Maxim MAX3471CUA, MAX3471EUA Datasheet

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________________General Description

The MAX3471 half-duplex transceiver is intended for
lithium battery-powered RS-485/RS-422 applications. It
draws only 1.6µA (typical) supply current from a 3.6V
supply with the receiver enabled and the driver dis­abled. Its wide 2.5V to 5.5V supply voltage guarantees
operation over the lifetime of a lithium battery.

This device features true fail-safe operation that guar­antees a logic-high receiver output when the receiver
inputs are open or shorted. This means that the receiv­er output will be a logic high if all transmitters on a ter­minated bus are disabled (high impedance). The
MAX3471 has a 1/8-unit load input resistance. When
driver outputs are enabled and pulled above VCCor
below GND, internal circuitry prevents battery back­charging.

The MAX3471 is available in an 8-pin µMAX package.

________________________Applications

Remote Meter Reading
Battery-Powered Differential Communications
Level Translators

____________________________Features

♦ 1.6µA Supply Current with Receiver Enabled
♦ +2.5V to +5.5V Single-Supply Operation
♦ True Fail-Safe Receiver Input
♦ Available in µMAX Package
♦ 1/8-Unit-Load Receiver Input
♦ -7V to +10V Common-Mode Input Voltage Range

MAX3471

1.6µA, RS-485/RS-422, Half-Duplex,

Differ ential T ransceiver for Battery-Powered Systems

________________________________________________________________

Maxim Integrated Products

1

1
2
3
4

8
7
6
5

V

CC

B
A
GNDDI

DE

RE

RO

MAX3471

µMAX

TOP VIEW

___________________Pin Configuration

MAX3471

B

A

B

A

R

DI

V

CC

V

CC

GND

GND

REMOTE UNIT

DE

RO

D

RE

R

DE

DI

RO

D

RE

R

DI DE

D

BA

RERO

TYPICAL HALF-DUPLEX RS-485 NETWORK

R

DI DE

D

BA

RERO

V

CC

GND

V

CC

V

CC

0.1µF

CENTRAL UNIT

REMOTE UNIT

REMOTE UNIT

19-0497; Rev 0; 2/98

PART

MAX3471CUA
MAX3471EUA -40°C to +85°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

8 µMAX
8 µMAX

_______________Ordering Information

Typical Application Circuit

MAX3471

1.6µA, RS-485/RS-422, Half-Duplex,
Differ ential T ransceiver for Battery-Powered Systems

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS (Note 1)

DC ELECTRICAL CHARACTERISTICS

(VCC= +2.5V to +5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VCC= +3.6V and TA= +25°C.) (Note 1)

Stresses beyond those listed under “Absolute Maximum 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.

Supply Voltage (VCC) ..............................................................7V

Control Input Voltage (

RE, DE)...................-0.3V to (VCC+ 0.3V)

Driver Input Voltage (DI).............................-0.3V to (V

CC

+ 0.3V)

Driver Output/Receiver Input Voltage (A, B).....................±10.5V

Receiver Output Voltage (RO)....................-0.3V to (V

CC

+ 0.3V)
Continuous Power Dissipation

µMAX (derate 4.5mW/°C above +70°C) ......................362mW

Operating Temperature Ranges

MAX3471CUA.....................................................0°C to +70°C

MAX3471EUA..................................................-40°C to +85°C

Storage Temperature Range.............................-65°C to +160°C

Lead Temperature (soldering, 10sec).............................+300°C

VIN= 10V
VIN= -7V -0.075

V

CC

≤ 5.5V

Figure 1

-130 130

Figure 1 (R = open)

IO = 2.2mA, VID= -450mV

IO = -0.8mA, VID= -50mV

V

CM

= 0

DE, DI, RE

-7V ≤ VCM≤ 10V

V

CC

≤ 3.6V

DE, DI, RE

Figure 1, R = 750Ω or 27Ω

Figure 1, R = 750Ω or 27Ω

DE = GND,
VCC= GND or 5.5V

Figure 1, R = 750Ω or 27Ω

DE, DI, RE

CONDITIONS

V0.4V

OL

Receiver Output Low Voltage

VVCC- 0.4V

OH

Receiver Output High Voltage

mV32∆V

TH

Receiver Input Hysteresis

mV-450 -250 -50V

TH

Receiver Differential Threshold
Voltage

mA

-60 60

I

OSD

Driver Short-Circuit Output
Current (Note 3)

mA

0.105

I

IN2

Input Current (A and B),
Half Duplex

µA±0.001 ±1I

IN1

Input Current

0.2 0.83
V

1.5 3.28

V

OD2

VV

CC

V

OD1

Differential Driver Output (no load)

Differential Driver Output
(with load)

mV100V

HYS

DI Input Hysteresis

V0.3 x V

CC

V

IL

Input Low Voltage

V0.7 x V

CC

V

IH

Input High Voltage

V0.2∆V

OC

Change in Magnitude of
Common-Mode Voltage (Note 2)

1.5

V0.2∆V

OD

Change in Magnitude of
Differential Output Voltage
(Note 2)

V0.6 x V

CC

V

OC

Driver Common-Mode Output
Voltage

UNITSMIN TYP MAXSYMBOLPARAMETER

R = 750Ω (RS-422)
R = 27Ω (RS-485)

R = 27Ω (RS-485),
V

CC

= 5V, TA= +25°C

0 ≤ VO≤ V

CC

µA±1I

OZR

Three-State Current at Receiver
Output

-7V ≤ VCM≤ 10V

kΩ

96R

IN

Receiver Input Resistance

-7V ≤ V

OUT

≤ 10V

Note 1: All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device

ground unless otherwise noted.

MAX3471

1.6µA, RS-485/RS-422, Half-Duplex,

Differ ential T ransceiver for Battery-Powered Systems

_______________________________________________________________________________________ 3

DC ELECTRICAL CHARACTERISTICS (continued)

(VCC= +2.5V to +5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VCC= +3.6V and TA= +25°C.) (Note 1)

SWITCHING CHARACTERISTICS

(VCC= +2.5V to +5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at VCC= +3.6V and TA= +25°C.)

Note 1: All currents into the device are positive; all currents out of the device are negative. All voltages are referred to device

ground unless otherwise noted.

Note 2: ∆V

OD

and ∆VOCare the changes in magnitude of VODand VOC, respectively, when the DI input changes state.

Note 3: Maximum and minimum current levels apply to peak current just prior to foldback-current limiting.

0 ≤ VRO≤ V

CC

CONDITIONS

-20 50

UNITSMIN TYP MAXSYMBOLPARAMETER

V

CC

≤ 3.6V

mAI

OSR

Receiver Output Short-Circuit
Current

Figures 3 and 5, R

DIFF

= 1.5kΩ,

C

L1

= CL2= 100pF

Figures 3 and 5, R

DIFF

= 1.5kΩ,

C

L1

= CL2= 100pF

CONDITIONS

µs0.025t

DSKEW

Driver Output Skew
(t

DPLH

- t

DPHL

)

µs

Driver Input to Output
Propagation Delay

UNITSMIN TYP MAXSYMBOLPARAMETER

t

DPLH,

t

DPHL

1.40 2.00

Figures 3 and 5, R

DIFF

= 1.5kΩ,

C

L1

= CL2= 100pF

µs0.75 1.34 1.75tDR, t

DF

Driver Rise or Fall Time

Figures 4 and 6, CL= 100pF, S2 closed, S1 open µs1.5 6.00t

DZH

Driver Enable Time to Output
High

Figures 4 and 6, CL= 100pF, S1 closed, S2 open µs0.86 4.00t

DZL

Driver Enable Time to Output
Low

Figures 4 and 6, CL= 15pF, S1 closed, S2 open µs0.4 1.5t

DLZ

Driver Disable Time from Low

Figures 4 and 6, CL= 15pF, S2 closed, S1 open µs0.6 1.5t

DHZ

Driver Disable Time from High

Figures 7 and 9, CL= 15pF, |V

ID

|

= 2V

µs

6.4 12t

RPHL

Receiver Input to Output
Propagation Delay

Figures 7 and 9, |V

ID

|

= 2V

µs1.2t

RSKEW

Differential Receiver Skew
(t

RPLH

- t

RPHL

)

Figure 9, CL= 100pF kbps64f

MAX

Data Rate

Figures 2 and 8, CL= 15pF, S2 closed, S1 open ns85 500t

RZH

Receiver Enable Time to
Output High

Figures 2 and 8, CL= 15pF, S1 closed, S2 open ns50 200t

RLZ

Receiver Disable Time from Low

Figures 2 and 8, CL= 15pF, S2 closed, S1 open ns35 200t

RHZ

Receiver DisableTime from High

V

CC

≤ 5.5V -40 110

DE = V

CC

µAI

CC

Supply Current

V

CC

≤ 3.6V, no load,

RE = DI = GND or V

CC

,

V

A

= VB= 0

50 60
DE = GND 1.6 2
DE = V

CC

V

CC

≤ 5.5V, no load,

RE = DI = GND or V

CC

,

V

A

= VB= 0

83 100
DE = GND 2.8 4

Figures 2 and 8, CL= 15pF, S1 closed, S2 open ns70 500t

RZL

Receiver Enable Time to
Output Low

t

RPLH

5.2 12