4

2005 Semtech Corp., Rev. 6, 2/28/05

www .semtech.com

TEST AND MEASUREMENT PRODUCTS

Edge211

Circuit Description

Driver Description

The Edge211 supports three distinct programmable driver

levels – high, low, and termination, along with high

impedance. There are no restrictions between any of these

three levels in that all three may vary independently over

the entire operating voltage range between VCC and VEE.

Digital Inputs

All digital inputs are wide voltage comparator inputs, and

are therefore technology independent. The Edge211 may

be driven by TTL, ECL, CMOS, or any custom level circuitry.

Figure 1. Driver Digital Inputs

Do NOT leave any driver digital inputs floating.

The DVR EN*, DATA, and VTT EN are digital input pins that

can be used to control the driver output level displayed at

the DOUT pin.

DVR EN, DATA*, and VTT EN* can be connected to a

reference voltage which defines the logic triggering level.

The relationship between the driver control pins and their

corresponding logic levels can be seen in Table 1.

Table 1.

Using the logic levels defined in Table 1, driver functionality

is described in Table 2.

Table 2.

Note that DVR EN* determines whether the driver output

state will be controlled by the VTT EN or the DATA pin.

With DVR EN high (Logic 1), the driver output pin, DOUT,

is controlled by the VTT EN pin and can be toggled between

the voltage value applied at VTT, and a high impedance

state. With DVR En* low (Logic 0), DOUT can be toggled

between the voltage values applied to the VL and VH pins

by using the DATA input pin.

VH, VL, and VTT

VH, VL, and VTT define the logical “1”, “0”, and

“termination” levels of the driver and can be adjusted

anywhere over the range spanned by VCC to VEE. There

is no restriction between VH, VL, and VTT, in that they can

all vary independently over the entire voltage range

determined by the power supply levels.

The VH, VL, and VTT inputs are unbuffered in that they

also provide the driver output current, so the sources of

these voltages must have ample current drive capability.

While VTT is referred to as the termination voltage, it may

also be used as a very high “programming” level on many

memory devices.

*

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