EDGE818 Просмотр технического описания (PDF) - Semtech Corporation

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EDGE818

Octal 18V Pin Electronics Driver/window Comparator

Semtech Corporation 

Edge818

TEST AND MEASUREMENT PRODUCTS

Application Information

Power Supply Decoupling

VCC and VEE should be decoupled to GND with a .1 µF

chip capacitor in parallel with a .001 µF chip capacitor. A

VCC and VEE plane, or at least a solid power bus, is

recommended for optimal performance.

VH and VL Decoupling

As the VH and VL inputs are unbuffered and supply the

driver output current, which can be quite large during edge

transitions, decoupling capacitors for these inputs are

recommended in proportion to the amount of output

current requirements.

The power sequence below can be used as a guideline

when operating the Edge818:

Power-on Sequencing

1. VCC (substrate)

2. VEE

3. I/O Pins

Power-off Sequencing

1. I/O Pins

2. VEE

3. VCC

The three diode configuration shown in Figure 3 should

be used on a once-per-board basis.

VCC

For applications where VH and VL are shared over multiple

channels, a solid power plane to distribute these levels is

preferred.

VBB

The two VBB pins are connected together on-chip.

Therefore, only one VBB needs to be connected to for

proper 818 operation.

External

Logic

VDD

Supply

External

System

Ground

1N5820 or

Equivalent

The two pins may be used to daisy chain a VBB signal

across a PC Board without having to route the actual signal

VEE

underneath the 818.

Power Supplies

The Edge818 has several power supply requirements to

protect the part in power supply fault situations, as well

as during power up and power down sequences.

The following power supply requirements must be satisfied

at all times:

VEE ≤ All I/O pins ≤ VCC at all times.

Figure 3.

Power Supply Protection Scheme

gure 5.

Warning: It is extremely important that the voltage

on any device pin does not exceed the range of VEE

–0.5V to VCC +0.5V at any time, either during power

up, normal operation, or during power down. Failure

to adhere to this requirement could result in latchup

of the device, which could be destructive if the system

power supplies are capable of supplying large

amounts of current. Even if the device is not

immediately destroyed, the cumulative damage

caused by the stress of repeated latchup may affect

device reliability.

 2004 Semtech Corp. / Rev. 5, 8/18/04

6

www .semtech.com

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