LTC2910

8

2910fb

APPLICATIONS INFORMATION

Voltage Monitoring

The LTC2910 is a low power octal voltage monitoring

circuit with eight individual undervoltage monitor inputs.

A timeout period that holds a reset after all faults have

cleared is adjustable using an external capacitor and is

Each voltage monitor is compared to a fixed 0.5V reference

for detecting undervoltage conditions. When configured

Using the configurations in Figures 1 and 2, a UV condi-

is less than its designed threshold.

Polarity Selection

The three-state polarity-select pin (SEL) selects one of three

possible polarity combinations for the input thresholds,

as described in Table 1. When an input is configured for

negative supply monitoring, a reset condition occurs when

the supply voltage is less negative than the configured

threshold.

left unconnected during normal operation. When the pin

is left unconnected, the maximum leakage allowed from

the pin is ±10µA to ensure it remains in the open state.

Table 1 shows the three possible selections of polarity

based on the SEL pin connection.

2-Step Design Procedure

The following 2-step design procedure allows selecting

appropriate resistances to obtain the desired UV trip point

for the positive voltage monitor circuit in Figure 1 and the

negative voltage monitor circuit in Figure 2.

trip point.

For negative supply monitoring, to compensate for the 1V

using each in the following equations.

undervoltage monitor.

R

V

V

V

A

m

UV

=

05

.

I

•

m

(1)

Figure 1. Positive UV Monitoring Configuration

Figure 2. Negative UV Monitoring Configuration

SEL

V7 INPUT

V8 INPUT

Positive

Positive

Open

Positive

Negative

GND

Negative

Negative

2910 F01

UVn

LTC2910

+

–

Vn

0.5V

2910 F02

REF

Vn

0.5V

UVn

+

–

–

+

1V

+

–

LTC2910