TLV3502-Q1
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SBOS507 –FEBRUARY 2010
APPLICATION INFORMATION
The TLV350x feature high-speed response and includes 6 mV of internal hysteresis for improved noise immunity
with an input common-mode range that extends 0.2 V beyond the power-supply rails.
Shutdown
A shutdown pin allows the device to go into idle when it is not in use. When the shutdown pin is high, the device
draws about 2 mA and the output goes to high impedance. When the shutdown pin is low, the TLV3501 is active.
When the TLV3501 shutdown feature is not used, connect the shutdown pin to the most negative supply, as
shown in Figure 1. It takes about 100 ns to come out of shutdown mode. The TLV3502 does not have the
shutdown feature.
VS
µ
0.1 F
µ
2.2 F
VIN
VOUT
TLV3501
VREF
Figure 1. Basic Connections for the TLV3501
Operating Voltage
TLV350x comparators are specified for use on a single supply from 2.7 V to 5.5 V (or a dual supply from ±1.35 V
to ±2.75 V) over a temperature range of −40°C to 125°C. The device continues to function below this range, but
performance is not specified.
Adding External Hysteresis
The TLV350x has a robust performance when used with a good layout. However, comparator inputs have little
noise immunity within the range of specified offset voltage (±5 mV). For slow moving or noisy input signals, the
comparator output may display multiple switching as input signals move through the switching threshold. In such
applications, the 6mV of internal hysteresis of the TLV350x might not be sufficient. In cases where greater noise
immunity is desired, external hysteresis may be added by connecting a small amount of feedback to the positive
input. Figure 2 shows a typical topology used to introduce 25 mV of additional hysteresis, for a total of 31-mV
hysteresis when operating from a single 5-V supply. Total hysteresis is approximated by Equation 1:
(V+)´R
1
V
=
+ 6mV
HYST
R +R
1
2
(1)
VHYST sets the value of the transition voltage required to switch the comparator output by enlarging the threshold
region, thereby reducing sensitivity to noise.
VS = 5V
µ
0.1 F
µ
2.2 F
VIN
VOUT
TLV3501
Ω
Ω
R2 = 10k
R1 = 51
VREF
Figure 2. Adding Hysteresis to the TLV350x
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