DS275 Maxim Integrated Products, DS275 Datasheet - Page 4

• Manufacturer Part Number: DS275
• Description: IC TXRX LINE-PWR RS232 8-DIP
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of DS275

• Number Of Drivers/receivers: 1/1
• Protocol: RS232
• Voltage - Supply: 4.5 V ~ 5.5 V
• Mounting Type: Through Hole
• Package / Case: 8-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

problem that may occur in this case is if the receiver at the other end requires a negative voltage for
recognizing a mark. In this situation, the full-duplex circuit shown in Figure 3 can be used as
analternative. The 22 F capacitor forms a negative-charge reservoir; consequently, when the TXD line is
spacing (positive), TX
capacitor and the load resistance at the other end (3-7 k ). This circuit was tested from 150-19,200 bps
with error-free operation using a SN75154 Quad Line Receiver as the receiver for the TX
that the SN75154 can have a marking input threshold below ground; hence there is the need for TX
swing both positive and negative in full-duplex operation with this device.
HANDHELD RS-232-C APPLICATION USING A STEREO MINI-JACK Figure 2
FULL-DUPLEX CIRCUIT USING NEGATIVE-CHARGE STORAGE Figure 3
NOTE:
The capacitor stores negative charge whenever the TXD signal from the PC serial port is in a marking
data state (a negative voltage that is typically -10 volts). The top DS275’s TX
charge reservoir when it is in a marking state. The capacitor will discharge to 0 volts when the TXD line
is spacing (and TX
resistance reflected back to TX
back to -10 volts. Note that TXD remains in a marking state when idle, which improves the performance
of this circuit.
ABSOLUTE MAXIMUM RATINGS*
V
V
CC
DRV
OUT
is still marking) at a time constant determined by its value and the value of the load
OUT
still has a negative source available for a time period determined by the
OUT
. However, when TXD is marking the capacitor will quickly charge
-0.3 to +7.0 volts
-0.3 to +13.0 volts
4 of 8
OUT
uses this negative
OUT
signal. Note
DS275
OUT
to