intersil ISL3179E DATA SHEET

®

ISL3179E

Data Sheet August 16, 2007

±15kV ESD Protected, +125°C, 40Mbps,

3.3V, Full Fail-Safe, RS-485/RS-422
Transceivers

Intersil’s ISL3179E is a ±15kV IEC61000 ESD Protected,

3.3V powered, single transceiver that meets both the
RS-485 and RS-422 standards for balanced communication.
This device has low bus currents (+220μA/-150μA), so it
presents a “1/5 unit load” to the RS-485 bus. This all ows up to
160 transceivers on the network without violating the RS-485
specification’s 32 unit load maximum, and without using
repeaters.

Receiver (Rx) inputs feature a “Full Fail-Safe” design, which
ensures a logic high Rx output if Rx inputs are floating,
shorted, or terminated but undriven.

Hot Plug circuitry ensures that the Tx and Rx outputs remain
in a high impedance state while the power supply stabilizes.

Ordering Information

PART

NUMBER

(Notes 1, 2)

ISL3179EFBZ 3179 EFBZ -40 to +125 8 Ld SOIC M8.15
ISL3179EFUZ 179FZ -40 to +125 8 Ld MSOP M8.118
ISL3179EFRZ 79FZ -40 to +125 10 Ld DFN L10.3x3C
ISL3179EIBZ 3179 EIBZ -40 to +85 8 Ld SOIC M8.15
ISL3179EIUZ 179IZ -40 to +85 8 Ld MSOP M8.118
ISL3179EIRZ 79IZ -40 to +85 10 Ld DFN L10.3x3C

NOTES:

1. Add “-T” suffix for tape and reel.

2. These Intersil Pb-free plastic packaged products employ special
Pb-free material sets; molding compounds/die attach materials
and 100% matte tin plate PLUS ANNEAL - e3 termination finish,
which is RoHS compliant and compatible with both SnPb and Pb­free soldering operations. Intersil Pb-free products are MSL
classified at Pb-free peak reflow temperatures that meet or
exceed the Pb-free requirements of IPC/JEDEC J STD-020.

PART

MARKING

TEMP.

RANGE

(°C)

PACKAGE

(Pb-Free)

PKG.

DWG. #

FN6365.1

Features

• IEC61000 ESD Protection on RS-485 I/O Pins . . . ±16.5kV

- Class 3 HBM ESD Level on all Other Pins. . . . . . .>9kV

• Specified for +125°C Operation

• High Data Rates. . . . . . . . . . . . . . . . . . . . . . up to 40Mbps

• 5V Tolerant Logic Inputs

• 1/5 Unit Load Allows up to 160 Devices on the Bus

• Full Fail-Safe (Open, Shorted, Terminated/Undriven)
Receiver

• Hot Plug - Tx and Rx Outputs Remain Three-State During
Power-Up

• Low Quiescent Current . . . . . . . . . . . . . . . . . . 4mA (Max)

• Low Current Shutdown Mode. . . . . . . . . . . . . . 1μA (Max)

• -7V to +12V Common Mode Input Voltage Range

• Three-State Rx and Tx Outputs

• 16/16.5ns (Max) Tx/Rx Propagation Delays; 1.5ns (Max)
Skew

• Operates from a Single +3.3V Supply (10% Tolerance)

• Current Limiting and Thermal Shutdown for driver
Overload Protection

• Pb-Free Plus (RoHS Compliant)

Applications

• Motor Controller/Position Encoder Systems

• Factory Automation

• Field Bus Networks

• Security Networks

• Building Environmental Control Systems

• Industrial/Process Control Networks

Pinouts

ISL3179E

(8 LD SOIC, MSOP)

TOP VIEW

RO

1

R

2

RE
DE

3

D

4

DI

1

ISL3179E

(10 LD DFN)

TOP VIEW

8

V

CC

7

B/Z

6

A/Y

5

GND

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

RO

1

RE

2

DE

3

DI

4

NC

5

| Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

Copyright Intersil Americas Inc. 2007. All Rights Reserved

V

10

CC

NC

9

B/Z

8

A/Y

7

GND

6

ISL3179E

Truth T able

TRANSMITTING

INPUTS OUTPUTS

RE

X1101
X1010
0 0 X High-Z High-Z
1 0 X High-Z* High-Z*

NOTE: *Shutdown Mode

DE DI B/Z A/Y

Truth Table

RECEIVING

INPUTS OUTPUT

RE

00 ≥ -0.05V 1
00 ≤ -0.2V 0
0 0 Inputs Open/Shorted 1
1 1 X High-Z
1 0 X High-Z*

DE A-B RO

NOTE: *Shutdown Mode

Pin Descriptions

PIN FUNCTION

RO Receiver output: If A-B ≥ -50mV, RO is high; If A-B ≤ -200mV, RO is low; RO = High if A and B are unconnected (floa ting) o r shorte d, o r

connected to a terminated bus that is undriven.

RE

Receiver output enable. RO is enabled when RE is low; RO is high impedance when RE is high. If the Rx enable function isn’t required,
connect RE

DE Driver output enable. The driver outputs, Y and Z, are enabled by bringing DE high, and they are high impedance when DE is low. If

the Tx enable function isn’t required, connect DE to V

DI Driver input. A low on DI forces output Y low and output Z high. Similarly, a high on DI forces output Y high and output Z low.

directly to GND.

through a 1kΩ or greater resistor.

CC

GND Ground connection.

A/Y ±16.5kV

IEC61000 ESD Protected RS-485/422 level, non-inverting receiver input and non-inverting driver output. Pin is an input (A)

if DE = 0; pin is an output (Y) if DE = 1.

B/Z ±16.5kV

IEC61000 ESD Protected RS-485/422 level, inverting receiver input and inverting driver output. Pin is an input (B) if DE = 0;

pin is an output (Z) if DE = 1.

V

System power supply input (3.0V to 3.6V).

CC

NC No Connection.

Typical Operating Circuit

+3.3V

8

V

RO

1
2

RE

3

DE

DI

4

CC

R

B/Z
A/Y

D

GND

5

ISL3179E

SOIC AND MSOP PIN NUMBERS SHOWN

+

0.1μF

R

T

7
6

0.1μF

R

T

+

+3.3V

8

V

CC

B/Z

7
6

A/Y

R

GND

5

4

DI

D

3

DE

2

RE

1

RO

2

FN6365.1

August 16, 2007

ISL3179E

Absolute Maximum Ratings Thermal Information

VCC to Ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7V

Input Voltages

DI, DE, RE

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 7V

Input/Output Voltages

A/Y, B/Z . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -9V to +13V

RO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to (V

CC

+0.3V)

Short Circuit Duration

Y, Z. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Continuous

ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . See Specification Table

Operating Conditions

Temperature Range

ISL3179EF . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +125°C

ISL3179EI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to +85°C

CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product reliability and
result in failures not covered by warranty.

NOTE:

is measured with the component mounted on a high effective thermal conductivity (with direct attach for DFN) test board in free air. See T ech

3. θ

JA

Brief TB379 for details.

Thermal Resistance (Typical, Note 3)

θ

JA

(°C/W)

8 Ld SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . 160

8 Ld MSOP Package . . . . . . . . . . . . . . . . . . . . . . . . 137

10 Ld DFN Package. . . . . . . . . . . . . . . . . . . . . . . . . 46

Maximum Junction Temperature (Plastic Package) . . . . . . +150°C

Maximum Storage Temperature Range. . . . . . . . . .-65°C to +150°C

Pb-free reflow profile . . . . . . . . . . . . . . . . . . . . . . . . . .see link below

http://www.intersil.com/pbfree/Pb-FreeReflow.asp

Electrical Specifications Test Conditions: V

(Note 4)

PARAMETER SYMBOL TEST CONDITIONS

DC CHARACTERISTICS

Driver Differential V

OUT

Change in Magnitude of Driver
Differential V
Complementary Output States

Driver Common-Mode V

OUT

for

OUT

Change in Magnitude of Driver
Common-Mode V
Complementary Output States

OUT

for

Logic Input High Voltage V
Logic Input Low Voltage V
Logic Input Current I
Input Current (A/Y, B/Z) I

Driver Short-Circuit Current,

= High or Low

V

O

Receiver Differential Threshold
Voltage

Receiver Input Hysteresis ΔV
Receiver Output High Voltage V
Receiver Output Low Voltage V
Receiver Output Low Current I

V

OD

ΔV

ODRL

V

OC

ΔV

OCRL

IH

IL
IN1
IN2

I

OSD1

V

TH

TH

OHIO
OLIO

OL

RL = 100Ω (RS-422) (Figure 1A), (Note 13) Full 2 2.3 - V
R

L

No Load Full - - V
RL = 60Ω, -7V ≤VCM ≤12V (Figure 1B),

(Note 13)

RL = 54Ω or 100Ω (Figure 1A) Full - 2 2.5 V

DI, DE, RE Full 2 - - V
DI, DE, RE Full - - 0.8 V
DI = DE = RE = 0V or V
DE = 0V, VCC = 0V or

3.6V

DE = VCC, -7V ≤VY or VZ ≤12V (Note 6) Full - - ±250 mA

-7V ≤ VCM ≤ 12V Full -200 - -50 mV

VCM = 0V 25 - 28 - mV

= -12mA, VID = -50mV Full VCC - 0.5 - - V
= +10mA, VID = -200mV Full - - 0.4 V

VOL = 1V, VID = -200mV Full 25 - - mA

= 3.0V to 3.6V; Unless Otherwise Specified. Typicals are at VCC = 3.3V, TA = +25°C,

CC

TEMP

(°C)

= 54Ω (RS-485) (Figure 1A) Full 1.5 2.1 V

MIN

(Note 14) TYP

MAX

(Note 14) UNITS

CC
CC

Full 1.5 2 - V

= 54Ω or 100Ω (Figure 1A) Full - 0.01 0.2 V

= 54Ω or 100Ω (Figure 1A) Full - 0.02 0.2 V

CC

Full -2 - 2 μA

VIN = 12V Full - - 220 μA

= -7V Full -160 - - μA

V

IN

V

3

FN6365.1

August 16, 2007

ISL3179E

Electrical Specifications Test Conditions: V

(Note 4) (Continued)

PARAMETER SYMBOL TEST CONDITIONS

Three-State (high impedance)

I

OZR

= 3.0V to 3.6V; Unless Otherwise Specified. Typicals are at VCC = 3.3V, TA = +25°C,

CC

TEMP

(°C)

MIN

(Note 14) TYP

MAX

(Note 14) UNITS

0.4V ≤ VO ≤ 2.4V Full -1 0.015 1 μA

Receiver Output Current
Receiver Input Resistance R
Receiver Short-Circuit Current I

OSR

-7V ≤ VCM ≤ 12V Full 54 80 - kΩ

IN

0V ≤ VO ≤ V

CC

Full ±20 - ±110 mA

SUPPLY CURRENT

No-Load Supply Current (Note 5) I
Shutdown Supply Current I

SHDN

DI = DE = 0V or V

CC

DE = 0V, RE = VCC, DI = 0V or V

CC

CC

Full - 2.6 4 mA
Full - 0.05 1 μA

ESD PERFORMANCE

RS-485 Pins (A/Y, B/Z) IEC61000-4-2, Air-Gap Discharge Method 25 - ±16.5 - kV

IEC61000-4-2, Contact Discharge Method 25 - ±9-kV
Human Body Model, From Bus Pins to GND 25 - ±16.5 - kV

All Pins HBM, per MIL-STD-883 Method 3015 25 - >±9- kV

Machine Model 25 - >±400 - V

DRIVER SWITCHING CHARACTERISTICS

Maximum Data Rate f

MAX

VOD ≥ ±1.5V, RD = 54Ω, CL = 100pF (Figure 4) -40 to 85 40 60 - Mbps

125 16 32 - Mbps
Driver Differential Output Delay t
Prop Delay Part-to-Part Skew t
Driver Differential Output Skew t
Driver Differential Rise or Fall Time t
Driver Enable to Output High t

SKP-PRD
SKEWRD

R

RD = 54Ω, CD = 50pF (Figure 2) Full - 11 16 ns

DD

= 54Ω, CD = 50pF (Figure 2), (Note 12) Full - - 4 ns
= 54Ω, CD = 50pF (Figure 2) Full - 0 1.5 ns

, tFRD = 54Ω, CD = 50pF (Figure 2) Full - 4 7 ns

RL = 110Ω, CL = 50pF, SW = GND (Figure 3),

ZH

Full - 18 25 ns

(Note 7)

Driver Enable to Output Low t

RL = 110Ω, CL = 50pF, SW = VCC (Figure 3),

ZL

Full - 16 25 ns

(Note 7)
Driver Disable from Output High t
Driver Disable from Output Low t
Time to Shutdown t
Driver Enable from Shutdown to

t

ZH(SHDN)RL

Output High
Driver Enable from Shutdown to

t

ZL(SHDN)RL

Output Low

SHDN

RL = 110Ω, CL = 50pF, SW = GND (Figure 3), Full - 15 25 ns

HZ

RL = 110Ω, CL = 50pF, SW = VCC (Figure 3), Full - 18 25 ns

LZ

(Note 9) Full 60 - 600 ns

= 110Ω, CL = 50pF, SW = GND (Figure 3),

Full - - 1000 ns

(Notes 9, 10)

= 110Ω, CL = 50pF, SW = VCC (Figure 3),

Full - - 1000 ns

(Notes 9, 10)

RECEIVER SWITCHING CHARACTERISTICS

Maximum Data Rate f
Receiver Input to Output Delay t

PLH

Prop Delay Part-to-Part Skew t

- t

Receiver Skew | t

PLH

|t

PHL

Receiver Enable to Output High t

MAX

SKP-P

SKD

VID = ±1.5V Full 40 60 - Mbps

, t

(Figure 5) Full - 10 16.5 ns

PHL

(Figure 5), (Note 12) Full - - 4 ns

(Figure 5) Full - 0 1.5 ns

RL = 1kΩ, CL = 15pF, SW = GND (Figure 6),

ZH

Full - 10 15 ns

(Note 8)
Receiver Enable to Output Low t

RL = 1kΩ, CL = 15pF, SW = VCC (Figure 6),

ZL

Full - 11 15 ns

(Note 8)
Receiver Disable from Output High t
Receiver Disable from Output Low t

RL = 1kΩ, CL = 15pF, SW = GND (Figure 6) Full - 10 15 ns

HZ

RL = 1kΩ, CL = 15pF, SW = VCC (Figure 6) Full - 10 15 ns

LZ

4

FN6365.1

August 16, 2007

ISL3179E

Electrical Specifications Test Conditions: V

(Note 4) (Continued)

PARAMETER SYMBOL TEST CONDITIONS

Time to Shutdown t
Receiver Enable from Shutdown to

Output High
Receiver Enable from Shutdown to

Output Low

SHDN

t

ZH(SHDN)RL

t

ZL(SHDN)RL

= 3.0V to 3.6V; Unless Otherwise Specified. Typicals are at VCC = 3.3V, TA = +25°C,

CC

TEMP

(°C)

MIN

(Note 14) TYP

MAX

(Note 14) UNITS

(Note 9) Full 60 - 600 ns

= 1kΩ, CL = 15pF, SW = GND (Figure 6),

Full - - 1000 ns

(Notes 9, 11)

= 1kΩ, CL = 15pF, SW = VCC (Figure 6),

Full - - 1000 ns

(Notes 9, 11)

NOTES:

4. All currents into device pins are positive; all currents out of device pins are negative. All voltages are referenced to device ground unless
otherwise specified.

5. Supply current specification is valid for loaded drivers when DE = 0V.

6. Applies to peak current. See “Typical Performance Curves” on page 10 for more information.

7. Because of the shutdown feature, keep RE

8. Because of the shutdown feature, the RE

9. These IC’s are put into shutdown by bringing RE

= 0 to prevent the device from entering SHDN.

signal high time must be short enough (typically <100ns) to prevent the device from entering SHDN.

high and DE low. If the inputs are in this st ate for less than 60ns, the p art s are guaranteed not
to enter shutdown. If the inputs are in this state for at least 700ns, the parts are guaranteed to have entered shutdown. See “Low Power
Shutdown Mode” on page 9.

10. Keep RE

11. Set the RE

12. This is the part-to-part skew between any two units tested with identical test conditions (Temperature, V

13. V

= VCC, and set the DE signal low time >700ns to ensure that the device enters SHDN.

signal high time >700ns to ensure that the device enters SHDN.

= 3.3V ±5%

CC

CC

, etc.).

14. Parts are 100% tested at +25°C. Over temperature limits established by characterization and are not production tested.

Test Circuits and Waveforms

DE

V

CC

DI

Z

D

Y

V

OD

FIGURE 1A. VOD AND V

RL/2

V

R

/2

OC

L

OC

FIGURE 1. DC DRIVER TEST CIRCUITS

DE

V

CC

DI

Z

D

Y

V

OD

RL = 60Ω

FIGURE 1B. VOD WITH COMMON MODE LOAD

375Ω

VCM

-7V TO +12V

375Ω

5

FN6365.1

August 16, 2007

Test Circuits and Waveforms (Continued)

ISL3179E

3V

DI

1.5V1.5V
0V

DE

V

CC

SIGNAL
GENERATOR

DI

Z

D

Y

R

D

C

D

FIGURE 2A. TEST CIRCUIT

FIGURE 2. DRIVER PROPAGATION DELAY AND DIFFERENTIAL TRANSITION TIMES

DE

SIGNAL
GENERATOR

DI

Z

D

Y

110Ω

SW

50pF

PARAMETER OUTPUT RE DI SW

t

HZ

t

LZ

t

ZH

t

ZL

t

ZH(SHDN)

t

ZL(SHDN)

Y/Z X 1/0 GND
Y/Z X 0/1 V
Y/Z 0 (Note 7) 1/0 GND
Y/Z 0 (Note 7) 0/1 V
Y/Z 1 (Note 10) 1/0 GND
Y/Z 1 (Note 10) 0/1 V

FIGURE 3A. TEST CIRCUIT FIGURE 3B. MEASUREMENT POINTS

FIGURE 3. DRIVER ENABLE AND DISABLE TIMES

V

CC

GND

CC

CC

CC

OUT (Z)

OUT (Y)

DIFF OUT (Y - Z)

FIGURE 2B. MEASUREMENT POINTS

DE

NOTE 9

tZH, t

ZH(SHDN)

NOTE 9

OUT (Y, Z)

t

, t

ZL

ZL(SHDN)

NOTE 9

OUT (Y, Z)

PLH

- t

t

PHL

t

t

PHL

|

1.5V1.5V

HZ

VOH - 0.5V

LZ

VOL + 0.5V

t

PLH

90% 90%

10% 10%

t

R

SKEW = |t

OUTPUT HIGH

50%

50%

OUTPUT LOW

V

OH

V

OL

+V

OD

-V

OD

t

F

3V

0V

V

OH

0V

V

CC

V

OL

V

CC

SIGNAL
GENERATOR

DE

DI

Z

D

Y

54Ω

FIGURE 4A. TEST CIRCUIT

6

+V

OD

3V

0V

0V

+

C

V

OD

-

L

C

L

DI

DIFF OUT (Y - Z)

-V

OD

FIGURE 4B. MEASUREMENT POINTS

FIGURE 4. DRIVER DATA RATE

FN6365.1

August 16, 2007

Test Circuits and Waveforms (Continued)

ISL3179E

RE

B

+1.5V

SIGNAL
GENERATOR

A

RO

R

FIGURE 5A. TEST CIRCUIT

RE

B
A

RO

R

SIGNAL
GENERATOR

GND

PARAMETER DE A SW

t

HZ

t

LZ

0 +1.5V GND
0 -1.5V V

tZH (Note 8) 0 +1.5V GND

(Note 8) 0 -1.5V V

t

ZL

t

ZH(SHDN)

t

ZL(SHDN)

(Note 11) 0 +1.5V GND
(Note 11) 0 -1.5V V

FIGURE 6A. TEST CIRCUIT

FIGURE 6. RECEIVER ENABLE AND DISABLE TIMES

15pF

A

RO

FIGURE 5B. MEASUREMENT POINTS

FIGURE 5. RECEIVER PROPAGATION DELAY

NOTE 9

1kΩ

15pF

SW

CC

CC

CC

V

CC

GND

tZH, t

t

ZL

RE

ZH(SHDN)

NOTE 9

RO

, t

ZL(SHDN)

NOTE 9

RO

FIGURE 6B. MEASUREMENT POINTS

t

PLH

1.7V 1.7V

OUTPUT HIGH

1.5V

1.5V

OUTPUT LOW

t

1.5V1.5V

PHL

t

t

1.5V1.5V

HZ

LZ

+3V

0V

3V

0V

VOH - 0.5V

VOL + 0.5V

V

CC

0V

V

OH

0V

V

CC

V

OL

Application Information

RS-485 and RS-422 are differential (balanced) data
transmission standards for use in long haul or noisy
environments. RS-422 is a subset of RS-485, so RS-485
transceivers are also RS-422 compliant. RS-422 is a
point-to-multipoint (multidrop) standard, which allows only
one driver and up to 10 (assuming one unit load devices)
receivers on each bus. RS-485 is a true multipoint standard,
which allows up to 32 one unit load devices (any mix of
drivers and receivers) on each bus. To allow for multipoint
operation, the RS-485 spec requires that drivers must
handle bus contention without sustaining any damage.

Another important advantage of RS-485 is the extended
common mode range (CMR), which specifies that the driver
outputs and receiver inputs withstand signals that range from
+12V to -7V. RS-422 and RS-485 are intended for runs as
long as 4000’ (~1200m), so the wide CMR is necessary to
handle ground potential differences, as well as voltages
induced in the cable by external fields.

Receiver (Rx) Features

This transceiver utilizes a differential input receiver for
maximum noise immunity and common mode rejection. Input
sensitivity is ±200mV, as required by the RS-422 and RS-485
specific a tions. Receiver inputs function with common mode
voltages as great as +9/-7V outside the power supplies (i.e.,
+12V and -7V), making them ideal for long networks, or
industrial environments, where induced voltages are a
realistic concern.

The receiver input resistance of 50kΩ surpasses the RS-422
spec of 4kΩ, and is five times the RS-485 “Unit Load” (UL)
requirement of 12kΩ minimum. Thus, the ISL3179E is
known as a “one-fifth UL” transceiver, and there can be up to
160 devices on the RS-485 bus while still complying with the
RS-485 loading spec.

The receiver is a “Full Fail-Safe” version that guarantees a
high level receiver output if the receiver inputs are
unconnected (floating), shorted together, or connected to a
terminated bus with all the transmitters disabled
(terminated/undriven).

7

FN6365.1

August 16, 2007

ISL3179E

Rx outputs deliver large low state currents (typically 28mA at
V

= 1V) to ease the design of optically coupled isolated

OL

networks.
Receivers easily meet the 40Mbps data rate supported by

the driver, and the receiver output is tri-statable via the active
low RE

input.

Driver (Tx) Features

The RS-485/RS-422 driver is a differential output device that
delivers at least 1.5V across a 54Ω load (RS-485), and at
least 2V across a 100Ω load (RS-422). The drivers feature
low propagation delay skew to maximize bit width, and to
minimize EMI.

Outputs of the drivers are not slew rate limited, so faster
output transition times allow data rates of at least 40Mbps.
Driver outputs are tri-statable via the active high DE input.

For parallel applications, bit-to-bit skews between any two
ISL3179E transmitter and receiver pairs are guaranteed to
be no worse than 8ns (4ns max for any two Tx, 4ns max for
any two Rx).

ESD Protection

All pins on the ISL3179E include class 3 (>9kV) Human
Body Model (HBM) ESD protection structures, but the
RS-485 pins (driver outputs and receiver inputs)
incorporate advanced structures allowing them to survive
ESD events in excess of ±16.5kV HBM and ±16.5kV
IEC61000-4-2. The RS-485 pins are particularly vulnerable
to ESD strikes because they typically connect to an
exposed port on the exterior of the finished product. Simply
touching the port pins, or connecting a cable, can cause an
ESD event that might destroy unprotected ICs. These new
ESD structures protect the device whether or not it is
powered up, and without degrading the RS-485 common
mode range of -7V to +12V. This built-in ESD protection
eliminates the need for board level protection structures
(e.g., transient suppression diodes), and the associated,
undesirable capacitive load they present.

IEC61000-4-2 Testing

The IEC61000 test method applies to finished equipment,
rather than to an individual IC. Therefore, the pins most likely
to suffer an ESD event are those that are exposed to the
outside world (the RS-485 pins in this case), and the IC is
tested in its typical application configuration (power applied)
rather than testing each pin-to-pin combination. The
IEC61000 standard’s lower current limiting resistor coupled
with the larger charge storage capacitor yields a test that is
much more severe than the HBM test. The extra ESD
protection built into this device’s RS-485 pins allows the
design of equipment meeting level 4 criteria without the need
for additional board level protection on the RS-485 port.

AIR-GAP DISCHARGE TEST METHOD

For this test method, a charged probe tip moves toward the
IC pin until the voltage arcs to it. The current waveform
delivered to the IC pin depends on approach speed,
humidity, temperature, etc., so it is more difficult to obtain
repeatable results. The ISL3179E RS-485 pins withstand
±16.5kV air-gap discharges.

CONTACT DISCHARGE TEST METHOD

During the contact discharge test, the probe contacts the
tested pin before the probe tip is energized, thereby
eliminating the variables associated with the air-gap
discharge. The result is a more repeatable and predictable
test, but equipment limits prevent testing devices at voltages
higher than ±9kV. The RS-485 pins of the ISL3179E survive
±9kV contact discharges.

Hot Plug Function

When a piece of equipment powers up, there is a period of
time where the processor or ASIC driving the RS -485 control
lines (DE, RE
Rx outputs are kept disabled. If the equipment is connected
to the bus, a driver activating prematurely during power up
may crash the bus. To avoid this scenario, the ISL3179E
incorporates a “Hot Plug” function. Circuitry monitoring V
ensures that, during power up and power down, the Tx and Rx
outputs remain disabled, regardless of the state of DE and RE
if V

is less than ~2.4V. This gives the processor/ASIC a

CC

chance to stabilize and drive the RS-485 control lines to the
proper states.

4
2

0

DRIVER Y OUTPUT (V)

FIGURE 7. HOT PLUG PERFORMANCE (ISL3179E) vs

) is unable to ensure that the RS-485 Tx and

2.5V

V

CC

A/Y

RO

ISL83485 WITHOUT HOT PLUG CIRCUITRY

ISL3179E

ISL3179E

TIME (40μs/DIV)

2.3V

DE, DI = V

RE = GND

RL = 1kΩ

RL = 1kΩ

CC

CC

4
2

0

4
2

0

,

(V)

CC

V

RECEIVER OUTPUT (V)

8

FN6365.1

August 16, 2007

ISL3179E

Data Rate, Cables, and Terminations

RS-485/422 are intended for network lengths up to 4000’,
but the maximum system data rate decreases as the
transmission length increases. Devices operating at 40Mbps
are limited to lengths less than 100’.

Twisted pair is the cable of choice for RS-485/RS-422
networks. Twisted pair cables tend to pick up noise and
other electromagnetically induced voltages as common
mode signals, which are effectively rejected by the
differential receiver in this IC.

Proper termination is imperative to minimize reflections. In
point-to-point, or point-to-multipoint (single driver on bus)
networks, the main cable should be terminated in its
characteristic impedance (typically 120Ω) at the end farthest
from the driver. In multi-receiver applications, stubs
connecting receivers to the main cable should be kept as
short as possible. Multipoint (multi-driver) systems require
that the main cable be terminated in its characteristic
impedance at both ends. Stubs connecting a transceiver to
the main cable should be kept as short as possible.

The ISL3179E may also be used at slower data rates over
longer cables, but there are some limitations. The Rx is
optimized for high speed operation, so its output may glitch if
the Rx input differential transition times are too slow.
Keeping the transition times below 500ns, which equates to
the Tx driving a 1000’ (305m) CAT 5 cable, yields excellent
performance over the full operating temperature range.

Built-In Driver Overload Protection

As stated previously, the RS-485 spec requires that drivers
survive worst case bus contentions undamaged. These
transmitters meet this requirement via driver output short
circuit current limits, and on-chip thermal shutdown circuitry.

The driver output stages incorporate short circuit current
limiting circuitry which ensures that the output current never
exceeds the RS-485 spec, even at the common mode voltage
range extremes. In the event of a major short circuit condition,
the device also includes a thermal shutdown feature that
disables the drivers whenever the die temperature becomes
excessive. This eliminates the power dissipation, allowing the
die to cool. The drivers automatically reenable after the die
temperature drops about +15°C. If the contention persists, the
thermal shutdown/reenable cycle repeats until the fault is
cleared. Receivers stay operational during thermal shutdown .

Low Power Shutdown Mode

This BiCMOS transceiver uses a fraction of the power
required by their bipolar counterparts, but it also includes a
shutdown feature that reduces the already low quiescent I
to a 50nA trickle. It enters shutdown whenever the receiver
and driver are simultaneously disabled (RE

=VCC and
DE = GND) for a period of at least 600ns. Disabling both the
driver and the receiver for less than 60ns guarantees that
the transceiver will not enter shutdown.

Note that receiver and driver enable times increase when
the transceiver enables from shutdown. Refer to Notes 7, 8,
9, 10 and 11, at the end of the “Electrical S pecification” table
on page 5, for more information.

CC

9

FN6365.1

August 16, 2007

ISL3179E

Typical Performance Curves V

90

80

70

60

50

40

30

20

DRIVER OUTPUT CURRENT (mA)

10

+125°C

0

0 0.5 1.0 1.5 2.0 2.5 3.0

DIFFERENTIAL OUTPUT VOLTAGE (V)

+85°C

+25°C

= 3.3V, TA = +25°C; Unless Otherwise Specified

CC

RD = 33Ω

RD = 54Ω

RD = 100Ω

FIGURE 8. DRIVER OUTPUT CURRENT vs DIFFERENTIAL

OUTPUT VOLTAGE

150

100

50

0

Y OR Z = LOW

3.3

2.40

2.35

2.30

2.25

2.20

2.15

2.10

2.05

2.00

1.95

DIFFERENTIAL OUTPUT VOLTAGE (V)

1.90

-40 -15 10 35 60 85 110

RD = 100Ω

RD = 54Ω

TEMPERATURE (°C)

FIGURE 9. DRIVER DIFFERENTIAL OUTPUT VOLTAGE vs

TEMPERATURE

(mA)
I

2.40

2.35

2.30

2.25

CC

2.20

DE = VCC, RE = X OR DE = GND, RE = GND

125

OUTPUT CURRENT (mA)

-50
Y OR Z = HIGH

-100

-7 -6 -4 -2 0 2 4 6 8 10 12
OUTPUT VOLTAGE (V)

FIGURE 10. DRIVER OUTPUT CURRENT vs SHORT CIRCUIT

VOLTAGE

13.0

12.5

12.0

11.5

11.0

10.5

10.0

9.5

PROPAGATION DELAY (ns)

9.0

8.5

8.0

-40 -15 10 35 60 85 110
TEMPERATURE (°C)

t

PLH

t

PHL

125

FIGURE 12. DRIVER DIFFERENTIAL PROPAGATION DELAY

vs TEMPERATURE

2.15

2.10

-40 -15 10 35 60 85 110 125
TEMPERATURE (°C)

FIGURE 11. SUPPLY CURRENT vs TEMPERATURE

0.25
|t

- t

PLH

0.20

0.15

SKEW (ns)

0.10

0.05

0

-40 -15 10 35 60 85 110

|

PHL

TEMPERATURE (°C)

FIGURE 13. DRIVER DIFFERENTIAL SKEW vs

TEMPERATURE

125

10

FN6365.1

August 16, 2007

ISL3179E

Typical Performance Curves V

R

= 54Ω, CD = 50pF

DIFF

DI

5
0

RECEIVER OUTPUT (V)

3
2

Y-Z

1
0

-1

-2

DRIVER OUTPUT (V)

-3

RO

TIME (5ns/DIV)

= 3.3V, TA = +25°C; Unless Otherwise Specified (Continued)

CC

5
0

DRIVER INPUT (V)

5
0

RECEIVER OUTPUT (V)

3
2
1
0

Y-Z

-1

-2

-3

DRIVER OUTPUT (V)

DI

R

DIFF

TIME (5ns/DIV)

= 54Ω, CD = 50pF

RO

FIGURE 14. DRIVER AND RECEIVER WAVEFORMS FIGURE 15. DRIVER AND RECEIVER WAVEFORMS

5.0
0

RECEIVER OUTPUT (V)

3.0

1.5

A - B

0

-1.5

-3.0

RECEIVER INPUT (V)

DI = 40Mbps

RO

DRIVER+CABLE DELAY (~160ns)

TIME (10ns/DIV)

5
0

FIGURE 16. DRIVER AND RECEIVER WAVEFORMS DRIVING

100 FEET (31 METERS) OF CAT5 CABLE
(DOUBLE TERMINATED WITH 120Ω)

DRIVER INPUT (V)

5.0
0

RECEIVER OUTPUT (V)

3.0

1.5

0

-1.5

RECEIVER INPUT (V)

-3.0

FIGURE 17. DRIVER AND RECEIVER WAVEFORMS DRIVING

DI = 2Mbps

RO

DRIVER+CABLE DELAY (~720ns)

A - B

TIME (200ns/DIV)

500 FEET (152 METERS) OF CAT5 CABLE
(DOUBLE TERMINATED WITH 120Ω)

5
0

DRIVER INPUT (V)

5
0

DRIVER INPUT (V)

60

VOL, +25°C

50

VOH, +25°C

40

VOH, +125°C

30

20

10

RECEIVER OUTPUT CURRENT (mA)

0

0 0.5 1.0 1.5 2.0 2.5 3.0

VOH, +85°C

RECEIVER OUTPUT VOLTAGE (V)

VOL, +85°C

VOL, +125°C

FIGURE 18. RECEIVER OUTPUT CURRENT vs RECEIVER

OUTPUT VOLTAGE

11

3.3

Die Characteristics

SUBSTRATE AND DFN THERMAL PAD POTENTIAL
(POWERED UP):

GND

TRANSISTOR COUNT:

768

PROCESS:

Si Gate BiCMOS

August 16, 2007

FN6365.1

ISL3179E

Mini Small Outline Plastic Packages (MSOP)

N

EE1

INDEX

AREA

AA1A2

TOP VIEW

-H-

SIDE VIEW

12

b

e

D

NOTES:

1. These package dimensions are within allowable dimensions of
JEDEC MO-187BA.

2. Dimensioning and tolerancing per ANSI Y14.5M-1994.

3. Dimension “D” does not include mold flash, protrusions or gate
burrs and are measured at Datum Plane. Mold flash, protrusion
and gate burrs shall not exceed 0.15mm (0.006 inch) per side.

4. Dimension “E1” does not include interlead flash or protrusions
and are measured at Datum Plane. Interlead flash and
protrusions shall not exceed 0.15mm (0.006 inch) per side.

5. Formed leads shall be planar with respect to one another within

0.10mm (0.004) at seating Plane.

6. “L” is the length of terminal for soldering to a substrate.

7. “N” is the number of terminal positions.

8. Terminal numbers are shown for reference only.

9. Dimension “b” does not include dambar protrusion. Allowable
dambar protrusion shall be 0.08mm (0.003 inch) total in excess
of “b” dimension at maximum material condition. Minimum space
between protrusion and adjacent lead is 0.07mm (0.0027 inch).

- H -

-A -

.

10. Datums and to be determined at Datum plane

11. Controlling dimension: MILLIMETER. Converted inch dimen­sions are for reference only.

-B-

0.20 (0.008) A

GAUGE

PLANE

SEATING

PLANE

0.10 (0.004) C

-A-

0.20 (0.008) C

- B -

0.25

(0.010)

-C-

SEATING
PLANE

a

0.20 (0.008) C

- H -

B

4X θ

C

D

4X θ

L1

C

C

L

E

1

END VIEW

R1

R

L

-B-

M8.118 (JEDEC MO-187AA)

8 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE

INCHES MILLIMETERS

SYMBOL

A 0.037 0.043 0.94 1.10 ­A1 0.002 0.006 0.05 0.15 ­A2 0.030 0.037 0.75 0.95 -

b 0.010 0.014 0.25 0.36 9

c 0.004 0.008 0.09 0.20 -

D 0.116 0.120 2.95 3.05 3
E1 0.116 0.120 2.95 3.05 4

e 0.026 BSC 0.65 BSC -

E 0.187 0.199 4.75 5.05 -

L 0.016 0.028 0.40 0.70 6

L1 0.037 REF 0.95 REF -

N8 87

R 0.003 - 0.07 - ­R1 0.003 - 0.07 - -

0 5

α

o

o

0

15

o

o

6

o

5

o

0

15

o

o

6

Rev. 2 01/03

NOTESMIN MAX MIN MAX

-

-

12

FN6365.1

August 16, 2007

Dual Flat No-Lead Plastic Package (DFN)

ISL3179E

(DAT UM B )

6

INDEX

AREA

(DATUM A)

NX (b)

5

SECTION "C-C"

6

INDEX
AREA

SEATING

PLANE

NX L

8

A

C

D

TOP

VIEW

SIDE VIEW

D2

D2/2

12

N

N-1

e
(Nd-1)Xe

REF .

BOTTOM VIEW

(A1)

2X

A3

E2/2

NX b

5

C

L

e

CC

FOR ODD TERMINAL/SIDE

87

0.10

ABC0.10

2X

0.10

E

//

A

NX k

E2

M

9

TERMINAL TIP

0.10

0.08

L

CB

BAC

L10.3x3C

10 LEAD DUAL FLAT NO-LEAD PLASTIC PACKAGE

MILLIMETERS

SYMBOL

A 0.85 0.90 0.95 ­A1 - - 0.05 ­A3 0.20 REF -

b 0.20 0.25 0.30 5, 8

D 3.00 BSC ­D2 2.33 2.38 2.43 7, 8

C

E 3.00 BSC ­E2 1.59 1.64 1.69 7, 8

C

e 0.50 BSC -

k0.20- - -

L 0.35 0.40 0.45 8

N102
Nd 5 3

NOTES:

1. Dimensioning and tolerancing conform to ASME Y14.5-1994.

2. N is the number of terminals.

3. Nd refers to the number of terminals on D.

4. All dimensions are in millimeters. Angles are in degrees.

5. Dimension b applies to the metallized terminal and is measured
between 0.15mm and 0.30mm from the terminal tip.

6. The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identi fier may be
either a mold or mark feature.

7. Dimensions D2 and E2 are for the exposed pads which provide
improved electrical and thermal performance.

8. Nominal dimensions are provided to assist with PCB Land
Pattern Design efforts, see Intersil Technical Brief TB389.

9. COMPLIANT TO JEDEC MO-229-WEED-3 except for
dimensions E2 & D2.

NOTESMIN NOMINAL MAX

Rev. 1 4/06

13

FN6365.1

August 16, 2007

Small Outline Plastic Packages (SOIC)

ISL3179E

N

INDEX
AREA

123

-A-

E

-B-

SEATING PLANE

D

A

-C-

0.25(0.010) BM M

H

L

h x 45°

α

e

B

0.25(0.010) C AM BS

M

NOTES:

1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of
Publication Number 95.

2. Dimensioning and tolerancing per ANSI Y14.5M-1982.

3. Dimension “D” does not include mold flash, protrusions or gate burrs.
Mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006
inch) per side.

4. Dimension “E” does not include interlead flash or protrusions. Inter­lead flash and protrusions shall not exceed 0.25mm (0.010 inch) per
side.

5. The chamfer on the body is optional. If it is not present, a visual index
feature must be located within the crosshatched area.

6. “L” is the length of terminal for soldering to a substrate.

7. “N” is the number of terminal positions.

8. Terminal numbers are shown for reference only.

9. The lead width “B”, as measured 0.36mm (0.014 inch) or greater
above the seating plane, shall not exceed a maximum value of

0.61mm (0.024 inch).

10. Controlling dimension: MILLIMETER. Converted inch dimensions
are not necessarily exact.

A1

C

0.10(0.004)

M8.15 (JEDEC MS-012-AA ISSUE C)

8 LEAD NARROW BODY SMALL OUTLINE PLASTIC PACKAGE

INCHES MILLIMETERS

SYMBOL

A 0.0532 0.0688 1.35 1.75 -

A1 0.0040 0.0098 0.10 0.25 -

B 0.013 0.020 0.33 0.51 9

C 0.0075 0.0098 0.19 0.25 -

D 0.1890 0.1968 4.80 5.00 3

E 0.1497 0.1574 3.80 4.00 4

e 0.050 BSC 1.27 BSC -

H 0.2284 0.2440 5.80 6.20 -

h 0.0099 0.0196 0.25 0.50 5

L 0.016 0.050 0.40 1.27 6

N8 87

α

0° 8° 0° 8° -

NOTESMIN MAX MIN MAX

Rev. 1 6/05

All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems.

Intersil Corporation’s quality certifications can be viewed at www.intersil.com/design/quality

Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time without
notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be accurate and
reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third parties which may result
from its use. No license is granted by implicat ion or oth erwise u nde r any p a tent or p at ent r ights of Intersil or its subsidiaries.

For information regarding Intersil Corporation and its products, see www.intersil.com

14

FN6365.1

August 16, 2007