Datasheet

ManualsBrandsANALOG DEVICES ManualsLinear ICsADM3251EARWZ-REEL

Isolated, Single-Channel

RS-232 Line Driver/Receiver

Data Sheet

ADM3251E

FEATURES

2.5 kV fully isolated (power and data) RS-232 transceiver

isoPower integrated, isolated dc-to-dc converter

460 kbps data rate

1 Tx and 1 Rx

Meets EIA/TIA-232E specifications

ESD protection on R

and T

OUT

pins

±8 kV: contact discharge

±15 kV: air gap discharge

0.1 μF charge pump capacitors

High common-mode transient immunity: >25 kV/μs

Safety and regulatory approvals

UL recognition

2500 V rms for 1 minute per UL 1577

VDE Certificate of Conformity

DIN EN 60747-5-2 (VDE 0884 Teil 2): 2003-01

CSA Component Acceptance Notice #5A

Operating temperature range: −40°C to +85°C

Wide body, 20-lead SOIC package

APPLICATIONS

High noise data communications

Industrial communications

General-purpose RS232 data links

Industrial/telecommunications diagnostic ports

Medical equipment

FUNCTIONAL BLOCK DIAGRAM

07388-001

DECODE

RECT REG

V–

0.1µF

16V

VOLTAGE

DOUBLER

C1+ C1–

V+

ISO

C2+

C2–

VOLTAGE

INVERTER

OUT

GND GND

ISO

OUT

ADM3251E

OSC

ENCODE

DECODE

*INTERNAL 5kΩ PULL-DOWN RESISTOR ON THE RS-232 INPUT.

0.1µF

10V

0.1µF

16V

0.1µF

16V

igure 1.

GENERAL DESCRIPTION

The ADM3251E

is a high speed, 2.5 kV fully isolated, single-

channel RS-232/V.28 transceiver device that operates from a

single 5 V power supply. Due to the high ESD protection on the

and T

OUT

pins, the device is ideally suited for operation in

electrically harsh environments or where RS-232 cables are

frequently being plugged and unplugged.

The ADM3251E incorporates dual-channel digital isolators

with isoPower™ integrated, isolated power. There is no requirement

to use a separate isolated dc-to-dc converter. Chip-scale trans-

former iCoupler® technology from Analog Devices, Inc., is used

both for the isolation of the logic signals as well as for the inte-

grated dc-to-dc converter. The result is a total isolation solution.

The ADM3251E contains isoPower technology that uses high

frequency switching elements to transfer power through the

transformer. Special care must be taken during printed circuit

board (PCB) layout to meet emissions standards. Refer to

Application Note AN-0971, Control of Radiated Emissions with

isoPower Devices, for details on board layout considerations.

The ADM3251E conforms to the EIA/TIA-232E and ITU-T V. 28

specifications and operates at data rates up to 460 kbps.

Four external 0.1 μF charge pump capacitors are used for the

voltage doubler/inverter, permitting operation from a single

5 V supply.

The ADM3251E is available in a 20-lead, wide body SOIC package

and is specified over the −40°C to +85°C temperature range.

Protected by U.S. Patents 5,952,849; 6,873,065; and 7,075,329.

Rev. G

Document Feedback

Information furnished by Analog Devices is believed to be accurate and reliable. However, no

responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other

rights of third parties that may result from its use. Specifications subject to change without notice. No

license is granted by implication or otherwise under any patent or patent rights of Analog Devices.

Trademarks and registered trademarks are the property of their respective owners.

ne Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Technical Support www.analog.com

Summary of content (16 pages)

PAGE 1
Isolated, Single-Channel RS-232 Line Driver/Receiver ADM3251E Data Sheet FEATURES FUNCTIONAL BLOCK DIAGRAM C3 0.1µF 10V C1 0.1µF 16V C1+ C1– V+ ADM3251E VCC OSC VISO 0.1µF C2+ C2– VOLTAGE DOUBLER RECT C2 0.1µF 16V C4 0.1µF 16V V– VOLTAGE INVERTER REG 0.1µF ROUT TIN DECODE ENCODE ENCODE DECODE GND R T RIN* TOUT GNDISO *INTERNAL 5kΩ PULL-DOWN RESISTOR ON THE RS-232 INPUT. 07388-001 2.
PAGE 2
ADM3251E Data Sheet TABLE OF CONTENTS Features .............................................................................................. 1 Theory of Operation ...................................................................... 11 Applications ....................................................................................... 1 Isolation of Power and Data ...................................................... 11 Functional Block Diagram ......................................................
PAGE 3
Data Sheet ADM3251E SPECIFICATIONS All voltages are relative to their respective ground; all minimum/maximum specifications apply over the entire recommended operating range; TA = 25°C and VCC = 5.0 V (dc-to-dc converter enabled), unless otherwise noted. Table 1.
PAGE 4
ADM3251E Data Sheet All voltages are relative to their respective ground; all minimum/maximum specifications apply over the entire recommended operating range; TA = 25°C, VCC = 3.3 V (dc-to-dc converter disabled), and the secondary side is powered externally by VISO = 3.3 V, unless otherwise noted. Table 2.
PAGE 5
Data Sheet ADM3251E PACKAGE CHARACTERISTICS Table 3. Parameter Resistance (Input-to-Output) Capacitance (Input-to-Output) Input Capacitance IC Junction-to-Air Thermal Resistance Symbol RI-O CI-O CI θJA Min Typ 1012 2.2 4.0 47.05 Max Unit Ω pF pF °C/W Test Conditions f = 1 MHz REGULATORY INFORMATION Table 4.
PAGE 6
ADM3251E Data Sheet DIN EN 60747-5-2 (VDE 0884 TEIL 2): 2003-01 INSULATION CHARACTERISTICS This isolator is suitable for reinforced isolation only within the safety limit data. Maintenance of the safety data is ensured by protective circuits. Table 6.
PAGE 7
Data Sheet ADM3251E ABSOLUTE MAXIMUM RATINGS Table 7. Parameter VCC, VISO V+ V− Input Voltages TIN RIN Output Voltages TOUT ROUT Short-Circuit Duration TOUT Power Dissipation θJA, Thermal Impedance Operating Temperature Range Industrial Storage Temperature Range Pb-Free Temperature (Soldering, 30 sec) Rating −0.3 V to +6 V (VCC − 0.3 V ) to +13 V –13 V to +0.3 V −0.3 V to (VCC + 0.3 V ) ±30 V Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device.
PAGE 8
ADM3251E Data Sheet NC 1 20 VISO VCC 2 19 V+ VCC 3 GND 4 ADM3251E GND 5 TOP VIEW (Not to Scale) GND 6 18 C1+ 17 C1– 16 TOUT 15 RIN GND 7 14 C2+ ROUT 8 13 C2– TIN 9 12 V– GND 10 11 GNDISO NC = NO CONNECT 07388-002 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Figure 2. Pin Configuration Table 8. Pin Function Descriptions Pin No.
PAGE 9
Data Sheet ADM3251E TYPICAL PERFORMANCE CHARACTERISTICS 12 12 Tx HIGH (VCC = 5V) 8 8 6 Tx HIGH (VISO = 3.3V) 0 –4 Tx OUTPUT HIGH (VISO = 3.3V) 4 Tx OUTPUT (V) 4 Tx OUTPUT (V) Tx OUTPUT HIGH (VCC = 5V) 10 Tx LOW (VISO = 3.3V) 2 0 –2 –4 Tx OUTPUT LOW (VISO = 3.3V) –6 –8 –10 Tx LOW (VCC = 5V) 0 200 400 600 LOAD CAPACITANCE (pF) 800 1000 Tx OUTPUT LOW (VCC = 5V) –12 07388-004 –12 0 Figure 3. Transmitter Output Voltage High/Low vs.
PAGE 10
ADM3251E Data Sheet 400 5V/DIV V– 300 1 5V/DIV 2 250 200 V+ 150 100 VCC = 5V LOAD = 3kΩ AND 1nF 0 3.00 3.25 3.50 3.75 4.00 4.25 4.50 VISO (V) 4.75 5.00 5.25 5.50 07388-010 50 07388-012 CHARGE PUMP IMPEDANCE (Ω) 350 TIME (500ns/DIV) Figure 11. 460 kbps Data Transmission Figure 9. Charge Pump Impedance vs. VISO 5.0 200 4.5 180 VCC = 5.5V TIN VOLTAGE THRESHOLD (V) 140 120 VCC = 5V 100 VCC = 4.5V 80 60 40 4.0 3.5 HIGH THRESHOLD 3.0 2.5 2.0 LOW THRESHOLD 1.5 1.
PAGE 11
Data Sheet ADM3251E THEORY OF OPERATION The TIN pin accepts CMOS input levels (and TTL levels at VCC = 3.3 V). The driver input signal that is applied to the TIN pin is referenced to logic ground (GND). It is coupled across the isolation barrier, inverted, and then appears at the transceiver section, referenced to isolated ground (GNDISO). Similarly, the receiver input (RIN) accepts RS-232 signal levels that are referenced to isolated ground.
PAGE 12
ADM3251E Data Sheet CHARGE PUMP VOLTAGE CONVERTER THERMAL ANALYSIS The charge pump voltage converter consists of a 200 kHz oscillator and a switching matrix. The converter generates a ±10.0 V supply from the input 5.0 V level. This is done in two stages by using a switched capacitor technique as illustrated in Figure 16 and Figure 17. First, the 5.0 V input supply is doubled to 10.0 V by using C1 as the charge storage element. The +10.0 V level is then inverted to generate −10.
PAGE 13
Data Sheet ADM3251E APPLICATIONS INFORMATION PCB LAYOUT EXAMPLE PCB FOR REDUCED EMI The ADM3251E requires no external circuitry for its logic interfaces. Power supply bypassing is required at the input and output supply pins (see Figure 21). Bypass capacitors are conveniently connected between Pin 3 and Pin 4 for VCC and between Pin 19 and Pin 20 for VISO. The capacitor value should be between 0.01 μF and 0.1 μF.
PAGE 14
ADM3251E Data Sheet V = (−dβ/dt)Σπrn2; n = 1, 2, … , N where: β is the magnetic flux density (gauss). N is the number of turns in the receiving coil. rn is the radius of the nth turn in the receiving coil (cm). DISTANCE = 100mm 1 DISTANCE = 5mm 0.1 1k 10k 100k 1M 10M 100M MAGNETIC FIELD FREQUENCY (Hz) 100 Figure 23.
PAGE 15
Data Sheet ADM3251E OUTLINE DIMENSIONS 13.00 (0.5118) 12.60 (0.4961) 20 11 7.60 (0.2992) 7.40 (0.2913) 10 2.65 (0.1043) 2.35 (0.0925) 0.30 (0.0118) 0.10 (0.0039) COPLANARITY 0.10 10.65 (0.4193) 10.00 (0.3937) 1.27 (0.0500) BSC 0.51 (0.0201) 0.31 (0.0122) SEATING PLANE 0.75 (0.0295) 45° 0.25 (0.0098) 8° 0° 0.33 (0.0130) 0.20 (0.0079) 1.27 (0.0500) 0.40 (0.