PCA9507 View Datasheet(PDF) - NXP Semiconductors.
Part Name
Description
MFG CO.
'PCA9507' PDF : 20 Pages View PDF
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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