E749BPJ Datasheet, PDF (4/14 Pages) Semtech Corporation – Octal Pin Electronics Driver/Receiver

Edge749
EDGE HIGH-PERFORMANCE PRODUCTS
Circuit Description
Driver Description
VHIGH
VLOW
DATA IN
DUT
DVR EN*
Figure 1. Driver Diagram
V_HIGH and V_LOW
V_HIGH and V_LOW define the logical “1” and “0” levels of
the DUT driver and can be adjusted anywhere over the
range determined by VCC and VEE. Table 1 documents
the relationship between the analog power to supplies
(VCC and VEE), the driver range (V_HIGH and V_LOW), and
the comparator threshold range (V_THRESHOLD).
The V_HIGH and V_LOW inputs are unbuffered in that they
also provide the driver output current (see Figure 3), so
the source of V_HIGH and V_LOW must have ample current
drive capability.
As shown in Figure 1, Edge749 supports programmable
high and low levels and tristate per channel. There are
no shared lines between any drivers. The DVR EN* and
DATA IN signals are TTL compatible inputs that control
the driver (see Figure 2).
VHIGH
With DVR EN* high, the DUT driver goes into a high
DUT
impedance state. With DVR EN* low, DATA IN high forces
the driver into a high state (DUT = V_HIGH), and DATA IN
low forces the driver low (DUT = V_LOW).
DVR EN*
DATA IN
DUT
VHIGH
VLOW
VLOW
Figure 3.
Simplified Model of the
Unbuffered Output Stage
Figure 2. Driver Functionality
Drive
Common Mode Range
VEE <= DUT <= VCC
Receive
Common Mode Range
Threshold
Range
VEE <= DUT <= VCC
VEE + 3V <= THRESHOLD <= VOC - 3V
Table 1. Headroom vs. Power Supplies
 2000 Semtech Corp.
4
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