KY485LEEN
ESD-Enhanced, Fail-safe, Slew-Rate-limited
RS-485/RS-422 Transceivers
General Description
The KY485LEEN +5V, half-duplex, ±20kV ESD-
protected RS-485/RS-422-compatible transceivers
feature one driver and one receiver.
The KY485LEEN include a hot-swap capability to
eliminate false transitions on the bus during power-
up or live insertion.
The KY485LEEN features reduced slew-rate drivers
that minimize EMI and reduce reflections caused by
improperly terminated cables, allowing error-free
transmission up to 1Mbps.
The KY485LEEN feature a 1/8-unit load receiver
input impedance, allowing up to 256 transceivers on
the bus. These devices are intended for half-duplex
communications. All driver outputs are protected to
±20kV ESD using the Human Body Model and
±20kV ESD using the Air-Gap Discharge Model.
TheKY485LEEN is available in an 8-pin SO pack-
age.
The devices operate over the extended -40°C to
+125°C temperature range.
Features
+5V Operation
Hot-Swappable for Telecom Applications
Enhanced Slew-Rate Limiting Facilitates Er-
ror-Free Data Transmission
Extended ESD Protection for RS-485 I/O
Pins ±16kV
High fanout driving 1/8Unit load , Allowing
up to 256 Transceivers on the Bus.
8 Pin-SO Package
Applications
Isolated RS-485 Interfaces
Utility Meters
Industrial Controls
Industrial Motor Drives
Automated HVAC Systems
Absolute Maximum Ratins
(All voltages referenced to GND.)
Supply Voltage VCC...............................................................+6V
DE, RE-, DI..............................................................-0.3V to +6
A, B........................................................................... -8V to +13V
Short-Circuit Duration (RO, A, B) to GND ..................Continuous
Continuous Power Dissipation (TA = +70°C)
8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW
Operating Temperature Range ...........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering 10s) ..................................+300°C
KY485LEEN
Stresses beyond those listed under “Absolute Maxi-
mum Ratings” may cause permanent damage to the
device. These are stress ratings only, and functional
operation of the device at these or any other conditions
beyond those indicated in the operational sections of
the specifications is not implied. Exposure to absolute
maximum rating conditions for extended periods may
affect device reliability.
Package SOIC8
Package Information
KY485LEEN Rev.1.0
KEYSEMI Proprietary Information Unauthorized Photocopy and Duplication
Prohibited © 2017 KEYSEMI All Rights Reserved
KY485LEEN
ESD-Enhanced, Fail-safe, Slew-Rate-limited
RS-485/RS-422 Transceivers
DC Electrical Characteristics
(VCC = +5V ± 5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.)
PARAMETER
DRIVER
Differential Driver Output (no load)
Differential Driver Output
Change in Magnitude of Differential
Output Voltage (Note 2)
Driver Common-Mode Output
Voltage
Change In Magnitude of
Common-Mode Voltage (Note 2)
Input High Voltage
Input Low Voltage
DI Input Hysteresis
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
OD1
V
OD2
∆V
OD
V
OC
∆V
OC
V
IH1
V
IL1
V
HYS
I
IN1
I
IN4
Figure1
Figure1,R = 50Ω (RS-422)
Figure1,R = 27Ω (RS-485)
Figure1,R =50Ωor R= 27Ω
Figure1,R=50Ωor R = 27Ω
Figure1,R=50Ωor R = 27Ω
DE , DI ,
DE, DI,
2.0
1.5
5
V
V
0.2
3
0.2
V
V
V
V
0.8
V
mV
±2
µA
µA
mA
250
mA
mA
RE
RE
2.0
KY485LEEN
DE, DI,
100
Input Current
Input Current (A and B)
Driver Short-Circuit Output
Current
(Note 3)
RECEIVER
Receiver Differential Threshold
Voltage
Receiver Input Hysteresis
Receiver Output High Voltage
Receiver Output Low Voltage
Three-State Output Current at
Receiver
Receiver Input Resistance
Receiver Output Short-Circuit
Current
SUPPLY CURRENT
Supply Current
Supply Current in Shutdown Mode
ESD Protection
RE
VIN=12V
VIN = -7V
DE = GND,
VCC=GND or
5.25V
125
-75
-250
V
OD1
-7V ≤ V
OUT
≤ V
CC
0V ≤ V
OUT
≤ 12V
0V ≤ V
OUT
≤ V
CC
±25
V
TH
∆V
TH
V
OH
V
OL
I
OZR
R
IN
I
OSR
-7V ≤ V
CM
≤ +12V
-200
25
-125
-50
mV
mV
V
I
O
= 4mA, V
ID
= -200mV;
I
O
= -4mA, V
ID
= -50mV
0.4V ≤ V
O
≤ 2.4V
-7V ≤ V
CM
≤ +12V
0V ≤ V
RO
≤ V
CC
Vcc-1.5
0.4
±1
96
±7
±95
V
µA
kΩ
mA
I
CC
I
SHDN
No load,
RE- =DI=GND or
VCC
DE = VCC
DE = GND
530
500
2.5
900
600
10
µA
µA
DE = GND, V
RE-
= V
CC
ESD Protection(A,B)
ESD Protection(all other pins)
Air Gap Discharge IEC 61000-4-2
Human Body Model
Human Body Model
±16
±8
±5
KV
KV
Note 1:
All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device
KY485LEEN Rev1.0
KEYSEMI CORPORATION
2
KY485LEEN
ESD-Enhanced, Fail-safe, Slew-Rate-limited
RS-485/RS-422 Transceivers
ground unless otherwise noted.
Note 2:
∆VOD and ∆VOC are the changes in VOD and VOC, respectively, when the DI input changes state.
Note 3:
Maximum current level applies to peak current just prior to fold-back-current limiting; minimum current level applies during
current limiting.
Switching Characteristics
(VCC = +5V ±5%, TA = TMIN to TMAX, unless otherwise noted. Typical values are at VCC = +5V and TA = +25°C.)
PARAMETER
SYMBOL
t
DPLH
CONDITIONS
Figures3 and 5, RDIFF = 54Ω, CL1 = CL2
= 100pF
Figures 3 and 5, RDIFF = 54Ω, CL1 = CL2
= 100pF
Figures 3 and 5, RDIFF = 54Ω, CL1 = CL2
= 100pF
MIN
250
1000
250
1000
±100
200
TYP
720
720
-3
530
1000
MAX
UNITS
Driver Input to Output
t
DPHL
Driver Output Skew
|
t
DPLH
- t
DPHL
|
Driver Rise or Fall Time
Maximum Data Rate
Driver Enable to Output High
ns
t
DSKEW
t
DR,
t
DF
f
MAX
t
DZH
ns
750
2000
2500
2500
100
100
ns
kbps
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
ns
Figures4 and 6, C
L
= 100pF, S2
closed
Driver Enable to Output Low
Driver Disable Time from Low
Driver Disable Time from High
t
DZL
t
DLZ
t
DHZ
t
RPLH
, t
RPHL
t
RSKD
t
RZL
t
RZH
t
RLZ
t
RHZ
t
SHDN
t
DZH(SHDN)
t
DZL(SHDN)
t
RZH(SHDN)
Figures4 and 6,C
L
= 100pF, S1
closed
Figures 4 and 6, C
L
= 15pF, S1
closed
Figures 4 and 6, C
L
= 15pF, S2
closed
Figures 7 and 9;
|
V
ID
|
≥ 2.0V;rise
and fall time of V
ID
≤ 15ns
Figures 7 and 9;
|
V
ID
|
≥ 2.0V;rise
and fall time of V
ID
≤ 15ns
Figures 2 and 8, C
L
= 100pF, S1
closed
Figures 2 and 8, C
L
= 100pF, S2
closed
Figures 2 and 8 , C
L
= 100pF, S1
closed
Figures 2 and 8, C
L
= 100pF, S2
closed
(Note 4)
Figures 4 and 6, C
L
= 15pF, S2
closed
Figures 4 and 6, C
L
= 15pF, S1
closed
Figures 2 and 8, C
L
= 100pF, S2
closed
50
Receiver Input to Output
200
3
20
20
20
20
200
250
±30
50
50
50
50
600
4500
4500
3500
3500
|
t
RPLH
- t
RPHL
|
Differential
Receiver Skew
Receiver Enable to Output Low
Receiver Enable to Output High
Receiver Disable Time from Low
Receiver Disable Time from High
Time to Shutdown
Driver Enable from Shutdown to
Output High
Driver Enable from Shutdown to
Output Low
Receiver Enable from Shutdown to
Output High
Receiver Enable from Shutdown to
Output Low
t
RZL(SHDN)
Figures 2 and 8, C
L
= 100pF, S1
closed
Note 4:
The device is put into shutdown by bringing
RE
high and DE low. If the enable inputs are in this state for less than 50ns,
the device is guaranteed not to enter shutdown. If the enable inputs are in this state for at least 600ns, the device is guaranteed to
have entered shutdown.
KY485LEEN Rev1.0
KEYSEMI CORPORATION
3
KY485LEEN
ESD-Enhanced, Fail-safe, Slew-Rate-limited
RS-485/RS-422 Transceivers
Figure 1 Driver DC Test Load
Figure 2 Receiver Enable/Disable Timing Test Load
Figure 3 Driver Timing Test Circuit
Figure 4 Driver Enable/Disable Timing Test Load
Figure 5 Driver Propagation Delays
Figure 6 Driver Enable and Disable Times
Figure 7 Receiver Propagation Delays
Figure 8 Receiver Enable and Disable Times
Figure 9 Receiver Propagation Delay Test Circuit
KY485LEEN Rev1.0
KEYSEMI CORPORATION
4
KY485LEEN
ESD-Enhanced, Fail-safe, Slew-Rate-limited
RS-485/RS-422 Transceivers
Pin Description
PIN
1
2
NAME
RO
FUNCTION
Receiver Output. When RE is low and if A - B ≥ -50mV, RO will be high; if A - B ≤ -200mV, RO will
be low.
Receiver Output Enable. Drive RE low to enable RO; RO is high impedance when RE is high.
Drive RE high and DE low to enter low-power shutdown mode.
RE is a hot-swap input (see the
Hot-Swap Capability
section for more details).
Driver Output Enable. Drive DE high to enable driver outputs. These outputs are high impedance
when DE is low. Drive RE high and DE low to enter low-power shutdown mode.
DE is a hot-swap input (see the
Hot-Swap Capability
section for more details).
Driver Input. With DE high, a low on DI forces non-inverting output low and inverting output high.
Similarly, a high on DI forces non-inverting output high and inverting output low.
Ground
Non-inverting Receiver Input and Non-inverting Driver Output
Inverting Receiver Input and Inverting Driver Output
Positive Supply, V
CC
= +5V ±5%. Bypass V
CC
to GND with a 0.1µF capacitor.
RE
3
4
5
6
7
8
DE
DI
GND
A
B
Vcc
Function Table
TRANSMITTING
INPUTS
DE
1
1
0
0
DI
1
0
X
X
OUTPUTS
B/Z
0
1
High-Z
Shutdown
A/Y
1
0
High-Z
RE
X
X
0
1
RECEIVING
INPUTS
RE
0
0
0
1
1
DE
X
X
X
1
0
A-B
≥ -0.05V
≤ -0.2V
Open/shorted
X
X
OUTPUTS
RO
1
0
1
High-Z
Shutdown
KY485LEEN Rev1.0
KEYSEMI CORPORATION
5
电子工程世界
模拟电子
