MICROCHIP TC1037, TC1038, TC1039 User Manual

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Linear Building Block – Single Comparator in SOT Packages
TC1037/TC1038/TC1039
Features
• TinySOT-23A Packages
• Optimized for Single Supply Operation
• Ultra Low Input Bias Current: Less than 100pA
• Low Quiescent Current: 4µA (TC1037), Shutdown Mode: 4µA, 0.05µA (TC1038), 6µA (TC1039)
• Shutdown Mode (TC1038)
• 2.0% Accurate IndependentVoltage Reference (TC1039)
• Rail-to-Rail Inputs and Outputs
• Operation Down to V
DD
=1.8V
Applications
• Power Management Circuits
• Battery Operated Equipment
• Consumer Products
Device Selection Table
Part Number Package
TC1037CECT 5-Pin SOT-23A -40°C to +85°C TC1038CECH 6-Pin SOT-23A -40°C to +85°C TC1039CECH 6-Pin SOT-23A -40°C to +85°C
Temperature
Range
General Description
The TC1037/TC1038/TC1039 are single, low-power comparatorsdesigned for low-power applications.
These comparators are specifically designed for operation from a single supply. However, operation from dual supplies also is possible, and power supply current is independent of the magnitude of the power supply voltage. The TC1037/TC1038/TC1039 operate fromtwo1.5ValkalinecellsdowntoV
= 1.8V.Active
DD
supply current is 4µA for the TC1037/TC1038 and 6µA for the TC1039. Input and output swing of these devices is rail-to-rail.
An active low shutdown input, SHDN
, is available on the TC1038 and disables the comparator, placing its output in a high-impedance state. The TC1038 draws only 0.05µA (typical) when the shutdown mode is active.
An internally biased 1.20V bandgap reference i s included in the TC1039. The reference is accurate to
2.0 percent tolerance. This referenceis independent of the comparator in the TC1039.
Packaged in a 5-Pin SOT-23A (TC1037) or 6-Pin SOT-23A (TC1038/TC1039),thesesinglecomparators are ideal for applications requiring high integration, small size and low power.
Functional Block Diagram
V
IN+
SS
1
2
3
+
5
V
DD
4
IN-
Package Types
5-Pin SOT-23A
V
DD
5
OUTPUT
6-Pin SOT-23A
IN-
4
V
DD
6
IN-SHDN
45
TC1037
TC1037ECT
2
1
OUTPUT
3
V
IN+
SS
6-Pin SOT-23A
V
DD
6
TC1039ECH
1
OUTPUT
NOTE: 5-Pin SOT-23A is equivalent to the EIAJ SC-74A.
6-PinSOT-23A is equivalenttothe EIAJ SC-74.
2002 Microchip TechnologyInc. DS21344B-page 1
V
2
SS
TC1038ECH
1
OUTPUT
IN-REF
45
3
IN+
V
IN+
SS
1
2
3
+
2
3
V
IN+
SS
OUTPUT
6
5
4
V
DD
SHDN
IN-
TC1038
OUTPUT
V
SS
IN+
1
Voltage
2
3
+
Reference
6
V
5
REF
4
IN-
TC1039
DD
TC1037/TC1038/TC1039
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......................................................6.0V
Voltage on Any Pin..........(V
– 0.3V) to (VDD+0.3V)
SS
operation sections of the specifications is not implied. Exposure to Absolute Maximum Rating conditions for extended periods may affectdevice reliability.
Junction Temperature.......................................+150°C
Operating Temperature Range.............-40°C to +85°C
StorageTemperature Range..............-55°C to +150°C
TC1037/TC1038/TC10 39 E LECTRICAL SPECIFICATIONS
Electrical Characteristics: Typical values apply at 25°C and VDD= 3.0V. Minimum and maximum values apply for TA= -40° to
+85°C and V
Symbol Parameter Min Typ Max Units Test Conditions
V
DD
I
Q
I
SHDN
Shutdown Input (TC1038 Only)
V
IH
V
IL
I
SI
Comparator
(SD) Output ResistanceinShutdown 20 M SHDN =VSS(TC1038 Only)
R
OUT
(SD) Output Capacitance in Shutdown 5 pF SHDN =VSS(TC1038 Only)
C
OUT
T
SEL
T
DESEL
V
ICMR
A
VOL
GBWP Gain BandwidthProduct 90 kHz V
V
OS
I
B
V
OH
V
OL
CMRR Common Mode Rejection Ratio 66 dB TA=25°C;VDD=5V;
PSRR Power Supply Rejection Ratio 60 dB TA=25°C;VCM=1.2V;
I
SRC
I
SINK
T
PD1
T
PD2
= 1.8V to 5.5V,unless otherwise specified.
DD
SupplyVoltage 1.8 5.5 V Supply Current, Operating (TC1039)
(TC1037/TC1038) Supply Current Shutdown Mode
(TC1038Only)
Input High Threshold 80% V Input Low Threshold 20% V
— —
6 4
10
µAµAAll Outputs Unloaded,
8
SHDN
=VDDfor TC1038
——0.3µA SHDN =V
——V
DD
V
DD
SS
Shutdown Input Current ±100 nA
Select Time 20 µsec V
DeselectTime 500 nsec V
Valid from SHDN =V
OUT
RL=10kΩ to VSS(TC1038 Only)
Valid from SHDN =V
OUT
RL=10kΩ to V
SS
Common Mode Input Voltage Range VSS–0.2 VDD+0.2 V Large SignalVoltage Gain 100 V/mV RL=10kΩ,VDD=5V
= 1.8V to 5.5V;
DD
Input Offset Voltage –5
–5
V
O=VDD
—+5+5mVmVVDD=3V,VCM=1.5V,TA=25°C,
T
A
to V
SS
= -40°C to 85°C
Input Bias Current ±100 pA TA=25°C;
IN+, IN- = V Output High Voltage VDD–0.3 V RL=10kΩ to V Output Low Voltage 0.3 V RL=10kΩ to V
V
CM=VDD
V
=1.8Vto5V
DD
Output Source Current 1 mA IN+ = VDD,IN-=V
Output Shorted to V
DD
to V
to V
SS DD
SS
SS
SS
SS
VDD=1.8V Output Sink Current 2 mA IN+ = VSS,IN-=V
Output Shorted to V
VDD=1.8V
SS
SS
Response Time 4 µsec 100mVOverdrive, CL= 100pF Response Time 6 µsec 10mV Overdrive, CL= 100pF
IH
IL
DS21344B-page 2
2002 Microchip TechnologyInc.
TC1037/TC1038/TC1039
TC1037/TC1038/TC1039 E LECTRICAL SPECIFICATIONS (CONTINUED)
Electrical Characteristics: Typical values apply at 25°C and VDD= 3.0V. Minimum and maximum values applyfor TA=-40°to
+85°Cand V
Symbol Parameter Min Typ Max Units Test Conditions
VoltageReference (TC1039Only)
V
REF
I
REF(SOURCE )
I
REF(SINK)
C
L(REF)
E
VREF
e
VREF
= 1.8V to 5.5V, unless otherwise specified.
DD
Reference Voltage 1.176 1.200 1.224 V Source Current 50 µA Sink Current 50 µA Load Capacitance 100 pF Noise Voltage 20 µV Noise VoltageDensity 1.0 µV/Hz 1kHz
RMS
100Hz to 100kHz
2002 Microchip TechnologyInc. DS21344B-page 3
TC1037/TC1038/TC1039
2.0 PIN DESCRIPTIONS
The description of the pins are listed in Table 2-1.
TABLE 2-1: PIN FUNCTION TABLE
Pin No.
TC1037
(5-Pin SOT-23A)
1 OUTPUT Comparator output. 2V 3 IN+ Comparator non-inverting input. 4 IN- Comparator inverting input. 5V
Pin No.
TC1038
(6-Pin SOT-23A)
1 OUTPUT Comparator output. 2V 3 IN+ Comparator non-inverting input. 4 IN- Comparator inverting input. 5 SHDN
6V
Symbol Description
SS
DD
Symbol Description
SS
DD
Negative power supply.
Positive power supply.
Negative power supply.
Active low shutdown input (TC1038 only). A low input on this pin disables the comparator and placesthe output terminal in a high impedance state.
Positive power supply.
Pin No.
TC1039
(6-Pin SOT-23A)
1 OUTPUT Comparator output. 2V 3 IN+ Comparator non-inverting input. 4 IN- Comparator inverting input. 5 REF 1.20V bandgap voltage reference output (TC1039 only). 6V
Symbol Description
SS
DD
Negative power supply.
Positive power supply.
DS21344B-page 4
2002 Microchip TechnologyInc.
TC1037/TC1038/TC1039
3.0 DETAILED DESCRIPTION
The TC1037/TC1038/TC1039 are a series of very low power, linear building block products targeted at low voltage, single supply applications. The TC1037/ TC1038/TC1039 minimum operating voltage is 1.8V and typical supply current is only 4µA for the TC1037 and TC1038 (fully enabled) and 6µA for the TC1039.
3.1 Comparator
The TC1037/8/9 contain one comparator. The comparator’s input range extends beyond both supply voltagesby 200mV and the outputswill swing to within several millivoltsof thesupplies depending on the load current being driven.
The comparator exhibits a propagation delay and supply current which is largely independent of supply voltage. The low input bias current and offset voltage makes it suitable for high impedance precision applications.
The TC1038 comparator is disabled during shutdown and has a high impedance output.
3.2 Voltage Reference
A 2.0% tolerance, internally biased, 1.20V bandgap voltage reference is i ncluded in the TC1039. It has a push-pull output capable of sourcing and sinking at least 50µA.
3.3 Shutdown Input (TC1038 Only)
SHDN at VILdisables the comparator and reduces the supply current to less than 0.3µA. The SHDN cannotbe allowedto float. When not used, connect it to V
. The comparator’s output is in a high impedance
DD
state when the TC1038 is disabled. The comparator’s inputs can be driven from rail-to-rail by an external voltage when the TC1038 is disabled. No latchup will occur when the device is driven to its enabled state when SHDN
is set to VIH.
input
4.0 TYPICAL APPLICATIONS
The TC1037/TC1038/TC1039 family lends itself to a wide variety of applications, particularly in battery powered systems. It typicallyfindsapplicationin power management, processor supervisory and interface circuitry.
4.1 External Hysteresis (Comparator)
Hysteresis can be set externally with two resistors using positive f eedback techniques (see Figure 4-1). The design procedure for setting external comparator hysteresisis as follows:
1. Choose the feedback resistor R input bias current of the comparator is at most 100pA, the current through R 100nA (i.e., 1000 times the input bias current) and retain excellent accuracy. The current through R R
where VRis a stable r eference voltage.
C
at the comparator’s trip point is VR/
C
2. Determinethehysteresisvoltage (V the upper and lower thresholds.
3. Calculate R
as follows:
A
EQUATION 4-1:
V
HY

=
-----------
C

V
DD
RAR
4. Choose the rising threshold voltage for V (V
).
THR
5. Calculate R
as follows:
B
EQUATION 4-2:
V
THR
1
1
-------
R
-----------------------------------------------------------=
R
B
---------------------
VRRA×
6. Verify the threshold voltages with these formulas:
V
rising:
SRC
.Sincethe
C
canbesetto
C
HY
1
------­R
A
C
)between
SRC
EQUATION 4-3:
1
1
B
1

-------

R
C
V
V
SRC
THR
falling:
VR()RA()
 
------­R
A

-------
++=

R
EQUATION 4-4:
RAVDD×

V
THFVTHR
2002 Microchip TechnologyInc. DS21344B-page 5
--------- ------------- ---
=

R
C
TC1037/TC1038/TC1039
4.2 Precision Battery Monitor
Figure 4-2 is a precision battery low/battery dead monitoring circuit. Typically, the battery low output warns the user that a battery dead condition is imminent. Battery dead typically initiates a forced shutdown to prevent operation at low internal supply voltages(which can cause unstablesystemoperation).
The circuit in Figure 4-2 uses a TC1034, a TC1037 and a TC1039, and only six external resistors. AMP 1 is a simple buffer, while CMPTR1 and CMPTR2 provide precision voltage detection using V Resistors R2 and R4 set the detection threshold for BATT LOW, thresholdforBATT FAIL assert BATT LOW
2.0V (typical). Total current consumed by this circuit i s typically 16µA at 3V. Resistors R5 and R6 provide hysteresis for comparators CMPTR1 and CMPTR2, respectively.
whileresistorsR1and R3 set the detection
.The componentvaluesshown
at 2.2V (typical) and BATT FAIL at
as a reference.
R
4.3 32.768 kHz “Time Of Day Clock” Crystal Controlled Oscillator
A very stable oscillator driver can be designedby using a crystalresonatorasthefeedbackelement. Figure 4-3 shows a typical application circuit using this technique to develop a clockdriverfora Time Of Day (TOD)clock chip.The value of R level at which the comparator trips – in this case one­half of V be set several times greaterthanthe crystaloscillator’s period,whichwill ensure a 50% duty cycle by maintain­ing a DC voltage at the inverting comparator input equal to the absolute average of the output signal.
. The RC time constant of RCand CAshould
DD
and RBdetermine the DC voltage
A
4.4 Non-Retriggerable One Shot Multivibrator
Using two comparators, a non-retriggerable one shot multivibratorcan be designed using t he circuit configu­ration of Figure 4-4. A key feature of this design is that the pulse width is independent of the magnitude of the supply voltage because the charging voltage and the intercept voltage are a fixed percentage of V addition,this one shot is capable of pulse width with as much as a 99% duty cycle and exhibits input lockoutto ensure that the circuit will not re-trigger before the outputpulsehascompletelytimedout.The triggerlevel is the voltage required at the input to raise the voltage at node A higher than the voltage at node B, and is set by the resistivedividerR4 and R10 and the impedance network composed of R1, R2 and R3. When the one shot has been triggered, the output of CMPTR2is high, causingthereferencevoltageatthenon-invertinginput of CMPTR1 to go to V input pulses from disturbing the circuit until the output pulse has timed out.
. This prevents any additional
DD
DD
.In
ThevalueofthetimingcapacitorC1mustbesmall enough to allow CMPTR1 to discharge C1 to a diode voltage before the feedback signal from CMPTR2 (through R10) switches CMPTR1 to its high state and allows C1 to start an exponential charge t hrough R5. Proper circuit action depends upon rapidly discharging C1 through the voltage set by R6, R9 and D2 to a final voltage of a small diode drop. Two propagation delays after the voltage on C1 drops below the level on the non-invertinginput of CMPTR2,the output of CMPTR1 switches to the positive rail and begins to charge C1 throughR5. The timedelay which sets the outputpulse width results from C1 charging to the reference voltage set by R6, R9 and D2, plus four comparator propaga­tion delays. When the voltage across C1 charges beyond the reference, the output pulse returns to ground and the input is again ready to accept a trigger signal.
4.5 Oscillators and Pulse Width Modulators
Microchip’s linear building block comparators adapt well to oscillator applications for low frequencies (less than 100kHz). Figure 4-5 shows a symmetrical square wave generator using a minimum number of compo­nents. The output is set by the RC time constant of R4 and C1, and the totalhysteresisoftheloopissetbyR1, R2 and R3. The maximum frequencyof the oscillator is limitedonly by the largesignalpropagationdelayof the comparator in addition to any capacitive loading at the output which degrades the slew rate.
To analyzethiscircuit, assume that the output is initially high. For thisto occur, the voltage at the inverting input must be less than the voltageat the non-invertinginput. Therefore, capacitor C1 is discharged. The voltage at the non-inverting input (V
EQUATION 4-5:
V
H
where, if R1 = R2 = R3, then:
EQUATION 4-6:
)is:
H
R2 VDD()
---------- ------------- ------------- ---------=
R2 R1 R3
V
H
||
()+[]
2VDD()
-------------------= 3
DS21344B-page 6
2002 Microchip TechnologyInc.
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