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Texas Instruments MSC1210 User Manual

Page 177

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Low-Voltage Detect

14-3

Additional MSC1210 Hardware

The detect circuit must activate whenever the supply voltage drops below the
programmed level. In order to account for temperature and process variations,
the trip levels are typically higher than the specified value, to provide some
margin. For example, when 4.5V is selected, the detect output will typically ac-
tivate when the supply drops below 4.7V.

14.2.1 Power Supply

V

SPD

powers the digital section resistor string and the comparators. V

SPA

powers the analog section resistor string and the bandgap voltage. Level
shifters, where needed, are included inside the block.

Table 14−1.Typical Sub-Circuit Current Consumption

Sub−Ckt Current Consumption

Band Gap

20

µ

A

Compartors

2

µ

A

Resistor String

6

µ

A

Total

40

µ

A

Table 14−2.Comparator Specification

Comparator Parameters

50mV

±

2mV

Hysteresis at 2.5V

100mV

±

8mV

Hysteresis at 4.7V

26mV

Hysteresis at Each Terminal

400nS

Response Time for Slow Input

Table 14−3.Band Gap Parameters

Band Gap Parameters

Bandgap Voltage Reference

(min) 1.00V

Bandgap Voltage Reference

(typ) 1.22V

Bandgap Voltage Reference

(max) 1.50V

Minimum Supply Voltage

(V

SPA

) 1.50V

Bandgap Startup Time

(typ) < 16

µ

S