Overview
The ADM3485EAR is a 3.3 V, low power half-duplex transceiver designed by Analog Devices Inc. for use in multipoint bus transmission lines. This device is compliant with TIA/EIA standards RS-485 and RS-422, making it suitable for balanced data transmission. It features separate enable inputs for the driver and receiver, allowing for flexible control over the communication interface. The ADM3485EAR is packaged in an 8-lead narrow SOIC package and is fully specified over the industrial temperature range, ensuring reliability in various environmental conditions.
Key Specifications
| Parameter | Min | Typ | Max | Unit | Test Conditions/Comments |
|---|---|---|---|---|---|
| Supply Voltage (VCC) | 3.0 | 3.3 | 3.6 | V | |
| Data Rate | 12 | 15 | Mbps | ||
| Differential Output Delay (tDD) | 1 | 22 | 35 | ns | RL = 60 Ω, CL1 = CL2 = 15 pF |
| Differential Output Transition Time (tTD) | 3 | 11 | 25 | ns | RL = 60 Ω, CL1 = CL2 = 15 pF |
| Propagation Delay From Low to High Level (tPLH) | 7 | 23 | 35 | ns | |
| ESD Protection (A, B Pins) | ±15 kV | Human body model | |||
| ESD Protection (All Pins Except A, B) | ±4 kV | Human body model | |||
| Shutdown Current (ISHDN) | 0.002 | 1 | µA | DE = 0 V, RE = VCC, DI = 0 V or VCC | |
| Receiver Input Impedance | 12 | kΩ | |||
| Common-mode Input Range | -7 | 12 | V |
Key Features
- TIA/EIA RS-485/RS-422 compliant
- ±15 kV ESD protection on RS-485 input/output pins
- Half-duplex transceiver with separate enable inputs for driver and receiver
- Up to 32 nodes on the bus
- Receiver open-circuit, fail-safe design ensuring logic high output when inputs are floating
- Low power shutdown current
- Outputs high-Z when disabled or powered off
- Thermal shutdown and short-circuit protection
- Industry-standard 75176 pinout
- 8-lead narrow SOIC package
Applications
- Power/energy metering
- Telecommunications
- EMI-sensitive systems
- Industrial control
- Local area networks
Q & A
- What is the primary function of the ADM3485EAR?
The ADM3485EAR is a half-duplex transceiver designed for balanced data transmission on multipoint bus transmission lines, complying with TIA/EIA standards RS-485 and RS-422. - What is the maximum data rate of the ADM3485EAR?
The maximum data rate of the ADM3485EAR is 15 Mbps. - How many nodes can be connected on the bus using the ADM3485EAR?
Up to 32 nodes can be connected on the bus. - What type of ESD protection does the ADM3485EAR offer?
The ADM3485EAR offers ±15 kV ESD protection on RS-485 input/output pins and ±4 kV on all other pins. - What is the common-mode input range of the ADM3485EAR?
The common-mode input range is from -7 V to +12 V. - Does the ADM3485EAR have thermal protection?
Yes, the ADM3485EAR features thermal shutdown and short-circuit protection. - In what package is the ADM3485EAR available?
The ADM3485EAR is available in an 8-lead narrow SOIC package. - What are some typical applications of the ADM3485EAR?
Typical applications include power/energy metering, telecommunications, EMI-sensitive systems, industrial control, and local area networks. - How does the receiver fail-safe feature work?
The receiver has a fail-safe feature that ensures a logic high output when the inputs are floating. - What is the shutdown current of the ADM3485EAR?
The shutdown current (ISHDN) is between 0.002 µA and 1 µA when DE = 0 V, RE = VCC, and DI = 0 V or VCC.
