SG1548

11/91 Rev 1.2 5/97

INFINITY

Microelectronics Inc.

1997

11861 Western Avenue

∞

Garden Grove, CA 92841

(714) 898-8121

∞

FAX: (714) 893-2570

SG1548/SG2548/SG3548

QUAD POWER FAULT MONITOR

DESCRIPTION

The SG1548 is an integrated circuit capable of monitoring up to four

positive DC supply voltages simultaneously for overvoltage and

undervoltage fault conditions. An on-chip inverting op amp also

allows monitoring one negative DC voltage. The fault tolerance

window is accurately programmable from ±5% to ±40% using a simple

divider network on the 2.5V reference. A single external capacitor sets

the fault indication delay, eliminating false outputs due to switching

noise, logic transition current spikes, and short-term AC line interrup-

tions. An additional comparator referenced to 2.5V allows the AC line

to be monitored for undervoltage conditions or for generation of a line

clock. The comparator can also be used for programmable

undervoltage lockout in a switching power supply. Uncommitted

collector and emitter outputs permit both inverting and non-inverting

operation. External availability of the precision 2.5V reference and

open-collector logic outputs permit expansion to monitor additional

voltage using available open-collector quad comparators.

FEATURES

•••••

Monitors four DC voltages and the AC line

•••••

Precision 2.5V ±1% low-drift reference

•••••

Fault tolerance adjustable from ±5% to ±40%

•••••

±3% trip threshold tolerance over temperature

•••••

Separate 10mA, 40V overvoltage, undervoltage

and AC line fault outputs

•••••

Fault delay programmable with a single capacitor

•••••

30mV comparator hysteresis to prevent oscilla-

tions

•••••

On-chip inverting op amp for negative voltage

•••••

Open-collector output logic or expandability

•••••

Operation from 4.5V to 40V supply

HIGH RELIABILITY FEATURES - SG1548

♦

Available to MIL-STD-883

♦

Radiation data available

♦

LMI level "S" processing available

BLOCK DIAGRAM

11/91 Rev 1.2 5/97

INFINITY

Microelectronics Inc.

1997

11861 Western Avenue

∞

Garden Grove, CA 92841

(714) 898-8121

∞

FAX: (714) 893-2570

ABSOLUTE MAXIMUM RATINGS

(Note 1)

SG1548/SG2548/SG3548

Inverting Op Amp Output Current ....................................

Operating Junction Temperature

Hermetic (J, L Packages) .............................................

Plastic (N, DW Packages) ............................................

Storage Temperature Range ............................

Lead Temperature ...........................................................

Supply Voltage (+V

) ..........................................................

Fault Output Collector Voltage ............................................

Sense Input Voltage Range .................................

Fault Output Sink Current ................................................

Line Sense Input Current .................................................

Inverting Op Amp Input Current ........................................

40V

-0.3V to 6.0V

20mA

±1mA

-5mA

25mA

150

-65

C to 150

300

Note 1. Values beyond which damage may occur.

THERMAL DATA

J Package:

Thermal Resistance-

Junction to Case

................... 30°C/W

Thermal Resistance-

Junction to Ambient

.............. 80°C/W

N Package:

Thermal Resistance-

Junction to Case

.................. 40°C/W

Thermal Resistance-

Junction to Ambient

............. 65°C/W

DW Package:

Thermal Resistance-

Junction to Case

.................. 40°C/W

Thermal Resistance-

Junction to Ambient

............. 95°C/W

L Package:

Thermal Resistance-

Junction to Case

.................. 35°C/W

Thermal Resistance-

Junction to Ambient

........... 120°C/W

Note A. Junction Temperature Calculation: T

= T

+ (P

Note B. The above numbers for

are maximums for the limiting

thermal resistance of the package in a standard mount-

ing configuration. The

numbers are meant to be

guidelines for the thermal performance of the device/pc-

board system. All of the above assume no ambient

airflow.

2.625

3.500

2.375

1.500

±0.6

100

DC Sense Inputs Section

PIN 1

= 0.95 x V

REF

PIN 1

= 0.60 x V

REF

PIN 1

= 0.95 x V

REF

PIN 1

= 0.60 x V

REF

SENSE

= 1.5V to 3.5V

= 4.5V to 35V

Overvoltage Threshold

Undervoltage Threshold

Input Bias Current

Threshold Supply Rejection

4.5V to 35V

5.0V to 35V

1.5V to 2.45V

±5% to ±40%

0 to 10mA

Supply Voltage Range

±25% Maximum Fault Window

(Note 3)

..............

±40% Maximum Fault Window ...........................

Lower Threshold Input Range .............................

Fault Tolerance Window Range ..........................

Fault Output Sink Current Range .............................

Line Sense Output Current Range ...........................

Voltage Reference Output Current ...........................

Operating Ambient Temperature Range

SG1548 .........................................................

SG2548 ...........................................................

SG3548 ...............................................................

0 to 10mA

-55

C to 125

-25

C to 85

C to 70

Note 2. Range over which the device is functional.

Note 3. Limited by inverter amplifier positive swing at -55

RECOMMENDED OPERATING CONDITIONS

(Note 2)

ELECTRICAL CHARACTERISTICS

(Unless otherwise specified, these specifications apply over the operating ambient temperatures for SG1548 with -55

≤

125

C, SG2548 with

-25

≤

C, SG3548 with 0

≤

C, and +V

= 15V. Low duty cycle pulse testing techniques are used which maintains junction and case

temperatures equal to the ambient temperature.)

Reference Section

(Note 4)

= 25

Over Temperature

= 4.5V to 35V

= 0 to 10mA

REF

= 0V

Output Voltage

Line Regulation

Load Regulation

Short Circuit Current

4.8

= 40V

Supply Current

Min. Typ. Max.

SG3548

SG1548/2548

Test Conditions

Parameter

Units

Supply Section

-0.4

PIN 1

= 1.5V to 2.45V

Input Bias Current

Fault Window Generator Section

Min. Typ. Max.

4.8

2.475

2.450

2.500

2.525

2.550

2.475

2.450

2.500

2.525

2.550

-2.0

-0.4

-2.0

2.547

3.396

2.304

1.455

2.704

3.606

2.447

1.545

±2.0

2.547

3.396

2.304

1.455

2.625

3.500

2.375

1.500

±0.6

100

2.704

3.606

2.447

1.545

±2.0

Note 4. I

= 0mA

11/91 Rev 1.2 5/97

INFINITY

Microelectronics Inc.

1997

11861 Western Avenue

∞

Garden Grove, CA 92841

(714) 898-8121

∞

FAX: (714) 893-2570

Fault Logic Outputs (Each output)

= 40V

= 10mA

Collector Leakage Current

Collector Saturation Voltage

2.500

0.2

AC Line Sense Section

PIN 5

= Low to High

PIN 5

= 2.5V

= 40V

= 10mA

PIN 5

= 1mA

PIN 5

= -1mA

Comparator Threshold

Comparator Hysteresis

Input Bias Current

Collector Leakage Current

Collector Saturation Voltage

Emitter Output Voltage

Diode Clamp Voltage

2.440

6.0

-0.3

2.560

0.5

7.5

-1.0

2.440

6.0

-0.3

2.500

0.2

-0.3

3.5

1.0

100

3.2

Inverting Op Amp Section

(Note 5)

SOURCE

= 5mA

SINK

= 5mA

= 10K

= 4.5V to 35V

Input Offset Voltage

Input Bias Current

Output High Voltage

Output Low Voltage

Large Signal Voltage Gain

Output Source Current

Power Supply Rejection Ratio

1.250

0.1

+3.2

1.200

32.5

PIN 8

= 0V

PIN 8

= 0mA

PIN 8

= 0mA

Comparator Threshold

Comparator Hysteresis

Delay Charging Current

On Saturation Voltage

OFF Clamp Voltage

SG1548/SG2548/SG3548

Min. Typ. Max.

SG3548

SG1548/2548

Test Conditions

Parameter

Units

ELECTRICAL CHARACTERISTICS

(continued)

Min. Typ. Max.

APPLICATION INFORMATION

Note 5. +V

= 4.5V.

Fault Delay Section

1.300

67.5

0.2

+3.6

1.200

32.5

1.250

0.1

+3.2

1.300

67.5

0.2

+3.6

-1.0

1.9

3.2

-0.3

3.5

1.0

100

-1.0

1.9

2.560

0.5

7.5

-1.0

0.5

0.2

0.5

0.2

SETTING THE FAULT TOLERANCE WINDOW

The fault tolerance window is set by applying a voltage less than

the +2.50Vreference to the Lower Threshold input (Pin 1). The

voltage is obtained by a resistor divider from the reference (Pin 3)

to ground. If ±5% tolerance is desired, then 95% of the reference

(+2.375V) is applied to Pin 1. If ±40% is wanted, then 60% of the

reference (+1.50V) is applied. In the example on the back page,

the tolerance is ±5%. The nominal overvoltage and undervoltage

thresholds are centered about the reference at +2.625V and

+2.375V (+2.500V ±0.125V).

SCALING THE MONITORED SUPPLY VOLTAGES

Each positive voltage to be monitored is divided down to +2.50V

with a resistor network and connected to one of the Sense inputs.

Unused Sense inputs should be connected to the reference. This

will not increase the bias current. A variation of the monitored

voltages out of the programmed tolerance range will cause the

appropriate overvoltage or undervoltage fault output to switch

LOW. The effective tolerance on any input may be broadened

with an additional resistor to the voltage reference. The example

on the back page shows a ±10% tolerance on the +5Vsupply

although the SG1548 is programmed for a ±5% tolerance. The

procedure for calculating the resistor value is found in the

SG1548 Application Note.

MONITORING A NEGATIVE VOLTAGE

A negative voltage can be converted to a positive one and

simultaneously scaled to +2.50V by using the internal operational

amplifier as an inverter. Only an input resistor and feedback

resistor are required.

SETTING THE FAULT DELAY

A single capacitor at the Delay pin sets the time an out-of-

tolerance fault must persist before a fault is actually declared.

This feature allows switching noise on the supplies to be rejected.

The delay time is given by: Delay = 25ms/

F .

AC LINE MONITORING

The AC line voltage can be monitored for single-cycle dropouts

with the few components shown in the example. A half-wave

rectifier charges the capacitor on positive line cycles. After the

positive peak and during the negative line cycle the capacitor

discharges from a fixed voltage controlled by the internal Zener

diode. If a positive cycle is missing, the capacitor discharges to

below the +2.5V trip point of the comparator, causing the output

transistor to turn on.

11/91 Rev 1.2 5/97

INFINITY

Microelectronics Inc.

1997

11861 Western Avenue

∞

Garden Grove, CA 92841

(714) 898-8121

∞

FAX: (714) 893-2570

SG1548/SG2548/SG3548

APPLICATION EXAMPLE

In this example, the SG1548 simultaneously monitors four DC voltages: +5V, +24V, and ±15V. Three different fault tolerances are

programmed: ±5% on the two 15V supplies, ±10% on the +5V supply, and ±20% on the +24V supply. The 5

F delay capacitor provides

125 milliseconds of fault delay.

CONNECTION DIAGRAMS & ORDERING INFORMATION

(See Notes Below)

Ambient

Temperature Range

Part No.

Package

Connection Diagram

16-PIN CERAMIC DIP

J - PACKAGE

SG1548J/883B

-55

C to 125

SG1548J

-55

C to 125

SG2548J

-25

C to 85

SG3548J

C to 70

SG2548N

-25

C to 85

SG3548N

C to 70

16-PIN PLASTIC DIP

N - PACKAGE

16-PIN WIDE BODY

PLASTIC S.O.I.C.

DW - PACKAGE

SG2548DW

-25

C to 85

SG3548DW

C to 70

INV. OUTPUT

INV. INPUT

SENSE 4

SENSE 3

SENSE 2

SENSE 1

U.V. FAULT

O.V. FAULT

DELAY

REF

GROUND

LOWER THRESHOLD

COLLECTOR OUTPUT

EMITTER OUTPUT

LINE SENSE

DELAY

REF

GROUND

LOWER THRESHOLD

LINE SENSE

COLLECTOR OUTPUT

EMITTER OUTPUT

INV. OUTPUT

INV. INPUT

SENSE 4

SENSE 3

SENSE 2

SENSE 1

U.V. FAULT

O.V. FAULT

20-PIN CERAMIC (LCC)

LEADLESS CHIP CARRIER

L- PACKAGE

SG1548L/883B

-55

C to 125

SG1548L

-55

C to 125

Note 1. Contact factory for JAN and DESC product availability.

2. All parts are viewed from the top.

11. N.C.

12. O.V. FAULT

13. U.V. FAULT

14. SENSE 1

15. SENSE 2

16. N.C.

17. SENSE 3

18. SENSE 4

19. INV. INPUT

20. INV. OUTPUT

1. N.C.

2. LOWER THRESHOLD

3. GROUND

4. V

REF

5. +V

6. N.C.

7. LINE SENSE

8. EMITTER OUTPUT

9. COLLECTOR

OUTPUT

11 12 13

20 19

10.DELAY