![](/html/6c/6ca8/6ca82047286f0eb3f035c3ebcba1abb51790addee09cc3928a7fac5ce807fd05/bg1.png)
M
3-Pin Reset Monitors for 5V Systems
TC1272/TC1273/TC1274
Features
• Precision VCC Monitor for 5.0V Systems
• 100 msec Minimum RESET
Duration
• Output Valid to V
Transient Immunity
•V
CC
• Small 3-Pin SOT-23B Package
• No External Components
CC
= 1.2V
, RESET Output
Applications
• Computers
• Embedded Systems
• Battery-Powered Equipment
• Critical µP Power Supply Monitoring
Package Type
3-Pin SOT-23B*
RESET
**(RESET)
* 3-Pin SOT-23B is equivalent to JEDEC TO-236
**( ) is for TC1274
1
TC1272
TC1273
TC1274
V
2
CC
3
GND
General Description
The TC1272/TC1273/TC1274 are cost-effective
system supervisor circuits designed to monitor V
digital systems and provide a reset signal to the host
processor when necessary. No external components
are required.
The reset output is driven active within 20 µsec of V
falling through the reset voltage threshold. RESET is
maintained active for a minimum of 100 msec after
V
rises above the reset threshold. The TC1274 has
CC
an active-high RESET output, while the TC1272 and
TC1273 have an active-low RESET
TC1272 and TC1274 each have a complimentary output, while the TC1273 has an open-drain output. The
output of the TC1272 and TC1273 is valid down to V
= 1.2V. The TC1274 is valid down to VCC = 1.8V. All
three devices are available in a 3-Pin SOT-23B
package.
The TC1272/TC1273/TC1274 devices are optimized to
reject fast transient glitches on the V
output. The
line.
CC
CC
in
CC
CC
Typical Operating Circuit
V
CC
2
V
CC
RESET
1
TC1272
GND GND
3
RESET
Input
Processor
V
CC
2003 Microchip Technology Inc. DS21382B-page 1
![](/html/6c/6ca8/6ca82047286f0eb3f035c3ebcba1abb51790addee09cc3928a7fac5ce807fd05/bg2.png)
TC1272/TC1273/TC1274
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 (VCC to GND) ............................. +6.0V
, RESET.......................... -0.3V to (VCC + 0.3V)
RESET
Input Current, V
Output Current, RESET
Power Dissipation (T
..............................................20 mA
CC
, RESET ........................20 mA
≤ 70°C)
A
operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended
periods may affect device reliability.
3-Pin SOT-23B (derate 4 mW/°C above +70°C)
................................................................ 230 mW
Operating Temperature Range.............-40°C to +85°C
Storage Temperature Range..............-65°C to +150°C
DC CHARACTERISTICS
Electrical Specifications: Unless otherwise noted, TA = -40°C to +85°C. Typical values are at TA = +25°C.
Parameters Sym Min Typ Max Units Conditions
Supply Voltage
TC1272, TC1273 V
TC1274 V
Output Voltage @ 0-500 µA V
CC
CC
OH
Output Current @ 2.4 Volts
= 5V TC1272 I
V
CC
= 4V TC1274 I
V
CC
Output Current @ 0.4 Volts I
OH
OH
OL
Operating Current
< 5.5V: TC1272, TC1274 I
V
CC
< VCC < 5.5V: TC1273 I
V
CCTP
< V
V
CC
Trip Point (TC1272/3/4-5) V
V
CC
Trip Point (TC1272/3/4-10) V
V
CC
Trip Point (TC1272/3/4-15) V
V
CC
: TC1273 I
CCTP
Output Capacitance C
Internal Pull-Up Resistor R
AC Electrical Characteristics: T
RESET Active Time t
Detect to RESET
V
CC
TC1272, TC1273
Detect to RESET - TC1274 t
V
CC
Slew Rate
V
CC
(V
(MAX) to V
CCTP
Slew Rate
V
CC
(V
(MIN) to V
CCTP
Detect to RESET
V
CC
TC1272, TC1273
Detect to RESET - TC1274 t
V
CC
CCTP
CCTP
(MIN))
(MAX))
CC
CC
CC
CCTP-5
CCTP-10
CCTP-15
OUT
P
= -40°C to +85°C unless otherwise noted. Typical values are at TA = +25°C.
A
RST
t
RPD1
RPD2
t
F
t
R
t
RPU1
RPU2
Note 1: All voltages referenced to ground.
2: Measured with V
3: Measured with RESET
4: t
= 5 µsec.
R
5: A 1 kΩ external resistor may be required in some applications for proper operation of the microprocessor reset control
≥ 2.7 volts.
CC
output open for TC1272/TC1273; measured with RESET output open for TC1274.
circuit when using the TC1273.
1.2 — 5.5 V Note 1
1.8 — 5.5 V
VCC – 0.5V VCC – 0.1V — V TC1272, TC1274 (Note 1)
—10—mANote 2
—8—mA
+10 30 — mA Note 2, Note 5
—1740µANote 3
—1740µANote 3
— 700 1200 µA Note 3
4.50 4.62 4.75 V Note 1
4.25 4.37 4.49 V Note 1
4.00 4.12 4.24 V Note 1
—9—pF
369kΩ
100 200 300 msec
—2050µsecV
—2050µsecV
CC(LOW)
CC(LOW)
= 1V, Figure 4-2
= 1V, Figure 4-4
300 — — µsec Figure 4-2, Figure 4-4
0 — — nsec Figure 4-1, Figure 4-3
100 200 300 msec Note 4, Figure 4-1
100 200 300 msec Note 4, Figure 4-3
DS21382B-page 2 2003 Microchip Technology Inc.
![](/html/6c/6ca8/6ca82047286f0eb3f035c3ebcba1abb51790addee09cc3928a7fac5ce807fd05/bg3.png)
TC1272/TC1273/TC1274
2.0 TYPICAL PERFORMANCE CURVES
Note: The graphs and tables provided following this note are a statistical summary based on a limited number of
samples and are provided for informational purposes only. The performance characteristics listed herein
are not tested or guaranteed. In some graphs or tables, the data presented may be outside the specified
operating range (e.g., outside specified power supply range) and therefore outside the warranted range.
Note: Unless otherwise indicated, T
Comparator Overdrive voltage (V
TA = 25°C
sec)
100000
µ
10000
1000
TO RESET DELAY (
100
CC
V
10
1
FIGURE 2-1: V
(RESET
).
VOD = 20mV
VOD = 100mV
VOD = 200mV
10
100
V
SLEW RATE (V/µsec)
CC
Detect to Reset
CC
VOD = 1V
1000
= -40°C to +85°C. Typical values are at TA = +25°C.
A
) is defined in Figure 4-5
OD
300
sec)
µ
200
VOD = 2V
10000
100000
100
TO RESET DELAY (
CC
V
0
0
COMPARATOR OVERDRIVE (V)
FIGURE 2-2: Reset Delays vs.
Comparator Overdrive.
TA = 25°C
12 3
4
5
2003 Microchip Technology Inc. DS21382B-page 3
![](/html/6c/6ca8/6ca82047286f0eb3f035c3ebcba1abb51790addee09cc3928a7fac5ce807fd05/bg4.png)
TC1272/TC1273/TC1274
3.0 PIN DESCRIPTIONS
The descriptions of the pins are listed in Table 3-1.
TABLE 3-1: PIN FUNCTION TABLES
Pin No. Symbol Function
1 RESET
1 RESET RESET Output (TC1274)
2V
3 GND Ground
CC
RESET Output (TC1272 and TC1273)
Supply voltage (1.2V to 5.5V TC1272 and TC1273; 1.8V to 5.5V TC1274)
3.1 RESET Output (RESET)
The RESET output remains low while VCC is below the
reset voltage threshold, and for 200 msec (100 msec
min.) after V
stage of the TC1272 is complimentary, while the output
stage of the TC1273 is open-drain.
rises above reset threshold. The output
CC
3.2 RESET Output (RESET)
The RESET output remains high while VCC is below the
reset voltage threshold, and for 200 msec (100 msec
min.) after V
stage of the TC1274 is complimentary.
rises above reset threshold. The output
CC
DS21382B-page 4 2003 Microchip Technology Inc.