NUP4114 Series
www.onsemi.com
5
APPLICATIONS INFORMATION
The new NUP4114 is a low capacitance ESD diode array
designed to protect sensitive electronics such as
communications systems, computers, and computer
peripherals against damage due to ESD events or transient
overvoltage conditions. Because of its low capacitance, it
can be used in high speed I/O data lines. The integrated
design of the NUP4114 offers low capacitance steering
diodes and an ESD diode integrated in a single package
(TSOP−6). If a transient condition occurs, the steering
diodes will drive the transient to the positive rail of the
power supply or to ground. This device protects the power
line against overvoltage conditions to avoid damage to the
power supply and any downstream components.
NUP4114 Configuration Options
The NUP4114 is able to protect up to four data lines
against transient overvoltage conditions by driving them to
a fixed reference point for clamping purposes. The steering
diodes will be forward biased whenever the voltage on the
protected line exceeds the reference voltage (V
f
or
V
CC
+ V
f
). The diodes will force the transient current to
bypass the sensitive circuit.
Data lines are connected at pins 1, 3, 4 and 6. The negative
reference is connected at pin 2. This pin must be connected
directly to ground by using a ground plane to minimize the
PCB’s ground inductance. It is very important to reduce the
PCB trace lengths as much as possible to minimize parasitic
inductances.
Option 1
Protection of four data lines and the power supply using
V
CC
as reference.
I/O 1
I/O 2
I/O 3
I/O 4
V
CC
6
5
4
1
2
3
For this configuration, connect pin 5 directly to the
positive supply rail (V
CC
), the data lines are referenced to
the supply voltage. The internal ESD diode prevents
overvoltage on the supply rail. Biasing of the steering diodes
reduces their capacitance.
Option 2
Protection of four data lines with bias and power supply
isolation resistor.
V
CC
10 k
I/O 1
I/O 2
I/O 3
I/O 4
6
5
4
1
2
3
The NUP4114 can be isolated from the power supply by
connecting a series resistor between pin 5 and V
CC
. A 10 kW
resistor is recommended for this application. This will
maintain a bias on the internal ESD and steering diodes,
reducing their capacitance.
Option 3
Protection of four data lines using the internal ESD diode
as reference.
I/O 1
I/O 2
I/O 3
I/O 4
NC
6
5
4
1
2
3
In applications lacking a positive supply reference or
those cases in which a fully isolated power supply is
required, the internal ESD can be used as the reference. For
these applications, pin 5 is not connected. In this
configuration, the steering diodes will conduct whenever the
voltage on the protected line exceeds the working voltage of
the ESD plus one diode drop (V
C
= V
f
+ VESD).
ESD Protection of Power Supply Lines
When using diodes for data line protection, referencing to
a supply rail provides advantages. Biasing the diodes
reduces their capacitance and minimizes signal distortion.
