MAX4397DACTM datasheet(17/30 Pages) MAXIM

17 / 30 page

Data Format of the I2C Interface

I2C Compatibility

The MAX4397DA/SA are compatible with existing I2C

systems. SCL and SDA are high-impedance inputs.

SDA has an open drain that pulls the bus line to a logic-

low during the 9th clock pulse. Figure 7 shows a typical

I2C interface application. The communication protocol

supports the standard I2C 8-bit communications. The

MAX4397DA/SA address is compatible with the 7-bit I2C

addressing protocol only; 10-bit format is not supported.

Digital Inputs and Interface Logic

The I2C-compatible, 2-wire interface has logic levels

defined as VIL = 0.8V and VIH = 2.0V. All of the inputs

include Schmitt-trigger buffers to accept low-transition

interfaces. The digital inputs are compatible with 3V

CMOS logic levels.

Programming

Connect DEV_ADDR to ground to set the MAX4397DA/SA

write and read address as shown in Table 2.

Data Register Writing and Reading

Program the SCART video and audio switches by writ-

ing to registers 00h through 0Dh. Registers 00h through

0Eh can also be read, allowing readback of data after

programming and facilitating system debugging. The

status register is read-only and can be read from

address 0Eh. See Tables 3–12 for register program-

ming information.

Applications Information

Hot Plug of SCART Connectors

The MAX4397DA/SA feature high-ESD protection on all

SCART inputs and outputs, and requires no external

transient-voltage suppressor (TVS) devices to protect

against floating chassis discharge. Some set-top boxes

have a floating chassis problem in which the chassis is

not connected to earth ground. As a result, the chassis

can charge up to 500V. When a SCART cable is con-

nected to the SCART connector, the charged chassis

can discharge through a signal pin. The equivalent cir-

cuit is a 2200pF capacitor charged to 311V connected

through less than 0.1Ω to a signal pin. The

MAX4397DA/SA are soldered on the PCB when it expe-

riences such a discharge. Therefore, the current spike

flows through the ESD protection diodes and is

absorbed by the supply bypass capacitors, which have

high capacitance and low ESR.

To better protect the MAX4397DA/SA against excess

voltages during the cable discharge condition, place

an additional 75Ω resistor in series with all inputs and

outputs to the SCART connector. For harsh environ-

ments where ±15kV protection is needed, the

MAX4385E and MAX4386E single and quad high-

speed op amps feature the industry’s first integrated

±15kV ESD protection on video inputs and outputs.

Audio/Video Switch for Dual SCART Connectors

______________________________________________________________________________________

µC

SCL

SDA

VVID

MAX4397DA/SA

SCL

SDA

VDD

SCL

SDA

VDD

DEVICE 2

DEVICE 1

SDA

Figure 7. Typical I2C Interface Application

ADDRESS PIN

STATE

WRITE

ADDRESS

READ ADDRESS

VVID

96h

97h

GNDVID

94h

95h

Table 2. Slave Address Programming

Slave Address

(Write address)

Address

Data

Write Mode

Slave

Address

(Write

address)

Address

A Sr

Slave

Address

(Read

address)

A Data

Read Mode

S = Start Condition, A = Acknowledge, NA = Not Acknowledge,

Sr = Repeat Start Condition, P = Stop Condition

MAX4397DACTM Datasheet(PDF) 17 Page - Maxim Integrated Products

MAX4397DACTM Datasheet(HTML) 17 Page - Maxim Integrated Products

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30

Datasheet Download

Link URL