LMV7235M5X/NOPB - NATIONAL SEMICONDUCTOR

LMV7235/LMV7239/

LMV7239Q

January 6, 2012

75 nsec, Ultra Low Power, Low Voltage, Rail-to-Rail Input

Comparator with Open-Drain/Push-Pull Output

General Description

The LMV7235/LMV7239/LMV7239Q are ultra low power, low

voltage, 75 nsec comparators. They are guaranteed to oper-

ate over the full supply voltage range of 2.7V to 5.5V. These

devices achieve a 75 nsec propagation delay while consum-

ing only 65µA of supply current at 5V.

The LMV7235/LMV7239/LMV7239Q have a greater than rail-

to-rail common mode voltage range. The input common mode

voltage range extends 200mV below ground and 200mV

above supply, allowing both ground and supply sensing.

The LMV7235 features an open drain output. By connecting

an external resistor, the output of the comparator can be used

as a level shifter.

The LMV7239/LMV7239Q features a push-pull output stage.

This feature allows operation without the need of an external

pull-up resistor.

The LMV7235/LMV7239/LMV7239Q are available in the 5-

Pin SC70 and 5-Pin SOT23 packages, which are ideal for

systems where small size and low power is critical.

Features

(VS = 5V, TA = 25°C

Typical values unless otherwise specified)

■Propagation delay 75 nsec

■Low supply current 65µA

■Rail-to-Rail input

■Open drain and push-pull output

■Ideal for 2.7V and 5V single supply applications

■Available in space saving packages

—5-pin SOT23

—5-pin SC70

■LMV7239Q is an automotive grade product that is AECQ

grade 1 qualified and is manufactured on an automotive

grade flow.

Applications

■Portable and battery powered systems

■Scanners

■Set top boxes

■High speed differential line receiver

■Window comparators

■Zero-crossing detectors

■High speed sampling circuits

■Automotive

Typical Application

10135902

Crystal Oscillator

LMV7235/LMV7239/LMV7239Q 45 nsec, Ultra Low Power, Low Voltage, Rail-to-Rail Input

Comparator with Open-Drain/Push-Pull Output

Connection Diagram

5-Pin SC70/SOT23

10135903

Top View

Ordering Information

Package Part Number Marking Supplied as NSC Drawing

5-pin SC70

LMV7235M7 C21 1k Units Tape and Reel

MAA05A

LMV7235M7X 3k Units Tape and Reel

LMV7239M7 C20 1k Units Tape and Reel

LMV7239M7X 3k Units Tape and Reel

LMV7239QM7 C42 1k Units Tape and Reel

LMV7239QM7X 3k Units Tape and Reel

5-pin SOT23

LMV7235M5 C21A 1k Units Tape and Reel

MF05A

LMV7235M5X 3k Units Tape and Reel

LMV7239M5 C20A 1k Units Tape and Reel

LMV7239M5X 3k Units Tape and Reel

* Automotive Grade (Q) product incorporates enhanced manufacturing and support processes for the automotive market, including

defect detection methodologies. Reliability qualification is compliant with the requirements and temperature defined in the AEC-

Q100 standard. Automotive grade products are defined with the letter Q. For more information, go to http://www.national.com/

automotive.

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LMV7235/LMV7239/LMV7239Q

Simplified Schematic

10135901

3 www.ti.com

LMV7235/LMV7239/LMV7239Q

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,

please contact the Texas Instruments Sales Office/

Distributors for availability and specifications.

ESD Tolerance (Note 2)

Human Model Body 1000V

Machine Body 100V

Differential Input Voltage ± Supply Voltage

Output Short Circuit Duration (Note 3)

Supply Voltage (V+ - V−)6V

Soldering Information

Infrared or Convection (20 sec) 235°C

Wave Soldering (10 sec) 260°C (lead temp)

Voltage at Input/Output Pins (V+) +0.3V, (V−) −0.3V

Current at Input Pin (Note 9) ±10mA

Operating Ratings

Supply Voltages (V+ - V−)2.7V to 5.5V

Temperature Range (Note 4)

LMV7235/LMV7239 −40°C to +85°C

LMV7239Q −40°C to +125°C

Storage Temperature Range −65°C to +150°C

Package Thermal Resistance

5-Pin SC70 478°C/W

5-Pin SOT23 265°C/W

2.7V Electrical Characteristics

Unless otherwise specified, all limits guaranteed for TA = 25°C, VCM = V+/2, V+ = 2.7V, V− = 0V−. Boldface limits apply at the

temperature extremes.

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)Units

VOS Input Offset Voltage 0.8 6

8mV

IBInput Bias Current 30 400

600 nA

IOS Input Offset Current 5 200

400 nA

CMRR Common Mode Rejection Ratio 0V < VCM < 2.7V

(Note 7)52 62 dB

PSRR Power Supply Rejection Ratio V+ = 2.7V to 5V 65 85 dB

VCM Input Common-Mode Voltage Range CMRR > 50dB V− −0.1V−−0.2 to 2.9 V+ +0.1V+V

Output Swing High

(LMV7239 only)

IL = 4mA,

VID = 500mV V+ −0.35 V+ −0.26 V

IL = 0.4mA,

VID = 500mV V+ −0.02 V

Output Swing Low

(LMV7235/LMV7239/LMV7239Q)

IL = −4mA,

VID = −500mV

230 350

450 mV

IL = −0.4mA,

VID = −500mV 15 mV

ISC Output Short Circuit Current

Sourcing, VO = 0V

(LMV7239 only)

(Note 3)

15 mA

Sinking, VO = 2.7V

(LMV7235, RL = 10k)

(Note 3)

20 mA

ISSupply Current No load 52 85

100 µA

tPD Propagation Delay

Overdrive = 20mV

CLOAD = 15pF

(Note 10)

96 ns

Overdrive = 50mV

CLOAD = 15pF

(Note 10)

87 ns

Overdrive = 100mV

CLOAD = 15pF

(Note 10)

85 ns

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LMV7235/LMV7239/LMV7239Q

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Max

(Note 6)Units

tSKEW

Propagation Delay Skew

(LMV7239 only)

Overdrive = 20mV

(Note 8) 2 ns

trOutput Rise Time

LMV7239/LMV7239Q

10% to 90% 1.7 ns

LMV7235

10% to 90%

(Note 10)

112 ns

tfOutput Fall Time 90% to 10% 1.7 ns

ILEAKAGE

Output Leakage Current

(LMV7235 only)

3 nA

5V Electrical Characteristics

Unless otherwise specified, all limits guaranteed for TA = 25°C, VCM = V+/2, V+ = 5V, V− = 0V. Boldface limits apply at the tem-

perature extremes.

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Limits

(Note 6)Units

VOS Input Offset Voltage 1 6

8mV

IBInput Bias Current 30 400

600 nA

IOS Input Offset Current 5 200

400 nA

CMRR Common Mode Rejection Ratio 0V < VCM < 5V 52 67 dB

PSRR Power Supply Rejection Ratio V+ = 2.7V to 5V 65 85 dB

VCM Input Common-Mode Voltage Range CMRR > 50dB V− −0.1V−−0.2 to 5.2 V+ +0.1V+V

Output Swing High

(LMV7239 only)

IL = 4mA,

VID = 500mV V+ −0.25 V+ −0.15 V

IL = 0.4mA,

VID = 500mV V+ −0.01 V

Output Swing Low

(LMV7235/LMV7239/LMV7239Q)

IL = −4mA,

VID = −500mV

230 350

450 mV

IL = −0.4mA,

VID = −500mV

10 mV

ISC Output Short Circuit Current

Sourcing, VO = 0V

(LMV7239 only)

(Note 3)

Sinking, VO = 5V

(LMV7235, RL = 10k)

(Note 3)

ISSupply Current No load 65 95

110 µA

tPD Propagation Delay

Overdrive = 20mV

CLOAD = 15pF

(Note 10)

89 ns

Overdrive = 50mV

CLOAD = 15pF

(Note 10)

82 ns

Overdrive = 100mV

CLOAD = 15pF

(Note 10)

75 ns

tSKEW

Propagation Delay Skew

(LMV7239 only)

Overdrive = 20mV

(Note 8) 1 ns

5 www.ti.com

LMV7235/LMV7239/LMV7239Q

Symbol Parameter Conditions Min

(Note 6)

Typ

(Note 5)

Limits

(Note 6)Units

trOutput Rise Time

LMV7239

10% to 90% 1.2 ns

LMV7235

10% to 90%

(Note 10)

100 ns

tfOutput Fall Time 90% to 10% 1.2 ns

ILEAKAGE

Output Leakeage Current

(LMV7235 only) 3 nA

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is

intended to be functional, but specific performance is not guaranteed. For guaranteed specifications and the test conditions, see the Electrical Characteristics.

Note 2: Human Body Model, applicable std. MIL-STD-883, Method 3015.7. Machine Model, applicable std. JESD22-A115-A (ESD MM std. of JEDEC)

Field-Induced Charge-Device Model, applicable std. JESD22-C101-C (ESD FICDM std. of JEDEC).

Note 3: Applies to both single-supply and split-supply operation. Continuous short circuit operation at elevated ambient temperature can result in exceeding the

maximum allowed junction temperature of 150°C. Output currents in excess of ±30mA over long term may adversely affect reliability.

Note 4: The maximum power dissipation is a function of TJ(MAX), θJA. The maximum allowable power dissipation at any ambient temperature is

PD = (TJ(MAX) – TA) / θJA. All numbers apply for packages soldered directly onto a PC Board.

Note 5: Typical values represent the most likely parametric norm as determined at the time of characterization. Actual typical values may vary over time and will

also depend on the application and configuration. The typical values are not tested and are not guaranteed on shipped production material.

Note 6: All limits are guaranteed by testing or statistical analysis.

Note 7: CMRR is not linear over the common mode range. Limits are guaranteed over the worst case from 0 to VCC/2 or VCC/2 to VCC.

Note 8: Propagation Delay Skew is defined as the absolute value of the difference between tPDLH and tPDHL.

Note 9: Limiting input pin current is only necessary for input voltages that exceed absolute maximum input voltage ratings.

Note 10: A 10k pull-up resistor was used when measuring the LMV7235. The rise time of the LMV7235 is a function of the R-C time constant.

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LMV7235/LMV7239/LMV7239Q

Typical Performance Characteristics (Unless otherwise specified, VS = 5V, CL = 10pF, TA = 25°C).

Supply Current vs. Supply Voltage

012345

100

120

SUPPLY CURRENT (μA)

SUPPLY VOLTAGE (V)

-40°C

25°C

85°C

125°C

10135925

Sourcing Current vs. Output Voltage

10135905

Sourcing Current vs. Output Voltage

10135906

Sinking Current vs. Output Voltage

10135907

Sinking Current vs. Output Voltage

10135908

Input Bias Current vs. Input Voltage

10135909

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LMV7235/LMV7239/LMV7239Q

Input Bias Current vs. Input Voltage

10135910

Propagation Delay vs. Temperature

-40 -20 0 20 40 60 80 100 120 140

100

110

120

130

140

150

160

PROPAGATION DELAY (ns)

TEMPERATURE (°C)

VS=2.7V

VOD=20mV

CLOAD=15pF

Falling Edge

Rising Edge

10135926

Propagation Delay vs. Temperature

-40 -20 0 20 40 60 80 100 120 140

100

110

120

130

140

PROPAGATION DELAY (ns)

TEMPERATURE (°C)

VS=5V

VOD=20mV

CLOAD=15pF

Falling Edge

Rising Edge

10135927

Propagation Delay vs. Capacitive Load

0 20 40 60 80 100

100

102

104

106

PROPAGATION DELAY (ns)

CAPACITANCE (pF)

Rising Edge

Falling Edge

VS= 2.7V

VOD=20mV

10135928

Propagation Delay vs. Capacitive Load

0 20 40 60 80 100

PROPAGATION DELAY (ns)

CAPACITANCE (pF)

Rising Edge

Falling Edge

VS= 5V

VOD=20mV

10135929

Propagation Delay vs. Input Overdrive

20 30 40 50 60 70 80 90 100

100

PROPAGATION DELAY (ns)

INPUT OVERDRIVE (mV)

Rising Edge

Falling Edge

VS= 2.7V

CLOAD=15pF

10135930

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LMV7235/LMV7239/LMV7239Q

Propagation Delay vs. Input Overdrive

20 40 60 80 100

PROPAGATION DELAY (ns)

INPUT OVERDRIVE (mV)

Rising Edge

Falling Edge

VS= 5V

CLOAD=15pF

10135931

Propagation Delay vs. Common Mode Voltage

0.0 0.5 1.0 1.5 2.0 2.5 3.0

100

105

110

115

120

PROPAGATION DELAY (ns)

INPUT COMMON MODE VOLTAGE (V)

Rising Edge Falling Edge

VS= 2.7V

VOD=20mV

CLOAD=15pF

10135932

Propagation Delay vs. Common Mode Voltage

012345

100

110

PROPAGATION DELAY (ns)

INPUT COMMON MODE VOLTAGE (V)

Rising Edge

Falling Edge

VS= 5V

VOD=20mV

CLOAD=15pF

10135933

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LMV7235/LMV7239/LMV7239Q

Application Information

The LMV7235/LMV7239/LMV7239Qare single supply com-

parators with 75ns of propagation delay and only 65µA of

supply current.

The LMV7235/LMV7239/LMV7239Qare rail-to-rail input and

output. The typical input common mode voltage range of

−0.2V below the ground to 0.2V above the supply. The

LMV7235/LMV7239/LMV7239Quse a complimentary PNP

and NPN input stage in which the PNP stage senses common

mode voltage near V− and the NPN stage senses common

mode voltage near V+. If either of the input signals falls below

the negative common mode limit, the parasitic PN junction

formed by the substrate and the base of the PNP will turn on

resulting in an increase of input bias current.

If one of the input goes above the positive common mode limit,

the output will still maintain the correct logic level as long as

the other input stays within the common mode range. How-

ever, the propagation delay will increase. When both inputs

are outside the common mode voltage range, current satu-

ration occurs in the input stage, and the output becomes

unpredictable.

The propagation delay does not increase significantly with

large differential input voltages. However, large differential

voltages greater than the supply voltage should be avoided

to prevent damage to the input stage.

The LMV7239 has a push-pull output. When the output

switches, there is a direct path between VCC and ground,

causing high output sinking or sourcing current during the

transition. After the transition, the output current decreases

and the supply current settles back to about 65µA at 5V, thus

conserving power consumption.

The LMV7235 has an open drain that requires a pull-up re-

sistor to a positive supply voltage for the output to switch

properly. When the internal output transistor is off, the output

voltage will be pulled up to the external positive voltage.

COMPARATOR WITH HYSTERESIS

The basic comparator configuration may oscillate or produce

a noisy output if the applied differential input voltage is near

the comparator's offset voltage. This usually happens when

the input signal is moving very slowly across the comparator's

switching threshold. This problem can be prevented by the

addition of hysteresis or positive feedback.

INVERTING COMPARATOR WITH HYSTERESIS

The inverting comparator with hysteresis requires a three re-

sistor network that is referenced to the supply voltage VCC of

the comparator, as shown in Figure 1. When VIN at the in-

verting input is less than VA, the voltage at the non-inverting

node of the comparator (VIN < VA), the output voltage is high

(for simplicity assume VO switches as high as VCC). The three

network resistors can be represented as R1||R3 in series with

R2. The lower input trip voltage VA1 is defined as

VA1 = VCCR2 / [(R1||R3) + R2]

When VIN is greater than VA (VIN > VA), the output voltage is

low, very close to ground. In this case the three network re-

sistors can be presented as R2||R3 in series with R1. The

upper trip voltage VA2 is defined as

VA2 = VCC (R2||R3) / [(R1)+ (R2||R3)]

The total hysteresis provided by the network is defined as

Delta VA = VA1- VA2

To assure that the comparator will always switch fully to VCC

and not be pulled down by the load the resistors, values

should be chosen as follow:

RPULL-UP << RLOAD

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LMV7235/LMV7239/LMV7239Q

10135919

FIGURE 1. Inverting Comparator with Hysteresis

NON-INVERTING COMPARATOR WITH HYSTERESIS

A non inverting comparator with hysteresis requires a two re-

sistor network, and a voltage reference (VREF) at the inverting

input. When VIN is low, the output is also low. For the output

to switch from low to high, VIN must rise up to VIN1 where

VIN1 is calculated by.

VIN1 = R1*(VREF / R2) + VREF

When VIN is high, the output is also high, to make the com-

parator switch back to it's low state, VIN must equal VREF

before VA will again equal VREF. VIN can be calculated by

VIN2 = [VREF (R1+ R2) - VCC R1] / R2

The hysteresis of this circuit is the difference between VIN1

and VIN2.

Delta VIN = VCC R1 / R2

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LMV7235/LMV7239/LMV7239Q

10135924

10135920

FIGURE 2. Non-Inverting Comparator with Hysteresis

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LMV7235/LMV7239/LMV7239Q

CIRCUIT LAYOUT AND BYPASSING

The LMV7235/LMV7239/LMV7239Qrequire high speed lay-

out. Follow these layout guidelines:

1. Use printed circuit board with a good, unbroken low-induc-

tance ground plane.

2. Place a decoupling capacitor (0.1µF ceramic surface

mount capacitor) as close as possible to VCC pin.

3. On the inputs and the output, keep lead lengths as short as

possible to avoid unwanted parasitic feedback around the

comparator. Keep inputs away from output.

4. Solder the device directly to the printed circuit board rather

than using a socket.

5. For slow moving input signals, take care to prevent parasitic

feedback. A small capacitor (1000pF or less) placed between

the inputs can help eliminate oscillations in the transition re-

gion. This capacitor causes some degradation to tPD when the

source impedance is low.

6. The topside ground plane runs between the output and in-

puts.

7. Ground trace from the ground pin runs under the device up

to the bypass capacitor, shielding the inputs from the outputs.

ZERO-CROSSING DETECTOR

The inverting input is connected to ground and the non-in-

verting input is connected to 100mVp-p signal. As the signal

at the non-inverting input crosses 0V, the comparator's output

changes state.

10135918

FIGURE 3. Zero-Crossing Detector

THRESHOLD DETECTOR

Instead of tying the inverting input to 0V, the inverting input

can be tied to a reference voltage. The non-inverting input is

connected to the input. As the input passes the VREF thresh-

old, the comparator's output changes state.

10135921

FIGURE 4. Threshold Detector

CRYSTAL OSCILLATOR

A simple crystal oscillator using the LMV7239 is shown below.

Resistors R1 and R2 set the bias point at the comparator's

non-inverting input. Resistors R3, R4 and C1 sets the invert-

ing input node at an appropriate DC average level based on

the output. The crystal's path provides resonant positive feed-

back and stable oscillation occurs. The output duty cycle for

this circuit is roughly 50%, but it is affected by resistor toler-

ances and to a lesser extent by the comparator offset.

10135922

FIGURE 5. Crystal Oscillator

IR RECEIVER

The LMV7239 is an ideal candidate to be used as an infrared

receiver. The infrared photo diode creates a current relative

to the amount of infrared light present. The current creates a

voltage across RD. When this voltage level cross the voltage

applied by the voltage divider to the inverting input, the output

transitions.

10135923

FIGURE 6. IR Receiver

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LMV7235/LMV7239/LMV7239Q

Physical Dimensions inches (millimeters) unless otherwise noted

5-Pin SC70

NS Package Number MAA05A

5-Pin SOT23

NS Package Number MF05A

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LMV7235/LMV7239/LMV7239Q

Notes

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LMV7235/LMV7239/LMV7239Q

Notes

LMV7235/LMV7239/LMV7239Q 45 nsec, Ultra Low Power, Low Voltage, Rail-to-Rail Input

Comparator with Open-Drain/Push-Pull Output

www.ti.com

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