IL3285/IL3222
Fractional Load Passive Input RS-485 and RS-422 Isolated Transceivers
Functional Diagrams
Features
• 3 V to 5 V power supplies
• 5 Mbps data rate
• ⅛ unit load
• 15 kV bus ESD protection
• 20 kV/µs typical common mode rejection
• No carrier or clock for low EMI emissions and susceptibility
• −40 °C to +85 °C temperature range
• Thermal shutdown protection
• 2500 VRMS isolation
• IEC 60747-17 (VDE 0884-17):2021-10; UL 1577
• 0.15" or 0.3" True 8™ mm 16-pin SOIC packages
DE
VCOIL1
D
VCOIL2
A
B
R
RE
IL3285
DE
Applications
• High node-count networks
• Security networks
• Building environmental controls
• Industrial control networks
• Gaming systems
VCOIL1
Y
Z
D
VCOIL2
A
B
R
RE
IL3222
IL3285 Truth Table
VID (A-B)
DE
RE
R
D
≥ 200 mV
L
L
H
X
≤−200mV
L
L
L
X
Mode
Notes
Receive
Open
L
L
H
X
A/B failsafe
≥ 1.5 V
H
L
H
H
≤−1.5 V
H
L
L
L
R reads back
D information
≥ 1.5 V
H
H
Z
H
≤−1.5 V
H
H
Z
L
X
L
H
Z
X
Drive
R tri-state
(no output)
Disabled
R tri-state;
A/B failsafe
Z = High Impedance X = Irrelevant
* “H”=no coil-current flowing; “L”=coil current.
IL3222 Receiver
RE
R
V(A-B)
H
Z
X
L
H
≥ 200 mV
L
L
≤−200 mV
L
H
Open
Selection Table
Full/Half
Model
Duplex
IL3285
half
IL3222
full
IL3222 Driver
DE
D
L
X
H
H
H
L
No. of Devices
Allowed on Bus
256
256
Data Rate
Mbps
5
5
V(Y-Z)
Z
≥2V
≤−2 V
Fail-Safe
yes
yes
Description
The IL3285 and IL3222 are galvanically isolated,
differential bus transceivers designed for bidirectional data
communication over balanced transmission lines. The
devices use NVE’s patented* IsoLoop spintronic Giant
Magnetoresistance (GMR) technology. The IL3285 delivers
at least 1.5 V into a 54 Ω load, and the IL3222 at least 2 V
into a 100 Ω load for excellent data integrity over long
cables. These devices are also compatible with 3.3 V input
supplies, allowing interface to standard microcontrollers
without additional level shifting.
A unique ceramic/polymer composite barrier provides
excellent isolation and virtually unlimited barrier life.
Both the IL3285 and IL3222 have current limiting and
thermal shutdown features to protect against output short
circuits and bus contentions that may cause excessive power
dissipation. The receivers also incorporate a “fail-safe if
open” design, ensuring a logic high on R if the bus lines are
disconnected or “floating.”
Receiver input resistance of 96 kΩ is eight times the
RS-485 “Unit Load” (UL) minimum of 12 kΩ. Thus these
products are known as “one-eighth UL” transceivers. There
can be up to 256 on a network while still complying with
the RS-485 loading specification.
IsoLoop® is a registered trademark of NVE Corporation.
*U.S. Patent numbers 5,831,426; 6,300,617 and others.
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
REV. S
(952) 829-9217
www.nve.com
YouTube.com/NveCorporation
iso-apps@nve.com
IL3285/IL3222
Absolute Maximum Ratings
Operating at absolute maximum ratings will not damage the device. However, extended periods of operation at the absolute maximum ratings may affect
performance and reliability.
Parameters
Symbol
Min.
Typ.
Max.
Storage Temperature
TS
−55
150
Junction Temperature
TJ
−55
150
Voltage Range at A or B Bus Pins
−7
12
Supply Voltage(1)
VDD1, VDD2
−0.5
7
Digital Input Voltage
−0.5
VDD+0.5
Digital Output Voltage
−0.5
VDD+1
ESD Protection
±15
Input Current
IIN
−25
+25
ESD (all bus nodes)
15
Note 1. All voltage values are with respect to network ground except differential I/O bus voltages.
Units
°C
°C
V
V
V
V
kV
mA
kV
Test Conditions
HBM
Units
Test Conditions
Recommended Operating Conditions
Parameters
Supply Voltage
Ambient Operating Temperature
Junction Temperature
Input Voltage at any Bus Terminal
(separately or common mode)
Input Threshold for Output Logic
High
Input Threshold for Output Logic Low
Differential Input Voltage
High-Level Output Current (Driver)
High-Level Digital Output Current
(Receiver)
Low-Level Output Current (Driver)
Low-Level Digital Output Current
(Receiver)
Digital Input Signal Rise, Fall Times
Symbol
VDD1
VDD2
TA
TJ
VI
VIC
IINH
Min.
3.0
4.5
−40
−40
IINL
VID
IOH
5
Typ.
1.5
Max.
5.5
5.5
85
100
12
−7
0.8
3.5
V
°C
°C
V
mA
−60
+12/−7
60
mA
V
mA
IOH
−8
8
mA
IOL
−60
60
mA
IOL
−8
8
mA
1
μs
tIR,tIF
2
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.isoloop.com
iso-info@nve.com
iso-apps@nve.com
IL3285/IL3222
Safety Approvals
IEC 60747-17 (VDE 0884-17):2021-10 (Basic Isolation; VDE File Number 5016933-4880-0001):
• Isolation voltage (VISO): 2500 VRMS
• Transient overvoltage (VIOTM): 4000 VPK
• Surge rating 4000 V
• Each part tested at 1590 VPK for 1 second, 5 pC partial discharge limit
• Samples tested at 4000 VPK for 60 sec.; then 1358 VPK for 10 sec. with 5 pC partial discharge limit
• Working Voltage (VIORM; pollution degree 2):
Package
Narrow-body SOIC16
Wide-body SOIC16/True 8™
Part No.
Suffix
-3
None
Safety-Limiting Values
Safety rating ambient temperature
Safety rating power (180 °C)
Supply current safety rating (total of supplies)
Working
Voltage
700 VRMS
600 VRMS
Symbol
TS
PS
IS
Value
180
270
54
Units
°C
mW
mA
UL 1577 (Component Recognition Program File Number E207481)
• 2500 V rating
• Each part tested at 3000 VRMS (4243 VPK) for 1 second
• Each lot sample tested at 2500 VRMS (3536 VPK) for 1 minute
Soldering Profile
Per JEDEC J-STD-020C, MSL 1
Electrostatic Discharge Sensitivity
This product has been tested for electrostatic sensitivity to the limits stated in the specifications. However, NVE recommends that all integrated
circuits be handled with appropriate care to avoid damage. Damage caused by inappropriate handling or storage could range from performance
degradation to complete failure.
3
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.isoloop.com
iso-info@nve.com
iso-apps@nve.com
IL3285/IL3222
IL3285-3 Pin Connections (0.15" SOIC Package)
1
VDD1
Input power supply
2
GND1
Ground return for VDD1
3
R
4
RE
Read enable
(if RE is high, R is high impedance)
5
DE
Drive enable
6
VCOIL1
7
D
8
DNC
Do not connect
9
GND2
Ground return for VDD2
(internally connected to pin 15)
10
NC
11
VDD2
12
A
Non-inverting bus line
13
B
Inverting bus line
14
NC
15
GND2
Ground return for VDD2
(internally connected to pin 9)
16
VCOIL2
Coil for R
Output data from bus
Coils for DE and D (connect to VDD1)
VDD1
VCOIL2
GND1
GND2
R
NC
Data input to bus
RE
B
DE
A
VDD2
VCOIL1
No internal connection
D
Output power supply
NC
NC
DNC
GND2
IL3285-3
No internal connection
IL3222-3 Pin Connections (0.15" SOIC Package)
1
VDD1
Input power supply
2
GND1
Ground return for VDD1
3
R
4
RE
Read enable
(if RE is high, R is high impedance)
5
DE
Drive enable
6
VCOIL1
7
D
8
DNC
9
GND2
10
Y
11
VDD2
Output data from bus
Coils for DE and D (connect to VDD1)
VDD1
VCOIL2
GND1
GND2
R
A
Do not connect
RE
B
Ground return for VDD2
(internally connected to pin 15)
DE
Z
Data input to bus
VCOIL1
Non-inverting driver bus line
D
Output power supply
12
Z
Inverting driver bus line
13
B
Inverting receiver bus line
14
A
Non-inverting receiver bus line
15
GND2
Ground return for VDD2
(internally connected to pin 9)
16
VCOIL2
Coil for R
VDD2
Y
NC
DNC
GND2
IL3222-3
4
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.isoloop.com
iso-info@nve.com
iso-apps@nve.com
IL3285/IL3222
IL3285 Pin Connections (0.3" SOIC Package)
1
VDD1
Input power supply
2
GND1
Ground return for VDD1
3
R
4
RE
Read enable
(if RE is high, R is high impedance)
5
DE
Drive enable
6
VCOIL1
7
D
8
GND1
Internally connected to pin 2 for 0.3" package;
no internal connection on 0.15" IL3285-3
9
GND2
Ground return for VDD2
(internally connected to pin 15)
10
NC
11
VDD2
12
A
Non-inverting bus line
13
B
Inverting bus line
14
NC
15
GND2
Ground return for VDD2
(internally connected to pin 9)
16
VCOIL2
Coil for R
Output data from bus
Coils for DE and D (connect to VDD1)
Data input to bus
No internal connection
Output power supply
IL3285
No internal connection
IL3222 Pin Connections (0.3" SOIC Package)
1
VDD1
Input power supply
2
GND1
Ground return for VDD1
3
R
Output data from bus
4
RE
Read enable
(if RE is high, R is high impedance)
5
DE
Drive enable
6
VCOIL1
7
D
8
GND1
Internally connected to pin 2 for 0.3" package;
no internal connection on 0.15" IL3222-3
9
GND2
Ground return for VDD2
(internally connected to pin 15)
10
Y
Non-inverting driver bus line
11
VDD2
Coils for DE and D (connect to VDD1)
Data input to bus
Output power supply
12
Z
Inverting driver bus line
13
B
Inverting receiver bus line
14
A
Non-inverting receiver bus line
15
GND2
Ground return for VDD2
(internally connected to pin 9)
16
VCOIL2
Coil for R
IL3222
5
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.isoloop.com
iso-info@nve.com
iso-apps@nve.com
IL3285/IL3222
Driver Section
Electrical Specifications (VDD1 = 3 V − 5.5 V; VDD2 = 4.5 V − 5.5 V; T = −40°C − 85°C unless otherwise stated)
Parameters
Symbol
Min.
Typ.
Max.
Units
Test Conditions
Coil Input Resistance
RCOIL
47
85
112
Ω
T = 25°C
Coil Input Resistance
RCOIL
31
85
128
Ω
T = −40°C − 85°C
Coil Resistance Temperature Coefficient
TC RCOIL
0.2
0.25
Ω/°C
Coil Inductance
LCOIL
9
nH
High Level Input Current
IINH
0.5
1
mA
tIR = tIF = 3 ns;
CBOOST = 16 pF
Low Level Input Current
IINL
3.5
5
mA
Output voltage
VDD
V
IO = 0
Differential Output Voltage
|VOD1|
VDD
V
IO = 0
Differential Output Voltage
|VOD2|
2
3
V
RL = 100 Ω, VDD = 5 V
Differential Output Voltage(6)
VOD3
1.5
2.3
V
RL = 54 Ω, VDD = 5 V
Change in Magnitude(7) of Differential
Δ|VOD|
±0.2
V
RL = 54 Ω or 100 Ω
Output Voltage
Common Mode Output Voltage
VOC
3
V
RL = 54 Ω or 100 Ω
Change in Magnitude(7) of Common
Δ|VOC|
0.2
V
RL = 54 Ω or 100 Ω
Mode Output Voltage
Output disabled,
1
mA
Output Current(4)
VO = 12 V
−0.8
mA
VO = −7 V
|Short-circuit Output Current|
IOS
60
250
mA
−7 V < VO < 12 V
Supply Current (VDD2 = +5 V)
IDD2
6
7
No Load
mA
(VDD1 = +5 V)
IDD1
2.5
3
(Outputs Enabled)
No Load
Supply Current (VDD1 = +3.3 V)
IDD2
1.3
2
mA
(Outputs Enabled)
Common Mode Rejection
|CMH|,|CML|
15
20
kV/μs
VT = 300 Vpeak
Switching Specifications (VDD1 = 5 V; VDD2 = 5 V; T = −40°C − 85°C)
Parameters
Symbol
Min.
Typ.
Max.
Units
Data Rate
5
Mbps
Differential Output Prop Delay
tD(OD)
40
65
ns
Pulse Skew(10)
tSK(P)
6
20
ns
Differential Output Rise and Fall Time
tT(OD)
3
12
25
ns
Drive Enable Time to High Level
tPZH
25
80
ns
Drive Enable Time to Low Level
tPZL
25
80
ns
Drive Disable Time from High Level
tPHZ
25
80
ns
Drive Disable Time from Low Level
tPLZ
25
80
ns
Skew Limit(3)
tSK(LIM)
8
ns
Switching Specifications (VDD1 = 3.3 V; VDD2 = 5 V; T = −40°C − 85°C)
Parameters
Symbol
Min.
Typ.
Max.
Units
Data Rate
5
Mbps
Differential Output Prop Delay
tD(OD)
40
65
ns
Pulse Skew(10)
tSK(P)
6
20
ns
Differential Output Rise and Fall Time
tT(OD)
3
12
25
ns
Drive Enable Time to High Level
tPZH
25
80
ns
Drive Enable Time to Low Level
tPZL
25
80
ns
Drive Disable Time from High Level
tPHZ
25
80
ns
Drive Disable Time from Low Level
tPLZ
25
80
ns
Skew Limit(3)
tSK(LIM)
8
ns
Test Conditions
RL = 54 Ω;
CL = 50 pF;
Cboost = 16pF
Test Conditions
RL = 54 Ω;
CL = 50 pF;
Cboost = 16pF
6
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.isoloop.com
iso-info@nve.com
iso-apps@nve.com
IL3285/IL3222
Receiver Section
Electrical Specifications (VDD1 = 3 V − 5.5 V; VDD2 = 4.5 V − 5.5 V; T = −40°C − 85°C unless otherwise stated)
Symbol
Min.
Typ.
Max.
Units
Test Conditions
47
85
112
Ω
T = 25°C
Coil Resistance
RCOIL
31
85
128
Ω
T = −40°C − 85°C
Coil Resistance Temperature Coefficient
TC RCOIL
0.2
0.25
Ω/°C
Positive-going Input Threshold
VIT+
0.2
V
−7 V < VCM < 12 V
Negative-going Input Threshold
VIT−
−0.2
V
−7 V < VCM < 12 V
Hysteresis Voltage (Vit+ − Vit−)
VHYS
70
mV
VCM = 0V, T = 25°C
High Level Digital Output Voltage
VOH
VDD − 0.2
VDD − 0.2
V
VID = 200 mV
IOH = 4 mA
Low Level Digital Output Voltage
VOL
0.8
V
VID = −200 mV
IOL = 4 mA
High impedance state output current
IOZ
10
µA
0.4≤VO≤(VDD2 − 0.5) V
Line Input Current(8)
II
1
mA
VI = 12 V
−0.8
VI = −7 V
Input Resistance
rI
96
kΩ
Parameters
Switching Characteristics (VDD1 = 5 V; VDD2 = 5 V; Cboost = 16pF; T = −40°C − 85°C)
Symbol
Min.
Typ.
Max.
Units
5
Mbps
Parameters
Data Rate
Propagation Delay(9)
Pulse Skew(10)
Skew Limit(3)
Read Enable Time to High Level
Read Enable Time to Low Level
Read Disable Time from High Level
Read Disable Time from Low Level
tPD
90
150
ns
tSK(P)
6
20
ns
tSK(LIM)
tPZH
tPZL
tPHZ
tPLZ
2
4
4
4
4
8
10
10
10
10
ns
ns
ns
ns
ns
Test Conditions
RL = 54 Ω, CL = 50 pF
−1.5 ≤ VO ≤ 1.5 V,
CL = 15 pF
−1.5 ≤ VO ≤ 1.5 V,
CL = 15 pF
RL = 54 Ω, CL = 50 pF
CL = 15 pF
Switching Characteristics (VDD1 = 3.3 V; VDD2 = 5 V; Cboost = 16pF; T = −40°C − 85°C)
Symbol
Min.
Typ.
Max.
Units
Test Conditions
5
Mbps
RL = 54 Ω, CL = 50 pF
−1.5 ≤ VO ≤ 1.5 V,
Propagation Delay(9)
tPD
100
150
ns
CL = 15 pF
−1.5 ≤ VO ≤ 1.5 V,
Pulse Skew(10)
tSK(P)
10
20
ns
CL = 15 pF
Skew Limit(3)
tSK(LIM)
4
10
ns
RL = 54 Ω, CL = 50 pF
Read Enable Time to High Level
tPZH
5
10
ns
Read Enable Time to Low Level
tPZL
5
10
ns
CL = 15 pF
Read Disable Time from High Level
tPHZ
5
10
ns
Read Disable Time from Low Level
tPLZ
17
10
ns
Parameters
Data Rate
Insulation Specifications
Parameters
Comparative Tracking Index
Endurance Voltage
AC
(Maximum Working Voltage
for Indefinite Life)
DC
Creepage Distance 0.15" SOIC
(external)
0.3" SOIC
Total Barrier Thickness (internal)
Barrier Resistance
Barrier Capacitance
Leakage Current
Symbol
CTI
Min.
≥175
1000
Typ.
Max.
Units
V
VRMS
VIO
1500
4.03
8.03
0.012
RIO
CIO
VDC
mm
8.3
0.013
>1014
7
0.2
mm
Ω
pF
μA
Test Conditions
Per IEC 60112
At maximum
operating temperature
Per IEC 60601
500 V
f = 1 MHz
240 VRMS, 60 Hz
7
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.isoloop.com
iso-info@nve.com
iso-apps@nve.com
IL3285/IL3222
Thermal Characteristics
Parameter
Junction–Ambient
Thermal Resistance
Junction–Case (Top)
Thermal Resistance
Junction–Ambient
Thermal Resistance
Junction–Case (Top)
Thermal Resistance
Power Dissipation
Symbol
0.15" SOIC
0.3" SOIC
0.15" SOIC
0.3" SOIC
Min.
θJA
θJC
Typ.
82
67
8
12
θJA
46
θJC
9
Max.
Units
Double-sided PCB in
free air
°C/W
2s2p PCB in free air
per JESD51
0.3" SOIC
0.15" SOIC
0.3" SOIC
700
1500
PD
Test Conditions
mW
Notes (apply to both driver and receiver sections):
1.
2.
3.
4.
5.
6.
7.
8.
All voltages are with respect to network ground except differential I/O bus voltages.
Differential input/output voltage is measured at the non-inverting terminal A with respect to the inverting terminal B.
Skew limit is the maximum difference in any two channels in one device.
The power-off measurement in ANSI Standard EIA/TIA-422-B applies to disabled outputs only and is not applied to combined inputs and outputs.
All typical values are at VDD1, VDD2 = 5 V or VDD1= 3.3 V and TA = 25°C.
While −7 V < VCM < 12 V, the minimum VOD2 with a 54 Ω load is either ½ VOD1 or 1.5 V, whichever is greater.
Δ|VOD| and Δ|VOC| are the changes in magnitude of VOD and VOC, respectively, that occur when the input is changed from one logic state to the other.
This applies for both power on and power off; refer to ANSI standard RS-485 for exact condition. The EIA/TIA-422-B limit does not apply for a combined
driver and receiver terminal.
9. Includes 10 ns read enable time. Maximum propagation delay is 25 ns after read assertion.
10. Pulse skew is defined as the |tPLH − tPHL| of each channel.
8
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
Phone: (952) 829-9217
www.isoloop.com
iso-info@nve.com
iso-apps@nve.com
IL3285/IL3222
Applications Information
Input Resistor Values
The IL3222 and IL3285 are current-mode devices. Changes in input coil current switch internal spintronic GMR sensors. Inputs
are logically high when the coil voltage is high, that is when there is no coil current.
A single resistor is required to limit the input coil current to the 5 mA threshold current. The absolute maximum current through
any coil is 25 mA.
Typical Input Resistor Values
VCOIL
3.3 V
5V
Coil
Resistor
510 Ω
820 Ω
The table shows typical values for the external coil resistors in 5 V and 3 V logic systems. As always,
these values as approximate and should be adjusted for temperature or other application specifics.
Boost Capacitor
The boost capacitor in parallel with the current-limiting resistor boosts
the instantaneous coil current at the signal transition. This ensures
switching and reduces propagation delay and reduces pulse-width
distortion.
50
1000
1000
Signal
Rise/Fall Time (ns)
20
500
C
3
16
100
2500
C Boost (pF )
Figure 2. Cboost Selector
210
5000
dV
dt
Select the value of the boost capacitor based on the rise and fall
times of the signal driving the inputs. The instantaneous boost
capacitor current is proportional to input edge speeds (
). Select a
capacitor value based on the rise and fall times of the input signal to be
isolated that provides approximately 20 mA of additional “boost”
current. Figure 2 is a guide to boost capacitor selection. For high-speed
logic signals (tr,tf < 10 ns), a 16 pF capacitor is recommended. The
capacitor value is generally not critical; if in doubt, choose a higher
value up to a maximum of 470 pF.
RS-485 and RS-422 Busses
RS-485 and RS-422 are differential (balanced) data transmission standards for use over long distances or in noisy environments.
RS-422 is an RS-485 subset, so RS-485 transceivers are also RS-422-compliant. RS-422 is a multi-drop standard allowing only
one driver and up to 10 receivers on each bus (assuming unit load receivers). RS-485 is a true multipoint standard which allows up
to 32 unit load devices (any combination of drivers and receivers) on each bus. To allow for multipoint operation, RS-485 requires
drivers to handle bus contention without damage. Another important advantage of RS-485 is the extended common-mode range
(CMR), which requires driver outputs and receiver inputs withstand +12 V to −7 V. RS-422 and RS-485 are intended for runs as
long as 4,000 feet (1,200 m), so the wide CMR is necessary for ground potential differences, as well as voltages induced in the
cable by external fields.
Receiver Features
IL3000 transceivers have differential input receivers for maximum noise immunity and common-mode rejection. Input sensitivity
is ±200 mV as required by the RS-422 and RS-485 specifications. The receivers include a “fail-safe if open” function that
guarantees a high level receiver output if the receiver inputs are unconnected (floating). Receivers easily meet the data rates
supported by the corresponding driver. IL3000-Series receiver outputs have tri-state capabilities with active low RE inputs.
Driver Features
The RS485/422 driver is a differential output device that delivers at least 1.5 V across a 54 Ω load (RS-485), and at least 2 V
across a 100 Ω load (RS-422). The driver features low propagation delay skew to maximize bit width and minimize EMI. IL3222
and IL3285 drivers have tri-state capability with an active high DE input.
9
NVE Corporation
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IL3285/IL3222
Cabling, Data Rate and Terminations
Cabling
Use twisted-pair cable. The cable can be unshielded if it is short (less than 10 meters) and the data rate is slow (less than
100 Kbps). Otherwise, use screened cable with the shield tied to earth ground at one end only. Do not tie the shield to digital
ground. The other end of the shield may be tied to earth ground through an RC network. This prevents a DC ground loop in the
shield. Shielded cable minimizes EMI emissions and external noise coupling to the bus.
Data Rate
The longer the cable, the slower the data rate. The RS-485 bus can transmit ground over 4,000 feet (1,200 meters) or at 10 Mbps,
but not both at the same time. Transducer and cable characteristics combine to act as a filter with the general response shown in
Figure 3. Other parameters such as acceptable jitter affect the final cable length versus data rate tradeoff. Less jitter means better
signal quality but shorter cable lengths or slower data rates. Figure 4 shows a generally accepted 30% jitter and a corresponding
data rate versus cable length.
4000
1000
Cable Length (feet)
100
40
100
1K
10K
100K
Data Rate (bps)
1M
10M
Figure 3. Cable Length vs. Data Rate (30% jitter).
Terminations
Transmission lines should be terminated to avoid reflections that cause data errors. In RS-485 systems both ends of the bus, not
every node, should be terminated. In RS-422 systems only the receiver end should be terminated.
100 Ω
Unterminated
Parallel
Proper termination is imperative when using IL3285 and IL3222 to minimize reflections. Unterminated lines are only suitable for
very low data rates and very short cable runs, otherwise line reflections cause problems. Parallel terminations are the most popular.
They allow high data rates and excellent signal quality.
Occasionally in noisy environments, fast pulses or noise appearing on the bus lines cause errors. One way of alleviating such errors
without adding circuit delays is to place a series resistor in the bus line. Depending on the power supply, the resistor should be
between 300 Ω (3 V supply) and 500 Ω (5 V supply).
10
NVE Corporation
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IL3285/IL3222
Typical Coil Connections
16pF ±50%
16pF ±50%
DE
VDD1
D
R1
DE
VCOIL1
VDD1
16pF ±50%
R2
16pF ±50%
R
VCOIL2
R3
D
VDD2
R1
VCOIL1
Y
Z 16pF ±50%
R2
VCOIL2
16pF ±50%
A
B
R
RE
R3
VDD2
A
B
RE
VDD1 = VDD2 = 5 V
R1, R2, R3 = 820 Ω
VDD1 = 3.3 V
R1, R2 = 510 Ω; R3 = 820 Ω
VDD1 = VDD2 = 5 V
R1, R2, R3 = 820 Ω
VDD1 = 3.3 V
R1, R2 = 510 Ω; R3 = 820 Ω
Fail-Safe Operation
“Fail-safe operation” is defined here as the forcing of a logic high state on the “R” output in response to an open-circuit condition
between the “A” and “B” lines of the bus, or when no drivers are active on the bus.
Proper biasing can ensure fail-safe operation, that is a known state when there are no active drivers on the bus. IL3285 and IL3222
Isolated Transceivers include internal pull-up and pull-down resistors of approximately 200 kΩ in the receiver section (RFS-INT; see
figure on following page). These internal resistors are designed to ensure failsafe operation but only if there are no termination
resistors. The entire VDD will appear between inputs “A” and “B” if there is no loading and no termination resistors, and there will
be more than the required 200 mV with up to four RS-485/RS-422 worst-case one-eighth unit loads of 96 kΩ. Many designs
operating below 1 Mbps or less than 1,000 feet are unterminated. Termination resistors may not be necessary for very low data
rates and very short cable runs because reflections have time to settle before data sampling, which occurs at the middle of the bit
interval.
In busses with low-impedance termination resistors, however, the differential voltage across the conductor pair will be close to
zero with no active drivers. In this case the state of the bus is indeterminate, and the idle bus will be susceptible to noise. For
example, with 120 Ω termination resistors (RT) on each end of the cable, and four eighth unit loads (96 kΩ each), without external
fail-safe biasing resistors the internal pull-up and pull-down resistors will produce a voltage between inputs “A” and “B” of only
about one millivolt. This is not nearly enough to ensure a known state. External fail-safe biasing resistors (RFS-EXT) at one end of
the bus can ensure fail-safe operation with a terminated bus. Resistors should be selected so that under worst-case power supply
and resistor tolerances there is at least 200 mV across the conductor pair with no active drivers to meet the input sensitivity
specification of the RS-422 and RS-485 standards.
Using the same value for pull-up and pull-down biasing resistors maintains balance for positive- and negative going transitions.
Lower-value resistors increase inactive noise immunity at the expense of quiescent power consumption. Note that each Unit Load
on the bus adds a worst-case loading of 12 kΩ across the conductor pair, and 256 one-eighth unit loads add 375 Ω worst-case
loading. The more loads on the bus, the lower the required values of the biasing resistors.
In the example with two 120 Ω termination resistors and four eighth unit loads, 560 Ω external biasing resistors provide more than
200 mV between “A” and “B” with adequate margin for power supply variations and resistor tolerances. This ensures a known
state when there are no active drivers. Other illustrative examples are shown in the following table:
11
NVE Corporation
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IL3285/IL3222
Fail-Safe Biasing
5V
RFS-EXT
VDD
200K
RFS-INT
A
R FS-EXT
Internal Only
Internal Only
560 Ω
510 Ω
RT
None
120 Ω
120 Ω
120 Ω
B
GND
RFS-EXT
200K
RFS-INT
IL32xx
RT
RT
R
Loading
Four eighth-unit loads (96 kΩ ea.)
Four eighth-unit loads (96 kΩ ea.)
Four eighth-unit loads (96 kΩ ea.)
256 eighth-unit loads (96 kΩ ea.)
Nominal VA-B Fail-Safe
Operation?
(inactive)
283 mV
Yes
1 mV
No
254 mV
Yes
243 mV
Yes
Power Supply Decoupling
Both VDD1 and VDD2 should be bypassed with 0.1 µF typical (0.047 µF minimum) capacitors placed as close as possible to
the VDD pins.
Maintaining Creepage
Creepage distances are often critical in isolated circuits. In addition to meeting JEDEC standards, NVE isolator packages have
unique creepage specifications. Standard pad libraries often extend under the package, compromising creepage and clearance.
Similarly, ground planes, if used, should be spaced to avoid compromising clearance. Package drawings and recommended pad
layouts are included in this datasheet.
Magnetic Field Immunity
IsoLoop Isolators operate by imposing a magnetic field on a GMR sensor, which translates the change in field into a change in
logic state. A magnetic shield and a Wheatstone Bridge configuration provide good immunity to external magnetic fields.
Immunity to external magnetic fields can be enhanced by proper orientation of the device with respect to the field direction and
larger boost capacitors.
An applied field in the “H1” direction is the worst case for magnetic immunity. In this case the external field is in the same
direction as the applied internal field. In one direction it will tend to
help switching; in the other it will hinder switching. This can cause
unpredictable operation.
VDD1
VCOIL2
GND1
GND2
R
RE
DE
NC
H2
VCOIL1
D
GND1
B
H1
A
VDD2
An applied field in the direction of “H2” has considerably less effect
on the sensor and will result in significantly higher immunity levels as
shown in Table 1.
NC
GND2
Figure 3. Orientation of External Magnetic Field
The greatest magnetic immunity is achieved by adding a larger boost
capacitor across the input resistor. Very high immunity can be
achieved with this method.
12
NVE Corporation
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IL3285/IL3222
Method
Approximate Immunity
Field applied in direction H1
±20 Gauss
Field applied in direction H2
±70 Gauss
Field applied in any direction but with
boost capacitor (470 pF) in circuit
Table 1. Magnetic Immunity
±250 Gauss
Immunity Description
A DC current of 16 A flowing in a conductor
1 cm from the device could cause disturbance
A DC current of 56 A flowing in a conductor
1 cm from the device could cause disturbance
A DC current of 200 A flowing in a conductor
1 cm from the device could cause disturbance
Data Rate and Magnetic Field Immunity
It is easier to disrupt an isolated DC signal with an external magnetic field than it is to disrupt an isolated AC signal. Similarly, a
DC magnetic field will have a greater effect on the device than an AC magnetic field of the same effective magnitude. For
example, signals with pulses longer than 100 μs are more susceptible to magnetic fields than shorter pulse widths. For input signals
faster than 1 MHz, rising in less than 3 ns, a 470 pF field-boost capacitor provides as much as 400 Gauss immunity, while the
same input capacitor might provide just 70 Gauss immunity at 50 kHz.
13
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IL3285/IL3222
Package Drawings
0.15" 16-pin SOIC Package (-3 suffix)
Dimensions in inches (mm); scale = approx. 5X
0.013 (0.3)
0.020 (0.5)
NOM
0.007 (0.2)
0.013 (0.3)
0.386 (9.8)
0.394 (10.0)
Pin 1 identified
by either an
indent or a
marked dot
0.016 (0.4)
0.050 (1.3)
0.054 (1.37)
0.062 (1.58)
0.054 (1.4)
0.072 (1.8)
0.150 (3.81)
0.157 (3.99)
0.049 (1.24)
0.051 (1.30)
0.228 (5.8)
0.244 (6.2)
NOTE: Pin spacing is a BASIC
dimension; tolerances
do not accumulate
0.004 (0.1)
0.012 (0.3)
0.3" 16-pin SOIC Package (no suffix)
Dimensions in inches (mm); scale = approx. 5X
0.033 (0.85)*
0.043 (1.10)
0.260 (6.60)*
0.280 (7.11)
0.013 (0.3)
0.020 (0.5)
0.007 (0.2)
0.013 (0.3)
0.397 (10.08)
0.413 (10.49)
0.017 (0.43)*
0.022 (0.56)
0.016 (0.4)
0.050 (1.3)
0.007 (0.18)*
0.010 (0.25)
0.092 (2.34)
0.105 (2.67)
Pin 1 identified by
either an indent
or a marked dot
0.08 (2.0)
0.10 (2.5)
0.292 (7.42)*
0.299 (7.59)
0.049 (1.24)
0.051 (1.30)
0.394 (10.00)
0.419 (10.64)
NOTE: Pin spacing is a BASIC
dimension; tolerances
do not accumulate
*Specified for True 8™ package to guarantee 8 mm creepage per IEC 60601.
0.004 (0.1)
0.012 (0.3)
14
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IL3285/IL3222
Recommended Pad Layouts
0.15" 16-pin SOIC Pad Layout
Dimensions in inches (mm); scale = approx. 5X
0.160 (4.06)
0.050 (1.27)
0.020 (0.51)
16 PLCS
0.275 (6.99)
0.3" 16-pin SOIC Pad Layout
Dimensions in inches (mm); scale = approx. 5X
0.317 (8.05)
0.050 (1.27)
0.020 (0.51)
16 PLCS
0.449 (11.40)
15
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IL3285/IL3222
Ordering Information and Valid Part Numbers
IL 32 85 -3 E TR13
Valid Part Numbers
Bulk Packaging
Blank = Tube
TR13 = 13'' Tape and Reel
IL3285E
IL3285E TR13
IL3285-3E
IL3285-3E TR13
Package
E = RoHS Compliant
IL3222E
IL3222E TR13
IL3222-3E
IL3222-3E TR13
Package Type
Blank = 0.3'' SOIC
-3 = 0.15'' SOIC
Channel Configuration
22 = RS-422
85 = RS-485
Base Part Number
32 = Passive-In, 1/8-Load Transceiver
Product Family
IL = Isolators
RoHS
COMPLIANT
16
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IL3285/IL3222
Revision History
ISB-DS-001-IL3285/22-S
October 2022
Changes
• Changed output drive table to 2 V output voltage (p. 1).
• Footnote that HIGH is no coil-current flowing and LOW is coil-current flowing (p. 1).
• Upgraded to VDE 0884-17 (p. 3).
• Increased Working Voltage ratings based on latest VDE testing (p. 3).
ISB-DS-001-IL3285/22-R
ISB-DS-001-IL3285/22-Q
ISB-DS-001-IL3285/22-P
ISB-DS-001-IL3285/22-O
ISB-DC-001-IL3285/22-N
ISB-DS-001-IL3285/22-M
Changes
•
Clarified RS-485 truth table (p. 1).
•
Increased Working Voltage (VIORM) to 600 VRMS (p.3).
•
Upgraded from VDE V 0884-10 to VDE V 0884-11 / IEC 60747-17 (p. 3).
•
Clarified IL3185-3E and IL3122-3E pin 8 should not be connected (p. 4).
•
Added thermal characteristics (p. 8).
Changes
•
IEC 60747-5-5 (VDE 0884) certification.
•
Upgraded from MSL 2 to MSL 1.
•
Rearranged low level input current specification so maximum is more than minimum.
Changes
•
Added VDE 0884 pending.
•
Clarified switching specifications.
•
Updated package drawings.
•
Added recommended solder pad layouts.
Changes
•
Detailed isolation and barrier specifications.
•
Cosmetic changes.
Changes
•
Added minimum/maximum coil resistance specifications.
•
Misc. cosmetic changes.
Change
•
ISB-DS-001-IL3285/22-L
Change
•
ISB-DS-001-IL3285/22-K
ISB-DS-001-IL3285/22-J
Update terms and conditions.
Clarified ground pin connections (pp. 3-4).
Changes
•
Changes to current-limiting resistor values (pp. 7 and 10).
•
Details for boost capacitor selection (p. 7).
Change
•
Noted UL1577 Approval.
17
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IL3285/IL3222
Datasheet Limitations
The information and data provided in datasheets shall define the specification of the product as agreed between NVE and its customer, unless NVE and
customer have explicitly agreed otherwise in writing. All specifications are based on NVE test protocols. In no event however, shall an agreement be valid
in which the NVE product is deemed to offer functions and qualities beyond those described in the datasheet.
Limited Warranty and Liability
Information in this document is believed to be accurate and reliable. However, NVE does not give any representations or warranties, expressed or implied,
as to the accuracy or completeness of such information and shall have no liability for the consequences of use of such information.
In no event shall NVE be liable for any indirect, incidental, punitive, special or consequential damages (including, without limitation, lost profits, lost
savings, business interruption, costs related to the removal or replacement of any products or rework charges) whether or not such damages are based on tort
(including negligence), warranty, breach of contract or any other legal theory.
Right to Make Changes
NVE reserves the right to make changes to information published in this document including, without limitation, specifications and product descriptions at
any time and without notice. This document supersedes and replaces all information supplied prior to its publication.
Use in Life-Critical or Safety-Critical Applications
Unless NVE and a customer explicitly agree otherwise in writing, NVE products are not designed, authorized or warranted to be suitable for use in life
support, life-critical or safety-critical devices or equipment. NVE accepts no liability for inclusion or use of NVE products in such applications and such
inclusion or use is at the customer’s own risk. Should the customer use NVE products for such application whether authorized by NVE or not, the customer
shall indemnify and hold NVE harmless against all claims and damages.
Applications
Applications described in this datasheet are illustrative only. NVE makes no representation or warranty that such applications will be suitable for the
specified use without further testing or modification.
Customers are responsible for the design and operation of their applications and products using NVE products, and NVE accepts no liability for any
assistance with applications or customer product design. It is customer’s sole responsibility to determine whether the NVE product is suitable and fit for the
customer’s applications and products planned, as well as for the planned application and use of customer’s third party customers. Customers should provide
appropriate design and operating safeguards to minimize the risks associated with their applications and products.
NVE does not accept any liability related to any default, damage, costs or problem which is based on any weakness or default in the customer’s applications
or products, or the application or use by customer’s third party customers. The customer is responsible for all necessary testing for the customer’s
applications and products using NVE products in order to avoid a default of the applications and the products or of the application or use by customer’s
third party customers. NVE accepts no liability in this respect.
Limiting Values
Stress above one or more limiting values (as defined in the Absolute Maximum Ratings System of IEC 60134) will cause permanent damage to the device.
Limiting values are stress ratings only and operation of the device at these or any other conditions above those given in the recommended operating
conditions of the datasheet is not warranted. Constant or repeated exposure to limiting values will permanently and irreversibly affect the quality and
reliability of the device.
Terms and Conditions of Sale
In case an individual agreement is concluded only the terms and conditions of the respective agreement shall apply. NVE hereby expressly objects to
applying the customer’s general terms and conditions with regard to the purchase of NVE products by customer.
No Offer to Sell or License
Nothing in this document may be interpreted or construed as an offer to sell products that is open for acceptance or the grant, conveyance or implication of
any license under any copyrights, patents or other industrial or intellectual property rights.
Export Control
This document as well as the items described herein may be subject to export control regulations. Export might require a prior authorization from national
authorities.
Automotive Qualified Products
Unless the datasheet expressly states that a specific NVE product is automotive qualified, the product is not suitable for automotive use. It is neither
qualified nor tested in accordance with automotive testing or application requirements. NVE accepts no liability for inclusion or use of non-automotive
qualified products in automotive equipment or applications.
In the event that customer uses the product for design-in and use in automotive applications to automotive specifications and standards, customer (a) shall
use the product without NVE’s warranty of the product for such automotive applications, use and specifications, and (b) whenever customer uses the
product for automotive applications beyond NVE’s specifications such use shall be solely at customer’s own risk, and (c) customer fully indemnifies NVE
for any liability, damages or failed product claims resulting from customer design and use of the product for automotive applications beyond NVE’s
standard warranty and NVE’s product specifications.
18
NVE Corporation
11409 Valley View Road, Eden Prairie, MN 55344-3617
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IL3285/IL3222
An ISO 9001 Certified Company
NVE Corporation
11409 Valley View Road
Eden Prairie, MN 55344-3617 USA
Telephone: (952) 829-9217
www.nve.com
e-mail: iso-info@nve.com
©NVE Corporation
All rights are reserved. Reproduction in whole or in part is prohibited without the prior written consent of the copyright owner.
ISB-DS-001-IL3285/22-S
October 2022
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