ST STM6905 User Manual

STM6905

Quintuple, ultralow voltage supervisor with push-button reset

Features

Quintuple voltage monitoring

Accurate ±1.8% across temperature voltage threshold (±1% at 25°C)

Primary supply (VCC) monitor. Fixed (factory - programmed) reset thresholds: 3.078 V to 2.866 V

Second fixed (V2IN) monitor. Fixed (factoryprogrammed) reset thresholds: 2.333 V to 1.050 V

Three additional adjustable supply monitor inputs (externally adjustable)

600 mV internal reference

RST output (open drain)

Output guaranteed for VCC 0.8 V

Reset delay time (trec) on power-up: 210 ms (typ)

Manual reset input (MR)

Low supply current of 12 µA (typ)

Power supply voltage 0.8 V to 5.5 V

RoHS compliant (green package)

8-pin MSOP/TSSOP

Operating temperature: –40°C to 85°C (industrial grade)

Table 1. Device summary(1)

MSOP8 (TSSOP8) (DS)

Applications

Set-top boxes

Multi-voltage systems

Cable/satellite applications

Computer systems

Data storage equipment

Order code

VRST1 (V)

VRST2 (V)

tREC (ms)

Package

STM6905TZEDS6F

3.078

2.333

210

MSOP8(TSSOP8)

 

 

 

 

 

STM6905TWEDS6F

3.078

1.683

210

MSOP8(TSSOP8)

 

 

 

 

 

STM6905TGEDS6F

3.078

1.110

210

MSOP8(TSSOP8)

 

 

 

 

 

STM6905SYEDS6F

2.955

2.188

210

MSOP8(TSSOP8)

 

 

 

 

 

STM6905SFEDS6F

2.955

1.050

210

MSOP8(TSSOP8)

 

 

 

 

 

STM6905PWEDS6F

2.866

1.683

210

MSOP8(TSSOP8)

 

 

 

 

 

1. Other reset threshold voltages and tREC time-out periods are offered. Minimum order quantities may apply. Contact local ST sales office for availability.

January 2008

Rev 3

1/19

www.st.com

Contents

STM6905

 

 

Contents

1

Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

5

2

Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

 

2.1

Push-button reset input

 

 

7

 

(MR)

 

2.2

VCC primary supply voltage monitoring input . . . . . . . . . . . . . . . . . . . . . . .

7

 

2.3

V2IN second fixed voltage monitoring input . . . . . . . . . . . . . . . . . . . . . . . .

7

 

2.4

VSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

 

2.5

V3IN, V4IN, and V5IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

7

 

2.6

 

active-low, open drain reset output

7

 

RST

3

Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

9

3.1 Setting the adjustable voltage levels for V3IN, V4IN, and V5IN inputs . . . . 9 3.2 Power on reset (tREC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4

Voltage monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10

5

Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

11

6

DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

12

7

Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

14

8

Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

16

9

Package marking information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

17

10

Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18

2/19

STM6905

List of tables

 

 

List of tables

Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Table 2. Signal names and functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Table 3. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Table 4. DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Table 5. TSSOP 8-lead package mechanical data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 6. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 7. Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 8. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3/19

List of figures

STM6905

 

 

List of figures

Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 2. MSOP/TSSOP-8 connections. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 3. Functional block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 4. Typical hardware hookup application diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Figure 5. MR timing waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 6. Voltage monitoring diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 7. TSSOP8, 3 x 3mm, package mechanical outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4/19

ST STM6905 User Manual

STM6905

Description

 

 

1 Description

The STM6905 supervisor is a low voltage/low supply current processor supervisor, designed to monitor up to five system power supply voltages. This device is targeted at applications such as set-top boxes (STBs), portable, battery-powered systems, networking and communication systems.

The device supports a push-button type manual reset input (MR). Two of the five supply monitors (VCC and V2IN) have fixed (customer-selectable, factory-trimmed) thresholds

(VRST1 and VRST2). The other three voltage monitor inputs (V3IN, V4IN and V5IN) are monitored using externally adjustable threshold (600 mV internal reference) to meet specific

level requirements.

If any of the five monitored voltages drops below its factory-trimmed or adjustable thresholds, or if the MR is asserted to logic low, the reset output RST is asserted (driven low). Once asserted, RST is maintained Low for a minimum delay period (trec) after ALL monitored supplies rise above their respective thresholds and MR returns to High. Reset output logic state is valid for VCC greater than 0.8 V.

The STM6905 is available in a standard 8-lead MSOP (TSSOP) package.

Figure 1. Logic diagram

VCC

V2IN

V3IN

V4IN

STM6905

RST

V5IN

MR

VSS

ai13970

 

Figure 2. MSOP/TSSOP-8 connections

 

 

 

 

 

 

 

 

 

 

 

 

 

RST

 

MR

1

8

VCC

2

7

V5IN

V2IN

3

6

V4IN

 

VSS

4

5

V3IN

ai13971

5/19

Description

 

 

 

 

 

 

STM6905

 

 

 

 

 

 

 

 

 

 

 

Table 2.

 

 

Signal names and functions

 

 

 

 

 

 

 

Pin

 

Name

Type

Function

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

 

 

Input

Active-low manual reset input with internal pull-up resistor

 

 

MR

 

 

 

 

 

 

 

 

 

 

 

2

 

 

VCC

Supply

Primary supply voltage input and integrated fixed threshold under-

 

 

 

voltage monitor

 

3

 

V2IN

Input

Second fixed threshold input monitor

 

 

 

 

 

 

 

 

4

 

 

VSS

Supply

Ground

 

5

 

V3IN

Input

Adjustable third reset comparator input

 

 

 

 

 

 

 

6

 

V4IN

Input

Adjustable fourth reset comparator input

 

 

 

 

 

 

 

7

 

V5IN

Input

Adjustable fifth reset comparator input

 

 

 

 

 

 

 

 

 

8

 

 

 

 

 

 

Output

Active-low open-drain reset output (10k ohm internal pull-up)

 

RST

 

 

 

 

 

 

 

 

 

 

6/19

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