LM2901-SR

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Technical content

Features

S ingle supply V oltage R ange or D ual S upplies: V to +36 V or ± 1 V to ± 18 V Very L ow S upply C urrent μ A ch I ndependent of Supply Voltage(0. mW/comparator at +5 V Low I nput B ias C urrent: n A typ. Low Offset Voltage: ± mV Max Offset Voltage Temperature Drift: μV/°C Input C ommon mode V oltage R ange I ncludes Ground Internal Differential I nput V oltage R ange E qual to T he Supply Voltage TTL, DTL, ECL, MOS, CMOS compatible Outputs O pen drain output ESD Clamps on the Inputs Increase the Ruggedness of the Device Without Affecting Performance Low Output Saturation 40° C to 125° C Operati on Range ESD Rating Robust KV HBM 2KV CDM High Performance Drop In Compatible With 3 2903, 2901 Series Product App lic ations High s peed L ine or Digital Line R eceiver s High S peed S ampling C ircuits Peak and Zero crossing D etectors Threshold Detectors/Discriminators Sensing at Ground or Supply Line

Description

comparators on a single monolithic substrate. The common mode input voltage range includes ground even when operated from a single supply, and the low power supply current drain makes these comparators suitable for battery operation. These types were designed to directly interface with TTL and CMOS Current drain is ind ependent of the supply voltage. The ou tputs can be connected to other open collector outputs to achieve wired AND relat ionships The LM2903 is dual channel version available in pin SOP package . The LM2901 is quad channel version avail able in 14 pin SOP package All devices are specified for the temperature range of 40° C to + 5° C. 3PEAK and the 3PEAK logo are registered trademarks of 3PEAK I NCORPORATED . All other trademarks are the property of their respective owners. Pin Configuration (Top View) Out A ﹢In A ﹣In A ﹢In B ﹣In B Out BA B LM2903 8-Pin SOIC ( -S Suffix) Out A ﹢In A ﹣In A C Out C ﹢In D ﹣In D Out B ﹢In B ﹣In B Out D ﹢In C ﹣In C LM2901 14-Pin SOIC (-S Suffix) A B D

L M2903 /LM2901 36V Low Power D ual/Quad Differential Comparators R ev. B www.3peakic.com.cn Order Information Model Name Order Number Package Transport Media, Quantity Marking Information LM2903 LM2903 S R Pin SO P Tape and Reel, 4,000 LM2903 LM2901 LM2901 S R Pin SO P Tape and Reel, 2,5 LM2901 Absolute Maximum Ratings Note 1 Supply Voltage: V V V 0.3 to V + 0.3 Input Current: +IN, IN, Note 2 0mA ... mA Output Short Circuit Duration Note 3 …... finite Operating Temperature Range.... ... 40° C to 125 65° C to 150° C Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Ra ting condition for extended periods may affect device reliability and lifetime. Note 2: The inputs are protected by ESD protection diodes to each power supply. If the input extends more than 0mV b eyo nd the power supply, the input current should be limite d to les s than 10mA. Note 3 : A heat sink may be required to keep the junction temperature below the absolute maximum. This depends on the power supply v oltage and how many amplifiers are shorted. Thermal resistance varies with the amount of PC board metal connected to the package. The specified values are for short traces connected to the leads. ESD, Electrostatic Discharge Protection Symbol Parameter Condition Minimum Level Unit HBM Human Body Model ESD MIL STD 883H Method 3015.8 kV CDM Charged Device Model ESD JEDEC EIA/JESD22 C101E kV

L M2903/LM2901 36V Low Power D ual/Quad Differential Comparators www.3peakic.com.cn R ev. B

Electrical Characteristics

denotes the specifications which apply over the full operating temperature range ~ +125 , otherwise specifications are at T A = 27° C. V DD V V IN+ = V DD , V IN 1.2 V , R PU =10k Ω , C L =15pF SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V DD Supply Voltage V V OS Input Offset Voltage Note 1 V CC = 5 V to MAX, V IC = V ICR (min), V O = 1.4V ± 0. mV V OS TC Input Offset Voltage Drift Note 1 V CM 1.2V μ V/° C I B Input Bias Current V DM 0.5 V n A C IN Input Capacitance Differential Common Mode pF V CM Common mode Input Voltage Range C V DD 1.5 V C ~ +125 C V DD V A VD Large signal D ifferential voltage A mplification V CC = 15 V, V O = 1.4 V to 11.4 V, R L 15 kΩ to V CC 400 V/mV I OH High level O utput C urrent V OH = 5 V, V ID = 1 V nA V OH = 30 V, V ID = 1 V μA V O L Low Level Output Voltage I OL mA, V ID = − 250 400 m V 700 m V I OL Low level O utput C urrent V OL = 1.5 V, V ID = −1 V m A I Q Quiescent Current per Comparator V CC V 150 300 μA V CC V 150 300 μA t RT Response time R L connected to 5 V through 5.1 kΩ, C L = 15 pF, See Note 100 mV input step with 5 mV overdrive μs TTL input level step Note 1: The input offset voltage is the average of the input referred trip points.

L M2903 /LM2901 36V Low Power D ual/Quad Differential Comparators R ev. B www.3peakic.com.cn Typical Performance Characteristics V S V, V CM = 0V, R L = Open, unless otherwise specified. Supply C urrent vs. S upply V oltage Response T ime for V arious I nput O verdrives P ositive T ransition Response T ime F or V arious I nput O verdrives Negative Output Swing vs. Sink Current Negative T ransition 50pF VOUT +5V 5.1kΩ VIN Response T ime Test Circuit 100 120 140 160 180 Supply Current(uA) Supply Voltage(V) 25° C -40° C 130° C -1.00E+00 0.00E+00 1.00E+00 2.00E+00 3.00E+00 4.00E+00 5.00E+00 6.00E+00 0.00E+00 2.00E-01 4.00E-01 6.00E-01 8.00E-01 1.00E+00 V OUT (V) Time( μ s Vov=20mV Vov=5mV Vov=100mV 0.2 0.4 0.6 0.8 1.2 V OUT (V) Time( μ Vov=100mV Vov=20mV Vov=5mV Vdrop(V) Isink (mA) T=25 T=130

L M2903/LM2901 36V Low Power D ual/Quad Differential Comparators www.3peakic.com.cn R ev. B Pin Functions IN: Inverting Input of the Comparator Voltage range of this pin can go from V to V 1.5 +IN: Non Inverting Input of Comparator. This pin has the same voltage range as IN. DD Positive Power Supply. Typically the voltage is from V to V. Split supplies are possible as long as the voltage between V+ and V is between V and V. A bypass capacitor of 0.1μF as close to the part as possible should be used between supply power between or pins and pins supply ground. V SS Negative Power Supply. It is normally tied to ground. It can also be tied to a voltage other than ground as long as the voltage between V and V is from V to If it is not connected to ground, bypass it with a capacitor of 0.1μF as close to the part as possible. OUT: Comparator Output. The voltage range extends to within millivolts of each supply rail. Operation The LM2903 /LM2901 family single supply comparators feature internal hysteresis, high speed, and low power. I nput signal range extends beyond the negative and positive power supplies. The output can even extend all the way to the negative supply. The input stag e is active over different ranges of common mode input voltage. Rail to rail input voltage range and low voltage single supply operation make these devices ideal for portable equipment. Applications Information Inputs The LM2903 /2901 comparator family uses CMOS transistors at the input which prevent phase inversion when the input pins exceed the supply voltages. Fig ure shows an input voltage exceeding both supplies with no resulting phase inversion. Fig ure Comparator Response to Input Voltage The electrostatic discharge (ESD) protection input structure o f two back to back diodes and 1 kΩ series resistors are used to limit the differential input voltage applied to the precision input of the comparator by clamping input Time (100μs/div) Vout Voltage (mV) VDD=5V Input Voltage Output Voltage

L M2903 /LM2901 36V Low Power D ual/Quad Differential Comparators R ev. B www.3peakic.com.cn voltages that exceed supply voltages , as shown in Fig ure Large differential voltage s exceeding the supply voltage should be avoided to prevent damage to the input stage. Chip 1KΩ 1KΩ Core +In -In Fig ure . Equivalent Input Structure External H ysteresis Greater flexibility in selecting hysteresis is achieved by using external resistors. Hysteresis reduces output chattering when one input is slowly moving past the other. It also helps in systems where it is best not to cycle between high and low states too frequently (e.g., air conditioner thermostatic control). Output chatter also increases the dynamic supply current. N on I nverting Comparator with Hysteresis A non inverting comparator with hysteresis requires a two resistor network, as shown in Fig ure and a voltage reference (V r ) at the inverting input. Vr Vi Vo Vr Vtr Vo V+=Vr Vr Vtf Vo V+=Vr VDD LM393 LM393 LM393 Fig ure Non Inverting Configuration with Hysteresis When V i is low, the output is also low. For the output to switch from low to high, V i must rise up to V tr When V i is high, the output is also high. In order for the comparator to switch back to a low state, V i must equal V tf before the non inverting input V is again equal to V r trV R2R1 rV tfV 1)tfVDD(VrV  RR R rV trV RR 

L M2903/LM2901 36V Low Power D ual/Quad Differential Comparators www.3peakic.com.cn R ev. B DDV rV tfV RRR  DDV tfVtrVhystV R I nverting Comparator with Hysteresis The inverting comparator w ith hysteresis requires a three resistor network that is referenced to the comparator supply voltage (V DD ), as shown in Fig ure Vi Vo VDD Vtr Vo VDD V+=Vtr Vtf Vo VDD V+=Vtf VDD LM393LM393 LM393 Fig ure Inverting Configuration with Hysteresis When V i is greater than V , the output voltage is low. In this case, the three network resistors can be presented as paralleled resistor R || R in series with R When V i at the inverting input is less than V , the output voltage is high. The three network resistors can be represented as R ||R in series with R DDV 23||1 trV RRR R DDV 13||2 3||2 tfV RRR RR DDV 32||1 2||1 tfVtrVhystV RRR RR  Low Input Bias Current The LM2903 /2901 family is a CMOS comparator family and features very low input bias current in pA range. The low input bias current allows the comparator s to be used in

applications

with high resistance sources. Care must be taken to minimize PCB Surface Leakage. See below section on “PCB Surface Leakage” for more details. PCB Surface Leakage In applications where low input bias current is critical, Printed Circuit Board (PCB) surface leakage effects need to be considered. Surface leakage is caused by humidity, dust or other contamination on the board. Under low humidity conditions, a typical resistance between nearby traces is 10 Ω. A 5V difference would ca use 5pA of

L M2903 /LM2901 36V Low Power D ual/Quad Differential Comparators R ev. B www.3peakic.com.cn current to flow, which is greater than the LM2903 LM2901 ’s input bias current at +27°C (± pA, typical). It is recommended to use multi layer PCB layout and rout e the comparator IN and +IN signal under the PCB surface. The effective way to reduc e surface leakage is to use a guard ring around sensitive pins (or traces). The guard ring is biased at the same voltage as the sensitive pin. An example of this type of layout is shown in Fig ure for Inverting configuration application. 1. For Non Inverting Configuration a) Connect the non inverting pin (V IN +) to the input with a wire that does not touch the PCB surface. b) Connect the guard ring to the inverting input pin (V IN ). This biases the guard ring to the same reference as the comparator 2. For Inverting Configuration a) Connect the guard ring to the non inverting input pin (V IN +). This biases the guard ring to the same reference voltage as the comparator (e.g., V DD /2 or ground). b) Connect the inverting pin (V IN ) to the input with a wire that does not touch the PCB surfac VIN+ VIN- +VSGuard Ring Fig ure Example Guard Ring Layout for Inverting Comparator Ground Sensing and Rail to Rail Output The LM2903 /2901 family implements a rail to rail topology that is capable of swinging to within 10mV of either rail. Since the inputs can go 00mV beyond either rail, the comparator can easily perform ‘true ground’ sensing. The maximum output current is a function of total supply voltage. As the supply voltage of the comparator increases, the output current capability also increases. Attention must be paid to keep the junction temperature of the IC below 150° C when the output is in continuous short circuit condition . The output of the amplifier has reverse biased ESD diodes connected to each su pply. The output should not be forced more than 0.5V beyond either supply, otherwise current will flow through these diodes. ESD The LM2903 /2901 family has reverse biased ESD protection diodes on all inputs and output. Input and out put pins cannot be biase d more than 00mV beyond either supply rail. Power Supply Layout a nd Bypass The LM2903 /2901 family ’s power supply pin should have a local bypass capacitor (i.e., 0.01μF to 0.1μF) within 2mm for good high frequency performance. It can also use a bulk capacitor (i.e., 1μF or larger) within 100mm to provide large, slow currents. This bulk capacitor can be shared with other analog parts. Good g round layout improves performance by decreasing the amount of stray capacitance and noise at the comparator inputs and outputs. To decrease stray capacitance, minimize PCB lengths and resistor leads, and place external components as close to the comparator ’ pins as possible. Prope r Board L ayout The LM2903 /2901 family is a series of fast s witching, high speed comparator and require s high speed layout considerations. For best results, the following layout guidelines should be follow ed: 1. Use a printed circuit board (PCB) with a good, unbroken low inductance ground plane. 2. Pl ace a decoupling capacitor (0.1 μF ceramic, surface mount capa citor) as close as possible to supply 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 the output.

L M2903/LM2901 36V Low Power D ual/Quad Differential Comparators www.3peakic.com.cn R ev. B 4. Solder the device directly to the PCB rather than using a socket. 5. For slow moving input signals, take care to prevent parasitic feedback. A small capacitor (1000 pF or less) placed between the inputs can help eliminate oscillations in the transition region. This capacitor causes some degradation to propagation delay when the impedance is low. The topside ground plane should be placed between the output and inputs. 6. The ground pin ground trace should run under the device up to the bypass capacitor, thus shielding the inputs from the outputs. Typical Applications IR R eceiver The LM2903 /2901 is an ideal candidate to be used as an infrared receiver shown in Figure The infrared photo diode creates a current relative to the amount of infrared light present. The current creates a voltage across R D When this voltage level cross the voltage applied by the voltage divider to the inverting input, the output transitions. Optional R o provides additional hysteresis for noise immunity. Vo Ro VDD LM393 RD Figure IR Receiver Relaxation Oscillator A relaxation oscillator using LM2903 /2901 is shown in Fig ure Resistors R and R set the bias point at the comparator's inverting inp ut. The period of oscillator is set by the time constant of R and C The maximum frequency is limited by the large s ignal prop agation delay of the comparator LM2903 /2901 s low propagation delay guarantees the high frequency oscillation. If the inverted input (V C ) is lower than the non inverting input (V A , the output is high which charges C through R until V is equal to V A The value of V A at this point is 2R3R||1R 2RDDV A1V At this point the comparator switches pulling down the output to the negative rail. The value of V A at this point is 3R||2R1R 3R||2RDDV A2V If R , then V =2V DD /3, and V V DD The capacitor C now discharges through R , and the voltage V C decreases till it is equal to V , at which point the comparator switches again, bringing it back to the initial stage. The time period is equal to twice the time it takes to discharge C from 2V DD /3 to V DD . Hence the frequency is:

L M2903 /LM2901 36V Low Power D ual/Quad Differential Comparators R ev. B www.3peakic.com.cn 1C4Rln22 Freq  Vo VDD LM393 R4C1 VC1 t VO R1=R2=R3 2/3VDD 1/3VDD t VC1 VA Fig ure Relaxation Oscillator W indowed Comparator Fig ure shows one approach to designing a windowed comparator using a single LM2903 /2901 chip Choose different thresholds by changing the values of R1, R2, and R3. O ut A provides an active low undervoltage indication, and O ut B gives an active low overvoltage indication. ANDing the two outputs provides an active high, power good signal. When input voltage V i reaches the overvoltage threshold V OH , the OutB gets low. Once V i falls to the undervolta ge threshold V UH , the OutA gets low. When V UH i OH , the AND Gate gets high. 1)/R3R2R1(RrVOHV  )2R1)/(R3R2R1(RrVUHV  OutA+InB +InA -InB -InA LM2903 OutB UnderVolt OverVolt Power GoodAND GateVr Vi Fig ure Windowed Comparator

L M2903/LM2901 36V Low Power D ual/Quad Differential Comparators www.3peakic.com.cn R ev. B D b E e θ C Package Outline Dimensions SO SOIC Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max 0.100 0.250 0.004 0.010 1.350 1.550 0.053 0.061 b 0.330 0.510 0.013 0.020 C 0.190 0.250 0.007 0.010 D 4.780 5.000 0.188 0.197 E 3.800 4.000 0.150 0.157 5.800 6.300 0.228 0.248 e 1.270TYP 0.050TYP 0.400 1.270 0.016 0.050 θ

L M2903 /LM2901 36V Low Power D ual/Quad Differential Comparators R ev. B www.3peakic.com.cn θ e b E1 E D A A2 L Package Outline Dimensions SO SOIC Symbol Dimensions In Millimeters MIN TYP MAX A 1.35 1.60 1.75 0.10 0.15 0.25 1.25 1.45 1.65 b 0.36 0.49 D 8.53 8.63 8.73 E 5.80 6.00 6.20 3.80 3.90 4.00 e

1.27 BSC

L 0.45 0.60 0.80

1.04 REF

0.25 BSC

θ