CS SCLK DIN D15 =0 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 DOUT D15 = 0 . Figure 5.
PAGE 10
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander It is acceptable to clock more than 16 bits into the MAX6957 between taking CS low and taking CS high again. In this case, only the last 16 bits clocked into the MAX6957 are retained. active-high interrupt output (INT). Note that the MAX6957 does not identify which specific port(s) caused the interrupt, but provides an alert that one or more port levels have changed.
PAGE 11
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 3.
PAGE 12
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 3. Register Address Map (continued) COMMAND ADDRESS D15 D14 D13 D12 D11 D10 D9 D8 HEX CODE Port 11 only (data bit D0. D7–D1 read as 0) R/W 0 1 0 1 0 1 1 0x2B Port 12 only (data bit D0. D7–D1 read as 0) R/W 0 1 0 1 1 0 0 0x2C Port 13 only (data bit D0. D7–D1 read as 0) R/W 0 1 0 1 1 0 1 0x2D Port 14 only (data bit D0.
PAGE 13
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 3.
PAGE 14
MAX6957 4-Wire-Interfaced, 2.5V to 5.
PAGE 15
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 4.
PAGE 16
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 5. Configuration Register Format REGISTER DATA FUNCTION ADDRESS CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0 Configuration Register 0x04 M 0 X X X X X S X = Don’t care bit. Table 6.
PAGE 17
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 9. Global Segment Current Register Format (continued) LED DRIVE FRACTION TYPICAL SEGMENT CURRENT (mA) ADDRESS CODE (HEX) D7 D6 D5 D4 D3 D2 D1 D0 HEX CODE 6/16 9 0x02 X X X X 0 1 0 1 0xX5 7/16 10.5 0x02 X X X X 0 1 1 0 0xX6 8/16 12 0x02 X X X X 0 1 1 1 0xX7 9/16 13.
PAGE 18
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Table 11. Even Individual Segment Current Format SEGMENT LED DRIVE CONSTANT ADDRESS CODE FRACTION CURRENT WITH (HEX) 1/16 RISET = 39kΩ (mA) D7 D6 D5 D4 D3 D2 D1 D0 HEX CODE 1.5 0x12 to 0x1F 0 0 0 0 0xX0 2/16 3 0x12 to 0x1F 0 0 0 1 0xX1 3/16 4.5 0x12 to 0x1F 0 0 1 0 0xX2 4/16 6 0x12 to 0x1F 0 0 1 1 0xX3 5/16 7.
PAGE 19
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Low-Voltage Operation up initially to at least 2.5V to trigger the device’s internal reset, and also that the serial interface is constrained to 10Mbps. The MAX6957 operates down to 2V supply voltage (although the sourcing and sinking currents are not guaranteed), providing that the MAX6957 is powered Table 12.
PAGE 20
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander SPI Routing Considerations 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 connections are longer that 100mm, particularly with higher supply voltages.
PAGE 21
MAX6957 4-Wire-Interfaced, 2.5V to 5.
PAGE 22
MAX6957 4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and 28-Port LED Display Driver and I/O Expander Package Information For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE DOCUMENT NO. LAND PATTERN NO.
PAGE 23
MAX6957 4-Wire-Interfaced, 2.5V to 5.