LTC2856-2 LINER [Linear Technology], LTC2856-2 Datasheet

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LTC2856-2

Manufacturer Part Number
LTC2856-2
Description
20Mbps and Slew Rate Limited 15kV RS485/RS422 Transceivers
Manufacturer
LINER [Linear Technology]
Datasheet
FEATURES
APPLICATIONS
TYPICAL APPLICATION
All other trademarks are the property of their respective owners.
, LT, LTC and LTM are registered trademarks of Linear Technology Corporation.
20Mbps or Low EMI 250kbps Maximum Data Rate
No Damage or Latchup to ESD: ±15kV HBM
High Input Impedance Supports 256 Nodes
(C, I-Grade)
Operation Up to 125°C (H-Grade)
Guaranteed Failsafe Receiver Operation Over the
Entire Common Mode Range
Current Limited Drivers and Thermal Shutdown
Delayed Micropower Shutdown: 5μA Maximum
(C, I-Grade)
Power Up/Down Glitch-Free Driver Outputs
Low Operating Current: 900μA Maximum in Receive
Mode
Compatible with TIA/EIA-485-A Specifi cations
Available in 8-Lead and 10-Lead 3mm × 3mm DFN
and 8-Lead and 10-Lead MSOP Packages
Low Power RS485/RS422 Transceiver
Level Translator
Backplane Transceiver
RO1
RO2
RE1
DE1
RE2
DE2
DI1
DI2
LTC2856-1
LTC2856-1
D
D
R
R
V
GND1
V
GND2
285678 TA01a
CC1
CC2
R
R
T
T
DESCRIPTION
The LTC
LTC2858-1 and LTC2858-2 are low power, RS485/RS422
transceivers operating on 5V supplies at maximum data
rates of 20Mbps or 250kbps for low EMI. The receiver has
a one-eighth unit load, supporting up to 256 nodes per
bus (C, I-Grade), and a failsafe feature that guarantees a
high output state under conditions of fl oating or shorted
inputs.
The driver maintains a high output impedance over the
entire common mode range when disabled or when the
supply is removed. Excessive power dissipation caused by
bus contention or a fault is prevented by current limiting
all outputs and by thermal shutdown.
Enhanced ESD protection allows these parts to withstand
±15kV (human body model) on the transceiver interface
pins without latchup or damage.
Limited 15kV RS485/RS422
LTC2856-1
LTC2856-2
LTC2857-1
LTC2857-2
LTC2858-1
LTC2858-2
NUMBER
PART
20Mbps and Slew Rate
®
2856-1, LTC2856-2, LTC2857-1, LTC2857-2,
LTC2857-1/LTC2857-2
LTC2858-1/LTC2858-2
RATE (Mbps)
MAX DATA
0.25
0.25
0.25
LTC2858-1 at 20Mbps
20
20
20
20ns/DIV
DUPLEX
Half
Half
Transceivers
Full
Full
Full
Full
Y-Z
MSOP-10, DFN-10
MSOP-10, DFN-10
DI
Y
Z
MSOP-8, DFN-8
MSOP-8, DFN-8
MSOP-8, DFN-8
MSOP-8, DFN-8
PACKAGE
2856 TA01b
285678fe
1

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LTC2856-2 Summary of contents

Page 1

... Limited 15kV RS485/RS422 DESCRIPTION ® The LTC 2856-1, LTC2856-2, LTC2857-1, LTC2857-2, LTC2858-1 and LTC2858-2 are low power, RS485/RS422 transceivers operating on 5V supplies at maximum data rates of 20Mbps or 250kbps for low EMI. The receiver has a one-eighth unit load, supporting up to 256 nodes per bus (C, I-Grade), and a failsafe feature that guarantees a high output state under conditions of fl ...

Page 2

... CC Logic Input Voltages (RE, DE, DI) ................ –0. Interface I/O ( ....................(V Receiver Output Voltage (RO) .......–0. Operating Temperature Range (Note 4) LTC285xC ................................................ 0°C to 70°C LTC285xI.............................................. –40°C to 85°C LTC285xH .......................................... –40°C to 125°C PACKAGE INFORMATION LTC2856 TOP VIEW ...

Page 3

... Consult LTC Marketing for information on non-standard lead based fi nish parts. For more information on lead free part marking, go to: For more information on tape and reel specifi cations, go to: PRODUCT SELECTION GUIDE PART NUMBER PART MARKING LTC2856-1 LTCMF, LCMG LTC2856-2 LTCMH, LCMJ LTC2857-1 LTCMC, LCMD LTC2857-2 LTCMK, LCMM LTC2858-1 LTCGQ, LCGR ...

Page 4

... 5V, 0V ≤ RO ≤ LTC2856-1, CC LTC2856-2, LTC2858-1, LTC2858-2 DE, DI, RE 5.5V CC DE, DI, RE 4.5V CC DE LTC2856, LTC2858 (C and I-Grade) LTC2856, LTC2858 (H-Grade) No Load 0V 0V, LTC2856-1, LTC2856-2, LTC2858-1, LTC2858-2 MIN TYP MAX UNITS ● ● 1 ● ● ...

Page 5

... Driver Enable or Disable Time ZLD ZHD LZD HZD Driver Enable from Shutdown ZHSD ZLSD t Time to Shutdown SHDN Driver in LTC2856-2, LTC2857-2, LTC2858-2 f Maximum Data Rate MAXS Driver Input to Output PLHDS PHLDS Δt Driver Input to Output Difference |t PDS t Driver Output A to Output B SKEWDS ...

Page 6

LTC2857-1/LTC2857-2 LTC2858-1/LTC2858-2 ELECTRICAL CHARACTERISTICS Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. High temperatures degrade ...

Page 7

TEST CIRCUITS Y DI DRIVER R DIFF Z 285678 F04a DRIVER GND Figure 5. Driver Enable and Disable Timing Measurement Y-Z ...

Page 8

... LTC2858-1/LTC2858-2 TEST CIRCUITS A ± RECEIVER CM B ± RECEIVER 285678 F07a FUNCTION TABLES LTC2856-1, LTC2856-2 LOGIC INPUTS MODE Receive 0 1 Shutdown 1 0 Transceive 1 1 Transmit A-B – ...

Page 9

TYPICAL PERFORMANCE CHARACTERISTICS Receiver Skew vs Temperature 1. 15pF –1 –40 – 100 120 TEMPERATURE (°C) 385678 G01 Driver Output Short-Circuit Current vs Temperature 160 SOURCE ...

Page 10

... Inverting Receiver Input (and Inverting Driver Output for the LTC2856-1 and LTC2856-2). Impedance is > 96kΩ in receive mode or unpowered. 9 Noninverting Receiver Input (and Noninverting Driver Output for the LTC2856-1 and LTC2856-2). Impedance is > 96kΩ in receive mode or unpowered. 10 Positive Supply. 4.5V < V < 5.5V. Bypass with a 0.1μF ceramic capacitor. ...

Page 11

... BLOCK DIAGRAMS LTC2856-1, LTC2856-2 RO RECEIVER RE SLEEP/SHUTDOWN LOGIC AND DELAY DE DRIVER (15kV) B (15kV) DI 2856 BD LTC2858-1, LTC2858-2 RO RECEIVER RE SLEEP/SHUTDOWN LOGIC AND DELAY DE DI DRIVER 2858 BD LTC2857-1/LTC2857-2 LTC2858-1/LTC2858-2 LTC2857-1, LTC2857-2 A (15kV) RECEIVER B (15kV) Z (15kV) DRIVER Y (15kV) 2857 BD A (15kV) B (15kV) Z (15kV) ...

Page 12

... Note 4). Slew Limiting for EMI Emissions Control The LTC2856-2, LTC2857-2 and the LTC2858-2 feature reduced slew rate driver outputs to control the high fre- quency EMI emissions from equipment and data cables. ...

Page 13

... RS485 standard. The dashed line at 250kbps shows the maximum data rate of 285678 F08 the low-EMI LTC2856-2, LTC2857-2, and LTC2858-2. The dashed line at 20Mbps shows the maximum data rates of the LTC2856-1, LTC2857-1 and LTC2858-1. pin CC Figure 9 ...

Page 14

LTC2857-1/LTC2857-2 LTC2858-1/LTC2858-2 APPLICATIONS INFORMATION Time-Based Traces Y, Z 1V/DIV Y-Z 2V/DIV 2μs/DIV Figure 10. LTC2858-1 Driver Output at 100kHz Into 100Ω Resistor 14 Y-Z 10dB/DIV 285678 F10a Frequency Spectrum 285678 F10b 1.25MHz/DIV 285678fe ...

Page 15

... Figure 11. LTC2858-2 Driver Output at 100kHz Into 100Ω Resistor TYPICAL APPLICATIONS Y-Z 10dB/DIV 285678 F11a Failsafe “0” Application (Idle State = Logic “0” 100k LTC2856-1 285678 TA02 LTC2857-1/LTC2857-2 LTC2858-1/LTC2858-2 Frequency Spectrum 285678 F11b 1.2MHz/DIV “A” “B” 285678fe 15 ...

Page 16

LTC2857-1/LTC2857-2 LTC2858-1/LTC2858-2 PACKAGE DESCRIPTION 3.5 0.05 1.65 0.05 2.15 0.05 (2 SIDES) 0.25 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS PIN 1 TOP MARK (NOTE 6) 0.200 REF 16 DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG ...

Page 17

PACKAGE DESCRIPTION 3.50 0.05 1.65 0.05 2.15 0.05 (2 SIDES) 0.25 0.05 0.50 BSC 2.38 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE ...

Page 18

LTC2857-1/LTC2857-2 LTC2858-1/LTC2858-2 PACKAGE DESCRIPTION 5.23 (.206) MIN 0.42 0.038 (.0165 .0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) GAUGE PLANE 0.18 (.007) NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS ...

Page 19

PACKAGE DESCRIPTION 5.23 (.206) MIN 0.305 0.038 (.0120 .0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) GAUGE PLANE 0.18 (.007) NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE ...

Page 20

... LTC2856-1/LTC2856-2 LTC2857-1/LTC2857-2 LTC2858-1/LTC2858-2 TYPICAL APPLICATION Multi-Node Network and End Termination Using the LTC2856 LTC2859 RELATED PARTS PART NUMBER DESCRIPTION LTC485 Low Power RS485 Interface Transceiver LTC491 Differential RS485 Driver and Receiver Pair LTC1480 3.3V Ultralow Power RS485 Transceiver ...

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