OUT

+

_

TLV3691

GND

REF3312

GND

TLV3691

www.ti.com

SBOS694 – DECEMBER 2013

CAPACITIVE LOADS

Under reasonable capacitive loads, the device maintains specified propagation delay (see the Typical

Characteristics). However, excessive capacitive loading under high switching frequencies may increase supply

current, propagation delay, or induce decreased slew rate.

CIRCUIT LAYOUT

Comparators are very sensitive to input noise. For best results, the following layout guidelines should be

maintained:

1. Use a printed circuit board (PCB) with a good, unbroken, low-inductance ground plane. Proper grounding

(use of a ground plane) helps maintain specified device performance.

2. To minimize supply noise, place a decoupling capacitor (0.1-

μF ceramic, surface-mount capacitor) as close

3. On the inputs and the output, keep lead lengths as short as possible to avoid unwanted parasitic feedback

around the comparator. Keep inputs away from the output.

4. Solder the device directly to the PCB rather than using a socket.

5. For slow-moving input signals, take care to prevent parasitic feedback. A small capacitor (1000 pF or less)

placed between the inputs can help eliminate oscillations in the transition region. This capacitor causes some

degradation to propagation delay when impedance is low. The topside ground plane runs between the output

and inputs.

6. The ground pin ground trace runs under the device up to the bypass capacitor, shielding the inputs from the

outputs.

SETTING THE REFERENCE VOLTAGE

Using a stable reference when setting the transition point for the device is important. The REF3312, as shown in

Figure 31, provides a 1.25-V reference voltage with low drift and only 3.9

μA of quiescent current.

Figure 31. Reference Voltage for the TLV3691

Copyright © 2013, Texas Instruments Incorporated

Submit Documentation Feedback

13

Product Folder Links: TLV3691