LTC2931HF 데이터 시트보기 (PDF) - Linear Technology

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LTC2931HF

Confi gurable Six Supply Monitor with Adjustable Reset and Watchdog Timers

Linear Technology 

LTC2931

APPLICATIONS INFORMATION

Table 1. Voltage Threshold Modes*

MODE V1 (V) V2 (V) V3 (V) V4 (V) R1 (kΩ) R2 (kΩ)

0 5.0 3.3 ADJ ADJ Open Short

1 5.0 3.3 ADJ –ADJ 93.1 9.53

2 3.3 2.5 ADJ ADJ 86.6 16.2

3 3.3 2.5 ADJ –ADJ 78.7 22.1

4 3.3 2.5 1.5 ADJ 71.5 28.0

5 5.0 3.3 2.5 ADJ 66.5 34.8

6 5.0 3.3 2.5 1.8 59.0 40.2

7 5.0 3.3 2.5 1.5 53.6 47.5

8 5.0 3.0 2.5 ADJ 47.5 53.6

9 5.0 3.0 ADJ ADJ 40.2 59.0

10 3.3 2.5 1.8 1.5 34.8 66.5

11 3.3 2.5 1.8 ADJ 28.0 71.5

12 3.3 2.5 1.8 –ADJ 22.1 78.7

13 5.0 3.3 1.8 –ADJ 16.2 86.6

14 5.0 3.3 1.8 ADJ 9.53 93.1

15 5.0 3.0 1.8 ADJ Short Open

*V5 and V6 are always adjustable (ADJ).

VPG

VREF

0.000

0.094

0.156

0.219

0.281

0.344

0.406

0.469

0.531

0.594

0.656

0.719

0.781

0.844

0.906

1.000

tion. The comparators are enabled and supply monitoring

begins. Do not add capacitance to the VPG pin.

Using The Adjustable Thresholds

The reference inputs on the V3 and/or V4 comparators

are set to 0.5V when the positive adjustable modes are

selected (Figure 3). The reference inputs on the V5 and V6

comparators are always set to 0.5V. The tap point on an

external resistive divider, connected between the positive

voltage being sensed and ground, is connected to the high

VTRIP

R3

1%

V3, V4, V5 OR V6

R4

1%

LTC2931

+– 0.5V

Table 2. Suggested 1% Resistor Values for the ADJ Inputs

VSUPPLY (V)

12

VTRIP (V)

11.25

R3 (kΩ)

2150

R4 (kΩ)

100

10

9.4

1780

100

8

7.5

1400

100

7.5

7

1300

100

6

5.6

1020

100

5

4.725

845

100

3.3

3.055

511

100

3

2.82

464

100

2.5

2.325

365

100

1.8

1.685

237

100

1.5

1.410

182

100

1.2

1.120

124

100

1

0.933

86.6

100

0.9

0.840

68.1

100

Table 3. Suggested 1% Resistor Values for the –ADJ Inputs

VSUPPLY (V)

–2

VTRIP (V)

–1.87

R3 (kΩ)

187

R4 (kΩ)

121

–5

–4.64

464

121

–5.2

–4.87

487

121

–10

–9.31

931

121

–12

–11.30

1130

121

impedance, adjustable inputs (V3, V4, V5, V6). Calculate

the trip voltage from:

VTRIP

=

0.5V

•

1+

R3

R4





In the negative adjustable mode, the reference level on the

V4 comparator is connected to ground (Figure 4). The tap

point on an external resistive divider, connected between

R4

1%

R3

1%

VTRIP

VREF

V4

LTC2931

2931 F03

Figure 3. Setting the Positive Adjustable Trip Point

10

2931 F04

Figure 4. Setting the Negative Adjustable Trip Point

2931fb

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