October 2009 1 M9999-100909
Micrel, Inc. MIC7211/7221
Pin Description
Pin Number Pin Name Pin Function
1 OUT Amplier Output
2 V+ Positive Supply
3 IN+ Noninverting Input
4 IN– Inverting Input
5 V– Negative Suppy
MIC7211/7221
IttyBitty® Rail-to-Rail Input Comparator
Functional Conguration
OUTV+
IN–
IN+
13
45
2
V–
SOT-23-5 (M5)
General Description
The MIC7211 and MIC7221 are micropower comparators
featuring rail-to-rail input performance in Micrel’s IttyBitty®
SOT-23-5 package. The MIC7211/21 is ideal for systems
where small size is a critical consideration.
The MIC7211/21 is optimized for single supply operation from
2.2V to 10V power supplies.
The MIC7211 features a conventional push-pull output while
the MIC7221 has an open-drain output for mixed-voltage
applications with an external pull-up resistor.
The MIC7211/21 benets small battery-operated portable
electronic devices where small size and the ability to place
the comparator close to the signal source are primary design
concerns.
Pin Conguration
OUTV+
IN–
IN+
13
45
2
V–
Axx
Part
Identification
Features
• Small footprint SOT-23-5 package
• Guaranteed performance at 2.2V, 2.7V, 5V, and 10V
• 7µA typical supply current at 5V
• <5µs response time at 5V
• Push-pull output (MIC7211)
• Open-drain output (MIC7221)
• Input voltage range may exceed supply voltage by 0.3V
• >100mA typical sink or source
Applications
• Battery-powered products
• Notebook computers and PDAs
• PCMCIA cards
• Cellular and other wireless communication devices
• Alarm and security circuits
• Direct sensor interface
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
Ordering Information
Part Number Marking Temp. Range Package Lead Finish
MIC7211BM5 A14 –40°C to +85°C SOT-23-5 Standard
MIC7221BM5 A15 –40°C to +85°C SOT-23-5 Standard
MIC7211YM5 A14 –40°C to +85°C SOT-23-5 Pb-Free
MIC7221YM5 A15 –40°C to +85°C SOT-23-5 Pb-Free
Micrel, Inc. MIC7211/7221
October 2009 2 M9999-100909
Absolute Maximum Ratings (Note 1)
Supply Voltage (VV+ – VV–) ........................................... 12V
Differential Input Voltage (VIN+, VIN–) .............. ±(VV+ – VV–)
I/O Pin Voltage (VIN+, VOUT), Note 3 ..................................
..............................................VV+ + 0.3V to VV– – 0.3V
Junction Temperature (TJ) ....................................... +150°C
Storage Temperature (TS) ........................ –65°C to +150°C
ESD, Note 6
Operating Ratings (Note 2)
Supply Voltage (VV+ – VV–) ...............................2.2V to 10V
Junction Temperature (TJ) .......................... –40°C to +85°C
Package Thermal Resistance (θJA) Note 5 .............235°C/W
Maximum Power Dissipation .................................... Note 4
DC Electrical Characteristics (2.2V)
VV+ = +2.2V, VV– = 0V, VCM = VOUT = VV+/2; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C; Note 7; unless noted
Symbol Parameter Condition Min Typ Max Units
VOS Input Offset Voltage 2 10 mV
TCVOS Input Offset Voltage 1 µV/°C
Temperature Drift
TCVOS Input Offset Voltage 3.3 µV⁄month
Drift Over Time
IB Input Bias Current 0.5 pA
IOS Input Offset Current 0.25 pA
CMRR Common-Mode Rejection Ratio 0V ≤ VCM ≤ 2.2V 60 dB
PSRR Positive Power Supply VV+ = 2.2V to 5V 90 dB
Rejection Ratio
AVOL Gain 125 dB
VOH Output Voltage (High) MIC7211, ILOAD = 2.5mA 2.1 2.18 V
VOL Output Voltage (Low) ILOAD = 2.5mA 0.02 0.1 V
IS Supply Current VOUT = low 5 12 µA
DC Electrical Characteristics (2.7V)
VV+ = +2.7V, VV– = 0V, VCM = VOUT = VV+/2; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C; Note 7; unless noted
Symbol Parameter Condition Min Typ Max Units
VOS Input Offset Voltage 2 10 mV
TCVOS Input Offset Voltage 1 µV/°C
Temperature Drift
TCVOS Input Offset Voltage 3.3 µV⁄month
Drift Over Time
IB Input Bias Current 0.5 pA
IOS Input Offset Current 0.25 pA
CMRR Common-Mode Rejection Ratio 0V ≤ VCM ≤ 2.7V 65 dB
PSRR Positive Power Supply VV+ = 2.7V to 5V 90 dB
Rejection Ratio
AVOL Gain 125 dB
VOH Output Voltage (High) MIC7211, ILOAD = 2.5mA 2.6 2.68 V
VOL Output Voltage (Low) ILOAD = 2.5mA 0.02 0.1 V
IS Supply Current VOUT = low 5 12 µA
October 2009 3 M9999-100909
Micrel, Inc. MIC7211/7221
DC Electrical Characteristics (5V)
VV+ = +5.0V, VV– = 0V, VCM = VOUT = VV+/2; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C; Note 7; unless noted
Symbol Parameter Condition Min Typ Max Units
VOS Input Offset Voltage 2 10 mV
TCVOS Input Offset Voltage 1 µV/°C
Temperature Drift
TCVOS Input Offset Voltage 3.3 µV⁄month
Drift Over Time
IB Input Bias Current 0.5 pA
IOS Input Offset Current 0.25 pA
CMRR Common-Mode Rejection Ratio 0V ≤ VCM ≤ 5.0V 70 dB
PSRR Positive Power Supply VV+ = 5.0V to 10V 90 dB
Rejection Ratio
AVOL Gain 125 dB
VOH Output Voltage (High) MIC7211, ILOAD = 5mA 4.9 4.95 V
VOL Output Voltage (Low) ILOAD = 5mA 0.05 0.1 V
IS Supply Current VOUT = low 7 14 µA
ISC Short Circuit Current MIC7211, sourcing 150 mA
sinking 110 mA
DC Electrical Characteristics (10V)
VV+ = +10V, VV– = 0V, VCM = VOUT = VV+/2; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C; Note 7; unless noted
Symbol Parameter Condition Min Typ Max Units
VOS Input Offset Voltage 2 10 mV
TCVOS Input Offset Voltage 1 µV/°C
Temperature Drift
TCVOS Input Offset Voltage 3.3 µV⁄month
Drift Over Time
IB Input Bias Current 0.5 pA
IOS Input Offset Current 0.25 pA
CMRR Common-Mode Rejection Ratio 0V ≤ VCM ≤ 10V 75 dB
PSRR Positive Power Supply VV+ = 5.0V to 10V 90 dB
Rejection Ratio
AVOL Gain 125 dB
VOH Output Voltage (High) MIC7211, ILOAD = 5mA 9.9 9.95 V
VOL Output Voltage (Low) ILOAD = 5mA 0.05 0.1 V
IS Supply Current VOUT = low 12 25 µA
ISC Short Circuit Current MIC7211, sourcing 165 mA
sinking 125 mA
Micrel, Inc. MIC7211/7221
October 2009 4 M9999-100909
AC Electrical Characteristics
VV– = 0V, VCM = VOUT = VV+/2; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +85°C; Note 7; unless noted
Symbol Parameter Condition Min Typ Max Units
tRISE Rise Time VV+ = 5.0V, f = 10kHz, CLOAD = 50pF 75 ns
overdrive = 10mV, Note 9
tFALL Fall Time VV+ = 5.0V, f = 10kHz, CLOAD = 50pF 70 ns
overdrive = 10mV, Note 9
tPHL Propagation Delay-High to Low VV+ = 2.2V, f = 10kHz, CLOAD = 50pF 10 µs
overdrive = 10mV, Note 9
V
V+ = 2.2V, f = 10kHz, CLOAD = 50pF 6.0 µs
overdrive = 100mV, Note 9
V
V+ = 5.0V, f = 10kHz, CLOAD = 50pF 13 µs
overdrive = 10mV, Note 9
V
V+ = 5.0V, f = 10kHz, CLOAD = 50pF 5 µs
overdrive = 100mV, Note 9
tPLH Propagation Delay-Low to High VV+ = 2.2V, f = 10kHz, CLOAD = 50pF 13.5 µs
overdrive = 10mV, Note 9
V
V+ = 2.2V, f = 10kHz, CLOAD = 50pF 4.0 µs
overdrive = 100mV, Note 9
V
V+ = 5.0V, f = 10kHz, CLOAD = 50pF 11.5 µs
overdrive = 10mV, Note 9
V
V+ = 5.0V, f = 10kHz, CLOAD = 50pF 3.0 µs
overdrive = 100mV, Note 9
Note 1. Exceeding the absolute maximum rating may damage the device.
Note 2. The device is not guaranteed to function outside its operating rating.
Note 3. I/O pin voltage is any external voltage to which an input or output is referenced.
Note 4. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(max); the junction-to-ambient thermal
resistance, θJA; and the ambient temperature, TA. The maximum allowable power dissipation at any ambient temperature is calculated using
PD(max) = (TJ(max) – TA) ÷ θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature.
Note 5. Thermal resistance, θJA, applies to a part soldered on a printed circuit board.
Note 6. Devices are ESD sensitive. Handling precautions recommended.
Note 7. All limits guaranteed by testing on statistical analysis.
Note 8. Continuous short circuit may exceed absolute maximum TJ under some conditions.
Note 9. The MIC7221 requires 5kΩ pull-up resistor.
V+
V–
OUT
MIC7211 Push-Pull Output
V+
V–
OUT
MIC7221 Open-Drain Output
Partial Functional Diagrams
October 2009 5 M9999-100909
Micrel, Inc. MIC7211/7221
Application Information
The small outline and low supply current (typically 7µA at
5V) of the MIC7211/21 are the primary advantages of these
comparators. They have been characterized for 2.2V, 2.7V,
5V, and 10V operation.
Their 2.2V capability is especially useful in low-battery voltage
situations. Low-voltage operation allows longer battery life
or deeper discharge capability. Even at 2.2V, the output can
drive several logic-gate inputs. At 2.5mA, the output stage
voltage drop is guaranteed to not exceed 0.1V.
Outputs
The MIC7211 has a push-pull output while the MIC7221 has
an open-drain output, otherwise both comparators share a
common design.
The open-drain MIC7221 output can be pulled up to 10V, even
when the supply voltage is as low as 2.2V. Conversely, the
output also can be pulled up to voltages that are lower than
the positive supply. Logic-level translation is readily facilitated
by the ability to pull the open-drain output to voltages above
or below the power supply.
Although specied short-circuit output current specied
for these parts typically exceeds 100mA, their output is
not intended to sink or source anywhere near 100mA. The
short-circuit rating is only presented as additional information
regarding output impedance and may be useful for deter-
mining the voltage drop one may experience when driving
a given load.
Input Bias Current
The low input-bias current (typically 0.5pA) requirement of
the MIC7211/21 provides exibility in the kinds of circuitry
and devices that can be directly interfaced.
Designs using an amplier for transducer-to-comparator
impedance transformation may be simplied by using the
MIC7211/21’s low-input-current requirement to eliminate
the amplier.
Input Signal Levels
Input signals may exceed either supply rail by up to 0.2V
without phase inversion or other adverse effects. The inputs
have internal clamp diodes to the supply pins.
RIN
VIN
(±100V)
VREF R1 RF
VOUT
≥100k
0.1µF
Note: RF and R1 control hysteresis (typically, RF >> R1).
V+
Figure 1. Driving the Input Beyond the Supply Rails
Larger input swings can be accommodated if the input cur-
rent is limited to 1mA or less. Using a 100k input resistor will
allow an input to swing up to 100V beyond either supply rail.
Because of the low input bias current of the device, even larger
input resistors are practical. See Figure 1. The ability to swing
the input beyond either rail facilitates some otherwise difcult
circuits, such as a single-supply zero-crossing detector or a
circuit that senses its own supply voltage.
The comparator must be powered if an input is pulled above
the rail, even with current limiting in effect. Figure 2 shows
a hypothetical situation where an input is pulled higher than
the rail when the power supply is off or not present. Figure 2
also shows external clamp diodes for additional input circuit
protection. Discrete clamp diodes can be arbitrarily more
robust than the internal clamp diodes.
The power supply has been simplied (real power supplies
do not have a series output diode); however, this illustrates
a common characteristic of most positive-voltage power sup-
plies: they are designed to source, but not sink, current. If the
supply is off, or disconnected, there is no limiting voltage for
the clamp diode to reference. The input signal can charge
the the bypass capacitor, and possibly the lter capacitor, up
to the applied input (VIN). This may be high enough to cause
a thin-oxide rupture in a CMOS integrated circuit.
V+
RIN
VIN
(>>V+)
VREF R1 RF
VOUT
0.1µF
Note: 1V ≤ V++ ≤ 10V
V++
RPU
POSSIBLE
DISCONNECT
0V WHEN
SUPPLY
IS OFF
Power
Supply
Output
Figure 2. Avoid This Condition
Ideally, the supply for the comparator and the input-producing
circuitry should the same or be switched simultaneously.
Bypass Capacitors
CMOS circuits, especially logic gates with their totem-pole
(push-pull) output stages, generate power supply current
spikes (noise) on the supply and/or ground lines. These spikes
occur because, for a nite time during switching, both output
transistors are partially on allowing “shoot-through current.”
Bypass capacitors reduce this noise.
Adequate bypassing for the MIC7211 comparator is 0.01µF;
in low-noise systems, where this noise may interfere with the
functioning or accuracy of nearby circuitry, 0.1µF is recom-
mended. Because the MIC7221 does not have a totem-pole
output stage, this spiking is not evident; however, switching
a capacitive load can present a similar situation.
Thermal Behavior
The thermal impedance of a SOT-23-5 package is 325˚C/W.
The 5V Electrical Characteristics table shows a maximum
voltage drop of 0.1V for a 5mA output current, making the
output resistance about 20Ω (R = 0.1/0.005 = 20Ω). At-
tempting to draw the typical specied output short-circuit
current of 150mA (sourcing) can be expected to cause a
die temperature rise of 146˚C. (Operating die temperature
for ICs should generally not exceed 125˚C.) Using a series
resistance is the simplest form of protecting against damage
by excessive output current.
Micrel, Inc. MIC7211/7221
October 2009 6 M9999-100909
Package Information
SOT-23-5 (M5)
October 2009 7 M9999-100909
Micrel, Inc. MIC7211/7221
MICREL INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
t e l + 1 (408) 944-0800 f a x + 1 (408) 474-1000 w e b http://www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use.
Micrel reserves the right to change circuitry and specications at any time without notication to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can
reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into
the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a signicant injury to the user. A Purchaser’s
use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2005 Micrel Incorporated.