First Release

Copyright © IXYS CORPORATION 2001

General Description

EVDD404

IXDD404 Gate Driver IC Evaluation Board

The EVDD404 evaluation board is a general-purpose circuit

board designed to simplify the evaluation of the IXYS

IXDD404 gate drive IC, as well as to provide a building block

for power circuit development. Either the DIP-8 (IXDD408PI)

or SO-16 (IXDD408SI-16) gate driver package types may be

installed in the driver (the DIP-8 package is factory

installed). The board enables the user to drive MOSFETs or

IGBTs in TO-220, TO-247, TO-264 or SOT-227 packages.

The evaluation board design allows these MOSFETS to be

attached to a heat sink, and in so doing the board assembly

can be used as a ground referenced, low side power switch

for both single-ended and push-pull configurations. Circuitry

for the Tri-State function is included on the evaluation board.

Figure 1 is a photograph of the IXDD404 Evaluation Board

loaded with an IXDD404PI DIP-8 driver and a SOT-227

MOSFET. The low level inputs are shown on the left side of

the board. CONTROL is a TTL high true input which controls

the on or off state of the power switch Q1, Q2, or Q3.

ENABLE is a low true input, which controls the Tri-State

output. VCC-IN is the low voltage, (8-25V) power input, (see

Figure 3 below). Figure 2 illustrates the MOSFET mounting

of a TO-220, TO-247, or TO-264 device. The MOSFET is

mounted on the back side of the PCB. A large through hole

is provided so that the device can be attached to a heat sink.

The SOT-227 (shown in the photograph) is mounted in a

similar manner.

Circuit Operation

The schematic diagram for the evaluation board is shown in

Figure 4. The control gate is applied to R4 then on the input

pins 2 and 4 of the IC U1 (or to pins 2 and 7 of U2, if loaded

in place of U1). This signal input is followed in time by the

output pins 5 and 7 of U1 (or pins 10, 11, 14 and 15 of U2, if

loaded). Pins 1 and 8 of U1 and U2 are attached to +VCC

via a de-coupling network comprised of R1, C3 and R10,

C4. Pin 3 of U1 and pins 4 and 5 of U2 are attached to the

circuit ground plane. This is the preferred arrangement of

the bypassing for the Vcc input power. The enable pins 1

and 8 of U1 and U2 are attached to the drain of Q4. This

device is used to level translate and provide an invert

function for the Tri-State mode. The drain of Q4 is also

attached to the gate of the MOSFET thru RA1 and DA1. In

the Tri-State mode the turn off time of the power MOSFET is

determined by the time constant of the input gate

capacitance C

See the

IXDD404 data sheet for additional information on this mode

of operation.

The U1 output is available at pins 5 and 7 of U1 (or pins 10,

11, 14 and 15 of U2, if loaded). These are attached to the

MOSFET via the two one-Ohm resistors R5 and R7. The

values of these resistors may be changed to optimize the

performance of the specific device being driven. The board

is designed to parallel the two outputs of the IXDD404 IC,

generating up to 8A of output current. If only one output

channel is desired, the other channel may be disabled by

removing either R5 or R7, thereby disconnecting that

The EVDD404 is supplied with the IXDD404PI DIP-8 device

installed. To use the evaluation board with a different

package type, the installed device must be removed, and

the new device installed in the appropriate location.

Part Number

Installed Device

EVDD404

IXDD404PI DIP-8

Ordering Information

channel's output from the MOSFET gate.

There are three test points on the board: Control, Gate and

Drain. These allow the user to easily attach an oscilloscope

probe and the associated ground to the circuit to verify

performance.

INPUT

FUNCTION

CONTROL

Control Input - 3V into 1K Ohms

GND1

Ground 1

ENABLE

LOW = True, HIGH = Tri-State Mode

GND2

Ground 2

VCC-IN

VCC input - 8V to 25V

GND 3

Ground 3

Figure 3 - Input Pin-Out Table

Figure 2 - EVDD404 Side View Showing Power Device

Installed In A High-Power Configuration

Evaluation PCB

Kapton Insulator

TO-220, TO-247,

TO-264, or SOT-227

Heat Sink

Figure 1 - EVDD404 Evaluation Board

SOT-227 Device Installed For Illustration Purposes Only