3.3 V, ± ±1 ꢀV ꢁESD-Proteotꢂ, ꢃHalD Hꢄꢂ
FuaaDSupatx, RED481/RED422 TPHꢄsetivtPs
ASM3070ꢁ/ASM307±ꢁ/ASM3072ꢁ/ASM3073ꢁ/ASM3074ꢁ/ASM3071ꢁ/ASM3076ꢁ/ASM3077ꢁ/ASM3078ꢁ
FEATURES
FUNCTIONAL BLOCK DIAGRAMS
V
TIA/EIA RS-485/RS-422 compliant
CC
15 kV ESD protection on RS-485 input/output pins
Data rates
ADM3070E/ADM3071E/ADM3072E: 250 kbps
ADM3073E/ADM3074E/ADM3075E: 500 kbps
ADM3076E/ADM3077E/ADM3078E: 16 Mbps
Half- and full-duplex options
ADM3070E/
ADM3073E/
ADM3076E
A
R
RO
B
RE
DE
True fail-safe receiver inputs
Up to 256 nodes on the bus
Z
Y
DI
D
−40°C to +125°C temperature option
Hot-swap input structure on DE and RE pins
Reduced slew rates for low EMI
GND
Figure 1.
Low power shutdown current (all except
ADM3071E/ADM3074E/ADM3077E)
Outputs high-Z when disabled or powered off
Common-mode input range: −7 V to +12 V
Thermal shutdown and short-circuit protection
8-lead and 14-lead narrow SOIC packages
V
CC
ADM3071E/
ADM3074E/
ADM3077E
A
B
R
RO
DI
APPLICATIONS
Z
Y
Power/energy metering
Industrial control
Lighting systems
D
GND
.
Telecommunications
Security systems
Figure 2.
V
Instrumentation
CC
ADM3072E/
ADM3075E/
ADM3078E
GENERAL DESCRIPTION
The ADM3070E to ADM3078E are 3.3 V, low power data
transceivers with ±±1 ꢀV ESD protection suitable for full- and
half-duplex communication on multipoint bus transmission
lines. They are designed for balanced data transmission, and they
comply with TIA/EIA standards RS-481 and RS-422.
R
RO
RE
DE
A
B
DI
D
The devices have an ⅛ unit load receiver input impedance,
which allows up to 216 transceivers on a bus. Because only one
driver should be enabled at any time, the output of a disabled or
powered-down driver is tristated to avoid overloading the bus.
GND
Figure 3.
The receiver inputs have a true fail-safe feature, which
eliminates the need for external bias resistors and ensures a
logic high output level when the inputs are open or shorted.
This guarantees that the receiver outputs are in a ꢀnown state
before communication begins and when communication ceases.
(continued on Page 3)
Rev. A
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