EVM692AHJ Semtech Corporation, EVM692AHJ Datasheet - Page 5

• Manufacturer Part Number: EVM692AHJ
• Description: 200 MHz Monolithic Dual Pin Electronics Driver
• Manufacturer: Semtech Corporation

The desired value for the external resistor can be
determined from the relationship:
The actual IBIAS level is determined by selecting the
desired performance and power level. The charts listed
in the Application Information section enable the user
to quickly determine the appropriate bias level.
Thermal Monitor
The Edge692 includes an on-chip thermal monitor
accessible through the THERMAL DIODE pin. This node
connects to 5 diodes in series to VEE (see Figure 2) and
may be used to accurately measure the junction
temperature at any time.
A bias current of 100 A is injected into this node, and
the measured voltage corresponds to a specific junction
temperature with the following equation:
TJ(˚C) = {[(VTHERMAL DIODE – VEE) / 5] – .7} / (–.00208).
EDGE HIGH-PERFORMANCE PRODUCTS
Circuit Description (continued)
2000 Semtech Corp.
IBIAS = (VCC - .7) / (Rext + 50).
Figure 2. Thermal Diode String
Slew Rate Adjustment
The driver rising and falling slew rates are adjustable
from 2 V/ns to 1 V/ns. The actual slew rate realized is a
function of the chip bias and slew rate adjust input
currents.
The SLEWADJ input is determined by selecting the
desired performance and power level (after the BIAS
current is first chosen.) The charts listed in the
Application Information section enable the user to quickly
determine the appropriate SLEWADJ level.
SLEWADJ is a current controlled input that varies the
rising and falling edge slew rates. Ideally, a current DAC
would be used to establish this current. However, a
resistor to a positive voltage, typically VCC, is acceptable.
Figure 3 shows a simplified schematic of the SLEWADJ
input stage. Once a desired input current is selected,
the external resistor value is determined by the following
relationship:
Notice that the driver A slew rate and driver B slew rate
are independent. However, the rising and falling edge
slew rates on each driver track each other and are not
independent.
5
(VCC - .7) / (Rext + 860) = Islewadj.
Figure 3. SLEWADJ input circuitry
www.semtech.com