ST STM1810, STM1811, STM1812, STM1813, STM1815 User Manual

STM1810 STM1811 STM1812 STM1813 STM1815 STM1816 STM1817 STM1818

Low power reset circuit

Features

■Precision monitoring of 3 V, 3.3 V, and 5 V supply voltages

■Four output configurations:

– Push-pull, active-high (STM1812,1817)

– Push-pull, active-low (STM1810,1815)

– Open-drain, active-low (STM1811,1816)

–Open-drain, active-low with push-button detect (STM1813,1818)

■ Reset pulse width - 100 ms (min.)

SOT23-3 (WX)

■Low supply current - 4 µA (typ.)

■Guaranteed assertion down to VCC = 1.0 V (0 °C to 105 °C)

■Factory-trimmed reset thresholds of 2.55 V, 2.88 V, 3.06 V, 4.37 V, and 4.62 V (typ.)

■Power supply transient immunity

■Push-button/manual reset detect (STM1813/1818)

■Operating temperature: –40 °C to 105 °C

Table 1. Device summary

■± 2.5% reset threshold accuracy: (–40 °C to 105 °C)

■Available in the SOT23-3 package

■Fully compatible with DS181x and MXD181x products.

		3.3 V/	Active-low	Active-low	Active-high	Active-low reset
Order codes	5 V		reset	reset	reset	(open-drain,
		3.0 V
			(push-pull)	(open-drain)	(push-pull)	bidirectional, with MR detect)
STM1810L/M
STM1811L/M				(1)
STM1812L/M
STM1813L/M
STM1815T/S/R
STM1816T/S/R				(1)
STM1817T/S/R
STM1818T/S/R

1. Active-low RST with internal pull-up resistor.

September 2010

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Contents	STM1810/1811/1812/1813/1815/1816/1817/1818

Contents

1	Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		5
	1.1	Functional block diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
	1.2	Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7

1.2.1 Active-low RST output (push-pull) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2.2 Active-low RST output (open-drain) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.2.3 Active-high RST output (push-pull) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.2.4Active-low RST output (open-drain with internal 5.5 kΩ pull-up) with

manual reset detect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.2.5 VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

1.2.6 VSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8

2	Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				. 9
	2.1	Reset output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			9
	2.2	Push-button detect reset (STM1813/1818) . . . . . . . . . . . . . . . . . . . . . . . .			9
	2.3	Interfacing to bidirectional microcontrollers (MCU’s) . . . . . . . . . . . . . . . . .			9
	2.4	Negative going VCC transients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			9
	2.5	Valid		output down to VCC = 0 V	10
			RST
3	Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				13
4	Maximum rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				17
5	DC and AC parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				18
6	Package mechanical . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				20
	6.1	ECOPACK® . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .			20
7	Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				22
8	Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .				24

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STM1810/1811/1812/1813/1815/1816/1817/1818	List of tables

List of tables

Table 1. Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Table 2. Signal names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Table 3. STM1810/STM1815 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Table 4. STM1811/STM1816 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Table 5. STM1812/STM1817 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Table 6. STM1813/STM1818 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Table 7. Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 8. Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Table 9. DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Table 10. SOT23-3 – 3-lead small outline transistor package mechanical data. . . . . . . . . . . . . . . . . 21 Table 11. Ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Table 12. Marking description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Table 13. Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

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List of figures	STM1810/1811/1812/1813/1815/1816/1817/1818

List of figures

Figure 1. Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Figure 2. SOT23-3 connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 3. Hardware hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Figure 4. Push-pull active-low output (STM1810/1812/1815/1817). . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 5. Open-drain, active-low output (STM1811/1816). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Figure 6. Open-drain, active-low output (bidirectional, manual reset detect, STM1813/1818) . . . . . . 7 Figure 7. Reset timing diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 8. Push-button manual reset with MR detect (STM1813/1818) . . . . . . . . . . . . . . . . . . . . . . . 10 Figure 9. Manual reset timing diagram, switch bounce/debounce (STM1813/1818). . . . . . . . . . . . . 11 Figure 10. Interfacing MCUs with bidirectional reset pins (RST, open-drain, STM1811/1816) . . . . . . 11

Figure 11. Valid reset (RST) output down to VCC = 0 V (push-pull). . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Figure 12. Valid reset (RST) output down to VCC = 0 V (push-pull). . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Figure 13. Supply current vs. temperature (no load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Figure 14. Normalized reset time-out period (trec) vs. temperature - VOD = VTH – VCC . . . . . . . . . . . 13 Figure 15. VCC-to-reset output delay vs. temperature - VOD = VTH – VCC . . . . . . . . . . . . . . . . . . . . . 14 Figure 16. Voltage output low vs. ISINK . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Figure 17. Voltage output high vs. ISOURCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 18. Normalized reset threshold vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Figure 19. Max. transient duration NOT causing reset pulse vs. reset threshold overdrive. . . . . . . . . 16 Figure 20. AC testing input/output waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 21. SOT23-3 – 3-lead small outline transistor package outline . . . . . . . . . . . . . . . . . . . . . . . . 20

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STM1810/1811/1812/1813/1815/1816/1817/1818	Description

1 Description

STM181x devices are low power reset devices used to monitor power supplies for microcontrollers. They perform a single function: asserting a reset signal whenever VCC supply voltage drops below a preset value and keeping it asserted until VCC has risen above the preset threshold for a minimum period of time (trec). They provide excellent circuit reliability without additional external components when used with +3.0 V / +3.3 V (STM1815–STM1818), and +5 V (STM1810–STM1813) power supply systems.

A precision voltage reference and comparator monitors the VCC input for an out-of-tolerance

condition. When an invalid VCC condition occurs, the reset output (RST) is forced low (or high in the case of RST) and remains asserted for trec after VCC rises above the reset threshold. The STM1813/1818 also keep reset asserted for trec after the output is momentarily pulled to ground by an external push-button switch.

The STM1812 and STM1817 have an active-high, push-pull output. The STM1810 and STM1815 (push-pull) and STM1811, STM1813, STM1816, and STM1818 (open-drain) have an active-low RST output. The open-drain devices (STM1811 / STM1813 / STM1816 / STM1818) also have an internal pull-up resistor to VCC. The STM1813 and STM1818

feature a debounced manual reset feature that asserts a reset if the RST pin is pulled low for more than 1.5 µs. When used to initiate manual reset, RST debounces signals from devices such as mechanical switches. For devices with this feature, the release of the external switch triggers the reset period.

The STM181x devices are guaranteed to output the correct logic state for VCC down to 1.0 V (0 °C to +105 °C). They also provide a reset comparator designed to ignore fast transients on VCC.

Reset thresholds are available between +2.55 V and +4.62 V. These small, low power devices are ideal for use in portable equipment. All are available in the space-saving 3-pin SOT23 package, and are specified from –40 °C to +105 °C.

Figure 1. Logic diagram

6##

34-X			2343 234

633

!)

1. For STM1812, STM1817.

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Description							STM1810/1811/1812/1813/1815/1816/1817/1818
	Table 2.	Signal names
	Symbol						Description
	VSS	Ground
	RST	Active-low reset output
	RST(1)	Active-high reset output
	VCC	Supply voltage and input for reset threshold monitor
	1. For STM1812, STM1817.
	Figure 2.	SOT23-3 connections
		2343 234							633
		6##
								!)

2. RST for STM1812 and STM1817.

Figure 3. Hardware hookup

6##

6##

6##

34- X

-#5

2ESET

234

)NPUT

0USH BUTTON

633

RESET

633

!) A

1.RST for STM1812 and STM1817 (see Table 1).

2.Only valid for STM1813 and STM1818.

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STM1810/1811/1812/1813/1815/1816/1817/1818	Description

1.1Functional block diagrams

Figure 4. Push-pull active-low output (STM1810/1812/1815/1817)

6##	6234	#/-0!2%	TREC	234
			GENERATOR
				!) A

1. RST for STM1812 and STM1817.

Figure 5. Open-drain, active-low output (STM1811/1816)

	6##	6234	#/-0!2%	TREC	234
				GENERATOR
					!)
1.	5.5 kΩ internal pull-up resistor.

Figure 6. Open-drain, active-low output (bidirectional, manual reset detect,

		STM1813/1818)
				0USH BUTTON
				DETECT	234
	6##
		6234	#/-0!2%	TREC
				GENERATOR
					!)
1.	5.5 kΩ internal pull-up resistor.

1.2Pin descriptions

See Figure 1 and Table 2 for a brief overview of the signals connected to this device.

1.2.1Active-low RST output (push-pull)

Pulses low when VCC drops below VRST, and stays low as long as VCC is below the reset threshold. It remains low for trec after VCC rises above the reset threshold.

1.2.2Active-low RST output (open-drain)

Pulses low when VCC drops below VRST, and stays low as long as VCC is below the reset threshold. It remains low for trec after VCC rises above the reset threshold. RST output has

an internal 5.5 kΩ pull-up resistor.

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Description	STM1810/1811/1812/1813/1815/1816/1817/1818

1.2.3Active-high RST output (push-pull)

Pulses high when VCC drops below VRST, and stays high as long as VCC is below the reset threshold. It remains high for trec after VCC rises above the reset threshold.

1.2.4Active-low RST output (open-drain with internal 5.5 kΩ pull-up) with manual reset detect

Pulses low when VCC drops below VRST, or RST is externally pulled low for at least 1.5 µs. It remains low for tPBRST after VCC rises above the reset threshold, or after the external manual reset is released (see Figure 9). RST output has an internal 5.5 kΩ pull-up resistor.

1.2.5VCC

Supply voltage and input for VRST comparator.

1.2.6VSS

Ground, is the reference for the power supply. It must be connected to the system ground.

Table 3.			STM1810/STM1815
Pin		Name			Function
1					Active-low reset output (push-pull)
			RST
2			VCC		Supply voltage and input for reset threshold monitor
3			VSS		Ground

Table 4.			STM1811/STM1816
Pin		Name			Function
1					Active-low reset output (open-drain, with internal 5.5 kΩ pull-up resistor)
			RST
2			VCC		Supply voltage and input for reset threshold monitor
3			VSS		Ground

Table 5.	STM1812/STM1817
Pin	Name	Function
1	RST	Active-high reset output (push-pull)
2	VCC	Supply voltage and input for reset threshold monitor
3	VSS	Ground

Table 6.		STM1813/STM1818
Pin	Name			Function
1				Active-low reset output (open-drain, with internal 5.5 kΩ pull-up) with push-
		RST
				button/manual reset detect
2		VCC		Supply voltage and input for reset threshold monitor
3		VSS		Ground

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