13

www.3peakic.com.cn

REV1.2

TP2011/TP2012/TP2014

Ultra-Low Power 200nA, 1.6V, RRIO, Push-Pull Output Comparators

2. For Inverting Configuration:

Figure 6. Example Guard Ring Layout for Inverting Comparator

Ground Sensing and Rail to Rail Output

The TP201x family implements a rail-to-rail topology that is capable of swinging to within 10mV of either rail. Since the

inputs can go 300mV beyond either rail, the comparator can easily perform ‘true ground’ sensing.

The maximum output current is a function of total supply voltage. As the supply voltage of the comparator increases,

the output current capability also increases. Attention must be paid to keep the junction temperature of the IC below

150°C when the output is in continuous short-circuit condition. The output of the amplifier has reverse-biased ESD

diodes connected to each supply. The output should not be forced more than 0.5V beyond either supply, otherwise

current will flow through these diodes.

ESD

The TP201x family has reverse-biased ESD protection diodes on all inputs and output. Input and output pins can not

be biased more than 300mV beyond either supply rail.

Power Supply Layout and Bypass

The TP201x family’s power supply pin should have a local bypass capacitor (i.e., 0.01μF to 0.1μF) within 2mm for

good high frequency performance. It can also use a bulk capacitor (i.e., 1μF or larger) within 100mm to provide large,

slow currents. This bulk capacitor can be shared with other analog parts.

Good ground layout improves performance by decreasing the amount of stray capacitance and noise at the

comparator’s inputs and outputs. To decrease stray capacitance, minimize PCB lengths and resistor leads, and place

external components as close to the comparator’ pins as possible.

Proper Board Layout

The TP201x family is a series of fast-switching, high-speed comparator and requires high-speed layout considerations.

For best results, the following layout guidelines should be followed:

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

2. Place a decoupling capacitor (0.1μF ceramic, surface-mount capacitor) as close as possible to supply.

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 the impedance is low. The topside ground plane should be placed

between the output and inputs.

6. The ground pin ground trace should run under the device up to the bypass capacitor, thus shielding the inputs

from the outputs.