TS824CX5DRF - Taiwan Semiconductor Co., Ltd.

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

1/8 Version: C07

SOT-25

General Description

The TS823/824/825 family allows the user to customize the CPU monitoring function without any external

components. The user has a large choice of reset voltage thresholds and output driver configurations, all of which are

present ant the factory. Each wafer is trimmed to the customer’s specifications.

These circuits will ignore fast negative going transients on Vdd. The state of the reset output is guaranteed to be

correct down to 1V. After Vdd crosses above a factory present threshold, the TS823/824/825 assert a reset signal.

After a predetermined time (the “reset” interval) the reset is deasserted. If Vdd ever drops below the threshold voltage

a reset is asserted immediately. In addition to a supply monitoring function the TS823/824/825 also monitor transitions

at the watchdog (WDI) input. If a logic transition does not occur at the WDI pin within a certain time interval (the

“watchdog” interval) then a reset is asserted. The reset deasserts after the reset interval, as explained earlier.

The TS823/824/825 can both assert a reset manually by pulling the MR input to ground, and the micro-power

quiescent current make this family a natural for portable battery powered equipment.

Ordering Information

Note: x is the threshold voltage type, option as

A

: 4.63V

B

: 4.38V

D

: 3.08V

E

: 2.93V

F

: 2.63V

G

: 2.32V

H

: 2.19V

Contact factory for additional voltage option

Part No.

Package

Packing

TS823CX5x RF

SOT-25

3Kpcs / 7” Reel

TS824CX5x RF

SOT-25

3Kpcs / 7” Reel

TS825CX5x RF

SOT-25

3Kpcs / 7” Reel

Features

● Precision monitoring of +3V, +3.3V and +5V power

supply voltage

● Tight voltage threshold tolerance +/-1.5%

● Fully specified over temperature

● 210mS min. power-on reset pulse width

● 3uA(typ) supply current

● Guaranteed reset valid to Vdd = +1V

● Power supply transient immunity

● No external components

Applications

● Computers and Controllers

● Embedded Controllers

● Intelligent instruments

● Critical uP monitoring

● Portable / Battery powered equipment

● Automotive Systems

Pin Descriptions

Function

TS823

TS824

TS825

RESET (Active-Low)

1

Ground

2

Manual Reset

3

-

4

(RESET) (Active-High)

-

3

Watchdog Input

4

-

Supply Voltage (Vdd)

5

Absolute Maximum Rating

Parameter

Symbol

Maximum

Unit

Supply Voltage

Vdd

6.0

V

Supply Voltage - Recommended

Vdd

0.9 ~ 5

V

Operating Junction Temperature Range

TOP

-40 ~ +125

oC

Storage Temperature Range

TSTG

-65 ~ +150

oC

Thermal Resistance

Θjc

256

oC/W

Maximum Lead Temperature (260oC)

TLEAD

10

S

Notes: Stress above the listed absolute rating may cause permanent damage to the device.

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

2/8 Version: C07

Electrical Specifications (Ta = 25oC, unless otherwise noted)

Parameter

Conditions

Symbol

Min

Typ

Max

Unit

Input Supply Voltage

Vdd

1.0

--

5.5

V

Supply Current

WDI and MRB unconnected

Idd

--

3

10

uA

TS823/824/825CX5A

4.56

4.63

4.7

TS823/824/825CX5B

4.31

4.38

4.45

TS823/824/825CX5D

3.03

3.08

3.13

TS823/824/825CX5E

2.89

2.93

2.97

TS823/824/825CX5F

2.59

2.63

2.67

TS823/824/825CX5G

2.28

2.32

2.36

Reset Threshold

TS823/824/825CX5H

VTH

2.15

2.19

2.23

V

RESET Output Voltage Low

Vdd<VTH(MIN), ISINK =1.2mA,

VOL

--

0.5

V

(RESET) Output Voltage High

Vdd>VTH(MAX), ISOURCE=0.5mA

VOH

0.8 Vdd

--

V

Vdd to Reset Delay

Vdd =VTH - 100mV

TD1

--

40

--

uS

Reset Active Timeout Period

Ta=-40oC ~+85oC

TD2

140

210

280

mS

Watchdog Timeout Period

TWD

1120

1760

2400

mS

WDI Pulse Width

TWDI

50

--

nS

WDIIL

--

0.7

V

WDI Input Threshold

Vdd = VTH x 1.2

WDIIH

0.8 Vdd

--

V

WDI =0V

IIL

-15

-8

0.7

uA

WDI Input Current

WDI =Vdd = 5V

IIH

--

8

15

uA

MRIL

--

0.7

V

MR Input Threshold

Vdd=VTH x 1.2

MRIH

0.8 Vdd

--

V

MR Pulse Width

TWMR

1

--

uS

MR Noise Immunity

Pulse width with no reset

--

100

--

nS

MR to Reset Delay

Vdd = VTH - 100mV

TDMR

--

500

--

nS

MR Pull Up Resistance

80

--

120

KΩ

Input Supply Voltage

Ta=-40oC~+85oC

VCC

1.0

--

5.5

V

Detail Description

Pin Function

Pin Name

Pin Description

Reset

Active Low

GND

Ground

(Reset)

Active High

MR

This pin is active low. Pulling this pin low to forces a reset. After a low to high transition reset remains

asserted for exactly one reset timeout period. This pin is internally pulled high. If this function is unused

then float this pin or tie it to Vdd.

WDI

Watch Dog Input. Any transition on this pin will reset the Watch Dog timer. If this pin remains high or

low for longer than the Watch Dog interval then a reset is asserted. Float or tri-state this pin to disable

the Watch Dog feature.

Vdd

Positive power supply. A reset is asserted after this voltage drops below a predetermined level. After

Vdd rises above that level reset remains asserted until the end of the reset timeout period.

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

3/8 Version: C07

Application Information

The TS823/824/825 are designed to interface with the reset input of a microprocessor and to prevent CPU execution

errors due to power up, power down, and other power supply errors. The TS823/824 also monitor the CPU health by

checking for signal transitions form the CPU at the WDI input.

Reset Output

Active low reset outputs are denoted as RESET, Active high reset output are denoted as (RESET),

A reset will be asserted if any of three things happen:

1. Vdd drops below the threshold (Vth)

2. The MR pin is pulled low.

3. The WDI pin does not detect a transition within the Watch Dog interval (TWD)

The reset will remain asserted for the prescribed reset interval after:

1. Vdd rises above the threshold (Vth)

2. MR goes high

3. The Watch Dog timer have timed out causing the reset to assert.

Manual Reset Input

The TS823 and TS825 feature a manual reset feature (MR). A logic low on the MR pin asserts a reset. The reset

remains asserted a long as the MR pin remains low. After the MR pin transitions to a high state the reset remains

asserted for the prescribed reset interval (TD2). The MR pin is internally pulled up to Vdd by a 100KΩ resistor. It is

internally de-bounced to reject switching transients.

The MR pin is ESD protected by diodes connected to Vdd and Gnd. So the MR pin should never be driven higher than

Vdd or lower than Gnd.

Watchdog Input

The TS823 and TS824 are equipped with a watchdog input (WDI). If the microprocessor does not produce a valid logic

edge at the watchdog input (WDI) within the prescribed watchdog interval (TWD) then a reset asserts. The reset

remains asserted for the required reset interval (TD2). Ata the end of the reset interval the reset is deasserted and the

watchdog interval timer starts again from zero.

If the watchdog input is left unconnected or is connected to a tri-stated buffer the watchdog function is disabled. As

soon as the WDI input is driven either low or high the watchdog function resumes with the watchdog timer set to zero.

Watchdog Input Current

The watchdog input pin (WDI) typically sources/sinks 8uA when driven high or low. So from a power dissipation point

of view the duty cycle of the waveform at WDI is unimportant. When the WDI pin is floating or tri-stated the power

supply current fall to less than 3uA.

Glitch Rejection

The TS823/824/825 family will reject negative going transients on the Vdd line to some extent. The smaller the

duration of the transient the larger its amplitude may be without triggering a reset. The “Glitch Rejection” chart in the

graphs section of this datasheet shows the relation between glitch amplitude and allowable glitch duration to avoid

unintended resets.

Accurate Output State at Low Vdd

With Vdd voltage on the order of the MOS transistor threshold (<1V) the outputs of the TS823/824/825 may become

undefined. For parts with active low output RESET a resistor placed between RESET and Gnd on the order of 100KΩ

will ensure that the RESET output stays low when Vdd is lower than the threshold voltage of the part. In a like manner

a resistor on the order of 100KΩ when placed between (RESET) and Vdd will ensure parts with active high output

(RESET) will remain high when Vdd is lower than the threshold voltage of the parts.

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

4/8 Version: C07

Reset Timing Diagram

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

5/8 Version: C07

Electrical Characteristics Curve

Figure 1. Glitch Rejection

Figure 2. Reset Time vs. Temperature

Figure 3. Iin vs. Temperature

Figure 4. Reset Vth vs. Temperature

Figure 5. Reset VOL vs. Temperature

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

6/8 Version: C07

Marking Information

Part No.

Identification

Code

Part No.

Identification

Code

Part No.

Identification

Code

TS823CX5A

BAC

TS824CX5A

BAD

TS825CX5A

BAE

TS823CX5B

--

TS824CX5B

ATW

TS825CX5B

--

TS823CX5D

ASM

TS824CX5D

ATL

TS825CX5D

ATN

TS823CX5E

ATX

TS824CX5E

ATV

TS825CX5E

AUS

TS823CX5F

ATG

TS824CX5F

ATC

TS825CX5F

AWW

TS823CX5G

BCW

TS824CX5G

--

TS825CX5G

--

Year Code definition

Identification

Code

Week Code

Year

X

W

xxx0

X

W

xxx1

X

W

xxx2

X

W

xxx3

X

W

xxx4

X

W

xxx5

X

W

xxx6

X

W

xxx7

X

W

xxx8

X

W

xxx9

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

7/8 Version: C07

SOT-25 Mechanical Drawing

SOT-25 DIMENSION

MILLIMETERS

INCHES

DIM

MIN

MAX

MIN

MAX.

A+A1

0.09

1.25

0.0354

0.0492

B

0.30

0.50

0.0118

0.0197

C

0.09

0.25

0.0035

0.0098

D

2.70

3.10

0.1063

0.1220

E

1.40

1.80

0.0551

0.0709

E

1.90 BSC

0.0748 BSC

H

2.40

3.00

0.09449

0.1181

L

0.35 BSC

0.0138 BSC

Ө1

0º

10º

0º

10º

S1

0.95 BSC

0.0374 BSC

TS823/824/825 Series

Microprocessor Supervisory Circuit

with Watchdog Timer & Manual Reset

8/8 Version: C07

Notice

Specifications of the products displayed herein are subject to change without notice. TSC or anyone on its behalf,

assumes no responsibility or liability for any errors or inaccuracies.

Information contained herein is intended to provide a product description only. No license, express or implied, to any

intellectual property rights is granted by this document. Except as provided in TSC’s terms and conditions of sale for

such products, TSC assumes no liability whatsoever, and disclaims any express or implied warranty, relating to sale

and/or use of TSC products including liability or warranties relating to fitness for a particular purpose, merchantability,

or infringement of any patent, copyright, or other intellectual property right.

The products shown herein are not designed for use in medical, life-saving, or life-sustaining applications. Customers

using or selling these products for use in such applications do so at their own risk and agree to fully indemnify TSC for

any damages resulting from such improper use or sale.