ST STM705, STM706, STM707, STM708, STM813L User Manual

Features

■ 5 V operating voltage

■ Precision V

– STM705/707/813L
–4.50 V
– STM706/708
–4.25

■ RST and RST outputs

■ 200 ms (typ) t

■ Watchdog timer - 1.6 s (typ)

■ Manual reset input (MR)

■ Power-fail comparator (PFI/PFO)

■ Low supply current - 40 µA (typ)

■ Guaranteed RST (RST) assertion down to

V

= 1.0 V

CC

■ Operating temperature: –40 °C to 85 °C

(industrial grade)

■ RoHS compliance

– Lead-free components are compliant with

the RoHS directive

≤

CC

≤

V

monitor

V

≤

RST

≤

RST

rec

4.75 V

4.50 V

STM705, STM706

STM707, STM708, STM813L

5 V supervisor

8

1

SO8 (M)

TSSOP8 3x3 (DS)

1. Contact local ST sales office for availability.

(1)

Table 1. Device summary

Watchdog

input

STM705 ✓✓✓ ✓ ✓

STM706 ✓✓✓ ✓ ✓

STM707 ✓✓ ✓ ✓

STM708 ✓✓ ✓ ✓

STM813L ✓✓ ✓✓ ✓

1. Push-pull output

August 2010 Doc ID 10520 Rev 9 1/33

Watchdog

output

(1)

Active-low

(1)

RST

Active-high

(1)

RST

Manual reset

input

Power-fail

comparator

www.st.com

1

Contents STM705, STM706, STM707, STM708, STM813L

Contents

1 Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2 Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.1 MR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.2 WDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.3 WDO

2.4 RST

2.5 RST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.6 PFI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.7 PFO

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 Reset output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.2 Push-button reset input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.3 Watchdog input (STM705/706/813L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.4 Watchdog output (STM705/706/813L) . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.5 Power-fail input/output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

3.6 Ensuring a valid reset output down to V

3.7 Interfacing to microprocessors with bidirectional reset pins . . . . . . . . . . . 13

= 0 V . . . . . . . . . . . . . . . . . . . 12

CC

4 Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

5 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

6 DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

8 Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

2/33 Doc ID 10520 Rev 9

STM705, STM706, STM707, STM708, STM813L List of tables

List of tables

Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Table 2. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Table 3. Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Table 4. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Table 5. Operating and AC measurement conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Table 6. DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

Table 7. SO8 - 8-lead plastic small outline, 150 mils body width, pack. mech. data . . . . . . . . . . . . 28

Table 8. TSSOP8 - 8-lead, thin shrink small outline, 3 x 3 mm body size, mechanical data . . . . . . 29

Table 9. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Table 10. Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Table 11. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Doc ID 10520 Rev 9 3/33

List of figures STM705, STM706, STM707, STM708, STM813L

List of figures

Figure 1. Logic diagram (STM705/706/813L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 2. Logic diagram (STM707/708) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 3. STM705/706/813L SO8 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 4. STM705/706/813L TSSOP8 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Figure 5. STM707/708 SO8 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 6. STM707/708 TSSOP8 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 7. Block diagram (STM705/706/813L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Figure 8. Block diagram (STM707/708) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 9. Hardware hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figure 10. Reset output valid to ground circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 11. Interfacing to microprocessors with bidirectional reset I/O . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 12. Supply current vs. temperature (no load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Figure 13. V

Figure 14. Reset comparator propagation delay vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 15. Power-up t

Figure 16. Normalized reset threshold vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 17. Watchdog time-out period vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 18. PFI to PFO
Figure 19. Output voltage vs. load current (V
Figure 20. RST

Figure 21. RST output voltage vs. supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Figure 22. RST

Figure 23. RST response time (assertion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 24. Power-fail comparator response time (assertion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 25. Power-fail comparator response time (de-assertion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 26. Maximum transient duration vs. reset threshold overdrive . . . . . . . . . . . . . . . . . . . . . . . . . 21

Figure 27. AC testing input/output waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 28. Power-fail comparator waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 29. MR

Figure 30. Watchdog timing (STM705/706/813L) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Figure 31. SO8 – 8-lead plastic small outline, 150 mils body width, outline . . . . . . . . . . . . . . . . . . . . 28

Figure 32. TSSOP8 – 8-lead, thin shrink small outline, 3 x 3 mm body size, outline . . . . . . . . . . . . . 29

threshold vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

PFI

vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

rec

propagation delay vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

= 5 V; TA = 25 °C) . . . . . . . . . . . . . . . . . . . . . . . . . . 17

output voltage vs. supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

response time (assertion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

timing waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

CC

4/33 Doc ID 10520 Rev 9

STM705, STM706, STM707, STM708, STM813L Description

1 Description

The STM705/706/707/708/813L supervisors are self-contained devices which provide
microprocessor supervisory functions. A precision voltage reference and comparator
monitors the V
occurs, the reset output (RST

These devices also offer a watchdog timer (except for STM707/708) as well as a power-fail
comparator to provide the system with an early warning of impending power failure.

These devices are available in a standard 8-pin SOIC package or a space-saving 8-pin
TSSOP package.

Figure 1. Logic diagram (STM705/706/813L)

input for an out-of-tolerance condition. When an invalid VCC condition

CC

) is forced low (or high in the case of RST).

V

CC

WDO

WDI

MR

PFI

STM705/706;

STM813L

RST

RST

PFO

(1)

(2)

1. For STM705/706 only.

2. For STM813L only.

Figure 2. Logic diagram (STM707/708)

MR

STM707/708

PFI

V

SS

AI08825

V

CC

RST

RST

PFO

V

SS

AI08826

Doc ID 10520 Rev 9 5/33

Description STM705, STM706, STM707, STM708, STM813L

Table 2. Signal names

MR Push-button reset input

WDI Watchdog input

Watchdog output

WDO

RST

Active-low reset output

(1)

RST

Supply voltage

V

CC

Active-high reset output

PFI Power-fail input

PFO Power-fail output

Ground

V

SS

NC No connect

1. For STM813L only.

Figure 3. STM705/706/813L SO8 connections

SO8

MR

V

CC

V

SS

PFI

1

2

3

4

8

7

6

5

WDO

RST (RST)

WDI

PFO

1. For STM813L, reset output is active-high.

Figure 4. STM705/706/813L TSSOP8 connections

TSSOP8

WDO

MR

V

(1)

CC

(RST) RST

1. For STM813L, reset output is active-high.

1

2

3

4

WDI

8

PFO

7

PFI

6

V

5

(1)

AI08827a

SS

AI09114

6/33 Doc ID 10520 Rev 9

STM705, STM706, STM707, STM708, STM813L Description

Figure 5. STM707/708 SO8 connections

SO8

MR

V

CC

V

SS

PFI

1

2

3

4

RST

8

RST

7

NC

6

PFO

5

AI08828a

Figure 6. STM707/708 TSSOP8 connections

TSSOP8

RST

RST

MR

V

CC

1

2

3

4

NC

8

PFO

7

PFI

6

V

5

SS

AI09115

Doc ID 10520 Rev 9 7/33

Pin descriptions STM705, STM706, STM707, STM708, STM813L

2 Pin descriptions

2.1 MR

A logic low on MR asserts the reset output. Reset remains asserted as long as MR is low
and for t
driven from a TTL or CMOS logic line, or shorted to ground with a switch. Leave open if
unused.

2.2 WDI

If WDI remains high or low for 1.6 s, the internal watchdog timer runs out and reset
(or WDO
WDI sees a rising or falling edge.

The watchdog function can be disabled by allowing the WDI pin to float.

2.3 WDO

after MR returns high. This active-low input has an internal pull-up. It can be

rec

) is triggered. The internal watchdog timer clears while reset is asserted or when

It goes low when a transition does not occur on WDI within 1.6 s, and remains low until
a transition occurs on WDI (indicating the watchdog interrupt has been serviced). WDO
goes low when V
goes high as soon as V

Note: For those devices with a WDO

is connected to MR

falls below the reset threshold; however, unlike the reset output, WDO

CC

exceeds the reset threshold. Output type is push-pull.

CC

.

2.4 RST

Pulses low when triggered, and stays low whenever VCC is below the reset threshold or
when MR
threshold, or MR

is a logic low. It remains low for t

goes from low to high.

2.5 RST

Goes high with triggered, and stays high whenever VCC is above the reset threshold or
when MR
or MR

is a logic high. It stays high for t

goes from high to low.

2.6 PFI

also

output, a watchdog timeout will not trigger reset unless WDO

after either VCC rises above the reset

rec

after either VCC falls below the reset threshold,

rec

When PFI is less than V
ground if unused.

8/33 Doc ID 10520 Rev 9

, PFO goes low; otherwise, PFO remains high. Connect to

PFI

STM705, STM706, STM707, STM708, STM813L Pin descriptions

2.7 PFO

When PFI is less than V

, PFO goes low; otherwise, PFO remains high. Leave open if

PFI

unused. Output type is push-pull.

Table 3. Pin description

STM813L

— 7 7 RST

— 6 — NC No connect

Pin

STM707
STM708

STM705
STM706

1 1 1 MR

Name Function

Push-button reset input

6 — 6 WDI Watchdog input

8 — 8 WDO Watchdog output (push-pull)

Active-low reset output

7 8 — RST Active-high reset output

2 2 2 VCC Supply voltage

4 4 4 PFI Power-fail input

5 5 5 PFO Power-fail output (push-pull)

3 3 3 V

Ground

SS

Figure 7. Block diagram (STM705/706/813L)

WDI

V

CC

MR

PFI

1. For STM813L only.

V

CC

WDI

transitional

detector

V

RST

V

PFI

WATCHDOG

TIMER

COMPARE

COMPARE

t

rec

generator

WDO

RST (RST)

PFO

(1)

AI08829

Doc ID 10520 Rev 9 9/33

Pin descriptions STM705, STM706, STM707, STM708, STM813L

Figure 8. Block diagram (STM707/708)

V

CC

MR

V

RST

V

CC

COMPARE

t

rec

generator

RST

RST

PFI

Figure 9. Hardware hookup

Unregulated

voltage

R1

R2

V

CC

COMPARE

0.1 mF

Push-button

V

PFI

Regulator

V

IN

From microprocessor

5 V

V

CC

STM705
STM706
STM707
STM708
STM813L

(1)

WDI

PFI

MR

(1)

WDO

PFO

RST To microprocessor reset

To microprocessor IRQ

To microprocessor NMI

PFO

AI08830

1. For STM705/706/813L.

10/33 Doc ID 10520 Rev 9

AI08831a