pca9507 NXP Semiconductors, pca9507 Datasheet - Page 5

• Manufacturer Part Number: pca9507
• Description: Pca9507 2-wire Serial Bus Extender For Hdmi Ddc I2c-bus And Smbus
• Manufacturer: NXP Semiconductors

NXP Semiconductors
PCA9507_1
Product data sheet
6.3.1 Port A (SDAA and SCLA)
6.3 Resistor pull-up value selection
SDAA and SCLA are open-drain I/O that have rise time accelerators and strong pull-down.
When the inputs transition above 0.3V
the pull-up current during rising edge to meet the I
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
applications like digital video player, recorder, or set-top box, the pull-up resistor is in the
range of 1.5 k to 2 k . For HDMI receiver applications like in LCD TV or video card, the
pull-up resistor is 47 k on the SCLA line, and there is no pull-up on the SDAA line.
Please refer to
pull-up resistor values (in k ) versus capacitance load (in nF) for 5 V supply voltage
complied with 1 s rise time per I
contrasts a shaded and unshaded region. Any resistor value chosen within the unshaded
region would comply with 1 s rise time, while any value chosen in the shaded region
would not.
Table 3.
Pin
SDAA
SCLA
Fig 5.
R
(k )
PU
10.5
8.5
6.5
4.5
2.5
0.5
rise time = 1 s; V
SDAA/SCLA line pull-up resistor versus load capacitance
HDMI DDC pull-up resistors specification
0
Table
complies with
1 s rise time
3,
Where
at the source (DVD/STB)
at the sink (LCD TV)
at the source (DVD/STB)
at the sink (LCD TV)
Rev. 01 — 7 February 2008
Figure 7
CC(A)
2-wire serial bus extender for HDMI DDC I
1.0
= 5 V
and
2
C-bus Standard-mode specification. The graph
does not comply with
Figure 8
CC(A)
1 s rise time
, the rise time accelerator activates and boosts
2.0
for more details.
Table
2
C-bus rise time specification when the
Minimum
1.5 k
-
1.5 k
3. For HDMI transmitter
3.0
Figure 5
47 k
C
L
(nF)
2
PCA9507
C-bus and SMBus
002aad620
© NXP B.V. 2008. All rights reserved.
Maximum
2.0 k
-
2.0 k
10 %
shows the port A
4.0
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