PCA9507D 데이터 시트보기 (PDF) - NXP Semiconductors.

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PCA9507D

2-wire serial bus extender for HDMI DDC I2C-bus and SMBus

NXP Semiconductors. 

NXP Semiconductors

PCA9507

2-wire serial bus extender for HDMI DDC I2C-bus and SMBus

6.3 Resistor pull-up value selection

6.3.1 Port A (SDAA and SCLA)

SDAA and SCLA are open-drain I/O that have rise time accelerators and strong pull-down.

When the inputs transition above 0.3VCC(A), the rise time accelerator activates and boosts

the pull-up current during rising edge to meet the I2C-bus rise time specification when the

device drives a long cable or heavier capacitance load. The strong pull-down enables the

output to drive to nearly zero voltage for logic LOW. The selection for pull-up resistors are

defined in the HDMI DDC specification shown in Table 3. For HDMI transmitter

applications like digital video player, recorder, or set-top box, the pull-up resistor is in the

range of 1.5 kΩ to 2 kΩ. For HDMI receiver applications like in LCD TV or video card, the

pull-up resistor is 47 kΩ on the SCLA line, and there is no pull-up on the SDAA line.

Please refer to Table 3, Figure 7 and Figure 8 for more details. Figure 5 shows the port A

pull-up resistor values (in kΩ) versus capacitance load (in nF) for 5 V supply voltage

complied with 1 µs rise time per I2C-bus Standard-mode specification. The graph

contrasts a shaded and unshaded region. Any resistor value chosen within the unshaded

region would comply with 1 µs rise time, while any value chosen in the shaded region

would not.

Table 3.

Pin

SDAA

SCLA

HDMI DDC pull-up resistors specification

Where

Minimum

at the source (DVD/STB)

1.5 kΩ

at the sink (LCD TV)

-

at the source (DVD/STB)

1.5 kΩ

at the sink (LCD TV)

Maximum

2.0 kΩ

-

2.0 kΩ

47 kΩ ± 10 %

10.5

RPU

(kΩ)

8.5

002aad620

6.5

4.5

complies with

1 µs rise time

2.5

does not comply with

1 µs rise time

0.5

0

1.0

2.0

3.0

4.0

CL (nF)

rise time = 1 µs; VCC(A) = 5 V

Fig 5. SDAA/SCLA line pull-up resistor versus load capacitance

PCA9507_1

Product data sheet

Rev. 01 — 7 February 2008

© NXP B.V. 2008. All rights reserved.

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