®
VN02ANSP
HIGH SIDE SMART POWER SOLID STATE RELAY
T YPE
VN02ANSP
s
V
DSS
60 V
R
DS( on
)
0.35
Ω
I
OUT
7 A
V
CC
36 V
s
s
s
s
s
OUTPUT CURRENT (CONTINUOUS):
7A @ T
c
=25
o
C
LOGIC LEVEL 5V COMPATIBLE INPUT
THERMAL SHUT-DOWN
UNDER VOLTAGE PROTECTION
OPEN DRAIN DIAGNOSTIC OUTPUT
FAST DEMAGNETIZATION OF INDUCTIVE
LOAD
10
1
DESCRIPTION
The VN02ANSP is a monolithic device made
using STMicroelectronics VIPower Technology,
intended for driving resistive or inductive loads
with one side grounded.
Built-in thermal shut-down protects the chip from
over temperature and short circuit. The diagnostic
output indicates an over temperature status.
Fast turn-off of inductive load is achieved by
negative (-18 V) load voltage at turn-off.
BLOCK DIAGRAM
PowerSO-10
TM
July 1998
1/9
VN02ANSP
FUNCTIONAL DESCRIPTION
The device has a diagnostic output which
indicates over temperature conditions.
The truth table shows input, diagnostic output
status and output voltage level in normal
operation and fault conditions. The output signals
are processed by internal logic.
To protect the device against short circuit and
over current conditions, the thermal protection
turns the integrated Power MOS off at a minimum
junction temperature of 140
o
C. When the
temperature returns to 125
o
C the switch is
automatically turned on again. To ensure the
protection in all V
CC
conditions and in all the
junction temperature range it is necessary to limit
the voltage drop across Drain and Source (pin 3
and 5) at 28V according to:
V
ds
= V
CC
- I
OV
* (R
i
+ R
w
+ R
l
)
where:
R
i
= internal resistence of Power Supply
R
w
= Wires resistance
R
l
= Short Circuit resistance
Driving inductive loads, an internal function of the
device ensures the fast demagnetization with
typical voltage (V
demag
) of -18V.
This function allows the reduction of the power
dissipation according to the formula:
P
dem
= 0.5 * L
load
* (I
load
)
2
* [(V
CC
+ V
dem
)/V
dem
] * f
Figure 2:
Over Current Test Circuit
where f = Switching Frequency
Based on this formula it is possible to know the
value of inductance and/or current to avoid a
thermal shut-down.
PROTECTING THE DEVICE AGAINST RE-
VERSE BATTERY
The simpliest way to protect the device against a
continuous reverse battery voltage (-36V) is to
insert a Schottky diode between pin 1 (GND) and
ground, as shown in the typical application circuit
(Fig. 3). The consequences of the voltage drop
across this diode are as follows:
If the input is pulled to power GND, a negative
voltage of -V
f
is seen by the device. (V
il
, V
ih
thresholds and Vstat are increased by V
f
with
respect to power GND).
The undervoltage shut-down level is increased by
V
f
.
If there is no need for the control unit to handle
external analog signals referred to the power
GND, the best approach is to connect the
reference potential of the control unit to node [1]
(see application circuit in fig. 4), which becomes
the common signal GND for the whole control
board avoiding shift of V
ih
, V
il
and V
stat
. This
solution allows the use of a standard diode.
5/9
RF/Wirelessly
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