DS14C238WM datasheet(4/5 Pages) NSC

4 / 5 page

Parameter Measurement Information (Continued)

Pin Descriptions

CC (pin 9) — Power supply pin for the device,

+5V (±10%).

V+ (pin 11) — Positive supply for TIA/EIA-232-E drivers. Recommended external capacitor: C4 = 1.0 µF (6.3V). This supply is not

intended to be loaded externally.

V− (pin 15) — Negative supply for TIA/EIA-232-E drivers. Recommended external capacitor: C3 = 1.0 µF (16V). This supply is not

intended to be loaded externally.

C1+, C1− (pins 10 and 12) — External capacitor connection pins. Recommended capacitor – 1.0 µF (6.3V).

C2+, C2− (pins 13 and 14) — External Capacitor connection pins. Recommended capacitor – 1.0 µF (16V).

IN 1–4 (pins 5, 18, 19, and 21) — Driver input pins are TTL/CMOS compatible. Inputs of unused drivers may be left open, an

internal pull-up resistor (500 k

Ω minimum, typically 5 MΩ) pulls input to V

CC. Output will be LOW for open inputs.

OUT 1–4 (pins 2, 1, 24, and 20) — Driver output pins conform to TIA/EIA-232-E levels.

IN1 1–4 (pins 3, 7, 23, and 16) — Receiver input pins accept TIA/EIA-232-E input voltages (±15V). Receivers feature a noise

filter and guaranteed hysteresis of 200 mV. Unused receiver input pins may be left open. Internal input resistor (5 k

Ω) pulls input

LOW, providing a failsafe HIGH output.

OUT 1–4 (pins 4, 6, 22, and 17) — Receiver output pins are TTL/CMOS compatible. Receiver output HIGH voltage is specified

for both CMOS and TTL load conditions.

GND (pin 8) — Ground Pin.

01128207

FIGURE 4. Receiver Propagation Delays and Noise Rejection

DS14C238WM Datasheet(PDF) 4 Page - National Semiconductor (TI)