10-Bit Bus LVDS Serializers

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5

Pin Description

PIN

NAME

FUNCTION

1, 2

SYNC 1,

SYNC 2

LVCMOS/LVTTL Logic Inputs. The two SYNC pins are ORed. When at least one of the two pins

are asserted high for at least six cycles of TCLK, the serializer initiates a transmission of 1024

SYNC patterns. If held high after 1024 SYNC patterns have been transmitted, SYNC patterns

continue to be sent until the SYNC pin is asserted low. Toggling a SYNC pin after six TCLK cycles

high and before 1024 SYNC patterns have been transmitted does not affect the output of the 1024

SYNC patterns.

3–12

IN0–IN9

LVCMOS/LVTTL Data Inputs. Data is loaded into a 10-bit latch by the selected TCLK edge.

13

TCLK_R/F

LVCMOS/LVTTL Logic Input. High selects a TCLK rising-edge data strobe. Low selects a TCLK

falling-edge data strobe.

14

TCLK

LVCMOS/LVTTL Reference Clock Input. The MAX9205 accepts a 16MHz to 40MHz clock. The

MAX9207 accepts a 40MHz to 66MHz clock. TCLK provides a frequency reference to the PLL and

strobes parallel data into the input latch.

15, 16

DGND

Digital Circuit Ground. Connect to ground plane.

17, 26

µF capacitor and a

0.001

18, 20,

23, 25

AGND

Analog Circuit Ground. Connect to ground plane.

19

EN

LVCMOS/LVTTL Logic Input. High enables serial data output. Low puts the bus LVDS output into

high impedance.

21

OUT-

Inverting Bus LVDS Differential Output

22

OUT+

Noninverting Bus LVDS Differential Output

24

PWRDN

LVCMOS/LVTTL Logic Input. Low puts the device into power-down mode and the output into high

impedance.

27, 28

µF capacitor and a 0.001µF

capacitor. Place the 0.001

Detailed Description

The MAX9205/MAX9207 are 10-bit serializers designed

to transmit data over balanced media that may be a

standard twisted-pair cable or PC board traces at

160Mbps to 660Mbps. The interface may be double-

terminated point-to-point or a heavily loaded multipoint

bus. The characteristic impedance of the media and

connected devices can range from 100

Ω for a point-to-

point interface to 54

Ω for a heavily loaded multipoint

bus. A double-terminated point-to-point interface uses

a 100

Ω-termination resistor at each end of the inter-

face, resulting in a load of 50

Ω. A heavily loaded multi-

point bus requires a termination as low as 54

Ω at each

end of the bus, resulting in a termination load of 27

Ω.

The serializer requires a deserializer such as the

MAX9206/MAX9208 for a complete data transmission

application.

A high-state start bit and a low-state stop bit, added

internally, frame the 10-bit parallel input data and

ensure a transition in the serial data stream. Therefore,

12 serial bits are transmitted for each 10-bit parallel

input. The MAX9205 accepts a 16MHz to 40MHz refer-

ence clock, producing a serial data rate of 192Mbps

(12 bits x 16MHz) to 480Mbps (12 bits x 40MHz). The

MAX9207 accepts a 40MHz to 66MHz reference clock,

producing 480Mbps to 792Mbps. However, since only

10 bits are from input data, the actual throughput is 10

times the TCLK frequency.

To transmit data, the serializers sequence through

three modes: initialization mode, synchronization mode,

and data transmission mode.