Key Specifications
Part Number | Description | Status | Supply Voltage(Nom)(V) | No. of TX | No. of RX | Duplex | Signaling Rate(Max)(Mbps) | ESD Contact (kV) | ESD Air (kV) | Number of Nodes | Common Mode Range(V) | Fail Safe | ICC(Max) (mA) | Operating Temperature Range(℃) | Pin/Package | EV Kit Available? |
UM3085EESA | 具有IEC ESD保护的低功耗,增强型驱动器,半双工RS485收发器 | Active | 5 | 1 | 1 | Half | 0.5 | ±8 | ±15 | 256 | -7 to 12 | Idle, Open, Short | 0.7 | -40 to 85 | 8/SOP | Y |
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Product Description
The UM3085EESA are ±15kV ESD-protected, high-speed transceivers for RS-485 communication that contain one driver and one receiver. These devices feature fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open, shorted or idle. This means that the receiver output will be logic high if all transmitters on a terminated bus are disabled (high impedance). The UM3085E features reduced slew-rate driver that minimizes EMI and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 500kbps. The devices feature enhanced ESD protection. All transmitter outputs and receiver inputs are protected to ±15kV using the Human Body Model and IEC61000-4-2, Air-Gap Discharge.
The transceivers typically draw 400μA of supply current when unloaded, or when fully loaded with the drivers disabled. All devices have a 1/8-unit-load receiver input impedance that allows up to 256 transceivers on the bus and are intended for half-duplex communications.
Features
- ESD Protection for RS-485 I/O Pins
±15kV—Human Body Model
±15kV—IEC61000-4-2, Air-Gap Discharge
- True Fail-Safe Receiver while Maintaining EIA/TIA-485 Compatibility
- Enhanced Slew-Rate Limiting Facilitates Error-Free Data Transmission
- 2nA Low-Current Shutdown Mode
- -7V to +12V Common-Mode Input Voltage Range
- Allows up to 256 Transceivers on the Bus
- Thermal Shutdown
- Current-Limiting for Driver Overload Protection
Typical Operating Circuits

Applications
- RS-485 Transceivers
- Level Translators
- Industrial-Control Local Area Networks
- Transceivers for EMI-Sensitive Applications
Communication Function Table
Table1. Transmitting
INPUTS | OUTPUTS | MODE |
RE | DE | DI | B | A |
X | 1 | 1 | 0 | 1 | Normal |
X | 1 | 0 | 1 | 0 | Normal |
0 | 0 | X | High-Z | High-Z | Normal |
1 | 0 | X | High-Z | High-Z | Shutdown |
X=Don’t care; High-Z=High Impedance
Table2. Receiving
INPUTS | OUTPUTS | MODE |
RE | DE | A, B | RO |
0 | X | >-50mV | 1 | Normal |
0 | X | <-200mV | 0 | Normal |
0 | X | Inputs Open | 1 | Normal |
1 | 0 | X | High-Z | Shutdown |
X=Don’t care; High-Z=High Impedance
Ordering Information
Part Number | Operating Temperature | Mark Code | Package Type |
UM3085EESA | -40°C to +85°C | UM3085EESA | SOP8 |