SN75LP1185

LOW-POWER MULTIPLE RS-232 DRIVERS AND RECEIVERS

SLLS335A – JANUARY 1999 – REVISED JANUARY 2001

7

POST OFFICE BOX 655303

• DALLAS, TEXAS 75265

PARAMETER MEASUREMENT INFORMATION

IO

II

CL

VI

VO

Inputs

Outputs

tPLH

tPHL

tTLH

tTHL

4 V

0 V

VOH

VOL

VI

VO

50%

50%

50%

50%

90%

90%

10%

10%

tw

NOTES: A. The pulse generator has the following characteristics: tw = 4 µs, PRR = 250 kbit/s, ZO = 50 Ω, tr and tf < 50 ns.

B. CL includes probe and jig capacitance.

Figure 4. Receiver Parameter Test Circuit and Waveform

IO

II

VI

VO

Inputs

Outputs

VCC

GND

Figure 5. Receiver IOS Test

APPLICATION INFORMATION

Diodes placed in series with the VDD and VSS leads protect the SN75LP1185 in the fault condition when the device

outputs are shorted to

±15 V and the power supplies are at low voltage and provide low-impedance paths to ground

(see Figure 6).

SN75LP1185

Output

SN75LP1185

Output

VDD

VSS

Figure 6. Power-Supply Protection to Meet Power-Off Fault Conditions of TIA/EIA-232-F