MAX7313 データシートの表示（PDF） - Maxim Integrated

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MAX7313

16-Port I/O Expander with LED Intensity Control, Interrupt, and Hot-Insertion Protection

Maxim Integrated 

16-Port I/O Expander with LED Intensity

Control, Interrupt, and Hot-Insertion Protection

blink phases (Tables 8 and 9). The effect of setting an

output’s blink phase x register bit to 0 or 1 is shown in

Table 12. LEDs can be flipped between either directly on

and off, or between a variety of high/low PWM intensities.

Global/O16 Intensity Control

The 4 bits used for output O16’s PWM individual inten-

sity setting also double as the global intensity control

(Table 13). Global intensity simplifies the PWM settings

when the application requires them all to be the same,

such as for backlight applications, by replacing the 17

individual settings with 1 setting. Global intensity is

enabled with the Global Intensity flag G in the configu-

ration register (Table 4). When global PWM control is

used, the 4 bits of master intensity and 4 bits of global

intensity effectively combine to provide an 8 bit, 240-

step intensity control applying to all outputs.

It is not possible to apply global PWM control to a sub-

set of the ports, and use the others as logic outputs. To

mix static logic outputs and PWM outputs, individual

PWM control must be selected (Table 10).

Applications Information

Hot Insertion

I/O ports P0–P15, interrupt output INT/016, and serial

interface SDA, SCL, AD0–2 remain high impedance

with up to 6V asserted on them when the MAX7313 is

powered down (V+ = 0V). The MAX7313 can therefore

be used in hot-swap applications.

Output Level Translation

The open-drain output architecture allows the ports to

level translate the outputs to higher or lower voltages

than the MAX7313 supply. An external pullup resistor

can be used on any output to convert the high-imped-

ance logic-high condition to a positive voltage level.

The resistor can be connected to any voltage up to

5.5V. For interfacing CMOS inputs, a pullup resistor

value of 220kΩ is a good starting point. Use a lower

resistance to improve noise immunity, in applications

where power consumption is less critical, or where a

faster rise time is needed for a given capacitive load.

Table 12. PWM Intensity Settings (Blink Enabled)

OUTPUT

(OR

GLOBAL)

INTENSITY

SETTING

0x0

0x1

0x2

0x3

0x4

0x5

0x6

0x7

0x8

0x9

0xA

0xB

0xC

0xD

0xE

0xF

PWM DUTY CYCLE

OUTPUT BLINK

PHASE X

REGISTER BIT = 0

PWM DUTY CYCLE

OUTPUT BLINK

PHASE X

REGISTER BIT = 1

EXAMPLES OF LED BLINK BEHAVIOR

(LED IS ON WHEN OUTPUT IS LOW)

BLINK PHASE 0

REGISTER BIT = 0

BLINK PHASE 0

REGISTER BIT = 1

LOW

TIME

1/16

2/16

3/16

4/16

5/16

6/16

7/16

8/16

9/16

10/16

11/16

12/16

13/16

14/16

15/16

Static low

HIGH

TIME

LOW

TIME

HIGH

TIME

BLINK PHASE 1

REGISTER BIT = 1

BLINK PHASE 1

REGISTER BIT = 0

15/16

15/16

1/16

14/16

13/16

12/16

11/16

14/16

13/16

12/16

11/16

2/16

3/16

4/16

Phase 0: LED on at low intensity Phase 0: LED on at high intensity

Phase 1: LED on at high intensity Phase 1: LED on at low intensity

5/16

10/16

9/16

8/16

7/16

6/16

10/16

9/16

8/16

7/16

6/16

6/16

7/16

8/16

9/16

10/16

Output is half intensity during both blink phases

5/16

5/16

11/16

4/16

4/16

12/16

Phase 0: LED on at high intensity Phase 0: LED on at low intensity

Phase 1: LED on at low intensity Phase 1: LED on at high intensity

3/16

3/16

13/16

2/16

2/16

14/16

1/16

1/16

15/16

Static low

Static high Static high

impedance impedance

Phase 0: LED on continuously

Phase 1: LED off continuously

Phase 0: LED off continuously

Phase 1: LED on continuously

20 ______________________________________________________________________________________

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