Datasheet TC1279-5ENB, TC1279-15ENB, TC1279-10ENB, TC1278-5ENB, TC1278-15ENB Datasheet (Microchip Technology)

TC1278/TC1279

3-Pin Reset Monitors for 5V Systems

Features

• PrecisionVCCMonitor for 5.0V System Supplies

• 250msec Minimum RESET Output Duration

• Output Validto V
TransientImmunity

•V

CC

CC

=1.2V

• Small 3-Pin SOT-23BPackage

• No External Components

Applications

• Computers

• Embedded Systems

• Battery Powered Equipment

• Critical µP Power Supply Monitoring

Device Selection Table

Part

Number

TC1278-xENB Open Drain 3-Pin SOT-23B -40°C to +85°C
TC1279-xENB Open Drain 3-Pin SOT-23B -40°C to +85°C

NOTE: “x” denotes a suffix for VCCthreshold (see table below).

Order Package

Suffix Reset VCCThreshold (V)

5 4.625
10 4.375
15 4.125

Temp.

Range

Package Type

General Description

The TC1278/TC1279 are cost-effective system super­visorcircuitsdesigned to monitor V

indigitalsystems

CC

and provide a reset signal to the host processor when
necessary. No external components are required.

The reset output is driven active within 5µsec of V

CC

falling through the reset voltage threshold. RESET is
maintainedactive for a minimum of 250msec after V

CC

rises above the r eset threshold. The TC1278 has an
active-high RESET output while the TC1279 has an
active-low RESET

output, and both devices have an
open drain output stage. The output is valid down to
V

= 1.2V.Both devices are available ina 3-Pin SOT-

CC

23B package.

Typical Operating Circuit

V

CC

2

V

CC

RESET

V

CC

1

Processor

RESET
Input

TC1279

GND GND

3

3-Pin SOT-23B

RESET

NOTE: 3-Pin SOT-23B is equivalent to JEDEC TO-236



2002 Microchip TechnologyInc. DS21384B-page 1

1

TC1278-xENB
TC1279-xENB

V

2

CC

GND

3

TC1278/TC1279

1.0 ELECTRICAL
CHARACTERISTICS

*Stresses above those listed under "Absolute Maximum
Ratings" may cause permanent damage to the device. These
are stress ratings only and functional operation of the device
at these or any other conditions above those indicated in the

Absolute Maximum Ratings*

Supply Voltage (VCCto GND)..............................+6.0V

, RESET...........................-0.3V to (VCC+0.3V)

RESET
Input Current, V

...............................................20mA

CC

operation sections of the specifications is not implied.
Exposure to Absolute Maximum Rating conditions for
extended periods may affectdevice reliability.

Output Current, RESET.......................................20mA

Power Dissipation (T

≤ 70°C)

A

3-Pin SOT-23B (derate 4mW/°C above +70°C)

.................................................................230mW

Operating Temperature Range.............-40°C to +85°C

StorageTemperature Range..............-65°C to +150°C

TC1278/TC1279 ELE CTRI CAL SPECIFICATIONS

Recommended DC Operating Conditions: TA= -40°C to +85°C unless otherwise noted. Typical values are at TA=+25°C.

Symbol Parameter Min Typ Max Units Device Test Conditions

V

CC

DC Electrical Characteristics: T

Symbol Parameter Min Typ Max Units Test Conditions

V

OL

I

OL

I

CC1

I

CC2

V

CCTP-5VCC

V

CCTP-10VCC

V

CCTP-15VCC

C

OUT

R

P

AC Electrical Characteristics: T

Symbol Parameter Min Typ Max Units Test Conditions

t

RST

t

RPD1

t

RPD2

t

F

t

R

t

RPU1

t

RPU2

Note 1: All voltages referenced to ground.

Supply Voltage 1.2 — 5.5 V Note 1

= -40°C to +85°C unless otherwise noted. Typical values are at TA=+25°C.

A

Low Level @ RESET
RESET

— — 0.4 V TC1278

TC1279

Note 1

Output Current @ 0.4 Volts +8 — — mA Note 2
Operating Current —

—

Operating Current —

—

0.9
—

—

0.9

2.040mAµATC1278
TC1279

40

2.0µAmA

TC1278
TC1279

VCC>V
VCC>V

VCC<V
VCC<V

CCTP(MAX)
CCTP(MAX)

CCTP(MIN)
CCTP(MIN)

Trip Point (TC1278/9-5) 4.50 4.625 4.74 V Note 1
Trip Point (TC1278/9-10) 4.25 4.375 4.49 V Note 1

Trip Point (TC1278/9-15) 4.00 4.125 4.24 V Note 1
Output Capacitance — 9 — pF
Internal Pull-Up Resistor 3 6 9 kΩ

= -40°C to +85°C unless otherwise noted. Typical values are at TA=+25°C.

A

RESET Active Time 250 350 450 msec
VCCDetect to RESET —25µsec TC1279 Figure 3-2
VCCDetect to RESET — 2 5 µsec TC1278 Figure 3-4
VCCSlew Rate

300 — — µsec Figure3-2, Figure 3-4

(4.75V-4.00V)
VCCSlew Rate

0 — — nsec Figure3-1,Figure 3-3

(4.00V-4.75V)
VCCDetect to RESET 250 350 450 msec TC1279 Figure 3-1
VCCDetect to RESET 250 350 450 msec TC1278 Figure 3-3

2: A1kΩ external resistor may be required in some applications for proper operation of the microprocessor reset control circuit when using

the TC1279. V

CC

=1.8V.

DS21384B-page 2



2002 Microchip TechnologyInc.

2.0 PIN DESCRIPTIONS

The descriptions of the pins are listed in Table 2-1.

TABLE 2-1: PIN FUNCTION TABLE

TC1278/TC1279

Pin No.

(3-Pin SOT-23B)

1 RESET

1 RESET (TC1278) RESET output remains high while V

2V
3 GND Ground.

Symbol Description

(TC1279) RESET outputremains low while VCCis below the reset voltage threshold,andfor

350msec (250msec min.) after V
TC1279 is open drain.

350msec (250msec min.) after V
TC1278 is open drain.

CC

Supply voltage (1.2V to 5.5V).

rises aboveresetthreshold. The outputstage of the

CC

is below the reset voltage threshold,andfor

CC

rises aboveresetthreshold. The outputstage of the

CC



2002 Microchip TechnologyInc. DS21384B-page 3

TC1278/TC1279

3.0 APPLICATIONS INFORMATION

3.1 Operation – P ow er Monitor

The TC1278/TC1279 provide the function of detecting
out-of-tolerance power supply conditions and war ning
a processor-based system of impending power failure.
When V
signal is asserted. On power-up, RESET is kept active
for approximately 350msec after the power supply has
reached the selected tolerance. This al lows the power
supply and microprocessor to stabilize before RESET
is released.

FIGURE 3-1: Timing Diagram –

V

CC

RESET

is detected as out-of-tolerance, the RESET

CC

Power Up (TC1279)

t

R

4.75V

V

4.00V

CCTP

t

RPU

1

V

OH

FIGURE 3-3: Timing Diagram –

Power Up (TC1278)

t

R

V

CCTP(MAX)

V

CCTP

t

RPU2

V

CC

RESET

V

CCTP(MIN)

FIGURE 3-4: Timing Diagram –

Power Down (TC1278)

t

F

V

CC

4.74V

V

CCTP

4.00V

t

RPD2

V

OL

FIGURE 3-2: Timing Diagram –

Power Dow n (TC1279)

t

F

4.00V

t

RPD1

V

OL

VCC

RESET

4.75V

V

CCTP

RESET

V

OH

RESET SLEWS WITH V

CC

DS21384B-page 4



2002 Microchip TechnologyInc.

TC1278/TC1279

,

5

3

4

0

5

00

000

(

A

C

n

O

e

8/9

3.2 VCCTransient Rejection

The TC1278/TC1279 provides accurate VCCmonitor­ing and reset timing during power-up, power-down,
and brownout/sag conditions, and rejects negative­going transients (glitches) on the power supply line.
Figure 3-5 shows the maximum transient duration vs.
maximum negative excursion (overdrive) for glitch
rejection. Any combination of duration and overdrive
that lays under the curve will not generate a reset
signal. Combinations above the curve are detected as
a brownout or power-down. Transient immunity can be
improvedbyaddingacapacitor in close proximitytothe
V

pin of the TC1278/TC1279.

CC

FIGURE 3-5: MAXIMUM TRANSIENT

DURATION VS.
OVERDRIVE FOR GLITCH
REJECTION AT 25°C

V

CC

CCTP

verdriv

Duratio

TC127

AXIMUM TRANSIENT DURATION

1

RESET COMPARATOR OVERDRIVE

[

V

- V

]

CCTP

CC

(mV)

1



2002 Microchip TechnologyInc. DS21384B-page 5

TC1278/TC1279

4.0 PACKAGING INFORMATION

4.1 Package Marking Information

1

2

& = part number code + temperature range

and voltage

4.2 Taping Form

Component Taping Orientation for 3-Pin SOT-23B (JEDEC TO-236) Devices

Device

Marking

Part Number Code

TC1278-5ENB PA
TC1278-10ENB PB
TC1278-15ENB PC

TC1279-5ENB RA
TC1279-10ENB RB
TC1279-15ENB RC

3

representsyear and 2-month code

4

represents production lot ID code

User Direction of Feed

W

PIN 1

Standard Reel Component Orientation
For TR Suffix Device
(Mark Right Side Up)

Carrier Tape, Number of Components Per Reel and Reel Size

Package Carrier Width (W) Pitch (P) Part Per Full Reel Reel Size

3-Pin SOT-23B 8 mm 4 mm 3000 7 in

P

DS21384B-page 6



2002 Microchip TechnologyInc.

4.3 Package Dimensions

)

)

)

)

)

)

)

)

)

)

)

)

)

)

)

)

)

)

)

)

8

.

3-Pin SOT-23B

TC1278/TC1279

.021 (0.54
.015 (0.37

.040 (1.02
.031 (0.79

.104 (2.64
.083 (2.10

.004 (0.10
.001 (0.02

.024 (0.60
.017 (0.44

.120 (3.05
.105 (2.67

.081 (2.05
.070 (1.78

.055 (1.40
.047 (1.20

MAX

.007 (0.18
.003 (0.08

.010 (0.25
.005 (0.13

Dimensions: inches (mm)



2002 Microchip TechnologyInc. DS21384B-page 7

TC1278/TC1279

NOTES:

DS21384B-page 8



2002 Microchip TechnologyInc.

TC1278/TC1279

Sales and Support

Data Sheets

Products supportedby a preliminary Data Sheet may have an errata sheet describing minor operational differences and recom­mendedworkarounds.To determine if an errata sheet exists for a particulardevice, please contactoneof the following:

1. Your local Microchip sales office

2. The Microchip CorporateLiterature Center U.S. FAX: [phone]

3. The Microchip Worldwide Site (www.microchip.com)
Pleasespecify which device, revision of silicon and Data Sheet (includeLiterature #) you are using.

New Customer Notification System

Register on our web site (www.microchip.com/cn) to receive the most current information on our products.

 2002 Microchip Technology Inc. DS21384B-page9

TC1278/TC1279

NOTES:

DS21384B-page10  2002 Microchip Technology Inc.

TC1278/1279

Information contained in this publication regarding device
applications and the like is intended through suggestion only
and may be superseded by updates. It is your responsibility to
ensure that your application meets with your specifications.
No representation or warranty is given and no liability is
assumed by Microchip Technology Incorporated with respect
to the accuracy or use of such information, or infringement of
patents or other intellectual property rights arising from such
use or otherwise. Use of Microchip’s products as critical com­ponents in life support systems is not authorized except with
express written approval by Microchip. No licenses are con­veyed, implicitly or otherwise, under any intellectual property
rights.

Trademarks

The Microchip name and logo, the Microchip logo, FilterLab,
K

EELOQ,microID,MPLAB,PIC,PICmicro,PICMASTER,

PICSTART, PRO MATE, SEEVAL and The Embedded Control
SolutionsCompany areregiste red trademarksof MicrochipTech­nologyIncorp or ated in the U.S.A. and other countries .

dsPIC, ECONOMONITOR, FanSense, Fle xR OM , fuzzyLAB,
In-Circuit Serial Programming, ICSP, ICEPIC, microPort,
Migratable Memory, MPASM, MPLIB, MPLINK, MPSIM,
MXDEV,MXLAB, PICC, PICDEM, PICDEM.net, rfPIC, Select
Mode and Total Endurance are trademarks of Microchip
TechnologyIncorporated in the U.S.A.

Serialized Quick Turn Programming (SQTP) is a service mark
of Microchip TechnologyIncorporated in t he U.S.A.

All other trademarks mentioned herein are property of their
respective companies.

© 2002, Microchip Technology Incorporated, Printed in the
U.S.A., All Rights Reserve d.

Printed on recycled paper.

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The Company’s quality system processes and
procedures are QS-9000 compliant for its

®

PICmicro
devices, Serial EEPROMs, microperipherals,
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addition, Microchip’s quality system for the
design and manufacture of development
systemsisISO 9001certified.



2002 Microchip TechnologyInc. DS21384B-page 11

8-bit MCUs, KEELOQ®code hopping

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DS21384B-page 12



2002 Microchip Technology Inc.