Datasheet

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LTM2882

2882fe

For more information www.linear.com/LTM2882

Typical applicaTion

DescripTion

Dual Isolated RS232

µModule Transceiver + Power

The LTM

2882 is a complete galvanically isolated dual

RS232 µModule

(micromodule)

transceiver. No external

components are required. A single 3.3V or 5V supply

powers both sides of the interface through an integrated,

isolated DC/DC converter. A logic supply pin allows easy

interfacing with different logic levels from 1.62V to 5.5V,

independent of the main supply.

Coupled inductors and an isolation power transformer

provide 2500V

RMS

of isolation between the line transceiver

and the logic interface. This device is ideal for systems

with different grounds, allowing for large common mode

voltages. Uninterrupted communication is guaranteed for

common mode transients greater than 30kV/μs.

This part is compatible with the TIA/EIA-232-F standard.

Driver outputs are protected from overload and can be

shorted to ground or up to ±15V without damage. An

auxiliary isolated digital channel is available. This channel

allows configuration for half-duplex operation by control

ling the DE pin.

Enhanced

ESD protection allows this part to withstand up

to ±10kV (human body model) on the transceiver interface

pins to isolated supplies and across the isolation barrier

to logic supplies without latchup or damage.

Isolated Dual RS232 µModule Transceiver

FeaTures

applicaTions

RS232 Transceiver: 2500V

RMS

for 1 Minute

UL Recognized

File #E15178

Isolated DC Power: 5V at Up to 200mA

No External Components Required

1.62V to 5.5V Logic Supply for Flexible Digital

Interfacing

High Speed Operation

1Mbps for 250pF/3kΩ Load

250kbps for 1nF/3kΩ Load

100kbps for 2.5nF/3kΩ TIA/EIA-232-F Load

3.3V (LTM2882-3) or 5V (LTM2882-5) Operation

No Damage or Latchup to ±10kV HBM ESD on

Isolated RS232 Interface or Across Isolation Barrier

High Common Mode Transient Immunity: 30kV/μs

Maximum Continuous Working Voltage: 560V

PEAK

True RS232 Compliant Output Levels

Low Profile (15mm × 11.25mm) Surface Mount

BGA and LGA Packages

Isolated RS232 Interface

Industrial Communication

Test and Measurement Equipment

Breaking RS232 Ground Loops

1Mbps Operation

2882 TA01a

DIN

T1IN

R1OUT

T2IN

R2OUT

DOUT

T1OUT

R1IN

T2OUT

R2IN

LTM2882

3.3V (LTM2882-3)

5V (LTM2882-5)

GND GND2

ISOLATION BARRIER

OFF

CC2

AVAILABLE CURRENT:

150mA (LTM2882-5)

100mA (LTM2882-3)

400ns/DIV

DRIVER OUTPUTS TIED TO RECEIVER INPUTS

TOUT LOAD = 250pF + RIN

ROUT LOAD = 150pF

10V/DIV

5V/DIV

TIN

T1OUT/R1IN

T2OUT/R2IN

5V/DIV

2882 TA01b

R1OUT

R2OUT

L, LT, LT C , LT M , Linear Technology, the Linear logo and µModule are registered trademarks of

Linear Technology Corporation. All other trademarks are the property of their respective owners.

Summary of content (22 pages)

PAGE 1
LTM2882 Dual Isolated RS232 µModule Transceiver + Power Description Features n RS232 Transceiver: 2500VRMS for 1 Minute UL Recognized File #E15178 Isolated DC Power: 5V at Up to 200mA No External Components Required 1.62V to 5.5V Logic Supply for Flexible Digital Interfacing High Speed Operation 1Mbps for 250pF/3kΩ Load 250kbps for 1nF/3kΩ Load 100kbps for 2.5nF/3kΩ TIA/EIA-232-F Load 3.
PAGE 2
LTM2882 Absolute Maximum Ratings Pin Configuration (Note 1) VCC to GND................................................... –0.3V to 6V VL to GND..................................................... –0.3V to 6V VCC2 to GND2................................................ –0.3V to 6V Logic Inputs T1IN, T2IN, ON, DIN to GND.........–0.3V to (VL + 0.3V) DE to GND2............................. –0.3V to (VCC2 + 0.3V) Logic Outputs R1OUT, R2OUT to GND................–0.3V to (VL + 0.3V) DOUT to GND2.............
PAGE 3
LTM2882 order information PART NUMBER LTM2882CY-3#PBF LTM2882IY-3#PBF LTM2882HY-3#PBF (OBSOLETE) LTM2882MPY-3#PBF (OBSOLETE) LTM2882CY-5#PBF LTM2882IY-5#PBF LTM2882HY-5#PBF (OBSOLETE) LTM2882MPY-5#PBF (OBSOLETE) LTM2882CV-3#PBF LTM2882IV-3#PBF LTM2882CV-5#PBF LTM2882IV-5#PBF INPUT VOLTAGE PART MARKING DEVICE FINISH CODE PAD OR BALL FINISH PACKAGE TYPE MSL RATING LTM2882Y-3 3V to 3.6V SAC305 (RoHS) 4.5V to 5.5V e1 BGA 3 LTM2882Y-5 3V to 3.6V LTM2882V-3 Au (RoHS) 4.5V to 5.
PAGE 4
LTM2882 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. LTM2882-3 VCC = 3.3V, LTM2882-5 VCC = 5.0V, VL = VCC, and GND = GND2 = 0V, ON = VL unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP VIR Receiver Input Threshold Input Low l Input High l VHYSR Receiver Input Hysteresis RIN Receiver Input Resistance Logic Input Threshold Voltage MAX UNITS 0.8 1.3 1.7 2.5 V l 0.
PAGE 5
LTM2882 switching Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. LTM2882-3 VCC = 3.3V, LTM2882-5 VCC = 5.0V, VL = VCC, and GND = GND2 = 0V, ON = VL unless otherwise noted. SYMBOL PARAMETER CONDITIONS MIN TYP MAX 0.2 0.
PAGE 6
LTM2882 Typical Performance Characteristics VCC = 5V, VL = 3.3V, and GND = GND2 = 0V, ON = VL unless otherwise noted. VCC Supply Current vs Temperature VCC = 3.3V LTM2882-3 100 65 90 VCC = 5.0V LTM2882-5 15 50 45 0 50 25 TEMPERATURE (°C) –25 100 75 2882 G01 100 3.3V CL = 250pF 80 60 5.0V CL = 1nF 40 THRESHOLD VOLTAGE (V) 3.3V CL = 1nF 200 600 400 DATA RATE (kbps) 800 75 2.5 60 INPUT HIGH 2.0 1.5 INPUT LOW 1.
PAGE 7
LTM2882 Typical Performance Characteristics TA = 25°C, LTM2882-3 VCC = 3.3V, LTM2882-5 VCC = 5V, VL = 3.3V, and GND = GND2 = 0V, ON = VL unless otherwise noted. VCC2 Output Voltage vs Load Current 3.5 5.2 3.0 5.1 2.5 VCC2 VOLTAGE (V) THRESHOLD VOLTAGE (V) Logic Input Threshold vs VL Supply Voltage INPUT HIGH 2.0 INPUT LOW 1.5 1.0 0.5 0 VCC = 3.0V TO 3.6V, LTM2882-3 VCC = 4.5V TO 5.5V, LTM2882-5 5.0 5.5V 4.9 3.0V 4.7 1 3 2 4 VL SUPPLY VOLTAGE (V) 4.5 6 5 3.6V 4.5V 4.6 0 5.0V 3.
PAGE 8
LTM2882 Typical Performance Characteristics VCC = 5V, VL = 3.3V, and GND = GND2 = 0V, ON = VL unless otherwise noted. VCC2 Surplus Current vs Temperature 70 300 EFFICIENCY (%) 150 60 VCC = 5.0V LTM2882-5 200 VCC = 3.3V LTM2882-3 100 T1OUT AND T2OUT 50 BAUD = 100kbps RL = 3k, CL = 2.5nF VCC2 = 4.8V 0 –50 –25 25 0 50 TEMPERATURE (°C) VCC2 Power Efficiency 1.2 1.0 LTM2882-5 50 0.8 LTM2882-3 40 0.6 30 0.4 20 75 100 10 POWER LOSS (W) VCC2 CURRENT (mA) 250 TA = 25°C, LTM2882-3 VCC = 3.
PAGE 9
LTM2882 TEST Circuits VL TIN TIN CL RL ½VL 0V TOUT TOUT tPLHD VOHD 0V –3V VOLD tr, tf ≤ 40ns tPHLD 3V tTHL tTLH 2882 F01 Figure 1. Driver Slew Rate and Timing Measurement VCC2 DE 0V 0 OR VL TOUT DE CL RL TOUT tPZHD VOHD tPHZD 5V VOHD – 0.5V 0V 0V TOUT tr, tf ≤ 40ns ½VCC2 tPZLD tPLZD VOLD – 0.5V –5V VOLD 2882 F02 Figure 2. Driver Enable/Disable Times 3V RIN ROUT –3V CL RIN tr, tf ≤ 40ns ROUT 1.
PAGE 10
LTM2882 Pin Functions LOGIC SIDE ISOLATED SIDE R2OUT (Pin A1): Channel 2 RS232 Inverting Receiver Output. Controlled through isolation barrier from receiver input R2IN. Under the condition of an isolation communication failure R2OUT is in a high impedance state. GND2 (Pins K1-K7): Isolated Side Circuit Ground. These pads should be connected to the isolated ground and/or cable shield. T2IN (Pin A2): Channel 2 RS232 Inverting Driver Input.
PAGE 11
LTM2882 Block Diagram 5V REG VCC VCC2 2.2µF 2.2µF VL GND2 2.2µF DE GND DOUT VDD DC/DC CONVERTER VEE ON DIN VDD T1IN R1OUT T1OUT ISOLATED COMMUNICATIONS INTERFACE ISOLATED COMMUNICATIONS INTERFACE VEE VDD R1IN 5k T2IN T2OUT VEE R2OUT R2IN 5k 2882 BD 2882fe For more information www.linear.
PAGE 12
LTM2882 Applications Information Overview ANY VOLTAGE FROM 1.62V TO 5.5V VL ON VCC DIN EXTERNAL DEVICE T1IN R1OUT T2IN LTM2882 GND VCC2 DE DOUT T1OUT R1IN T2OUT R2IN R2OUT µModule Technology GND2 2882 F05 The LTM2882 utilizes isolator µModule technology to translate signals and power across an isolation barrier. Signals on either side of the barrier are encoded into pulses and translated across the isolation boundary using coreless transformers formed in the µModule substrate.
PAGE 13
LTM2882 applications information Channel Timing Uncertainty Driver Overvoltage and Overcurrent Protection Multiple channels are supported across the isolation boundary by encoding and decoding of the inputs and outputs. The technique used assigns T1IN/R1IN the highest priority such that there is no jitter on the associated output channels T1OUT/R1OUT, only delay. This preemptive scheme will produce a certain amount of uncertainty on T2IN/ R2IN to T2OUT/R2OUT and DIN to DOUT.
PAGE 14
LTM2882 Applications Information PCB Layout The high integration of the LTM2882 makes PCB layout very simple. However, to optimize its electrical isolation characteristics, EMI, and thermal performance, some layout considerations are necessary. • Under heavily loaded conditions VCC and GND current can exceed 300mA. Sufficient copper must be used on the PCB to insure resistive losses do not cause the supply voltage to drop below the minimum allowed level.
PAGE 15
LTM2882 applications information TECHNOLOGY Figure 7a. Low EMI Demo Board Layout Figure 7b. Low EMI Demo Board Layout (DC1747A), Top Layer Figure 7c. Low EMI Demo Board Layout (DC1747A), Inner Layer 1 2882fe For more information www.linear.
PAGE 16
LTM2882 Applications Information Figure 7d. Low EMI Demo Board Layout (DC1747A), Inner Layer 2 Figure 7e. Low EMI Demo Board Layout (DC1747A), Bottom Layer 60 DETECTOR = QuasiPeak 50 RBW = 120kHz VBW = 300kHz 40 SWEEP TIME = 17sec dBµV/m 30 20 10 0 –10 –20 –30 DC1747A-A DC1747A-B CISPR 22 CLASS 8 LIMIT 0 100 200 300 400 500 600 700 800 900 1000 FREQUENCY (MHz) 2882 F08 Figure 8. Low EMI Demo Board Emissions 16 2882fe For more information www.linear.
PAGE 17
LTM2882 typical applications VL ON VCC DE DIN RX TX T1IN 3.3k R1OUT T2IN 3.3k LTM2882 DOUT ISOLATION BARRIER 3.3V (LTM2882-3) 5V (LTM2882-5) T1OUT R1IN T2OUT R2IN R2OUT GND GND2 2882 F09 Figure 9. Single Line Dual Half-Duplex Isolated Transceiver VL VCC LTM2882 ON DE DIN DOUT T1IN R1OUT T2IN ISOLATION BARRIER 3.3V (LTM2882-3) 5V (LTM2882-5) T1OUT R1IN CL R2IN R2OUT GND 3k T2OUT DATA RATE CL (nF) (kbps) GND2 2882 F10 100 250 1000 5 2 0.5 Figure 10.
PAGE 18
LTM2882 typical applications 3.3V (LTM2882-3) 5V (LTM2882-5) VL ON VCC LTM2882 ISOLATION BARRIER T1IN R1OUT T2IN VL ON OFF ON DE DIN µP 3.3V (LTM2882-3) 5V (LTM2882-5) DOUT DIN T1OUT T1IN R1IN R1OUT T2OUT T2IN R2IN R2OUT GND VCC LTM2882 R1IN T2OUT R2IN GND 2882 F11 GND2 2882 F12 Figure 12. Isolated 5V Power Supply Figure 11. 1.8V Microprocessor Interface 5V REGULATED 3.
PAGE 19
For more information www.linear.com/LTM2882 aaa Z 0.630 ±0.025 Ø 32x 4 0.000 1.905 3.175 SUGGESTED PCB LAYOUT TOP VIEW 0.635 PACKAGE TOP VIEW E 0.635 PIN “A1” CORNER 1.905 Y X D 6.350 5.080 0.000 5.080 6.350 aaa Z 2.45 – 2.55 3.175 4.445 4.445 SYMBOL A A1 A2 b b1 D E e F G aaa bbb ccc ddd eee NOM 3.42 0.60 2.82 0.75 0.63 15.0 11.25 1.27 12.70 8.89 DIMENSIONS 0.15 0.10 0.20 0.30 0.15 MAX 3.62 0.70 2.92 0.90 0.
PAGE 20
4 For more information www.linear.com/LTM2882 3.175 1.905 SUGGESTED PCB LAYOUT TOP VIEW 0.635 PACKAGE TOP VIEW 11.25 BSC 0.635 PAD “A1” CORNER 1.905 Y X 6.350 5.080 0.000 5.080 6.350 DETAIL c 15.00 BSC aaa Z 2.400 – 2.600 eee S X Y 0.290 – 0.350 SUBSTRATE DETAIL C 0.630 ±0.025 Ø 32x DETAIL B eee S X Y DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED.
PAGE 21
LTM2882 Revision History REV DATE DESCRIPTION A 3/10 Changes to Features PAGE NUMBER Add BGA Package to Pin Configuration, Order Information and Package Description Sections Changes to LGA Package in Pin Configuration Section 1 2, 15 2 Update to Pin Functions 9 Update to RF, Magnetic Field Immunity Section 12 “PCB Layout Isolation Considerations” Section Replaced 13 B 3/11 H-Grade parts added. Reflected throughout the data sheet. 1-20 C 1/12 MP-Grade parts added.
PAGE 22
LTM2882 Typical Applications 3.3V (LTM2882-3) 5V (LTM2882-5) 1.62V TO 5.5V VL ON µC VCC TXD R XD PY PZ T1IN R2OUT T2IN PERIPHERAL VL ON OFF ON T1OUT R1IN T2OUT R2IN R2OUT GND VCC T1IN RX TX 0V R1OUT VL T2IN RTS CTS 0V LTM2882 DE DIN DOUT ISOLATION BARRIER DIN VCC2 DE LTM2882 DOUT ISOLATION BARRIER 3.3V (LTM2882-3) 5V (LTM2882-5) T1OUT R1IN GND GND2 R2IN –25V TO 0V 2882 F15 Figure 14.