SI5345 Datasheet, PDF (50/62 Pages) Silicon Laboratories – 10-CHANNEL, ANY-FREQUENCY, ANY-OUTPUT JITTER ATTENUATOR/CLOCK MULTIPLIER

Si5345/44/42
Table 19. Si5345/44/42 Pin Descriptions (Continued)
Pin Number
Pin Name
Pin Type¹
Si5345 Si5344 Si5342
Function
Serial Interface
I2C_SEL
39
38
38
SDA/SDIO 18
13
13
A1/SDO
17
15
15
SCLK
16
14
14
A0/CS
19
16
16
I
I²C Select²
This pin selects the serial interface mode as I²C
(I2C_SEL = 1) or SPI (I2C_SEL = 0). This pin is internally
pulled up by a ~ 20 k resistor to the voltage selected by
the IO_VDD_SEL register bit.
I/O Serial Data Interface²
This is the bidirectional data pin (SDA) for the I²C mode,
or the bidirectional data pin (SDIO) in the 3-wire SPI
mode, or the input data pin (SDI) in 4-wire SPI mode.
When in I²C mode, this pin must be pulled-up using an
external resistor of at least 1 k. No pull-up resistor is
needed when is SPI mode. Tie low when unused.
I/O Address Select 1/Serial Data Output²
In I²C mode this pin functions as the A1 address input pin
and does not have an internal pull-up or pull-down resis-
tor. In 4-wire SPI mode this is the serial data output (SDO)
pin and drives high to the voltage selected by the
IO_VDD_SEL bit. Leave disconnected when unused.
I
Serial Clock Input²
This pin functions as the serial clock input for both I²C and
SPI modes. When in I²C mode, this pin must be pulled-up
using an external resistor of at least 1 k. No pull-up
resistor is needed when in SPI mode. Tie high or low
when unused.
I
Address Select 0/Chip Select²
This pin functions as the hardware controlled address A0
in I²C mode. In SPI mode, this pin functions as the chip
select input (active low). This pin is internally pulled-up by
a ~20 k resistor and can be left unconnected when not
in use.
Notes:
1. I = Input, O = Output, P = Power
2. The IO_VDD_SEL control bit (0x0943 bit 0) selects 3.3 V or 1.8 V operation.
3. The voltage on the VDDS pin(s) determines 3.3 V or 1.8 V operation.
4. Refer to the Si5345/44/42 Family Reference Manual for more information on register setting names.
50
Rev. 1.0