E646ATF 查看數據表（PDF） - Semtech Corporation

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E646ATF

Pin Electronics Driver, Window Comparator, and Switch Matrix

Semtech Corporation 

Edge646

TEST AND MEASUREMENT PRODUCTS

Circuit Description (continued)

Receiver Functionality

Load

The Edge646 supports an on-board window comparator.

CVB and CVA are high impedance analog inputs which

establish the threshold voltages. COMPA and COMPB are

the digital outputs which reflect the real time status of

VINP. Table 2 summarizes the relationship between the

threshold levels, VINP, and the output signals.

VINP

COMPA

COMPB

The Edge646 provides a total of 3 analog switches.

Individual switches vary in both their on resistance and

their on/off time (see Table 4).

Like the driver digital inputs, the switch matrix control inputs

SW0-3 EN* are technology independent as VBB

determines their threshold level. The switch control is

documented in Table 3.

VINP < CVA

1

X

VINP > CVA

0

X

VINP < CVB

X

0

VINP > CVB

X

1

Table 2. Comparator Truth Table

Comparator Outputs

Control Inputs

SW0 EN* = 1

SW0 EN* = 0

SW1 EN* = 1

SW1 EN* = 0

SW2 EN* = 1

SW2 EN* = 0

Status

SW0 disconnected

SW0 connected

SW1 disconnected

SW1 connected

SW2 disconnected

SW2 connected

The comparator outputs are 50Ω output impedance non-

tristatable drivers designed to cleanly drive 50Ω

transmission lines without requiring any external series

termination resistors. Input pins LOW LEVEL and HIGH

LEVEL establish the logic 0 and 1 levels respectively. In

normal operation, LOW LEVEL would be connected to

ground and HIGH LEVEL would be connected to a system

VDD supply, producing CMOS digital swings at the output.

However, the comparator outputs are technology

independent in that they can drive PECL, 3V CMOS, ECL,

LV CMOS, GTL, and custom levels by varying LOW LEVEL

and HIGH LEVEL. For example, should a 3V swing be

desired, HIGH LEVEL could be connected to a 3.0V power

supply.

Table 3. Switch Matrix Truth Table

Switch

SW0

SW1

SW2

Rout

50 Ω

50 Ω

50 Ω

On/Off Time

100 ns

100 ns

100 ns

Table 4. Switch Matrix Characteristics

Do NOT leave any digital input pins floating.

Notice that HIGH LEVEL and LOW LEVEL provide both the

voltage level and the current for the comparator outputs.

HIGH LEVEL and LOW LEVEL may be varied between +5V

and -2V.

Revision 2 / October 21, 2002

5

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