Fairchild FAN3241TMX Smart dual-coil relay driver Datasheet

FAN3240 / FAN3241
Smart Dual-Coil Relay Drivers
Features

8-V to 60-V Operation Range for use with 12-V,
24-V or 48-V Relays

Strong DC Current to Break through Welded
Contacts without using External Switches

Integrated Linear Regulator for Isolated or
Non-Isolated Meter Power Designs



Accurate Input Filter Time and XOR input protection




3.3-V or 5-V Square-Wave Logic Input Signals
Accurate maximum output pulse width
Two output operating modes – follows input width
or maximum value
Enable Pin for Operational Flexibility
Internal Thermal Shutdown Protection
Rated from –40°C to +105°C Ambient
Applications

Smart E-Meters, Energy Generation & Distribution,
Building and Home Control, Industrial dual-coil
relay Driving Applications
Description
The FAN324x family includes dual high-current relay
drivers designed to drive dual-coil polarized latching
relays that connect and disconnect power in smart
electronic meters and solar inverter applications.
The output of the FAN324x is rated for operation with
supply voltage range from 8 V to 60 V. The filter / timer
block prevents inadvertent switching from noisy input
signals by providing input-pulse qualification (tQUAL) and
maximum output pulse width limit (tMAX). The output can
operate in follow-input mode or maximum width mode.
These parameters are factory adjustable and additional
configurations are available. XOR input protection is
also provided so that both outputs are prevented from
being on at the same time. Under-Voltage Lockout
(UVLO) function disables the outputs until the supply
voltage is within the operating range.
The FAN324x has two separate driver channels with
non-inverting logic. One enable / disable pin allows
shutdown of both channels, independent of the input
signals. Internal thermal shutdown function is provided
for thermal protection. The FAN324x is available in an
Lead (Pb)-Free 8-lead SOIC package.
+SUPPLY
10 V ~ 60.0 V
VS
8
EN 1
UVLO
Ref
5VB
OUT1
Regulator
2
EN
Internal
Bias
7
TSD
A
GND
B
6
Osc
Relay Open
3
C
IN1
100 kΩ
Processor
IN2
Timer /
Filter /
Protection
OUT2
EN
5
4
Relay Close
100 kΩ
Figure 1.
© 2012 Fairchild Semiconductor Corporation
FAN3240 / FAN3241 • Rev. 1.0.2
Product
tQUAL
tMAX
FAN3240
15 ms
150 ms
OUT Mode
tOUT = tIN
FAN3241
1 ms
30 ms
tOUT = tMAX
Typical Application Diagram
www.fairchildsemi.com
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
May 2014
Part
Number
Minimum Input
Time
Maximum Pulse
Width
Package
Packing
Method
Reel
Quantity
FAN3240TMX
15 ms
150 ms
SOIC-8
Tape & Reel
2,500
FAN3241TMX
1 ms
30 ms
SOIC-8
Tape & Reel
2,500
All standard Fairchild Semiconductor products are RoHS compliant and many are also “GREEN” or going green. For Fairchild’s
definition of “green” please visit: http://www.fairchildsemi.com/company/green/rohs_green.html.
Package Outline
EN
1
8
VS
5VB
2
7
OUT1
IN1
3
6
GND
IN2
4
5
OUT2
Figure 2.
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Ordering Information
SOIC-8 (Top View)
Thermal Characteristics(1)
ΘJL
ΘJT
ΘJA
ΨJB
ΨJT
Unit
40
31
89
43
3.0
°C/W
(2)
Package
8-Pin, Small-Outline Integrated Circuit (SOIC)
(3)
(4)
(5)
(6)
Notes:
1.
2.
3.
4.
5.
6.
Estimates derived from thermal simulation; actual values depend on the application.
Theta_JL (ΘJL): Thermal resistance between the semiconductor junction and the bottom surface of all the leads (including any
thermal pad) that are typically soldered to a PCB.
Theta_JT (ΘJT): Thermal resistance between the semiconductor junction and the top surface of the package, assuming it is
held at a uniform temperature by a top-side heatsink.
Theta_JA (ΘJA): Thermal resistance between junction and ambient, dependent on the PCB design, heat sinking, and airflow.
The value given is for natural convection with no heatsink, as specified in JEDEC standards JESD51-2, JESD51-5, and
JESD51-7, as appropriate.
Psi_JB (ΨJB): Thermal characterization parameter providing correlation between semiconductor junction temperature and an
application circuit board reference point for the thermal environment defined in Note 4. For the MLP-8 package, the board
reference is defined as the PCB copper connected to the thermal pad and protruding from either end of the package. For the
SOIC-8 package, the board reference is defined as the PCB copper adjacent to pin 6.
Psi_JT (ΨJT): Thermal characterization parameter providing correlation between the semiconductor junction temperature and
the center of the top of the package for the thermal environment defined in Note 4.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
www.fairchildsemi.com
2
8
VS
7
OUT1
EN 1
UVLO
Ref
Regulator
5VB 2
EN
Internal
Bias
TSD
Osc
6 GND
IN1 3
100 kΩ
Timer /
Filter /
Protection
EN
5
OUT2
IN2 4
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Block Diagram
100 kΩ
Figure 3.
Block Diagram
Pin Definitions
Pin
Name
Pin Description
1
EN
Enable input for both channels. Pull pin LOW to inhibit operation of the drivers. This input
has a precision threshold and comparator input stage.
2
5VB
5 V bypass pin for the internal 5 V regulator that provides power to the IC control circuitry.
3
IN1
Input to driver Channel 1. This input has TTL thresholds.
4
IN2
Input to driver Channel 2. This input has TTL thresholds.
5
OUT2
Relay drive output 2: Open-drain output. HIGH impedance unless required active input(s)
are present and VS is above UVLO threshold.
6
GND
Ground. Common ground reference for input and output circuits.
7
OUT1
Relay drive output 1: Open-drain output. HIGH impedance unless required active input(s)
are present and VS is above UVLO threshold.
8
VS
Supply voltage. Provides power to the device. Usually connected to the bias voltage of the
relay being driven by the device.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
www.fairchildsemi.com
3
The FAN324x products are set at the factory with the following configurations.
tQUAL
tMAX
OUT Mode
FAN3240
15 ms
150 ms
tOUT = tIN
FAN3241
1 ms
30 ms
tOUT = tMAX
Contact your Fairchild sales representatives for additional configurations. The parameter tQUAL can be configured between 128 µs
and 20 ms and tMAX can be programmed between 1 ms and 350 ms.
where:
tQUAL:
Qualification Time. The minimum input pulse width duration recognized as a valid input command.
tMAX:
Maximum Output Pulse Width. Output pulses are terminated after this time interval even if the input
pulse is longer or held in a HIGH state continuously.
OUT Mode: Output Mode. TheFAN324x offers two fundamentally different output pulse generation methods:
tOUT = tIN < tMAX. In this mode, the output pulse duration (tOUT) replicates the length of the input pulse
(tIN) up to tMAX.
tOUT = tMAX. The output is on for a fixed time interval of tMAX, regardless of the input pulse width.
The mode of operation has no impact on the qualification requirements or on the maximum output pulse
width limiting. In both output operating modes, the qualification requirement must be met (tIN > tQUAL) to
produce an output pulse.
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Configurations
Output Logic(7)
EN
IN1
IN2
OUT1
OUT2
0
0
0
H
H
0
0
1
H
H
0
1
0
H
H
0
1
1
H
H
1
0
0
H
H
1
0
1
H
L
1
1
0
L
H
1
1
1
H
H
Note:
7. Inputs and EN are defined as logic signals (positive logic; 1 is active), outputs are defined as HIGH or LOW
impedance due to the open-drain output structures. Low output impedance is needed to energize the relay coil.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
www.fairchildsemi.com
4
Stresses exceeding the absolute maximum ratings may damage the device. The device may not function or be
operable above the recommended operating conditions and stressing the parts to these levels is not recommended.
In addition, extended exposure to stresses above the recommended operating conditions may affect device reliability.
The absolute maximum ratings are stress ratings only.
Symbol
Parameter
Min.
Max.
Unit
VS
VS to GND
-0.3
70.0
V
V5VB
5VB to GND
-0.3
6.0
V
VEN
EN to GND
GND - 0.3
6.0
V
VIN
IN1 and IN2 to GND
GND - 0.3
6.0
V
OUT1 and OUT2 to GND
GND - 0.3
VS + 0.3
V
+260
ºC
VOUT
TL
Lead Soldering Temperature (10 Seconds)
TJ
Junction Temperature
-55
+125
ºC
TSTG
Storage Temperature
-65
+150
ºC
Recommended Operating Conditions
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Absolute Maximum Ratings
The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended
operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not
recommend exceeding them or designing to Absolute Maximum Ratings.
Symbol
Parameter
Min.
Typ.
Max.
Unit
60
V
VS
Output Supply Voltage Range
8
VEN
Enable Voltage EN
0
3.3 to 5.0
5.5
V
VIN
Input Voltage IN1, IN2
0
3.3 to 5.0
5.5
V
CVS
Bypass Capacitor at VS Pin
C5VB
Bypass Capacitor at 5VB Pin
100
Operating Ambient Temperature
-40
TA
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
1
µF
220
nF
+105
ºC
www.fairchildsemi.com
5
Unless otherwise noted, VS = 40 V, C5VB = 0.22 µF, and TJ = -40°C to +105°C. Currents are defined as positive into
the device and negative out of the device.
Symbol
Parameter
Conditions
Min.
Typ. Max.
Unit
Supply (VS)
ISTDBY
Standby Current
INx = 0 V, EN = 0 V
350
550
µA
ISUPPLY
Operating Current
IN1 or IN2 = 5 V, EN = 5 V
400
600
µA
VON
Turn-On Voltage
IN1 = IN2 = EN = 5 V
6.9
7.9
8.9
V
VOFF
Turn-Off Voltage
IN1 = IN2 = EN = 5 V
5.7
6.7
7.7
V
VHYS
Turn-On Hysteresis
0.5
1.2
V
0.8
1.1
V
Inputs (IN1, IN2)
(9)
VINL
INx Logic Low Threshold
VINH
INx Logic High Threshold
1.6
VIN_HYS
INx Logic Input Hysteresis
0.5
IIN
tQUAL
Input Current
INx = 5 V
(11)
2.0
V
V
55
80
µA
FAN3240
13.5
15.0
16.5
ms
FAN3241
0.9
1.0
1.1
ms
Valid Input Qualification Time
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Electrical Characteristics
ENABLE (EN)
VENL
Enable Logic Low Threshold
EN from 5 V to 0 V
1.25
1.30
1.35
V
VENH
Enable Logic High Threshold
EN from 0 V to 5 V
1.35
1.40
1.45
V
VHYS_T
Enable Logic Input Hysteresis
tDEL
0.1
(11)
EN to Output Propagation Delay
EN from 5 V to 0 V,
Logic Signal
V
5
9
µs
5.0
5.1
V
V
Internal Regulator (5VB)
V5VB
IOUT
5VB Output Voltage
TA = 25°C
4.9
Total Variation Over Line (1 0V
to 60 V), Load (0 mA to 5 mA),
(10)
and Temperature
4.8
5.2
Line Regulation, 10 V to 60 V
-1%
1%
Load Regulation, 0 mA to 5 mA
-2%
2%
Output Current
5.0
mA
Protection
TSD
Thermal Shutdown Threshold
TSDHYS
Thermal Shutdown Threshold
(10)
Hysteresis
(10)
150
°C
25
°C
Continued on the following page…
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
www.fairchildsemi.com
6
Unless otherwise noted, VS = 40 V, C5VB = 0.22 µF, and TJ = -40°C to +105°C. Currents are defined as positive into
the device and negative out of the device.
Symbol
Parameter
Conditions
Min.
Typ.
Max.
0.4
0.7
1.0
0.7
1.0
1.3
1.2
1.6
2.0
Unit
Outputs (OUT1, OUT2)
(10)
ISINK = 500 mA, –40°C
RDS(ON)
(10)
On Resistance (OUT1, OUT2)
ISINK = 500 mA, 25°C
(10)
ISINK = 500 mA, 105°C
tRISE
Output Rise Time
RPULL-UP = 36 kΩ
IMAX
Maximum Current Driving Capability
tMAX = 30 ms, 25°C
(10,11)
7
tFALL
Output Fall Time
tMAX
Maximum Pulse Width
IRVS
Output Reverse Current Withstand
µs
1.5
RPULL-UP = 36 kΩ
(10,11)
Ω
A
7
20
FAN3240
135
150
165
FAN3241
27
30
33
ns
ms
(10)
500
Notes:
8. Lower supply current due to inactive TTL circuitry.
9. EN inputs have TTL thresholds; refer to the ENABLE section.
10. Not tested in production.
11. See Timing Diagram of Figure 4.
mA
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Electrical Characteristics (Continued)
Timing Diagrams
VINH
Input
VINL
90%
Output
10%
tMAX
tQUAL
tFALL
Figure 4.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
t RISE
Timing (with EN HIGH)
www.fairchildsemi.com
7
Typical characteristics are provided at TA = 25°C and VS = 40 V unless otherwise noted.
Figure 5.
Figure 7.
Figure 9.
Supply Current vs. Supply Voltage
Figure 6.
Supply Current vs. Temperature
ON / OFF Thresholds vs. Temperature
Figure 8.
5VB Reference vs. Temperature
EN to OUTx Delay vs. Temperature
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Typical Performance Characteristics
Figure 10. 5VB Current Capability at 4.75 V Output vs.
Supply Voltage and Temperature
www.fairchildsemi.com
8
Typical characteristics are provided at TA = 25°C and VS = 40 V unless otherwise noted.
Figure 11. RDS(ON) vs. Temperature
Figure 12. Base Timer % Change vs. Temperature
Figure 13. FAN3240 Qualification Time
vs. Temperature
Figure 14. FAN3240 Max. Pulse vs. Temperature
Figure 15. FAN3241 Qualification Time
vs. Temperature
Figure 16. FAN3241 Max. Pulse vs. Temperature
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Typical Performance Characteristics
www.fairchildsemi.com
9
1.
Polarized, bi-stabile, latching relays are utilized in many
kinds of electronic equipment and diverse applications.
These relays usually employ two coils; one to move the
relay contact(s) from open to closed position and
another coil to move the contact(s) from closed to open
position. To facilitate the mechanical movement, the
relay coils need to be energized for a specific time
interval. Once the contact(s) have changed position, the
voltage should be removed from the winding of the
relay. A simplified, typical circuit diagram is shown in
Figure 17 with example waveforms.
During power-up, the FAN324x receives its bias voltage
from the VS pin. As the voltage rises at the VS pin, the
5 V output internal bias regulator starts working. The
voltage of the 5VB pin starts rising simultaneously with
the bias voltage at the VS pin. Once the VS voltage is
sufficiently high (as described below), the on-board
linear regulator enters regulation and provides bias for
the FAN324x internal circuitry.
Dual-Coil Relay
ON
VS
Due to the low power consumption of the internal control
circuits; the on-board, low drop-out linear regulator is
fully functional and in regulation from approximately
5.5 V on the VS pin. At this point, the FAN324x is still in
under-voltage lockout (UVLO); i.e. the relay drive
outputs are disabled and exhibit high impedance
regardless of the status of the input and enable pins.
The device becomes fully functional when the VS
voltage exceeds the UVLO turn-on threshold and stays
operational until the VS voltage falls below the UVLO
turn-off threshold. The nominal UVLO hysteresis is
about 1 V to prevent turning on and off the device due to
noise when the VS voltage is near the UVLO threshold.
The startup behavior is shown in Figure 18.
OFF
Figure 17. Simplified Diagram of a Relay Drive
As Figure 17 shows, a dual-coil relay is connected to its
supply rail at the center point of the two relay windings.
Each winding can be energized by the switches
connected to the relay coils. The two switches must not
be on at the same time because that would cause
excessive currents drawn from the supply rail, VS.
Furthermore, to accommodate the relatively long time
required for the relay contact to travel between its
stationary positions (ON and OFF positions), the pulse
must be longer than the minimum duration specified in
the relay datasheet. It is also desirable to limit the
maximum length of the drive pulse to prevent potential
saturation of the relay winding and to avoid over heating
the coils and drive electronics. The relay specification
also defines the minimum and maximum operating
voltages for reliable operation of the contact(s).
Figure 18. Startup Waveforms
The FAN324x family of relay drivers is designed to
minimize component count and board space, while
increasing the reliability of the system and the noise
immunity of the circuitry driving the coils of the relay.
The integrated solution provides input signal
qualification for the control signals, protection against
simultaneous activation of the two relay coils, a
maximum drive pulse duration limit, and many basic
functions; such as monitoring the relay bias voltage (VS)
for sufficient voltage level, driver enable input, and
thermal protection for the IC.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
Powering the Device (VS Pin)
The FAN324x device is powered through its VS pin by a
single voltage source, which should be the same source
powering the relay. In general, the VS pin should be
connected to the highest potential in the system
because the voltage stresses on all other pins shall not
exceed the VS pin voltage by more than the forwardvoltage drop of a P-N junction, as indicated in the
Absolute Maximum Ratings table.
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Functional Description
Theory of Operation
As Figure 18 demonstrates, the startup behavior of the
FAN324x devices are well controlled, the bias generator
enters regulation smoothly without overshoot or
oscillation, and the outputs remain high impedance
during the entire startup interval.
www.fairchildsemi.com
10
This functionality can be used to monitor other vital
voltage levels in the system, such as the supply
voltage for the logic generating the control signals for
the FAN324x or the power rail of the relay being driven
by the device. An example implementation of this
monitoring functionality is shown in Figure 20.
Internal Bias Regulator (5VB Pin)
The FAN324x’s internal bias generator is a low dropout
linear regulator with a 5 V output. The regulator is
designed to operate with minimum overhead; it is able
to regulate its output with very low voltage drop across
its bypass element.
3.3V or VS
The 5 V output of the regulator can be used to power
external circuitry as well. In addition to the internal
power consumption of the FAN324x, the regulator can
deliver at least 5 mA additional current for an external
load connected to the 5VB pin of the device.
EN
pin
1
Similar to other linear regulator circuits, the on-board
regulator needs to be bypassed externally for stabile
operation. It is recommended that the output of the
regulator is bypassed by at least a 100 nF, good-quality,
high-frequency, ceramic capacitor placed in close
proximity to the 5VB and GND pins.
3.
1.4V/1.3V
Internal
Enable
Signal
Figure 20. Voltage Monitoring Example Using the
EN Input Circuit
Enable Operation (EN Pin)
The enable (EN) input is a level-sensitive input and it is
the most dominant input of the FAN324x during normal
operation. The enable pin must be above the input
threshold to generate an output pulse and energize the
relay coil. The input circuit of the enable input is
comprised of a comparator circuit with a precise voltage
source connected to the inverting input of the
comparator and the EN pin connected to the noninverting input. To avoid erroneous operation due to
potential noise superimposed on the incoming control
signal, the enable signal goes through a low-pass filter
before it connects to the non-inverting input of the
comparator. The filter is designed with a large timeconstant; thus the enable input has an approximately
5 µs delay before it can act on the received command
level. Once the EN pin is pulled LOW and the signal
propagates through the filter, the relay drive outputs
become high impedance and the internal control circuit
returns to its initial inactive state.
As Figure 20 indicates, the input comparator is
implemented with a fixed internal hysteresis of
approximately 100 mV. The incoming low-pass filter and
the built-in hysteresis of the comparator provide enough
noise immunity to prevent inadvertent toggling of the
internal enable signal. Additional filtering can be added
by connecting an additional high-frequency capacitor
between the EN pin and GND (pin 6).
Since the input threshold of the comparator is
compatible with TTL logic signal levels, the EN input can
also be driven directly from a logic source, such as a
microcontroller or other similar digital circuits. When the
EN pin is driven by a logic signal, the resistors shown in
Figure 20 are not needed and additional filtering is not
required because of the fast rise and fall times of such
digital signals.
It is important to note that while the EN input is the most
dominant input during normal operation, the UnderVoltage Lockout (UVLO) and Thermal Shutdown
protection (TSD) override the enable input and can
disable the operation of the device.
4.
Input Signal Processing (IN1 and IN2 Pins)
The FAN324x features two drive channels, one to
energize the relay coil to close the relay contact(s) and
another one to open it. The channels utilize their
respective inputs (IN1 and IN2 pins) and outputs (OUT1
and OUT2 pins). Since the circuitry comprising the two
driver channels inside the FAN324x are identical in
implementation and in operation, they can be assigned
to perform either the opening or closing functions.
Time Base:
5μs/div
The voltage thresholds of the FAN324x inputs meet
industry-standard TTL-logic levels independent of the
supply voltage, VS. Therefore, the input pins can be
driven from a range of logic signal levels for which a
voltage over 2 V is considered logic HIGH (active).
Figure 19. Enable Operating Waveforms
Due to the precise thresholds, the EN input can also
be used as a voltage monitoring input that enables or
disables the relay drive based on the monitored
voltage level.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
Filter
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
2.
www.fairchildsemi.com
11
a)
The input qualification circuit provides additional
protection against erroneous input pulses and noise at
the input terminals. Figure 22 shows the presence of an
erroneous input pulse at the IN2 input while the IN1
pulse is being qualified.
Input Qualification
One of the fundamental functions of the FAN324x is to
qualify the incoming logic signals and differentiate
between a valid command and noise at its inputs. For
reliable operation, all input pulses shorter than the
qualification time (tQUAL) of the device are ignored. That
means that only qualified input pulses produce an
energizing pulse for the relay at output of the device. An
input signal becomes qualified if it stays continuously in
the HIGH state for a time interval longer than the
qualification time.
Figure 22. Pending Qualification Waveform
Before IN1 is fully qualified, an erroneous signal
appears at the IN2 input. In this case, the qualification of
IN1 continues, but the result is pending. If IN2 stays
HIGH for longer than tQUAL, both inputs are valid. That
scenario falls under XOR protection, which is discussed
in the next section. In the example shown in Figure 22,
IN2 is shorter than the qualification time and is ignored.
At the time when IN2 goes LOW, the IN1 signal is
already HIGH for longer than tQUAL. Therefore, IN1 is a
valid command and is executed as demonstrated by the
waveforms in Figure 22.
b)
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
The inputs of the FAN324x are edge-sensitive inputs,
which means that an input command is not recognized
by the input being HIGH, but rather it is acknowledged
when a LOW-to-HIGH transition is sensed at the input
pin (IN1 or IN2). This is imperative to avoid erroneous
output pulse generation in case an input would be
permanently connected to a voltage above the TTL
input threshold level. Such a scenario is plausible in
case of a manufacturing mistake or if the signal source
driving the INx pin stops working and stays permanently
in HIGH state.
Additional Input Protection Functions
It is also possible that activating one of the inputs and its
corresponding output signal will create noise in the
system which will show up at the inactive input.
Figure 21. Input Qualification Waveforms
The waveforms shown in Figure 21 were taken with a
FAN3240 device. The qualification time of this particular
IC is 15 ms. The IN1 pulse width shown in Figure 21 is
10 ms long and it is ignored because it is shorter than
tQUAL. The IN2 input receives a 50 ms wide pulse, which
is longer than tQUAL; therefore, it qualifies as a valid
command. Once the input signal stays continuously
HIGH for longer than the qualification time, the relay
drive output turns on (OUT2 waveform). In the FAN3240
device, the output pulse width equals the duration of the
input signal, as shown in Figure 21.
The length of the output pulse width (an exact copy of
the incoming pulse width, as shown, or always the
maximum limit), as well as the duration of the
qualification time and the maximum allowable length of
the output pulse, are factory-adjustable parameters and
can be fine tuned to application requirements. These
options and the adjustment range of these parameters
are described in Section 6 of this Functional Description.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
Figure 23. Noise at the Inactive Input
As Figure 23 shows, noise on the inactive input pin is
suppressed and ignored. The FAN324x family of relay
drivers can handle excessive noise signatures reliably.
www.fairchildsemi.com
12
Figure 26. Overlapping Qualified Inputs Case
The XOR protection prevents simultaneous drive signals
being delivered to the two coils of the relay and is an
important feature of the device.
Figure 24. Exclusion of Overlapping Commands
5.
Figure 24 illustrates the operation of the FAN324x with
overlapping commands. The IN2 input signal is being
received while the previous command on channel one is
still being executed. It is signified by the fact that OUT1
is still LOW when the rising edge of the IN2 signal
arrives. Because the previous command is still active,
the IN2 signal is discarded by the input protection logic
of the FAN324x. That means that once the FAN324x is
committed to an output pulse, it ignores the other input
(except the EN input, which is the most dominant input
of the device).
c)
Relay Drive Outputs (OUT1 and OUT2 Pins)
The actual relay is driven through the dedicated drive
outputs of the FAN324x. These outputs utilize
monolithic MOSFET power devices, in an open-drain
configuration, which are capable of handling the voltage
level and drive current required to energize the relay
coils. The typical RDSON resistance of these devices is
0.9 Ω and they are designed for approximately 1 A
output currents. Carrying the rated output current
continuously through the relay coil and the output
transistors of the FAN324x would cause excessive
power dissipation in the relay coil as well as in the
driver. It is therefore necessary to prevent the outputs to
be on continuously.
XOR Input Protection
The XOR protection implemented in the FAN324x
devices prohibits output pulses when two qualified input
signals have been received at the same time. The XOR
protection works when both inputs are asserted together
or a second qualified input is received while the first one
is being qualified. The two cases of the XOR protection
are illustrated in Figure 25 and Figure 26.
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Another aspect of protecting the integrity of the system
is to ensure that a new command cannot be received
and executed until the previous command execution is
finished.
The maximum on-time of the FAN324x outputs is limited
by the protection logic circuit. Under no circumstances
should the outputs be on longer than the duration
specified by the tMAX parameter. Figure 27 demonstrates
operation of the output pulse width limiter of the device.
Figure 27. Maximum Output Pulse Width Limiting
Figure 25. Simultaneous Insertion of Two
Qualified Inputs
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
www.fairchildsemi.com
13
This protection feature works for any event that would
produce a longer-than-allowed input command. Figure
27 shows typical cases of receiving a long input signal.
In the case of IN1, the input signal is a square wave, but
its HIGH state is longer than tMAX. The corresponding
OUT1 output is terminated 150 ms after its start time,
which is the exact maximum on-time of the FAN3240
device used in the measurement.
Figure 27 shows the IN2 input staying HIGH
permanently. Similar behavior to the long square wave
input case can be observed on the OUT2 output. The
drive signal is terminated when the pulse width reaches
the tMAX limit.
6.
Operating Modes
Figure 28. FAN3240 Operation
Some aspects of the FAN324x family of relay drivers’
operation can be adjusted through the below factoryconfigurable parameters:
1.
tQUAL: Qualification Time. This is the minimum input
pulse width duration recognized as a valid input
command.
2.
tMAX: Maximum Output Pulse Width. Output pulses
are terminated after this time interval even if the
input pulse is longer or held in a HIGH state
continuously.
3.
Output Mode: The FAN324x offers two output pulse
generation methods:
The FAN3240 is configured to produce an output pulse
that equals the length of the incoming control signal. As
Figure 28 indicates, the incoming signals might not be
the same length. They are accurately reproduced at the
respective outputs of the device. The delay between the
input and output pulses is the qualification time. Further
detail of the timing relationship between the input and
output pulses are illustrated in Figure 29.
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
The Figure 28 and Figure 29 scope pictures clarify the
operation of the FAN3240 device. The configuration
options are listed in Table 1.
If the input pulse is longer than the maximum on-time
listed in the datasheet, the duration of the output pulse
width is equal to tMAX.
tOUT = tIN < tMAX. In this mode, the output pulse
duration (tOUT) replicates the length of the input
pulse (tIN) up to tMAX.
tOUT = tMAX. The output is on for a fixed time interval
of tMAX, regardless of the input pulse width.
The mode of operation has no impact on the
qualification requirements or on the maximum
output pulse width limiting. In both output operating
modes, the qualification requirement must be met
(tIN > tQUAL) to produce an output pulse.
Figure 29. Timing Details of FAN3240 Operation
The input pulse width received at IN1 is measured by
the oscilloscope and can be found under the label P1.
The measurement P2 is the length of the output pulse
generated by the FAN3240. Note the extremely
accurate reproduction of the input pulse duration at the
output of the device. The third measurement, labeled
P5, is the time between the rising edge of IN_1 and the
falling edge of OUT_1 traces. It is the qualification time
measured by the oscilloscope.
T able 1. Factory Set Configurations
Product
tQUAL
tMAX
OUT Mode
FAN3240
15 ms
150 ms
tOUT = tIN
FAN3241
1 ms
30 ms
tOUT = tMAX
Contact a Fairchild sales representatives for additional
configurations. The parameter tQUAL can be configured
between 128 µs and 20 ms. Parameter tMAX can be
programmed between 1 ms and 350 ms.
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
Similar measurements demonstrating the operation of
the FAN3241 are shown in Figure 30 and Figure 31.
www.fairchildsemi.com
14
Figure 31. Timing Waveforms of the FAN3241
The FAN3241 produces fixed length output pulses as
long as the incoming pulse width meets the qualification
requirements. The timing details are shown in Figure 31.
Similar to the previous example, the P1 measurement of
the oscilloscope shows the length of the input
command, IN_1. The tMAX duration is shown under the
label P2 and tQUAL is measured under P5. The results
show accurate timing performance for both factory
programmable parameters.
Applications Information
The FAN324x significantly improves reliability and offers
many protection functions that would be impractical to
implement using discrete circuit components. In
addition, it also greatly reduces component count and
simplifies the relay drive circuit. A typical relay drive
application is depicted in Figure 32.
schematic of Figure 34 for isolated designs. The
maximum guaranteed output current that can be used
by external circuits is 5 mA; the regulator can deliver at
least 5 mA to the external load and still meet all
specifications listed in the parametric tables.
5VB Power Dissipation Considerations
Input Connections
The output current of the 5VB bias regulator is supplied
from the VS pin. While the recommended output current
is 5 mA or less, the regulator is capable of sourcing
significantly more current before its current limit is
activated. Figure 10 of the typical performance
characteristics curves shows the maximum current
capability of the on-board linear regulator as a function
of the input voltage and ambient temperature.
The inputs of the relay driver can be directly driven from
any appropriate signal source producing a TTLcompatible logic signal. The IN1 and IN2 inputs have
100 kΩ internal pull-down resistors, ensuring the offstate of the drive outputs during the high-impedance
state of the source. This could happen during startup
when a microcontroller is used to control the system.
If FAN324x is within recommended operating conditions
(I5VB < 5 mA), the power dissipation of the regulator
remains below 275 mW even at the highest operating
voltage (60 V). However, at higher current levels, the
power dissipation of the regulator and the thermal
capabilities of the SOIC-8 package must be considered.
Enable Connection
The enable (EN) pin of the device must be connected to
the 5VB pin if it is not used. There is no pull-up or pulldown termination at this pin because any internal
impedance might impact the accuracy of the comparator
circuit when this pin is used for voltage monitoring.
At high input voltage levels (VS > 25 V) and currents
over the guaranteed 5 mA level, the power loss of the
on-board regulator might be high enough to elevate the
junction temperature to the thermal protection shutdown
threshold. If this occurs, the device shuts down to
protect itself and functionality is lost until the junction
temperature falls approximately 25°C (the thermal
shutdown hysteresis).
5VB Bypass Recommendations
The 5VB pin is the output of the internal bias regulator
of the FAN324x. For stability of the negative feedback
loop of the linear regulator and for noise filtering, a good
quality high-frequency capacitor must be connected
between this pin and the ground (GND) pin of the
device. The recommended minimum capacitance is
100 nF. The capacitor should be placed near the 5VB
and GND pins for best result.
To preserve full functionality and reliable operation, it is
recommended to check the output current rating of the
linear regulator and to always calculate the power
dissipation and the maximum temperature rise due to
self heating.
The output voltage of the on-board linear regulator is
5 V. This 5 V output can be used to power external
circuitry. An example is shown in the application
© 2011 Fairchild Semiconductor Corporation
FAN3240 • Rev. 1.0.2
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Figure 30. Operating Waveforms
www.fairchildsemi.com
15
Good-quality, high-frequency, ceramic capacitors should
be placed in close proximity to the VS and GND pins for
local bypass for the IC. A recommended value is 1 µF.
This capacitor serves as separate energy storage for
the FAN324x. As it is shown in Figure 32, a low value
(~10 Ω) resistor could be used to form a filter with the
VS pin bypass capacitor and prevent large noise spikes
propagating from the relay power supply to the bias
voltage of the device.
It is recommended that the clamp diodes are placed
near the OUT1 and OUT2 pins and the VS pin as shown
in Figure 32.
If deep discharge of the relay bypass capacitor is
anticipated during the switching of the relay, an optional
small-signal diode in series with the filter resistor is
recommended. The diode can avert the discharge of the
local VS pin bypass capacitor even if the relay supply
voltage would fall during switching. This technique can
prevent accidental activation of the under-voltage
lockout mechanism.
If using the small blocking diode, the inductive energy
is fully absorbed by the VS pin bypass capacitor. This
might require increasing the size of the local bypass
capacitor to effectively clamp the voltage at the VS pin.
Consider that the quiescent current consumption of the
FAN324x is the only load on the VS bypass capacitor.
Rapid repetitive switching action might increase the
voltage across the capacitor. To address this concern,
Figure 33 (shows an alternative termination of the
clamp diodes, back to the center point of the relay,
directly to the relay power supply output, which has a
much higher capacitance.
Output Connections
The FAN324x devices feature an open-drain MOSFET
output structure which is designed to carry the required
current to energize the relay coils. The relay coils can
be considered as a series combination of an inductor
Typical Configurations
1N4148
(Optional)
Relay
Bias
Dual-Coil Relay
10 Ω
1 EN
2x
Clamp
Diode
VS 8
VDD
2 5VB OUT1 7
CLOSE
Microcontroller
(or similar
logic source)
OPEN
RELAY_CLOSE
2.2 µF
3 IN1
GND 6
4 IN2
OUT2 5
RELAY_OPEN
Bypass for
Relay Bias
0.22 µF
Figure 32. Typical Application Schematic
1N4148
(Optional)
Relay
Bias
Dual-Coil Relay
10 Ω
1 EN
2x
Clamp
Diode
VS 8
VDD
2 5VB OUT1 7
CLOSE
Microcontroller
(or similar
logic source)
OPEN
RELAY_CLOSE
2.2 µF
3 IN1
GND 6
4 IN2
OUT2 5
RELAY_OPEN
Bypass for
Relay Bias
0.22 µF
Figure 33. Application Schematic with Alternate Clamp Diode Connections
© 2012 Fairchild Semiconductor Corporation
FAN3240 / FAN3241 • Rev. 1.0.2
www.fairchildsemi.com
16
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
and a resistor. Like in many other applications where
substantial inductive load current is being interrupted,
switching spikes can present excessive voltage stresses
on the output devices. Therefore, it is necessary to use
two clamp diodes to protect each output of the FAN324x
against the inductive spikes. It is important to
emphasize that the clamp diodes sole responsibility is to
protect the switches. Thus their location on the printed
circuit board layout is very important.
VS Pin Bypass Guidelines
In some cases, it might be desirable to completely
separate the power system of the actual relay drive from
the supply voltages of the control electronics. The
FAN324x relay drivers can facilitate an isolated relay
drive implementation, as shown in the Figure 34
schematic. The solution can be as simple as inserting
the opto-couplers in the command signal path. As
indicated in Figure 34, the opto-couplers need a pull-up
resistor to a positive voltage rail, which is available at
the 5VB pin. Having the internal 5 V bias voltage
accessible externally eliminates the need to generate an
additional low voltage on the isolated side just for the
pull-up resistors of the opto-couplers.
Note that the opto-couplers might also invert the control
signals as they transmit them through the isolation
boundary. The circuit in Figure 34 is an inverting optocoupler implementation. When the logic signal goes
HIGH at the microcontroller output, the input connection
to the FAN324x is pulled LOW. This is the exact
opposite of the required control sequence. The solution
is to use negative logic at the output of the
microcontroller in anticipation of the inversion at the
opto-coupler output. The other option is to connect the
anodes of the opto diodes to the bias supply of the
digital logic (VDD) and exert the control from the
microcontroller at the cathode of the opto-coupler.
1N4148
(Optional)
Relay
Bias
Dual-Coil Relay
10 Ω
1 EN
2x
Clamp
Diode
VS 8
VDD
10kΩ
CLOSE
Microcontroller
(or similar
logic source)
10kΩ
CLOSE
OPEN
OPEN
2 5VB OUT1 7
RELAY_CLOSE
2.2 µF
3 IN1
GND 6
4 IN2
OUT2 5
RELAY_OPEN
Bypass for
Relay Bias
0.22 µF
D-GND
A-GND
Figure 34. Application Schematic for Isolated Designs
Layout and Connection Guidelines
The FAN324x relay drivers incorporate fast input circuits
and powerful output stages capable of delivering high
current peaks. The following layout and connection
guidelines are strongly recommended:

Keep high-current output and power ground paths
separate from the logic and enable input signals
and signal ground paths.
© 2012 Fairchild Semiconductor Corporation
FAN3240 / FAN3241 • Rev. 1.0.2

Keep the driver as close to the load as possible to
minimize the length of high-current traces.

Minimize the relay current loop. Keep in mind that
the current of the relay coil flows through the relay
bias power supply’s output capacitor, the coils
themselves, the integrated output switches of the
FAN324x and the GND connections.
www.fairchildsemi.com
17
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Isolated Applications
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
Physical Dimensions
0.65
A
4.90±0.10
(0.635)
5
8
B
1.75
6.00±0.20
1
PIN ONE
INDICATOR
5.60
3.90±0.10
4
1.27
1.27
0.25
C B A
LAND PATTERN RECOMMENDATION
SEE DETAIL A
0.175±0.075
0.22±0.30
C
1.75 MAX
0.10
0.42±0.09
OPTION A - BEVEL EDGE
(0.86) x 45°
R0.10
GAGE PLANE
R0.10
OPTION B - NO BEVEL EDGE
0.36
NOTES: UNLESS OTHERWISE SPECIFIED
8°
0°
A) THIS PACKAGE CONFORMS TO JEDEC
MS-012, VARIATION AA.
B) ALL DIMENSIONS ARE IN MILLIMETERS.
C) DIMENSIONS DO NOT INCLUDE MOLD
FLASH OR BURRS.
D) LANDPATTERN STANDARD: SOIC127P600X175-8M.
E) DRAWING FILENAME: M08Arev15
F) FAIRCHILD SEMICONDUCTOR.
SEATING PLANE
0.65±0.25
(1.04)
DETAIL A
SCALE: 2:1
Figure 35. 8-Lead, Small-Outline Integrated Curcuit (SOIC)
Package drawings are provided as a service to customers considering Fairchild components. Drawings may change in any manner
without notice. Please note the revision and/or date on the drawing and contact a Fairchild Semiconductor representative to verify or
obtain the most recent revision. Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions,
specifically the warranty therein, which covers Fairchild products.
Always visit Fairchild Semiconductor’s
http://www.fairchildsemi.com/packaging/.
online
packaging
area
for
the
most
recent
package
drawings:
For current packing container specifications, visit Fairchild Semiconductor’s online packaging area:
http://www.fairchildsemi.com/packing_dwg/PKG-M08A_GEM.pdf.
© 2012 Fairchild Semiconductor Corporation
FAN3240 / FAN3241 • Rev. 1.0.2
www.fairchildsemi.com
18
FAN3240 / FAN3241 — Smart Dual-Coil Relay Drivers
© 2012 Fairchild Semiconductor Corporation
FAN3240 / FAN3241 • Rev. 1.0.2
www.fairchildsemi.com
19