RLC-1 3V/5V RS232 Level Converter Datasheet
Introduction
The RLC-1 RS232 to 3-Volt or 5-Volt (CMOS/TTL) Level converter provides a simple, low-cost and easy to use solution to interfacing a CMOS or TTL based circuit to an RS232/EIA232 serial port.
The RLC-1 contains an internal circuit to provide the positive and negative voltages needed for true RS232/EIA232 compatibility and to convert these voltages back to logic levels.
It is particularly suited to micro-controller applications; for instance the PIC or ATMEL families of devices and products using these.
RLC-1 with shell removed
The RLC-1 is built into a small DB9 backshell with a short (10cm or 4") lead terminating in a standard 0.1" (2.54mm) Molex KK-series 6 pin connector. The connector is used to provide power to the converter and deliver the Serial data signals to the attached circuit.
Its small size and convenience make it ideal for prototype or one-off systems, eliminating the need to design and debug extra level shifting circuits. It is also useful for circuits that need periodic connection to a host like dataloggers where a single converter can be used with many products, reducing the parts count and therefore cost for the individual units.
Connections
RS232 Interface
The RLC-1 is built into a DB9 Backshell and comes with a female DB9 connector.
The DB9 RS232 connector is wire as a standard "Null Modem"; DTR, DSR and CD are permanently wired together but the RTS and CTS signals are provided to the logic level interface and must be connected together if not used in the attached circuit.
Logic Level Interface
The logic level (CMOS and TTL compatible)
interface is a Molex KK Series, locking and polarised 6 pin crimp terminal
housing. A compatible header for these connectors should be available from most
electronics stores, alternatively a 0.1" (2.54mm) universal header could be
used.
Note that the logic level interface is not isolated from the RS232 level interface and they share a common Ground.
RLC-1 logic level connector
| Pin | Signal | Description |
|---|---|---|
| 1 | Vcc | Power supply to the RLC-1. 3 to 5 Volts. |
| 2 | Gnd | Ground Connection (0V). |
| 3 | Data Out (TX) | Data sent from the logic level device to the RS232 device. If unused, this CMOS input should be connected to Vcc to ensure correct operation of the RLC-1 and the connected RS232 equipment. |
| 4 | Data In (RX) | Data sent from the RS232 device to the logic level device. |
| 5 | RTS | Request to Send signal sent from the RS232 device to the logic level device to indicate it wishes to transmit data. This signal is Active Low. |
| 6 | CTS | Clear to Send signal sent from the logic level device to the
RS232 device indicating that it can begin sending data. This signal is Active
Low. If unused, this CMOS input should be connected to RTS or to Ground to ensure correct operation of the RLC-1 and to maintain the "Null Modem" RS232 signals. |
Specifications
Absolute Maximum Ratings:
Absolute Maximum Ratings are those values
beyond which damage to the device may occur. Functional operation under these
conditions is not to be implied.
| Symbol | Parameter | Value | Unit | Notes |
|---|---|---|---|---|
| Vcc | Unit Power Supply | -0.3 to 6 | V | Relative to Ground |
| VDout | Input Voltage on Data Out Connection | -0.3 to (Vcc + 0.3) | V | Relative to Ground |
| VDin | Output Voltage on Data In Connection | -0.3 to (Vcc + 0.3) | V | Relative to Ground |
| TStore | Storage Temperature Range | -55 to +125 | Deg C |
Electrical Characteristics:
Vcc = 5V +/-10%,
TA = -40 to 85 Deg C, unless otherwise specified. Typical Values are
referred to TA = 25 Deg C.
| Symbol | Parameter | Conditions | Value | Unit | ||
|---|---|---|---|---|---|---|
| Min | Typical | Max | ||||
| Isupply | Vcc Power Supply Current | No Load, TA = 25 Deg C | 0.3 | 1 | mA | |
| VIL | Logic Level Input Threshold Low | 0.8 | V | |||
| VIH | Logic Level Input Threshold High | 2 | V | |||
| VOL | Logic Level Output Voltage Low | Iout = 1.6mA (to Vcc) | 0.4 | V | ||
| VOH | Logic Level Output Voltage High | Iout = 1mA (to Gnd) | Vcc - 0.6 | Vcc - 0.1 | V | |
| DR | Data Rate | 300 | 400 | Kbits/s | ||
Options Available
Digital Nemesis Pty Ltd makes a single standard unit, but is able to adapt them as needed. Note that a minimum order quantity may apply for non-standard configurations. For more information, please contact us.
The following are some of the available options:
- Rugged All Metal Backshell
- No Backshell
- Bare Leads for Logic Level Interface
- Custom Connector for Logic Level Interface
- RTS and CTS internally connected and a 4 Pin connector for the Logic Level Interface
