User Manual

D
D
i
i
g
g
i
i
l
l
e
e
n
n
t
t
P
P
m
m
o
o
d
d
O
O
D
D
1
1
™
™
O
O
p
p
e
e
n
n
D
D
r
r
a
a
i
i
n
n
O
O
u
u
t
t
p
p
u
u
t
t
M
M
o
o
d
d
u
u
l
l
e
e
B
B
o
o
a
a
r
r
d
d
R
R
e
e
f
f
e
e
r
r
e
e
n
n
c
c
e
e
M
M
a
a
n
n
u
u
a
a
l
l
®
www.digilentinc.com
Revision: February 23, 2007
Note: This document applies to REV A of the board.
215 E Main Suite D | Pullman, WA 99163
[phone] Voice and Fax
Doc: 502-125 page 1 of 2
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Overview
The Digilent PmodOD1 Open Drain Output
Module Board (PmodOD1) can drive high
current devices using On-Semiconductor
NTHD4508NT power FET output transistors.
The output transistors are driven by logic
signals from a Digilent system board.
The output transistors function as low side
switches, sinking current from an external
voltage source to ground. The outputs can be
used to drive DC motors, stepper motors,
relays, solenoids or other electrical devices
operated via a switch closure to ground.
Flyback protection diodes are included on each
output to allow the outputs to drive inductive
loads.
Features include:
• two NTHD4508 dual power FETs
• 4.1A peak output current (t < 5s)
• 3.0A continuous current (at 25°C), 2.2A
continuous current (at 85°C)
• a 6-pin header for inputs
• two screw terminal blocks for outputs
• 20V max. output voltage
• small form factor (0.80” x 1.15”).
Functional Description
The PmodOD1 module is designed to work
with either Digilent programmable logic system
boards or embedded control boards. Most
Digilent system boards, like the Basys, Nexys
or Cerebot , have 6-pin connectors that allow
the PmodOD1 to plug directly into the system
board or to connect via a Digilent 6-pin cable.
Some older Digilent boards may need a
Digilent Module Interface Board (MIB) and a 6-
pin cable to connect to the PmodOD1.
The
MIB plugs into the system board and the cable
connects the MIB to the PmodOD1.
(6) Vcc (3.3 - 5V)
(5) GND
(1) G1
(2) G2
(3) G3
(4) G4
Figure 2 PmodOD1 Input Connector, J1
The PmodOD1 provides four logic level inputs,
G1-G4. Each input connects to a Schmitt
trigger, non-inverting buffer that drives the gate
of the corresponding output transistor. Driving
an input high will drive
the gate of the
corresponding output transistor high,
J1
J2
J3
Typical Circuit (4x)
J4
G1
G2
G3
G4
OD1
OD2
OD3
OD4
JP1
Vcc
GND
VL
GND
VL
OD
Figure 1 PmodOD1 Block Diagram