PCA9539BS 查看數據表（PDF） - NXP Semiconductors.

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PCA9539BS

16-bit I2C-bus and SMBus low power I/O port with interrupt and reset

NXP Semiconductors. 

NXP Semiconductors

PCA9539; PCA9539R

16-bit I2C-bus and SMBus low power I/O port with interrupt and reset

8.1 Minimizing IDD when the I/Os are used to control LEDs

When the I/Os are used to control LEDs, they are normally connected to VDD through a

resistor as shown in Figure 16. Since the LED acts as a diode, when the LED is off the I/O

VI is about 1.2 V less than VDD. The supply current, IDD, increases as VI becomes lower

than VDD.

Designs needing to minimize current consumption, such as battery power applications,

should consider maintaining the I/O pins greater than or equal to VDD when the LED is off.

Figure 17 shows a high value resistor in parallel with the LED. Figure 18 shows VDD less

than the LED supply voltage by at least 1.2 V. Both of these methods maintain the I/O VI at

or above VDD and prevents additional supply current consumption when the LED is off.

VDD

3.3 V

5V

VDD

LEDn

LED

100 kΩ

VDD

LED

LEDn

002aac189

002aac190

Fig 17. High value resistor in parallel with Fig 18. Device supplied by a lower voltage

the LED

9. Limiting values

Table 13. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter

Conditions

Min

Max

Unit

VDD

supply voltage

VI/O

voltage on an input/output pin

IO

output current

on an I/O pin

II

input current

−0.5

+6.0

V

VSS − 0.5 6

V

-

±50

mA

-

±20

mA

IDD

supply current

-

160

mA

ISS

Ptot

Tstg

Tamb

Tj(max)

ground supply current

total power dissipation

storage temperature

ambient temperature

operating

maximum junction temperature

-

200

mA

-

200

mW

−65

+150

°C

−40

+85

°C

-

125

°C

PCA9539_PCA9539R_5

Product data sheet

Rev. 05 — 28 July 2008

© NXP B.V. 2008. All rights reserved.

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