SP809EK-L-2-6/TR - Exar Corporation

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February 2011 Rev. 2.0.0

Exar Corporation www.exar.com

48720 Kato Road, Fremont CA 94538, USA Tel. +1 510 668-7000 – Fax. +1 510 668-7001

GENERAL DESCRIPTION

The SP809/SP810 are low power

microprocessor (μP) supervisory circuits used

to monitor power supplies in μP and digital

systems.

They provide applications with benefits of

circuit reliability and low cost by eliminating

external components. If the VCC supply

voltage falls below preset threshold then a

reset signal is asserted for at least 140ms

after V

CC

has risen above the reset threshold.

Both the SP809 and SP810 were designed with

a reset comparator to help identify invalid

signals, which last less than 140ms. The only

difference between them is that they have an

active-low RESET output and active-high

RESET output, respectively. Low supply

current (1μA) makes SP809/SP810 ideal for

portable equipment.

The devices are available in 3 pin SOT-23

package.

Part Number Output Type

SP809N Open Drain Active Low

SP809 Push-Pull Low

SP810 Push-Pull Active High

APPLICATIONS

• Portable Electronic Devices

• Electrical Power Meters

• Digital Still Cameras

• µP Power Monitoring

FEATURES

• Ultra Low Supply Current 1µA (typ)

• Guaranteed Reset valid to V

CC

= 0.9V

• 140ms Power-On Reset Pulse Width

• Internally Fixed Threshold

2.3V, 2.6V, 2.9V, 3.1V, 4.4V, 4.6V

• 1.5% Voltage Threshold Tolerance

• 3 Pin SOT-23 Package

TYPICAL APPLICATION DIAGRAM

Fig. 1: SP809 / SP810 Application Diagram

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ABSOLUTE MAXIMUM RATINGS

These are stress ratings only and functional operation of

the device at these ratings or any other above those

indicated in the operation sections of the specifications

below is not implied. Exposure to absolute maximum

rating conditions for extended periods of time may affect

reliability.

V

CC

.......................................................... -0.3V to 6.5V

RESET, RESET .................................... -0.3V to V

CC

+0.3V

Output Current (RESET, RESET) ............................. 20mA

Power Dissipation (T

A

=70°C) .............................. 320mW

Junction Temperature .......................................... 125°C

Storage Temperature .............................. -65°C to 150°C

OPERATING RATINGS

Input Voltage Range V

CC

................................ 0.9V to 6V

Junction Temperature Range ..................... -40°C to 85°C

ELECTRICAL SPECIFICATIONS

Specifications with standard type are for an Operating Temperature of T

A

= 25°C only; limits applying over the full

Operating Temperature range are denoted by a “•”. Minimum and Maximum limits are guaranteed through test, design, or

statistical correlation. Typical values represent the most likely parametric norm at T

A

= 25°C, and are provided for reference

purposes only. Unless otherwise indicated, T

A

= 25°C.

Parameter Min. Typ. Max. Units Conditions

Operating Voltage Range V

CC

0.9 6.0 V

Supply Current I

CC

1.0 3.0 µA

V

CC

=V

TH

+0.1V

Reset Threshold V

TH

2.265 2.3 2.335

V

T

A

=+25°C

2.254 2.346 • T

A

=-40°C to 85°C

2.561 2.6 2.639 T

A

=+25°C

2.548 2.652 • T

A

=-40°C to 85°C

2.857 2.9 2.944 T

A

=+25°C

2.842 2.958 • T

A

=-40°C to 85°C

3.054 3.1 3.147 T

A

=+25°C

3.038 3.162 • T

A

=-40°C to 85°C

4.334 4.4 4.466 T

A

=+25°C

4.312 4.488 • T

A

=-40°C to 85°C

4.531 4.6 4.669 T

A

=+25°C

4.508 4.692 • T

A

=-40°C to 85°C

V

CC

Reset Delay V

TRIP

20 µs

V

CC

=V

TH

to (V

TH

+ 0.1V), V

TH

=3.1V

Reset Active Timeout Period T

RP

140 230 560 ms T

A

=+25°C

100 1030 • T

A

=-40°C to 85°C

RESET Output Voltage V

OH

0.8V

CC

V V

CC

=V

TH

- 0.1V, I

SOURCE

= 1.2mA

RESET Output Voltage V

OL

0.3 V

CC

=V

TH

+ 0.1V, I

SINK

= 1.2mA

RESET Output Voltage V

OH

0.8V

CC

V V

CC

=V

TH

+ 0.1V, I

SOURCE

= 1.2mA

RESET Output Voltage V

OL

0.3 V

CC

=V

TH

- 0.1V, I

SINK

= 1.2mA

Note 1: RESET output is for SP809; RESET output is for SP810.

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BLOCK DIAGRAM

Fig. 2: SP809 / SP810 Block Diagram

PIN ASSIGNMENT

Fig. 3: SP809 / SP810 Pin Assignment

PIN DESCRIPTION

Name Pin Number Description

GND 1 Ground Signal

RESET

2

Active Low Output Pin.

RESET Output remains high while VCC is below the reset threshold

RESET Active High Output Pin.

RESET Output remains high while VCC is below the reset threshold

V

CC

3 Supply Voltage

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ORDERING INFORMATION

Part Number Temperature

Range Marking Package Packing

Quantity Note 1 Note 2

SP809EK-L-2-3/TR -40°C≤T

A

≤+85°C N4WW

SOT23-3 2.5K/Tape & Reel Lead Free

SP809EK-L-2-6/TR -40°C≤T

A

≤+85°C P4WW

SP809EK-L-2-9/TR -40°C≤T

A

≤+85°C Q4WW

SP809EK-L-3-1/TR -40°C≤T

A

≤+85°C R4WW

SP809EK-L-4-6/TR -40°C≤T

A

≤+85°C U4WW

SP809NEK-L-2-3/TR -40°C≤T

A

≤+85°C V4WW

SP809NEK-L-2-9/TR -40°C≤T

A

≤+85°C X4WW

SP809NEK-L-3-1/TR -40°C≤T

A

≤+85°C Y4WW

SP809NEK-L-4-6/TR -40°C≤T

A

≤+85°C C5WW

SP810EK-L-2-6/TR -40°C≤T

A

≤+85°C E5WW

SP810EK-L-4-4/TR -40°C≤T

A

≤+85°C J5WW

“YY” = Year – “WW” = Work Week – “X” = Lot Number; when applicable.

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TYPICAL PERFORMANCE CHARACTERISTICS

All data taken at T

A

= 25°C, unless otherwise specified - Schematic and BOM from Application Information section of this

datasheet.

Fig. 4: Supply Current versus Temperature

Fig. 5: Power-Down Reset Delay versus Temperature

Fig. 6: Power-Down Reset Delay versus Temperature

Fig. 7: Power-Down Reset Delay versus Temperature

Fig. 8: Normalized Reset Threshold versus Temperature

Fig. 9: Power-Up Reset Time-out versus Temperature

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THEORY OF OPERATION

μP will be activated at a valid reset state.

These μP supervisory circuits assert reset to

prevent code execution errors during power-

up,

power-down, or brownout conditions.

Reset is guaranteed to be a logic low for

V

TH

>V

CC

>0.9V. Once V

CC

exceeded the reset

threshold, an internal timer keeps RESET low

for the reset timeout period; after this

interval,

RESET goes high.

If a brownout condition occurs (V

CC

drops

below the reset threshold), RESET goes low.

Any time V

CC

goes below the reset threshold,

the internal timer resets to zero, and RESET

goes low. The internal timer is activated after

V

CC

returns above the reset threshold, and

RESET remains low for the reset timeout

period.

BENEFIT OF HIGHLY ACCURATE RESET

THRESHOLD

SP809/810 with specified voltage as 5V±10%

or 3V±10% are ideal for systems using a

5V±5% or 3V±5% power supply. The reset is

guaranteed to assert after the power supply

falls below the minimum specified operating

voltage range of the system ICs. The pre-

trimmed thresholds are reducing the range

over which an undesirable reset may occur.

APPLICATION INFORMATION

NEGATIVE GOING V

CC

TRANSIENTS

In addition to issuing a reset to the µP during

power-up, power-down, and brownout

conditions, SP809 series are relatively

resistant to short-duration negative-going V

CC

transient.

ENSURING A VALID RESET OUTPUT DOWN

TO V

CC

=0

When V

CC

falls below 0.9V, SP809 RESET

output no longer sinks current; it becomes an

open circuit. In this case, high-impedance

CMOS logic inputs connecting to RESET can

drift to undetermined voltages. Therefore,

SP809/810 with CMOS is perfect for most

applications of V

CC

down to 0.9V.

However in applications where RESET must be

valid down to 0V, adding a pull-down resistor

to RESET causes any leakage currents to flow

to ground, holding RESET low.

INTERFACING TO µP WITH BIDIRECTIONAL

RESET PINS

The RESET output on the SP809N is open

drain, this device interfaces easily with μPs

that have bidirectional reset pins. Connecting

the μP supervisor's RESET output directly to

the microcontroller's RESET pin with a single

pull-up resistor allows either device to assert

reset.

TEST CIRCUIT

Fig. 10: Test Circuit

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PACKAGE SPECIFICATION

3-PIN SOT23

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REVISION HISTORY

Revision Date Description

2.0.0 Reformat of Datasheet

Correction of package drawing

FOR FURTHER ASSISTANCE

Email: customersupport@exar.com

Exar Technical Documentation: http://www.exar.com/TechDoc/default.aspx?

E

XAR CORPORATION

HEADQUARTERS AND SALES OFFICES

48720 Kato Road

Fremont, CA 94538 – USA

Tel.: +1 (510) 668-7000

Fax: +1 (510) 668-7030

www.exar.com

NOTICE

EXAR Corporation reserves the right to make changes to the products contained in this publication in order to improve

design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any circuits described herein,

conveys no license under any patent or other right, and makes no representation that the circuits are free of patent

infringement. Charts and schedules contained here in are only for illustration purposes and may vary depending upon a

user’s specific application. While the information in this publication has been carefully checked; no responsibility, however,

is assumed for inaccuracies.

EXAR Corporation does not recommend the use of any of its products in life support applications where the failure or

malfunction of the product can reasonably be expected to cause failure of the life support system or to significantly affect its

safety or effectiveness. Products are not authorized for use in such applications unless EXAR Corporation receives, in

writing, assurances to its satisfaction that: (a) the risk of injury or damage has been minimized; (b) the user assumes all

such risks; (c) potential liability of EXAR Corporation is adequately protected under the circumstances.

Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.