STMicroelectronics CLT3-4BT6 Current limited over-voltage protected quad digital termination Datasheet

CLT3-4B
Current limited over-voltage protected quad digital termination
Features
■
■
■
■
■
■
4 channel topology
Wide range input dc Voltage:
– VI= - 0.3 to 30 V with RI = 0
– VI = - 30 to 30 V with RI = 1.8 kΩ
– Low side configuration with common
ground
Current limiter:
– IGEN = 3 mA
– Input current limiter activation voltage < 5 V
– Temperature compensated operation
Opto-coupler drive:
– No coupler activation below 1.5 mA input
current
Input protection (RI = 1.2 kΩ):
– IEC 61000-4-2 electrostatic discharge
ESD, Class 3
In contact, ± 6 kV; in air, ± 8 kV
Level B: temporary disruption; no
change of opto-coupler state
– IEC 61000-4-5 voltage surge, Class 3
± 1000 V with 42 Ω serial resistor in
differential mode
Level B: temporary disruption
– IEC 61000-4-4 transient burst immunity
± 4 kV peak voltage; 5 kHz repetitive
rate
Level A: fully functional
Operating ambient temperature: - 25 to 85° C
TSSOP20
Applications
■
Industrial automation
■
Programmable logic controller
■
Communication field bus nodes
■
Peripheral input / output modules
■
Machine tool interface
Description
The CLT3-4 is a quadruple input digital
termination device designed for 24 V dc
automation applications. It provides the front-end
circuitry of a digital input module (I/O) in industrial
automation, and drives an isolating opto-coupler.
Figure 1.
COM
Pin configuration
COM
OUT1
OUT2
COM34
COM
OUT3
OUT4
COM12
COM
20
19
18
17
16
15
14
13
12
11
1
2
3
4
5
6
7
8
9
10
Benefits
■
■
■
■
■
■
■
Reduced overall dissipation
Compact with high integration
Enables input to meet type 1 and 3
characteristic of IEC 61131-2 standard
Compatible operation with 2 and 3 wires
proximity sensor according EN60947-5-2
standard
Insensitive to the on state sensor impedance
Surface mount package for highly automated
assembly
Enhanced functional reliability
November 2007
IN
COM
IN2
ESD12
ESDC
VC
ESD34
IN3
COM
IN4
The pins ESD, COMIJ, COM (pins # 1, 3, 6, 8, 10, 11,
13, 15, 16, 18, 20) must be connected together
externally. This common pad COM is enlarged to
reduce the thermal resistance and improve the device
cooling. The COM and IN pins are designed to
minimize the EMI effects on the circuit.
Rev 5
1/13
www.st.com
Characteristics
1
CLT3-4B
Characteristics
Figure 2.
Functional block diagram
OPTO COUPLER DRIVER
OUT1
IN1
I1
0.75xILIM
ESD
OVER
VOLTAGE
PROTECTION
I1
0.25xILIM
CURRENT LIMITER ILIM
1.5mA
ESD12
COM12
ESD
OVER
VOLTAGE
PROTECTION
CURRENT LIMITER ILIM
1.5mA
0.25xILIM
I2
0.75xILIM
I2
IN2
OUT2
OPTO COUPLER DRIVER
Vc
BIASING
CIRCUIT
ESD
Volt Prot
TO COMPARATORS
COM
ESDC
OPTO COUPLER DRIVER
IN3
OUT3
I3
0.75xILIM
I3
0.25xILIM
ESD
OVER
VOLTAGE
PROTECTION
CURRENT LIMITER ILIM
1.5mA
ESD34
COM34
ESD
OVER
VOLTAGE
PROTECTION
CURRENT LIMITER ILIM
I4
OPTO COUPLER DRIVER
VI
(1)
IIN
Parameter
VC
IN
IN
Value
Unit
Supply steady state voltage, RC = 0 kΩ
- 0.3 to 30
V
Supply steady state voltage, RC = 4.7 kΩ
- 30 to 30
V
Input steady state voltage, RI = 0 kΩ
- 0.3 to 30
V
Input steady state voltage, RI = 1.2 kΩ
- 0.3 to 32
V
Input repetitive pulse voltage, RI = 1.2 kΩ
- 0.3 to 35
V
Input repetitive pulse voltage,
RI = 1.8 kΩ, RC = 4.7 kΩ (2)
- 30 to 30
V
Input maximum forward current,
RI = 1.2 kΩ, RC = 4.7 kΩ
5
mA
Input maximum reverse current,
RI = 1.8 kΩ, RC = 4.7 kΩ (2)
20
mA
2.5
V
- 4 to 4
mA
Operating ambient temperature
- 25 to 85
°C
Operating and storage junction temperature
- 25 to 150
°C
VOM
OUT
Maximum output steady state voltage
IOM
OUT
Output current
TAMB
TJ
AII
1. VI = VIN + RI x IIN; VIN = voltage at the input pin itself
2. According to test diagram and design recommendations described in Section 2.2.
2/13
OUT4
Absolute ratings (limiting values)
Symbol
VCC
I4
0.75xILIM
IN4
Table 1.
1.5mA
0.25xILIM
CLT3-4B
Characteristics
Table 2.
Thermal resistance
Symbol
Rth(j-a)
Table 3.
Symbol
Parameter
Value
Unit
90
°C/W
TSSOP20 thermal resistance junction to ambient
Board copper surface = 2 cm2, copper thickness = 35 µm
Electrical characteristics (TJ = 25 °C, VCC = 24 V and COM pin voltage
referred unless otherwise specified)
Pin
Name
Conditions
Min.
Typ
Max.
Unit
2.1
3
3.7
mA
Current limitation
ILIM
IN
Input limiting current
VOUT = 0.9 to 2.0 V
VIN = 5 to 27 V
TAMB = - 25 to 85° C
VLOW
IN
Maximum off state
voltage
IIN = 100 µA
1.5
VTH
IN
Activation threshold
IIN = 2.1 mA
3.4
5
V
31
38
-
V
VI = 5 V, (1)
-
10
40
µA
IIN = 1.5 mA, (2)
-
10
40
µA
0.15
0.5
V
V
Input and Supply Protection
VCL
IN
Clamping voltage
IIN = 7 mA; tP = 1 ms
Opto-coupler driver operation
IOFF
OUT
VOFF
OUT
Off state output voltage
ION
OUT
On state output current
Off state output current
IIN = 1.5 mA
VIN = 5 V
1.5
2
-
mA
VIN = 4.2 V, VC = 10 V
1.5
2
-
mA
Supply and biasing circuit
VC
VC
Supply voltage
TAMB = - 25 to 85° C
IC
VC
Supply current
VIN = VC = 30 V
10
V
550
800
µA
1. According to Figure 9: Robust application diagram on page 8 with use of a
RI = 1.8 kΩ resistor, and an opto-coupler (RLED (0 V) = 15 kΩ)
2. According to Figure 9: Robust application diagram on page 8 with use of a
RI = 0 kΩ resistor, and an opto-coupler (RLED (0 V) = 15 kΩ)
Table 4.
Symbol
Switching electrical characteristics (TJ = 25 °C, VCC = 24V and COM pin
voltage referred unless otherwise specified)
Pin
Name
FMAX
IN-OUT Input to output running frequency
tPLH
IN-OUT Input activation propagation time
tPHL
IN-OUT Input de-activation propagation time
Conditions
Min.
Typ
Max.
Unit
5
kHz
COUT = 22 nF
6
µs
COUT = 22 nF
10
µs
3/13
Characteristics
Table 5.
Symbol
VPP
CLT3-4B
CLT3 System electromagnetic compatibility ratings,
RI = 1.8 kΩ, RC = 4.7 kΩ (unless otherwise specified)
Node
IN
Parameter name and conditions
Value
Unit
ESD protection, IEC 61000-4-2, per input, in air
±8
kV
ESD protection, IEC 61000-4-2, per input, in contact
±6
kV
ESD protection, IEC 61000-4-2, per input, in air, RI = 0 Ω
±3
kV
ESD protection, IEC 61000-4-2, per input, in contact, RI = 0 Ω
±3
kV
±4
kV
±1
kV
±1
kV
VPPB
VI
Total Peak Pulse Voltage Burst, IEC 61000-4-4
CIN = 100 pF, COUT = 22 nF, F = 5 kHz (1)
VPP
VI
Peak Pulse Voltage Surge, IEC 61000-4-5, R = 42 Ω (2)
VPP
VCC
Peak Pulse Voltage Surge, IEC 61000-4-5, R = 2 Ω
(2)
1. Refer to Application note AN2527 for test conditions.
2. See test circuit in Figure 12.
Figure 3.
Typical junction to ambient thermal resistance versus copper surface
under common pad (FR4 epoxy, copper thickness is 35 µm)
Rth(j-a)(° C/W)
160
140
120
100
80
60
40
20
0
0.0
1.1
S(cm²)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
Functional description
The CLT3-4 is a quadruple input digital termination device designed for 24 V DC automation
applications. It provides the front-end circuitry of a digital input module (I/O) in industrial
automation, and drives an isolating opto-coupler.
Available in a four channels configuration, it offers a high-density termination by minimizing
the external components count. It is housed in a TSSOP20 surface mount package to
reduce the printed board size.
Made of an input voltage protection, a serial current limiting circuit and an opto-coupler
driver, each channel circuit terminates the connection between the logic input and the
associated high side sensor or switch.
The CLT3-4 is a 3 mA quad channel device compatible the type 1 and 3 characteristics of
the IEC 61131-2 standard.
Each input voltage clamping block protects the module input against electromagnetic
interferences such as those described in the IEC 61131-2 standard and IEC 61000-4-2
(ESD), 4-4 (transient burst), 4-5 (voltage surge) standards. The supply input is also
designed with such a protection structure.
4/13
CLT3-4B
Characteristics
The current limiting circuit connected between the input and the output pins is compensated
all over the temperature range. Thanks to its low tolerance, the current limitation allows
reducing drastically the dissipation of the input compared to a resistive input: the overall
module requires less cooling capability and becomes smaller.
The output block of each termination channel controls the operation of an opto-coupler that
is enabled by a Light Emitting Diode.
When the input current is less than 1.5 mA, this output circuit derivates the input current to
maintain the opto-coupler off.
The original structure of the CLT limiter allows its activation threshold to be low and
insensitive to the output voltage up to a maximum value of 2.0 V.
When the CLT input voltage VIN is higher than 5 V, or the module input voltage Vi higher
than 11 V and a series resistor RI = 1.2 kΩ, the output current that is a share of the input
current (3/4) is higher than 1.5 mA. The whole termination channel including the optocoupler is on.
Depending on the input type operation that is described by the IEC 61131-2 standard, the
input resistance RI can be adjusted because of the different on-state threshold VON MIN.
This document describes operation and characteristics for type 3 operation with
VON MIN = 11 V and RI = 1.2 kΩ.
In type 1 operation the on state threshold VON MIN is 12.34 V instead, and the input resistor
RI is set 2.2 kΩ.
1.2
Input characteristics of CLT3-4
Figure 4.
Typical input characteristics of each CLT3-4 channel
VIN(V)
30
30
25
3.7
20
15
10
On-state
5
5
Off-state
0
0
0.5
1
1.5
2
2.5
3
3.5
4
IIN(mA)
5/13
Characteristics
Figure 5.
CLT3-4B
Typical current limiter variation
versus junction temperature
0.9 V < VOUT < 2 V
Figure 6.
IIim / IIim (25° C)
3.6
102%
Typical limiter threshold voltage
variation versus junction
temperature for IIN = 2.1 mA
VTH (V)
100%
VIN = 27 V
98%
3.5
96%
94%
3.4
92%
VIN = 5 V
90%
3.3
88%
86%
Tj (° C)
Tj (°C)
3.2
84%
-25
0
25
50
75
100
125
-25
0
25
50
75
100
125
1.3
CLT3-4 Input / output transfer characteristics (with respect to
common pin COM)
Figure 7.
Current tranfer characteristic
Figure 8.
IOUT (mA)
4
3
Forbidden
2.5
IOUT (mA)
4
ISOLATOR ON
Transition zone
3.5
ISOLATOR ON
3.5
3.7
3
2.1
2.5
2
2
1.5
1.5
1
1
Transition zone
0.04
0.5
0.5
0
0
0.5
1
ISOLATOR OFF
6/13
Transconductance characteristic
1.5
2
IIN (mA)
2.5
3
3.5
4
0
0
5
10
15
VI (V)
20
25
30
CLT3-4B
Application information
2
Application information
2.1
Application description
The CLT device is used between the input module and the opto-coupler of an I/O module. To
secure the coupler off state and the non-conduction of its diode, the maximum CLT output
current is 40 µA with R opto = 15 kΩ. When the CLT input voltage VIN is higher than 5 V, a
minimum CLT output current of 1.5 mA will secure the opto-coupler on state.
The CLT limiter is insensitive to the output voltage up to 2.0V. Therefore, its output is able to
drive any state of the art opto-coupler. Some additional device can be added in series with
the opto-coupler if the output voltage remains within its functional limits.
A stand-alone sensor is normally connected on the CLT input. For a good off state control,
its quiescent current has to be less than 1.5 mA (EN60947-5-2 standard compatible)
keeping then the opto-coupler off thanks to the CLT device (IOUT < 40 µA). And its maximum
ON state voltage VS-ON will be lower than 8 V (EN60947-5-2 standard compatible)
corresponding to the difference between the minimum supply voltage (VCC MIN = 19.2 V)
and the maximum current limitation activation voltage:
VCC MIN = VS-ON + VI
VI = VIN + RI x IIN MAX
(VI = 11 V when VIN = 5 V, RI = 1.2 kΩ, IIN < 3.7 mA).
2.2
Input reverse polarity robustness
Each input of the CLT device may be biased to a reverse polarity. This case corresponds to
a connection mistake or a reverse biasing that is generated by the demagnetization of a
monitored inductive solenoid.
The involved input can withstand the reverse current up to 20 mA (in the configuration
shown in Figure 10) through its input protection diode while its opto-coupler remains OFF.
Such a case is not critical for the CLT3-4 itself, as it represents less than 15 mW per
disturbed input. But the input resistors should be designed with care regardless of their
thermal characteristics (refer to Application note AN2527).
When the reverse polarity operation is required in types 3 input mode, it is recommended to
increase the input resistance RI to 1.8 kΩ in order to reduce its dissipation and keep the
input current below its maximum allowed level (20 mA). The surge and transient immunity
robustness of the CLT3 is then also increased.
A 1.8 kΩ value allows the reverse input current to be reduced to 16.2 mA and the resistor
dissipation to be reduced to 0.47 W, for 30 V VCC and a - 30 V VI voltages.
The CLT3 normal operation in type 3 is fully compatible with this recommended resistance
since its internal state threshold is monitored at VIN = 4.2 V and VC = 10V - corresponding to
VI = 11 V and VCC = 19 V.
In type 1 input operation where RI = 2.2 kΩ the dissipation of this resistor is less than
0.39 W.
The other inputs remain operational, as long as the power supply is working properly
(VCC >19 V). Refer to Application note AN 2527 for representative application design case.
7/13
Application information
CLT3-4B
The CLT3-4 and the 24 V bus power supply have the same ground COM = GND. The
reverse polarity of the power supply will shutdown the device. And the power supply resistor
RC will limit the default current protecting the power supply pin VC. Its dissipation will be less
than 0.2 W.
Then, the whole module supply voltage rating is extended to from 0 to 30 V to -30 to +30 V.
2.3
EMC considerations
Figure 9 gives a typical application diagram where output capacitors are used to increase
CLT device immunity against fast transient bursts.
Figure 11 gives the printed circuit board layout associated with this schematic.
Refer to AN2527 for EMC considerations.
Figure 9.
Robust application diagram
VI
1
COM
COM
IN1
OUT1
VIN
2 wires sensor
RI
ESD12
24V
SUPPLY
3 wires sensor
COM12
RI
VC
VCC
IN2
OUT2
VC
COM
ESDC
COM
IN3
OUT3
RC
RI
Contact switch
ESD34
COM34
RI
2 wires sensor
8/13
IN4
OUT4
COM
COM
CLT3-4B
Application information
Figure 10. Current sharing in the CLT device when IN4 is biased at - 30 V and the
others at + 30 V, RI = 1.8 kΩ
0.8 mA
Vcc = + 30 V
4.7 k Ω
INN
VCL= 38 V
3.7 mA
I1 = + 30 V
VC
IREG N
OUT1
1.8 kΩ
OPTO N
GND (0 V)
COM
OPTO 4
1.8 kΩ
I2 = -30
- V
16.2 mA
IN4
IREG4
OUT2
CLT3 - 4
Figure 11. TSSOP20 printed circuit board example
COMMON PAD
MODULE
CONNECTOR
COM
COM
IN1
OUT1
ESD12
COM12
IN2
OUT2
VC
COM
ESDC
COM
IN3
OUT3
ESD34
GND
COM34
IN4
OUT4
COM
COM
COOLING PAD
The input and supply pins are designed to withstand electromagnetic interferences. As
shown on the device block diagram, each channel input is protected by a clamping diode
that is connected to the common pin COM. Combined with a serial input resistance
RI = 1.2 kΩ, this clamping diode implements an effective protection against transient voltage
burst (± 4 kV, IEC 61000-4-4) and voltage surge (± 1 kV, IEC 61000-4-5).
9/13
Application information
CLT3-4B
Depending on the input type operation the input resistance RI can be adjusted because of
the different on-state threshold VON MIN. So the surge voltage is also increased from the
minimum level of the type 3 to the type as shown in Table 6.
Table 6.
Setting the input resistor RI according to the input type operation
Type
VON MIN (V)
RI (kΩ)
VPP surge (kV)
1
15
2.2
2
3
11
1.2 to 1.8
1
This combination allows the surge voltage to be applied from each input to other inputs, the
ground and the supply contacts in differential or common modes (see Figure 12).
Thanks to its high resistance RC = 4.7 kΩ, the supply pin VC withstands IEC 61000-4-5 with
±1000 V surge voltage (see Figure 12).
Finally, an external output capacitor may be placed in parallel with the opto-coupler diode to
filter the transient disturbances injected in the inputs of the module and secure the immunity
of the opto-coupler itself.
Figure 12. Input pin IN and supply pin VC voltage surge test circuit
VPPS = ± 1 kV with 2 Ω
VCC
RC
VC
RI
VPPI
IN1
I
VPPS
VPP
RI
VPPI = ± 1 kV with 42 Ω
IN2
RI
CLT3 -4
VPPI
GND
COMP
5 nF
PE/FE
10/13
CLT3-4B
3
Package information
Package information
●
Epoxy meets UL94,V0
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second level interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
Table 7.
TSSOP20 dimensions
Dimensions
Ref.
Millimeters
Min.
E1
D
A
A2
aaa
A
A1
b
C
C
PIN 1 INDENTIFICATION
20
11
Seating
plane
0.25 mm
Gage plane
C
E
k
L
1
10
Typ.
L1
0.05
A2
0.8
b
c
D
6.4
E
6.2
E1
Min.
Typ.
4.3
Max.
0.047
0.15
0.002
1.05
0.031 0.039 0.041
0.19
0.3
0.007
0.012
0.09
0.2
0.003
0.007
6.5
6.6
0.252 0.256 0.259
6.4
6.6
0.244 0.252 0.256
4.4
4.5
0.169 0.173 0.177
e
1.0
0.65
0.45
L1
k
Max.
1.2
A1
L
e
Inches
0.6
0.026
0.75
0.017 0.023 0.029
1.0
0°
0.039
8°
aaa
0.006
0.1
0°
8°
0.004
Figure 13. TSSOP20 footprint (dimensions in mm)
7.26
4.93
0.36
6.21
0.65
11/13
Ordering information
4
Ordering information
Table 8.
5
CLT3-4B
Ordering information
Order code
Marking
Package
Weight
Base qty
Delivery mode
CLT3-4BT6
CLT3-4B
TSSOP20
0.074 g
74
Tube
CLT3-4BT6-TR
CLT3-4B
TSSOP20
0.074 g
2500
Tape and reel
Revision history
Table 9.
Document revision history
Date
Revision
August-2002
4A
27-Nov-2007
12/13
5
Changes
Previous release.
Reformatted and restructured to current standard. Updated
Figure 2, Figure 9, Figure 10, Figure 11, and deleted Figure 12.
Added paragraphs to Functional description and Application
information. Extended application field with a new diagram
(Figure 11) for reverse polarity test. Updated Package information.
CLT3-4B
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13/13
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