Texas Instruments TPS3305-18DGN, TPS3305-18D, TPS3305-33DR, TPS3305-33DGNR, TPS3305-33DGN Datasheet

TPS3305-18, TPS3305-25, TPS3305-33

DUAL PROCESSOR SUPERVISORS

SLVS198 – DECEMBER 1998

1

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

D

Dual Supervisory Circuits for DSP and

Processor-Based Systems

D

Power-On Reset Generator with Fixed

Delay Time of 200 ms, no External

Capacitor Needed

D

Watchdog Timer Retriggers the RESET

Output at SENSEn ≥ V

IT+

D

T emperature-Compensated Voltage

Reference

D

Maximum Supply Current of 40 µA

D

Supply Voltage Range...2.7 V to 6 V

D

Defined RESET Output from V

DD

≥ 1.1 V

D

MSOP-8 and SO-8 Packages

D

T emperature Range...–40°C to 85°C

typical applications

Figure 1 lists some of the typical applications for the TPS3305 family , and a schematic diagram for a DSP-based

system application. This application uses TI part numbers TPS3305–25, TPS7133, TPS71025, and

TMS320VC549.

TPS7133

V

O

V

I

GND

TPS71025

V

O

V

I

GND

V

DD

GND

SENSE 1

SENSE 2

MR

RESET

WDI

DSP

GND

DV

DD

CV

DD

TMS320VC549TPS3305–25

RESET

XF

2.5 V

3.3 V

5 V – 10 V

External

Reset

Source

Figure 1. Applications Using the TPS3305 Family

• Applications using DSPs, Microcontrollers

or Microprocessors

• Industrial Equipment

• Programmable Controls

• Automotive Systems

• Portable/Battery Powered Equipment

• Intelligent Instruments

• Wireless Communication Systems

• Notebook/Desktop Computers

description

The TPS3305 family is a series of micropower supply voltage supervisors designed for circuit initialization,

primarily in DSP and processor-based systems, which require two supply voltages.

The product spectrum of the TPS3305 is designed for monitoring two independent supply voltages of

3.3 V/1.8 V, 3.3 V/2.5 V or 3.3 V /5 V.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of Texas Instruments

standard warranty. Production processing does not necessarily include

testing of all parameters.

Copyright  1998, Texas Instruments Incorporated

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

1

2

3

4

8

7

6

5

SENSE1

SENSE2

WDI

GND

V

DD

MR

RESET

RESET

D OR DGN PACKAGE

(TOP VIEW)

TPS3305-18, TPS3305-25, TPS3305-33

DUAL PROCESSOR SUPERVISORS

SLVS198 – DECEMBER 1998

2

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

description (continued)

The various supply voltage supervisors are designed to monitor the nominal supply voltage, as shown in the

following supply voltage monitoring table.

SUPPLY VOLTAGE MONITORING

NOMINAL SUPERVISED VOLTAGE THRESHOLD VOLTAGE (TYP)

DEVICE

SENSE1 SENSE2 SENSE1 SENSE2

TPS3305-18 3.3 V 1.8 V 2.93 V 1.68 V

TPS3305-25 3.3 V 2.5 V 2.93 V 2.25 V

TPS3305-33 5 V 3.3 V 4.55 V 2.93 V

During power-on, RESET is asserted when the supply voltage V

DD

becomes higher than 1.1 V . Thereafter , the

supply voltage supervisor monitors the SENSEn inputs

and keeps RESET active as long as SENSEn remains

below the threshold voltage V

IT+

.

An internal timer delays the return of the RESET

output to the inactive state (high) to ensure proper system reset.

The delay time, t

d

typ

= 200 ms, starts after SENSE1 and SENSE2 inputs have risen above the threshold voltage

V

IT+

. When the voltage at SENSE1 or SENSE2 input drops below the threshold voltage V

IT–

, the RESET output

becomes active (low) again.

The TPS3305-xx devices integrate a watchdog timer that is periodically triggered by a positive or negative

transition of WDI. When the supervising system fails to retrigger the watchdog circuit within the time-out interval,

t

t(out)

= 1.6 s, RESET becomes active for the time period t

d

. This event also reinitializes the watchdog timer.

Leaving WDI unconnected disables the watchdog.

The TPS3305-xx family of devices incorporates a manual reset input, MR

. A low level at MR causes RESET

to become active. In addition to the active-low RESET output, the TPS3305-xx family includes an active-high

RESET output.

The TPS3305-xx devices are available in either 8-pin MSOP or standard 8-pin SO packages.

The TPS3305-xx family is characterized for operation over a temperature range of – 40°C to 85°C.

AVAILABLE OPTIONS

PACKAGED DEVICES

T

A

SMALL OUTLINE

(D)

PowerPAD

µ-SMALL OUTLINE

(DGN)

MARKING

DGN PACKAGE

CHIP FORM

(Y)

TPS3305-18D TPS3305-18DGN TIAAM TPS3305-18Y

–40

_

C to 85

_

C

TPS3305-25D TPS3305-25DGN TIAAN TPS3305-25Y

TPS3305-33D TPS3305-33DGN TIAAO TPS3305-33Y

PowerPAD is a trademark of Texas Instruments Incorporated.

TPS3305-18, TPS3305-25, TPS3305-33

DUAL PROCESSOR SUPERVISORS

SLVS198 – DECEMBER 1998

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POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

description (continued)

FUNCTION/TRUTH TABLES

MR

SENSE1>V

IT1

SENSE2>V

IT2

RESET RESET

L X

†

X

†

L H

H 0 0 L H

H 0 0 L H

H 0 1 L H

H 0 1 L H

H 1 0 L H

H 1 0 L H

H 1 1 L H

H 1 1 H L

†

X = Don’t care

functional block diagram

_

+

_

+

R4

R2

R1

R3

Reference

Voltage

of 1.25 V

RESET

Logic + Timer

Oscillator

14 kΩ

V

DD

MR

SENSE 1

SENSE 2

GND

WDI

RESET

RESET

TPS3305

Watchdog

Logic + Timer

40 kΩ

Transition

Detection

TPS3305-18, TPS3305-25, TPS3305-33

DUAL PROCESSOR SUPERVISORS

SLVS198 – DECEMBER 1998

4

POST OFFICE BOX 655303 • DALLAS, TEXAS 75265

timing diagram

t

d

t

d

t

d

RESET Because of WDI

RESET Because of MR

RESET Because of SENSE Below V

IT–

RESET Because of SENSE Below V

IT–

SENSEn

V

(nom)

V

IT–

MR

1

0

1

0

RESET

t

t

t

1

0

WDI

t

t(out)

t

t

d

RESET Because

of SENSE Below V

IT–