Order this document by MC34064/D
Undervoltage Sensing Circuit
The MC34064 is an undervoltage sensing circuit specifically designed for
use as a reset controller in microprocessor-based systems. It offers the
designer an economical solution for low voltage detection with a single
external resistor. The MC34064 features a trimmed-in-package bandgap
reference, and a comparator with precise thresholds and built-in hysteresis
to prevent erratic reset operation. The open collector reset output is capable
of sinking in excess of 10 mA, and operation is guaranteed down to 1.0 V
input with low standby current. These devices are packaged in 3-pin
TO-226AA, 8-pin SO–8 and Micro–8 surface mount packages.
Applications include direct monitoring of the 5.0 V MPU/logic power
supply used in appliance, automotive, consumer and industrial equipment.
•
Trimmed-In-Package Temperature Compensated Reference
MC34064
MC33064
UNDERVOLTAGE
SENSING CIRCUIT
SEMICONDUCTOR
TECHNICAL DATA
•
•
•
•
•
•
•
•
Comparator Threshold of 4.6 V at 25°C
Precise Comparator Thresholds Guaranteed Over Temperature
Comparator Hysteresis Prevents Erratic Reset
Reset Output Capable of Sinking in Excess of 10 mA
Internal Clamp Diode for Discharging Delay Capacitor
Guaranteed Reset Operation with 1.0 V Input
Low Standby Current
Economical TO–226AA, SO–8 and Micro–8 Surface Mount Packages
D SUFFIX
PLASTIC PACKAGE
CASE 751
(SO–8)
8
1
P SUFFIX
PLASTIC PACKAGE
CASE 29
(TO–226AA)
1
2
3
Pin 1. Reset
2. Input
3. Ground
Representative Block Diagram
Input
2 (2)
Reset
DM SUFFIX
PLASTIC PACKAGE
CASE 846A
(Micro–8)
8
1
Reset 1
8 N.C.
7 N.C.
6 N.C.
5 N.C.
(Top View)
1 (1)
Input 2
N.C. 3
Ground 4
1.2 Vref
ORDERING INFORMATION
Device
Operating
Temperature Range
Package
SO–8
TA = 0° to +70°C
Micro–8
TO–226AA
SO–8
Micro–8
TO–226AA
Gnd
3 (4)
= Sink Only
Positive True Logic
MC34064D–5
MC34064DM–5
MC34064P–5
Pin numbers adjacent to terminals are for the 3–pin TO–226AA package.
Pin numbers in parenthesis are for the 8–lead packages.
This device contains 21 active transistors.
MC33064D–5
MC33064DM–5 TA = – 40° to +85°C
MC33064P–5
©
Motorola, Inc. 1996
Rev 2
MOTOROLA ANALOG IC DEVICE DATA
1
MC34064 MC33064
MAXIMUM RATINGS
Rating
Power Input Supply Voltage
Reset Output Voltage
Reset Output Sink Current (Note 1)
Clamp Diode Forward Current, Pin 1 to 2 (Note 1)
Power Dissipation and Thermal Characteristics
P Suffix, Plastic Package
Maximum Power Dissipation @ TA = 25°C
Thermal Resistance, Junction–to–Air
D Suffix, Plastic Package
Maximum Power Dissipation @ TA = 25°C
Thermal Resistance, Junction–to–Air
DM Suffix, Plastic Package
Maximum Power Dissipation @ TA = 25°C
Thermal Resistance, Junction–to–Air
Operating Junction Temperature
Operating Ambient Temperature
MC34064
MC33064
Storage Temperature Range
NOTE:
ESD data available upon request.
Symbol
Vin
VO
ISink
IF
Value
–1.0 to 10
10
Internally
Limited
100
Unit
V
V
mA
mA
PD
R
θJA
PD
R
θJA
PD
R
θJA
TJ
TA
625
200
625
200
520
240
+150
0 to +70
–40 to +85
mW
°C/W
mW
°C/W
mW
°C/W
°C
°C
Tstg
–65 to +150
°C
ELECTRICAL CHARACTERISTICS
(For typical values TA = 25°C, for min/max values TA is the operating ambient temperature range
that applies [Notes 2 and 3] unless otherwise noted.)
Characteristics
COMPARATOR
Threshold Voltage
High State Output (Vin Increasing)
Low State Output (Vin Decreasing)
Hysteresis
RESET OUTPUT
Output Sink Saturation
(Vin = 4.0 V, ISink = 8.0 mA)
(Vin = 4.0 V, ISink = 2.0 mA)
(Vin = 1.0 V, ISink = 0.1 mA)
Output Sink Current (Vin, Reset = 4.0 V)
Output Off-State Leakage (Vin, Reset = 5.0 V)
Clamp Diode Forward Voltage, Pin 1 to 2 (IF = 10 mA)
TOTAL DEVICE
Operating Input Voltage Range
Quiescent Input Current (Vin = 5.0 V)
Vin
Iin
1.0 to 6.5
–
–
390
–
500
V
µA
VOL
–
–
–
ISink
IOH
VF
10
–
0.6
0.46
0.15
–
27
0.02
0.9
1.0
0.4
0.1
60
0.5
1.2
mA
µA
V
V
V
VIH
VIL
VH
4.5
4.5
0.01
4.61
4.59
0.02
4.7
4.7
0.05
Symbol
Min
Typ
Max
Unit
NOTES:
1. Maximum package power dissipation limits must be observed.
2. Low duty cycle pulse techniques are used during test to maintain junction temperature as close to ambient as possible.
3. Tlow = 0°C for MC34064
Thigh = +70°C for MC34064
–40°C for MC33064
+85°C for MC33064
2
MOTOROLA ANALOG IC DEVICE DATA
MC34064 MC33064
Figure 1. Reset Output Voltage versus
Input Voltage
1
0
VO , OUTPUT VOLTAGE (V)
8.0
6.0
4.0
2.0
0
5.0
RL = 10 k to Vin
TA = 25°C
VO , OUTPUT VOLTAGE (V)
4.0
3.0
2.0
1.0
0
RL = 10 k to Vin
TA = 25°C
Figure 2. Reset Output Voltage versus
Input Voltage
0
2.0
4.0
6.0
Vin, INPUT VOLTAGE (V)
8.0
1
0
4.56
0
4.58
4.60
4.62
0 V , INPUT VOLTAGE (V) 0
0
in
4.64
0
Figure 3. Comparator Threshold Voltage
versus Temperature
4.630
V th, THRESHOLD VOLTAGE (V)
RL = 10 k to Vin
4.620
4.610
4.600
4.590
4.580
4.570
–55
Lower Threshold
Low State Output
–25
0
25
50
75
100
125
I in , INPUT CURRENT (mA)
Upper Threshold
High State Output
0.8
0.6
1.0
Figure 4. Input Current versus Input Voltage
TA = +25°C
–40°C
+85°C
0.4
0.2
0
TA = +25°C
+85°C
–40°C
0
2.0
4.0
6.0
8.0
10
TA, AMBIENT TEMPERATURE (°C)
Vin, INPUT VOLTAGE (V)
Figure 5. Reset Output Saturation versus
Sink Current
2.0
Vin = 4.0 V
V OL, OUTPUT SATURATION (V)
1.5
TA = 85°C
TA = –40°C
1.0
4.0 V –
Vin
Figure 6. Reset Delay Time
Reset
Vin = 5.0 V to 4.0 V
RL = 10 k
TA = 25°C
TA = 25°C
90%
Vin
5.0 V –
10k
Reset
0.5
10%
0
5.0V
4.0V
REF
0
10
20
30
ISink, SINK CURRENT (mA)
40
200 ns/DIV
MOTOROLA ANALOG IC DEVICE DATA
3
MC34064 MC33064
Figure 7. Clamp Diode Forward Current
versus Voltage
80
I F , FORWARD CURRENT (mA)
Vin = 0 V
TA = 25°C
60
40
20
0
0
0.4
0.8
1.2
VF , FORWARD VOLTAGE (V)
1.6
Figure 8. Low Voltage Microprocessor Reset
+
Power
Supply
2 (2)
1 (1)
R
Reset
Microprocessor
Circuit
–
–
+
1.2 Vref
CDLY
3 (4)
A time delayed reset can be accomplished with the
addition of CDLY. For systems with extremely fast
power supply rise times (<500 ns) it is recommended
that the RCDLY time constant be greater than 5.0
µs.
Vth(MPU) is the microprocessor reset input threshold.
1
tDLY = RCDLY In
1–
Vth(MPU)
Vin
Figure 9. Low Voltage Microprocessor Reset with Additional Hysteresis
RH
+
Power
Supply
1 (1)
–
–
+
1.2Vref
VH
≈
4.6 RH
+ 0.02
RL
Iin
Test Data
2 (2)
RL
Reset
Microprocessor
Circuit
VH
(mV)
20
51
40
81
71
112
100
164
190
327
∆V
th
(mV)
0
3.4
6.8
6.8
10
10
16
16
34
34
51
51
RH
(Ω)
0
10
20
20
30
30
47
47
100
100
150
150
RL
(kΩ)
0
1.5
4.7
1.5
2.7
1.5
2.7
1.5
2.7
1.5
2.7
1.5
∆V
th(lower)
≈
340 RH x 10–6
Where: RH
≤
150
Ω
Where:
RL
≥
1.5
Ω, ≤
10 kΩ
3 (4)
Comparator hysteresis can be increased with the addition of resistor RH. The hysteresis equation has been
simplified and does not account for the change of input current Iin as VCC crosses the comparator threshold
(Figure 4). An increase of the lower threshold
∆V
th(lower) will be observed due to Iin which is typically 340
µA
at
4.59 V. The equations are accurate to
±10%
with RH less than 150
Ω
and RL between 1.5 kΩ and 10 kΩ
.
276
480
4
MOTOROLA ANALOG IC DEVICE DATA
MC34064 MC33064
Figure 10. Voltage Monitor
1.0k
+
Power
Supply
–
–
+
1.2Vref
3 (4)
2 (2)
1 (1)
–
+
1.2Vref
3 (4)
Solar
Cells
+
–
2 (2)
1 (1)
Figure 11. Solar Powered Battery Charger
Figure 12. Low Power Switching Regulator
25µH
Vin = 11.5
to 14.5V
470
22
4.7k
330
2 (2)
1N756
Test
1 (1)
–
+
1.2Vref
3 (4)
Line Regulation
Load Regulation
Output Ripple
Efficiency
Conditions
Vin = 11.5 V to 14.5 V, IO = 50 mA
Vin = 12.6 V, IO = 0 mA to 50 mA
Vin = 12.6 V, IO = 50 mA
Vin = 12.6 V, IO = 50 mA
Results
35 mV
12 mV
60 mVpp
77%
+
680
1.2k
MPSW51A
+
470
1N5819
+
VO = 5.0 V
IO = 50 mA
Figure 13. MOSFET Low Voltage Gate Drive Protection
VCC
RL
MTP3055EL
270
4.6V
2 (2)
1 (1)
–
+
1.2Vref
3 (4)
Overheating of the logic level power MOSFET due to insufficient gate voltage can be prevented with the above
circuit. When the input signal is below the 4.6 V threshold of the MC34064, its output grounds the gate of the L2
MOSFET.
MOTOROLA ANALOG IC DEVICE DATA
5
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