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© Semiconductor Components Industries, LLC, 2016
July, 2016 − Rev. 0
1 Publication Order Number:
EVBUM2484/D
NCV7748GEVB
NCV7748 Evaluation Board
User's Manual
Eight Channel Low-Side Relay Drivers
with LIN Communication
Description
The NCV7748 is an octal low-side relay driver for automotive
applications targeted for use in a Power Distribution Box (PDB).
Communication to the device is through a LIN bus compliant to SAE
J2602 and LIN 2.x. All drivers have passive output clamps for limiting
output voltage spikes during flyback events during inductive relay
turn-off events.
This evaluation board is intended for evaluation of the output
drivers, and highlights many of the features of the device.
The NCV7748 has two types of low-side drivers. One is intended to
run outside of the module and the other is targeted for use inside the
module. All outputs have Overcurrent Detection, but the output
drivers intended for use external to the module (OUT4, OUT8) have
added Open Load detection and individual Overtemperature (Thermal
Shutdown) detection. The evaluation board includes NEC EX2
automotive relay loads, with the option to disconnect these loads and
use customer defined external loads.
Output control is interfaced with the use of dip switches and
a push-button. Output Control Commands as well as Output errors can
be read from the LCD display. Truth tables are included in silk screen
on the PCB for ease of use for both command control and error
deciphering.
Features
• Individual Output Drive Control
• On-board Relay Demonstration with Option for Off-board
Connections
• Get Status Request for Error Reporting from ERR and APPINFO
Registers
Application
The NCV7748 device includes 8 low-side drivers. Each includes an
output clamp for inductive loads. A 41 V (typ) clamp from the drain to
gate of the output driver helps protect the output driver from seeing
excessive voltage during a flyback event from an inductive load. The
minimum specification for the clamp voltage is 38 V. It is important to
limit external DC supply voltages to less than 38 V to avoid a high
power situation.
Primary target loads are coils of relays for a power distribution box
(PDB). These can include, but not limited to loads for Engine Control
Unit (ECU), Windshield Wipers, Sunroof, Cruise Control, Rear
Window Defroster, Fog Lights, Cooling Fans, Ignition, Headlights,
Tail Lights, Hazard Lights, Horn, Cooling Fan, Cluster, Heated
Mirror, External Accessory Voltage, Instrument Cluster, Keyless
Entry, Fuel Pump, etc.
www.onsemi.com
EVAL BOARD USER’S MANUAL
Figure 1. NCV7748 Evaluation Board
Figure 2. 1.5 W Output Drivers
Figure 3. 0.8 W Output Drivers
OUT
5
OUT
3
OUT
2
OUT
1
1.5 W
(Typ)
OUT
6
OUT
7
41 V
(Typ)
Over CurrentFault
0.8 W
(Typ)
41 V
(Typ)
OUT
8
OUT
4
Thermal Shutdown
Over Current
Open Load
Fault
