Document Outline
- Return to Contents
- List of Figures
- 1. Maximum Transient Duration vs.
- 2. Ensuring RESET Valid to VCC = 0V
- 3. Interfacing to Bidirectional Reset I/O
- Features
- Typical Applications
- Typical Operating Circuit
- Pin Configuration
- General Description
- Ordering Information
- Absolute Maximum Ratings*
- Electrical Characteristics
- Pin Description
- Applications Information
- VCC Transient Rejection
- RESET Signal Integrity During Power-Down
- Processors With Bidirectional I/O Pins
- Typical Characteristics
5-15
TELCOM SEMICONDUCTOR, INC.
7
6
5
4
3
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PRELIMINARY INFORMATION
3-PIN
P RESET MONITORS
FEATURES
s
Precision V
CC
Monitor for 3.0V, 3.3V, 5.0V
Nominal System V Supplies
s
140msec Guaranteed Minimum RESET, RESET
Output Duration
s
RESET Output Guaranteed to V
CC
= 1.0V (TCM809)
s
Low 17
A Supply Current
s
V
CC
Transient Immunity
s
Small SOT-23B-3 Package
s
No External Components
TYPICAL APPLICATIONS
s
Computers
s
Embedded Systems
s
Battery Powered Equipment
s
Critical
P Power Supply Monitoring
GENERAL DESCRIPTION
The TCM809 and TCM810 are cost-effective system
supervisor circuits designed to monitor V
CC
in digital sys-
tems and provide a reset signal to the host processor when
necessary. No external components are required.
The reset output is driven active within 20msec of V
CC
falling through the reset voltage threshold. Reset is main-
tained active for a minimum of 140msec after V
CC
rises
above the reset threshold. The TCM810 has an active-high
reset output while the TCM809 has an active-low reset
output. The output of the TCM809 is guaranteed valid down
to V
CC
= 1V. Both devices are available in a
SOT-23B-3 package.
The TCM809/810 are optimized to reject fast transient
glitches on the V
CC
line. Low supply current of 17
A
(V
CC
= 3.3V) makes these devices suitable for battery
powered applications.
TYPICAL OPERATING CIRCUIT
TCM809
TCM810
ORDERING INFORMATION
Part No.
Package
Temp. Range
TCM809xENB
SOT-23B-3
40
C to +85
C
TCM810xENB
SOT-23B-3
40
C to +85
C
NOTE: The "X" denotes a suffix for V
CC
threshold - see table below.
PIN CONFIGURATION
Suffix
Reset V
CC
Threshold (V)
L
4.63
M
4.38
T
3.08
S
2.93
R
2.63
TCM809
V
CC
V
CC
V
CC
RESET
RESET
INPUT
GND
GND
PROCESSOR
VCC
RESET (RESET)
GND
TCM809xENB
TCM810xENB
1
2
3
*SOT-23B-3
NOTE: *SOT-23B-3 is equivalent to JEDEC (TO-236)
** () is for TCM810
TCM809/810-04 8/29/96
5-16
TELCOM SEMICONDUCTOR, INC.
PRELIMINARY INFORMATION
3-PIN
P RESET MONITORS
TCM809
TCM810
ABSOLUTE MAXIMUM RATINGS*
Supply Voltage (V
CC
to GND) ................................ +6.0V
RESET, RESET ............................ 0.3V to (V
CC
+ 0.3V)
Input Current, V
CC
.. .................................................. 20mA
Output Current, RESET, RESET ............................. 20mA
dV/dt (V
CC
) .......................................................... 100V/
S
Operating Temperature Range ............... 40
C to +85
C
Power Dissipation (T
A
70
C)
SOT-23B-3 (derate 4mW/
C above +70
C) ... 230mW
Storage Temperature Range ................ 65
C to +150
C
Lead Temperature (Soldering, 10 sec) ................. +260
C
*This is a stress rating only and functional operation of the device at these
or any other conditions above those indicated in the operational sections of
the specifications is not implied. Exposure to Absolute Maximum Rating
Conditions for extended periods may affect device reliability.
ELECTRICAL CHARACTERISTICS:
V
cc
= 5V, T
A
= Operating Temperature Range unless otherwise noted.
Symbol Parameter
Test Conditions
Min
Typ
Max
Unit
V
CC
Range
T
A
= 0
C to +70
C
1.0
--
5.5
V
T
A
= 40
C to +85
C
1.2
--
5.5
I
CC
Supply Current
TCM8xxL/M: V
CC
< 5.5V
--
24
60
A
TCM8xxR/S/T: V
CC
< 3.6V
--
17
50
V
TH
Reset Threshold
(Note 2)
TCM8xxL: T
A
= +25
C
4.56
4.63
4.70
V
T
A
= 40
C to +85
C
4.50
--
4.75
TCM8xxM: T
A
= +25
C
4.31
4.38
4.45
T
A
= 40
C to +85
C
4.25
--
4.50
TCM8xxT: T
A
= +25
C
3.04
3.08
3.11
T
A
= 40
C to +85
C
3.00
--
3.15
TCM8xxS: T
A
= +25
C
2.89
2.93
2.96
T
A
= 40
C to +85
C
2.85
--
3.00
TCM8xxR: T
A
= +25
C
2.59
2.63
2.66
T
A
= 40
C to +85
C
2.55
--
2.70
Reset Threshold Tempco
--
30
--
ppm/
C
V
CC
to Reset Delay
(Note 2)
V
CC
= V
TH
to (V
TH
100mV)
--
20
--
sec
Reset Active Timeout Period
140
240
560
msec
V
OL
RESET Output Voltage Low
TCM809R/S/T: V
CC
= V
TH
min, I
SINK
= 1.2mA
--
--
0.3
V
(TCM809)
TCM809L/M: V
CC
= V
TH
min, I
SINK
= 3.2mA
--
--
0.4
V
CC
> 1.0V, I
SINK
= 50
A
--
--
0.3
V
OH
RESET Output Voltage High
TCM809R/S/T: V
CC
> V
TH
max, I
SOURCE
= 500
A
0.8 V
CC
--
--
V
(TCM809)
TCM809L/M: V
CC
> V
TH
max, I
SOURCE
= 800
A
V
CC
1.5
--
--
V
OL
RESET Output Voltage Low
TCM810R/S/T: V
CC
= V
TH
max, I
SINK
= 1.2mA
--
--
0.3
V
(TCM810)
TCM810L/M: V
CC
= V
TH
max, I
SINK
= 3.2mA
--
--
0.4
V
OH
RESET Output Voltage High
1.8 < V
CC
< VTH min, I
SOURCE
= 150
A
0.8 V
CC
--
--
V
(TCM810)
NOTES:
1. Production testing done at T
A
= +25
C, over temperature limits guaranteed by design.
2. RESET output for TCM809, RESET Output for TCM810.
PIN DESCRIPTION
Pin No.
(SOT-23B-3)
Symbol
Description
1
GND
Ground
2
RESET (TCM809)
RESET output remains low while V
CC
is below the reset voltage threshold, and
for 240msec (140msec min.) after V
CC
rises above reset threshold.
2
RESET (TCM810)
RESET output remains high while V
CC
is below the reset voltage threshold,
and for 240msec (140msec min.) after V
CC
rises above reset threshold.
3
V
CC
Supply voltage (Typ. +3.0V to +5.0V)
5-17
TELCOM SEMICONDUCTOR, INC.
7
6
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4
3
1
2
8
PRELIMINARY INFORMATION
TCM809
TCM810
3-PIN
P RESET MONITORS
valid to V
CC
= 0V, a pull-down resistor must be connected
from RESET to ground to discharge stray capacitances and
hold the output low (Figure 2). This resistor value, though
not critical, should be chosen such that it does not apprecia-
bly load RESET under normal operation (100k
will be
suitable for most applications). Similarly, a pull-up resistor to
V
CC
is required for the TCM810 to ensure a valid high
RESET for V
CC
below 1.0V.
Processors With Bidirectional I/O Pins
Some
P's (such as Motorola 68HC11) have bidirec-
tional reset pins. Depending on the current drive capability
of the processor pin, an indeterminate logic level may result
if there is a logic conflict. This can be avoided by adding a
4.7k resistor in series with the output of the TCM809/810
(Figure 3). If there are other components in the system
which require a reset signal, they should be buffered so as
not to load the reset line. If the other components are
required to follow the reset I/O of the
P, the buffer should
be connected as shown with the solid line.
APPLICATIONS INFORMATION
V
CC
Transient Rejection
The TCM809/810 provides accurate V
CC
monitoring
and reset timing during power-up, power-down, and brown-
out/sag conditions, and rejects negative-going transients
(glitches) on the power supply line. Figure 1 shows the
maximum transient duration vs. maximum negative excur-
sion (overdrive) for glitch rejection. Any combination of
duration and overdrive which lies 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 improved by adding a capacitor in close proximity to
the V
CC
pin of the TCM809/810.
RESET Signal Integrity During Power-Down
The TCM809 RESET output is valid to V
CC
= 1.0V.
Below this voltage the output becomes an "open circuit" and
does not sink current. This means CMOS logic inputs to the
P will be floating at an undetermined voltage. Most digital
systems are completely shutdown well above this voltage.
However, in situations where RESET must be maintained
Figure 2. Ensuring RESET Valid to V
CC
= 0V
Figure 1. Maximum Transient Duration vs.
Overdrive for Glitch Rejection at 25
C
Figure 3. Interfacing to Bidirectional Reset I/O
RESET COMPARATOR OVERDRIVE,
(VTH - VCC (mV)
400
240
160
320
80
0
1
10
100
1000
MAXIMUM TRANSIENT DURATION (
sec)
T
A
= +25
C
V
TH
Duration
Overdrive
V
CC
TCM8xxLM
TCM8xxR/S/T
TCM809
V
CC
V
CC
R1
100k
RESET
GND
TCM809
V
CC
RESET
GND
RESET
GND
BUFFERED RESET
TO OTHER SYSTEM
COMPONENTS
BUFFER
P
4.7k
V
CC
V
CC
5-18
TELCOM SEMICONDUCTOR, INC.
PRELIMINARY INFORMATION
TYPICAL CHARACTERISTICS
TEMPERATURE (
C)
20
25
30
35
15
10
5
0
20
25
30
15
10
5
0
40
0
20
20
40
60
85
SUPPLY CURRENT (
A)
Supply Current vs.Temperature
(No Load, TCM8xxR/S/T)
VCC = 5V
VCC = 3V
VCC = 1V
TEMPERATURE (
C)
60
80
100
40
20
0
40
0
20
20
40
60
85
POWER-DOWN RESET DELAY (
sec)
Power-Down Reset Delay vs. Temperature
(TCM8xxR/S/T)
VOD = VTH VCC
VOD = 10mV
VOD = 20mV
VOD = 100mV
VOD = 200mV
TEMPERATURE (
C)
40
0
20
20
40
60
85
SUPPLY CURRENT (
A)
Supply Current vs.Temperature
(No Load, TCM8xxL/M)
VCC = 5V
VCC = 3V
VCC = 1V
1.001
1.002
1.003
1.000
0.999
0.998
0.997
TEMPERATURE (
C)
40
0
20
20
40
60
85
NORMALIZED THRESHOLD
Normalized Reset Threshold vs. Temperature
TEMPERATURE (
C)
240
245
250
235
230
225
40
0
20
20
40
60
85
POWER-UP RESET TIMEOUT (msec)
Power-Up Reset Timeout vs. Temperature
TCM8xxL/M
TCM8xxR/S/T
TEMPERATURE (
C)
100
120
140
80
60
40
20
0
40
0
20
20
40
60
85
POWER-DOWN RESET DELAY (
sec)
Power-Down Reset Delay vs. Temperature
(TCM8xxL/M)
VOD = VTH VCC
VOD = 10mV
VOD = 20mV
VOD = 100mV
VOD = 200mV
TCM809
TCM810
3-PIN
P RESET MONITORS
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