LTC1440/LTC1441/LTC1442 Ultralow Power Single/Dual Comparator with Reference U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Ultralow Quiescent Current: 2.1µA Typ (LTC1440) Reference Output Drives 0.01µF Capacitor Adjustable Hysteresis (LTC1440/LTC1442) Wide Supply Range: Single: 2V to 11V Dual: ±1V to ±5.5V Input Voltage Range Includes the Negative Supply TTL/CMOS Compatible Outputs 12µs Propagation Delay with 10mV Overdrive No Crowbar Current 40mA Continuous Source Current Pin Compatible Upgrades for MAX921/922/923 3mm x 3mm x 0.75mm DFN Package (LTC1440) U APPLICATIO S ■ ■ ■ ■ Battery-Powered System Monitoring Threshold Detectors Window Comparators Oscillator Circuits , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. The LTC ®1440/LTC1441/LTC1442 are ultralow power single and dual comparators with built-in references. The comparators feature less than 3.7µA supply current over temperature (LTC1440), a 1.182V ±1% reference, programmable hysteresis (LTC1440/LTC1442) and TTL/CMOS outputs that sink and source current. The reference output can drive a bypass capacitor of up to 0.01µF without oscillation. The comparators operate from a single 2V to 11V supply or a dual ±1V to ±5.5V supply (LTC1440). Comparator hysteresis is easily programmed by using two resistors and the HYST pin (LTC1440/LTC1442). Each comparator’s input operates from the negative supply to within 1.3V of the positive supply. The comparator output stage can continuously source up to 40mA. By eliminating the cross-conducting current that normally happens when the comparator changes logic states, the power supply glitches are eliminated. The LTC1440 is available in 8-pin PDIP, SO, MSOP and DFN packages. The LTC1441/LTC1442 are available in 8-pin PDIP and SO packages. U TYPICAL APPLICATIO Micropower 2.9V VCC Threshold Detector LTC1440 Supply Current vs Temperature 3.3V 5.0 R2 1.13M 1% 7 4.5 V+ 3 IN + + 8 4 IN– – 5 HYST V + = 5V V – = GND = 0V 4.0 3.5 3.0 2.5 2.0 LTC1440 6 REF OUT SUPPLY CURRENT (µA) R1 1.65M 1% 1.5 –40 –20 V– 2 GND 1 40 20 60 0 TEMPERATURE (°C) 80 100 1440/1/2 TA02 1440 TA01 144012fc 1 LTC1440/LTC1441/LTC1442 U W W W ABSOLUTE MAXIMUM RATINGS (Note 1) Voltage V + to V –, V + to GND, GND to V – ...........12V to – 0.3V IN +, IN –, HYST ................. (V + + 0.3V) to (V – – 0.3V) REF ................................... (V + + 0.3V) to (V – – 0.3V) OUT (LTC1440) .............. (V + + 0.3V) to (GND – 0.3V) OUT (LTC1441/LTC1442) ... (V + + 0.3V) to (V – – 0.3V) Current IN +, IN –, HYST ................................................. 20mA REF ................................................................... 20mA OUT .................................................................. 50mA OUT Short-Circuit Duration (V + ≤ 5.5V) .......Continuous Power Dissipation .............................................. 500mW Operating Temperature Range LTC144XC ............................................... 0°C to 70°C LTC144XI ........................................... – 40°C to 85°C Storage Temperature Range ................. – 65°C to 150°C Storage Temperature Range (DD Package) ................................... – 65°C to 125°C Junction Temperature ........................................... 150°C Junction Temperature (DD Package) .................... 125°C Lead Temperature (Soldering, 10 sec).................. 300°C W U U PACKAGE/ORDER INFORMATION TOP VIEW TOP VIEW GND 1 8 OUT V– 2 7 V+ IN + 3 6 REF IN – 4 5 HYST TJMAX = 125°C, θJA = 160°C/ W (DD) UNDERSIDE METAL CONNECTED TO V– (PCB CONNECTION OPTIONAL) DD8 PART MARKING* LBTH ORDER PART NUMBER LTC1440CDD LTC1440IDD TOP VIEW OUT A 1 8 OUT B V– 2 7 V+ IN A + 3 6 IN B + 4 5 – N8 PACKAGE 8-LEAD PDIP S8 PACKAGE 8-LEAD PLASTIC SO IN A – IN B OUT 2 7 V + IN + 3 6 REF IN – 4 5 HYST N8 PACKAGE 8-LEAD PDIP S8 PACKAGE 8-LEAD PLASTIC SO V DD PACKAGE 8-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 150°C, θJA = 130°C/ W (N8) TJMAX = 150°C, θJA = 175°C/ W (S8) TOP VIEW 8 GND 1 – GND V– IN + IN – 1 2 3 4 8 7 6 5 OUT V+ REF HYST MS8 PACKAGE 8-LEAD PLASTIC MSOP TJMAX = 150°C, θJA = 250°C/ W TJMAX = 150°C, θJA = 130°C/ W (N8) TJMAX = 150°C, θJA = 175°C/ W (S8) ORDER PART NUMBER LTC1440CN8 LTC1440CS8 LTC1440IN8 LTC1440IS8 ORDER PART NUMBER LTC1441CN8 LTC1441CS8 LTC1441IN8 LTC1441IS8 S8 PART MARKING 1441 1441I S8 PART MARKING 1440 1440 1440I 1440I ORDER PART NUMBER LTC1440CMS8 LTC1440IMS8 TOP VIEW OUT A 1 8 OUT B V– 2 7 V+ IN A+ 3 6 REF – 4 5 HYST N8 PACKAGE 8-LEAD PDIP S8 PACKAGE 8-LEAD PLASTIC SO IN B TJMAX = 150°C, θJA = 130°C/ W (N8) TJMAX = 150°C, θJA = 175°C/ W (S8) MS8 PART MARKING* LTBX ORDER PART NUMBER LTC1442CN8 LTC1442CS8 LTC1442IN8 LTC1442IS8 S8 PART MARKING 1442 1442I Order Options Tape and Reel: Add #TR Lead Free: Add #PBF Lead Free Tape and Reel: Add #TRPBF Lead Free Part Marking: http://www.linear.com/leadfree/ Consult LTC Marketing for parts specified with wider operating temperature ranges. * The temperature grade is identified by a label on the shipping container. 2 144012fc LTC1440/LTC1441/LTC1442 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V + = 5V and V – = GND = 0V unless otherwise noted. SYMBOL PARAMETER Power Supply V+ Supply Voltage Range Supply Current ICC Comparator VOS Comparator Input Offset Voltage Input Leakage Current (IN +, IN –) IIN Input Leakage Current (HYST) Comparator Input Common VCM Mode Range CMRR Common Mode Rejection Ratio PSRR Power Supply Rejection Ratio NOISE VHYST tPD Voltage Noise Hysteresis Input Voltage Range Propagation Delay VOH VOL Output High Voltage Output Low Voltage Reference Reference Voltage VREF CONDITIONS MIN IN + = IN – + 80mV LTC1440 0°C ≤ TA ≤ 70°C HYST = REF (LTC1440/LTC1442) –40°C ≤ TA ≤ 85°C LTC1441 LTC1442 ● ● ● ● VCM = 2.5V VIN + = VIN – = 2.5V V – to V + – 1.3V V + = 2V to 11V (LTC1441) V + = 2.5V to 11V (LTC1440/LTC1442) 100Hz to 100kHz LTC1440/LTC1442 COUT = 100pF Overdrive = 10mV Overdrive = 100mV IO = – 13mA IO = 1.8mA LTC1440 LTC1441/LTC1442 No Load ISOURCE ISINK ∆VREF Reference Output Source Current Reference Output Sink Current Reference Source Current Reference Sink Current ∆VREF ≤ 1mV (LTC1442) ∆VREF ≤ 2.5mV (LTC1442) 0 ≤ ISOURCE ≤ 2mA (LTC1440) 0 ≤ ISINK ≤ 10µA (LTC1440) NOISE Voltage Noise 100Hz to 100kHz ● ● ● ● ● LTC1440/LTC1442 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C LTC1440 (MSOP, DFN) ● TYP MAX UNITS 11.0 4.0 4.4 5.7 5.7 V µA µA µA µA ±3 ±0.01 ±0.02 ±10 ±1.0 ±1.0 V + – 1.3V mV nA nA V 0.1 0.1 0.1 100 1 1 1 2.0 2.1 3.5 3.5 V– REF – 50mV 15 8 ● ● ● V + – 0.4V ● ● ● ● 1.170 1.164 1.164 100 10 ● mV/V mV/V mV/V µVRMS REF V µs µs V GND + 0.4V V V – + 0.4V V 1.194 1.200 1.200 20 0.8 0.5 ● 100 5 1.5 5 V V V µA µA mV mV mV µVRMS 144012fc 3 LTC1440/LTC1441/LTC1442 ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. V + = 3V and V – = GND = 0V unless otherwise noted. SYMBOL PARAMETER Power Supply Supply Voltage Range V+ CONDITIONS ICC IN + = IN – Supply Current Comparator VOS Comparator Input Offset Voltage Input Leakage Current (IN +, IN –) IIN Input Leakage Current (HYST) Comparator Input Common VCM Mode Range CMRR Common Mode Rejection Ratio PSRR Power Supply Rejection Ratio NOISE VHYST tPD Voltage Noise Hysteresis Input Voltage Range Propagation Delay VOH Output High Voltage Comparator Output Low Voltage VOL Reference Reference Voltage VREF MIN ● + 80mV HYST = REF (LTC1440/LTC1442) LTC1440 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C LTC1441 LTC1442 V – to V + – 1.3V V + = 2V to 11V (LTC1441) V + = 2.5V to 11V (LTC1440/LTC1442) 100Hz to 100kHz LTC1440/LTC1442 COUT = 100pF Overdrive = 10mV Overdrive = 100mV IO = – 8mA IO = 0.8mA LTC1440 LTC1441/LTC1442 No Load LTC1440/LTC1442 0°C ≤ TA ≤ 70°C –40°C ≤ TA ≤ 85°C LTC1440 (MSOP, DFN) ISOURCE ISINK ∆VREF Reference Output Source Current Reference Output Sink Current Reference Source Current Reference Sink Current ∆VREF ≤ 1mV (LTC1442) ∆VREF ≤ 2.5mV (LTC1442) 0 ≤ ISOURCE ≤ 1mA (LTC1440) 0 ≤ ISINK ≤ 10µA (LTC1440) NOISE Voltage Noise 100Hz to 100kHz 2 ● ● ● ● ● ● ● ● VCM = 1.5V VIN + = VIN – = 1.5V ● TYP MAX 11 V 3.9 4.3 5.7 5.7 µA µA µA µA ±3 ±0.01 ±0.02 ±10 ±1 ±1 V + – 1.3V mV nA nA V 0.1 0.1 0.1 100 1 1 1 2 3.5 3.5 V– REF – 50mV REF 14 5 ● V + – 0.4V ● ● ● ● ● ● ● GND + 0.4V V – + 0.4V 1.170 1.164 1.164 60 10 UNITS 1.182 120 20 0.8 0.5 ● 100 1.194 1.200 1.200 5.5 1.5 5 mV/V mV/V mV/V µVRMS V µs µs V V V V V V µA µA mV mV mV µVRMS Note 1: Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. Exposure to any Absolute Maximum Rating condition for extended periods may affect device reliability and lifetime. 144012fc 4 LTC1440/LTC1441/LTC1442 U W TYPICAL PERFOR A CE CHARACTERISTICS Comparator Response Time vs Input Overdrive Comparator Response Time vs Input Overdrive 3 100mV 50mV OUTPUT VOLTAGE (V) TA = 25°C 4 10mV 20mV 2 1 0 0 100 0 –1 2 4 6 RESPONSE TIME (µs) 8 10 INPUT VOLTAGE (mV) INPUT VOLTAGE (mV) OUTPUT VOLTAGE (V) 5 5 TA = 25°C 4 100mV 3 50mV 20mV 10mV 2 1 0 100 0 –1 0 2 4 6 8 10 12 14 16 18 RESPONSE TIME (µs) 1440/1/2 G01 1440/1/2 G02 Comparator Short-Circuit Sink Current vs Supply Voltage Comparator Short-Circuit Source Current vs Supply Voltage 200 160 TA = 25°C 180 140 140 SOURCE CURRENT (mA) SINK CURRENT (mA) 160 OUT CONNECTED TO V + 120 100 80 60 120 OUT CONNECTED TO V – = GND = 0V 100 80 60 40 40 20 20 0 0 0 1 2 3 4 5 6 7 8 SUPPLY VOLTAGE (V) 9 10 1440/1/2 G03 0 1 2 3 SUPPLY VOLTAGE (V) 4 5 1440/1/2 G04 144012fc 5 LTC1440/LTC1441/LTC1442 U W TYPICAL PERFOR A CE CHARACTERISTICS Comparator Response Time vs Load Capacitance with 100mV Input Overdrive Comparator Response Time at Low Supply Voltage 12 10000 t PHL RESPONSE TIME (µs) RESPONSE TIME (µs) 10 8 t PLH 6 1000 20mV OVERDRIVE 100 4 2 0 20 60 80 40 LOAD CAPACITANCE (nF) 10 100mV OVERDRIVE 1 100 1.0 1440/1/2 G05 1.1 1.2 1.3 1.4 SUPPLY VOLTAGE (V) 1.5 1.6 1440/1/2 G06 Comparator Output Voltage High vs Load Current 5 OUTPUT VOLTAGE HIGH (V) TA = 25°C V + = 5V 4 3 V + = 3V 2 V + = 2V 1 0 10 20 30 40 LOAD CURRENT (mA) 50 60 1440/1/2 G07 144012fc 6 LTC1440/LTC1441/LTC1442 U W TYPICAL PERFOR A CE CHARACTERISTICS Comparator Output Voltage Low vs Load Current LTC1440/LTC1442 Hysteresis Control POSITIVE-TO-NEGATIVE INPUT VOLTAGE (mV) 2.5 2.0 + V = 3V V + = 2V 1.5 V + = 5V 1.0 0.5 0 0 10 50 60 20 30 40 LOAD CURRENT (mA) 70 80 60 OUTPUT HIGH 40 20 0 OUTPUT LOW –20 –40 –60 –80 0 80 10 20 30 VREF – VHYST (mV) 40 50 1440/1/2 G09 1440/1/2 G08 LTC1440 Supply Current vs Temperature 6 5 SUPPLY CURRENT (µA) OUTPUT VOLTAGE LOW (V) TA = 25°C V + = 5V V – = –5V 4 3 V + = 3V V – = GND = 0V 2 V + = 5V V – = GND = 0V 1 –60 –40 –20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) 1440/1/2 G10 144012fc 7 LTC1440/LTC1441/LTC1442 U W TYPICAL PERFOR A CE CHARACTERISTICS Reference Output Voltage vs Output Load Current (Sink) Reference Output Voltage vs Output Load Current 1.200 1.190 REFERENCE OUTPUT VOLTAGE (V) REFERENCE OUTPUT VOLTAGE (V) VCC = 5V 1.185 SOURCE 1.180 1.175 1.170 1.165 1.160 1.155 V CC = 2V 1.195 V CC = 5V 1.190 1.185 SINK 1.180 1.175 1.170 0 0.5 1.0 1.5 2.0 2.5 3.0 OUTPUT LOAD CURRENT (mA) 3.5 0 25 10 15 20 5 OUTPUT LOAD CURRENT (µA) 30 1440/1/2 G12 1440/1/2 G11 Reference Voltage vs Temperature 1.186 REFERENCE VOLTAGE (V) 1.184 1.182 1.180 1.178 1.176 1.174 1.172 1.170 –60 –40 –20 0 20 40 60 80 100 120 140 TEMPERATURE (°C) 1440/1/2 G13 144012fc 8 LTC1440/LTC1441/LTC1442 U U U PIN FUNCTIONS 1 GND LTC1440 – 2 V OUT 8 1 OUT A 7 2 V– V+ 3 IN 4 IN– + REF 6 – HYST 5 OUT B 8 V+ + + LTC1441 A – + – B 7 1 OUT A 2 V– + LTC1442 3 IN A IN B 4 IN A– IN B– 5 6 – – V+ 7 + 3 IN A+ 4 IN B– 8 B A + + OUT B REF 6 V– HYST 5 1440/1/2 PD LTC1440 GND (Pin 1): Ground. Connect to V – for single supply operation. V – (Pin 2): Negative Supply. Connect to ground for single supply operation. Potential should be more negative than GND. IN + (Pin 3): Noninverting Comparator Input. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. IN B – (Pin 5): Inverting Input of Comparator B. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. IN B + (Pin 6): Noninverting Input of Comparator B. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. V + (Pin 7): Positive Supply. 2V to 11V. OUT B (Pin 8): Comparator B CMOS Output. Swings from V – to V +. Output can source up to 40mA and sink 5mA. IN – (Pin 4): Inverting Comparator Input. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. LTC1442 HYST (Pin 5): Hysteresis Input. Connect to REF if not used. Input voltage range is from VREF to VREF – 50mV. V – (Pin 2): Negative Supply. REF (Pin 6): Reference Output. 1.182V with respect to V –. Can source up to 200µA and sink 15µA at 25°C. Drive 0.01µF bypass capacitor without oscillation. IN A+ (Pin 3): Noninverting Input of Comparator A. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. V + (Pin 7): Positive Supply. 2V to 11V. IN B– (Pin 4): Inverting Input of Comparator B. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. OUT (Pin 8): Comparator CMOS Output. Swings from GND to V +. Output can source up to 40mA and sink 5mA. LTC1441 OUT A (Pin 1): Comparator A CMOS Output. Swings from V – to V +. Output can source up to 40mA and sink 5mA. V – (Pin 2): Negative Supply. IN A+ (Pin 3): Noninverting Input of Comparator A. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. OUT A (Pin 1): Comparator A CMOS Output. Swings from V – to V +. Output can source up to 40mA and sink 5mA. HYST (Pin 5): Hysteresis Input. Connect to REF if not used. Input voltage range is from VREF to VREF – 50mV. REF (Pin 6): Reference Output. 1.182V with respect to V –. Can source up to 200µA and sink 15µA at 25°C. Drive 0.01µF bypass capacitor without oscillation. V + (Pin 7): Positive Supply. 2V to 11V. OUT B (Pin 8): Comparator B CMOS Output. Swings from V – to V +. Output can source up to 40mA and sink 5mA. IN A– (Pin 4): Inverting Input of Comparator A. Input common mode range from V – to V + –1.3V. Input current typically 10pA at 25°C. 144012fc 9 LTC1440/LTC1441/LTC1442 U W U U APPLICATIONS INFORMATION LTC1440/LTC1441/LTC1442 are a family of micropower comparators with built-in 1.182V reference. Features include programmable hysteresis (LTC1440/LTC1442), wide supply voltage range (2V to 11V) and the ability of the reference to drive up to a 0.01µF capacitor without oscillation. The comparators’ CMOS outputs can source up to 40mA and the supply current glitches, that normally occur when switching logic states, have been eliminated. capacitor of up to 0.01µF without oscillation and by inserting a series resistor, capacitance values up to 100µF can be used (Figure 1). Power Supplies Figure 3 shows the bypassed reference output with a square wave applied to the V + pin. Resistors R2 and R3 set 10mV of hysteresis voltage band while R1 damps the reference response. Note that the comparator output doesn’t trip. The comparator family operates from a single 2V to 11V supply. The LTC1440 includes a separate ground for the comparator output stage, allowing a split supply ranging from ±1V to ±5.5V. Connecting V – to GND on the LTC1440 will allow single supply operation. If the comparator output is required to source more than 1mA, or the supply source impedance is high, V + should be bypassed with a 0.1µF capacitor. Figure 2 shows the resistor value required for different capacitor values to achieve critical damping. Bypassing the reference can help prevent false tripping of the comparators by preventing glitches on V + or reference load transients from disturbing the reference output voltage. REFERENCE OUTPUT REF R1 Comparator Inputs The comparator inputs can swing from the negative supply V – to within 1.3V max of the positive supply V +. The inputs can be forced 300mV below V – or above V + without damage and the typical input leakage current is only ±10pA. C1 LTC144X V– 1440/1/2 F01 Figure 1. Damping the Reference Output Comparator Outputs Voltage Reference The internal bandgap reference has a voltage of 1.182V referenced to V –. The reference accuracy is 1.5% from – 40°C to 85°C. It can source up to 200µA and sink up to 20µA with a 5V supply. The reference can drive a bypass 1000 RESISTOR VALUE (kΩ) The LTC1440 comparator output swings between GND and V + to assure TTL compatibility with a split supply. The LTC1441 and LTC1442 outputs swing between V – and V +. The outputs are capable of sourcing up to 40mA and sinking up to 5mA while still maintaining microampere quiescent currents. The output stage does not generate crowbar switching currents during transitions which helps minimize parasitic feedback through the supply pins. 100 10 1 0.1 0.001 0.01 0.1 1 CAPACITOR VALUE (µF) 10 1440/1/2 F02 Figure 2. Damping Resistance vs Bypass Capacitor Value 144012fc 10 LTC1440/LTC1441/LTC1442 U U W U APPLICATIONS INFORMATION 7 V+ 3 IN + + 8 4 IN– 5V TO 8V OUT up to 15%. If hysteresis is not wanted, the HYST pin should be shorted to REF. Acceptable values for IREF range from 0.1µA to 5µA. If 2.4M is chosen for R2, then the value of R1 is equal to the value of VHB. – 5 HYST R2 10k R3 2.4M 2 C1 1µF HYST R2 = VHB (2)(IREF) ( 1.182V – VHB 2 ) IREF V– R2 GND 2 1 1440/1/2 F04 Figure 4. Programmable Hysteresis 1440/1/2 F03a Figure 3a. Reference Transient Response Test Circuit Level Detector The LTC1440 is ideal for use as a micropower level detector as shown in Figure 5. R1 and R2 form a voltage divider from VIN to the noninverting comparator input. R3 and R4 set the hysteresis voltage, and R5 and C1 bypass the reference output. The following design procedure can be used to select the component values: 8V V+ 5V 2mV/DIV LTC1440 5 V– R1 = REF R1 LTC1440 6 REF R1 430Ω 6 IREF VREF 1. Choose the VIN voltage trip level, in this example 4.65V. OUT 2ms/DIV 1440/1/2 F03b Figure 3b. Reference and Comparator Output Transient Response Hysteresis Hysteresis can be added to the LTC1440 by connecting a resistor (R1) between the REF and HYST pins and a second resistor (R2) from HYST to V – (Figure 4). The difference between the upper and lower threshold voltages, or hysteresis voltage band (VHB), is equal to twice the voltage difference between the REF and HYST pins. When more hysteresis is added, the upper threshold increases the same amount as the low threshold decreases. The maximum voltage allowed between REF and HYST pins is 50mV, producing a maximum hysteresis voltage band of 100mV. The hysteresis band could vary by V IN 5V R2 3.4M 1% 7 V+ 3 IN + + 8 R1 1.18M 1% 4 IN – OUT – 5 HYST R3 15k 1% R4 2.4M 1% LTC1440 6 REF R5 430Ω 5% C1 1µF V– 2 GND 1 1440/1/2 F05 Figure 5. Glitch-Free Level Detector with Hysteresis 144012fc 11 LTC1440/LTC1441/LTC1442 U W U U APPLICATIONS INFORMATION 2. Calculate the required resistive divider ratio. Ratio = VREF/ VIN Ratio = 1.182V/4.65V = 0.254 3. Choose the required hysteresis voltage band at the input VHBIN, in this example 60mV. Calculate the hysteresis voltage band referred to the comparator input VHB. ⎤ ⎡ ⎥ ⎢ 4.65V − 1⎥ R2 = 1.18M ⎢ 15mV ⎥ ⎢ ⎥⎦ ⎢⎣ 1.182V + 2 R2 = 3.40M VHB = (VHBIN)(Ratio) Low Voltage Operation VHB = (60mV)(0.254) The guaranteed minimum operating voltage is 2V or (±1V). As the total supply voltage is reduced below 2V, the performance degrades and the supply current falls. Both the reference and the comparator are still functioning with supply voltage down to 1.5V. The reference will have slightly worse temperature coefficient. While the comparator would have less output drive and the propagation delay increases. The useful input voltage range extends from the negative supply to a little under 1V below the positive supply, which is slightly closer to the positive rail than the device operating from higher supply voltages. VHB = 15.24mV 4. Choose the values for R3 and R4 to set the hysteresis. R4 = 2.4M R3(kΩ) = VHB = 15k 5. Choose the values for R1 and R2 to set the trip point. V 1.182V = 1.18M R1 = REF = IBIAS 1µA ⎤ ⎡ ⎥ ⎢ VIN R2 = R1⎢ − 1⎥ VHB ⎥ ⎢ ⎥⎦ ⎢⎣ VREF + 2 144012fc 12 LTC1440/LTC1441/LTC1442 U TYPICAL APPLICATIONS 10-Bit 30µA A/D Converter 32.768kHz 1M 5V 470k + C2 1/2 LTC1441 5V EIN 0V TO 3V – 1.2M 100k ® LT 1034 1.2V 10pF + 365k* C1 1/2 LTC1441 2N3809 STATUS – 0.033µF POLYSTYRENE 150k VN2222LL 1N914 74C00 10M Q 74C00 DATA OUT 74C00 Q 74C74 74C00 D Low Battery Detect Operates Down to 1.5V V+ 2.6M 3 IN + 4 IN– 32.768kHz 1M +V LTC1440 470k + 8 1M 1440/1/2 TA03 32.768kHz “Watch Crystal” Oscillator 7 2-CELL NiCd CLK CONV COMMAND *TRW-IRC MRT–5/+120ppm/°C OUT + 1/2 LTC1441 OUT – – V+ 1.2M 10pF 6 REF 1440/1/2 TA05 20k 5 1.3M HYST GND 1 V– 1440 TA06 2 1M 144012fc 13 LTC1440/LTC1441/LTC1442 U PACKAGE DESCRIPTIO DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698) R = 0.115 TYP 5 0.38 ± 0.10 8 0.675 ±0.05 3.5 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) 1.65 ± 0.10 (2 SIDES) 3.00 ±0.10 (4 SIDES) PIN 1 TOP MARK (NOTE 6) PACKAGE OUTLINE (DD8) DFN 1203 0.25 ± 0.05 4 0.25 ± 0.05 0.75 ±0.05 0.200 REF 0.50 BSC 2.38 ±0.05 (2 SIDES) 1 0.50 BSC 2.38 ±0.10 (2 SIDES) 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-1) 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON TOP AND BOTTOM OF PACKAGE MS8 Package 8-Lead Plastic MSOP (Reference LTC DWG # 05-08-1660) 0.889 ± 0.127 (.035 ± .005) 5.23 (.206) MIN 3.20 – 3.45 (.126 – .136) 0.42 ± 0.038 (.0165 ± .0015) TYP 3.00 ± 0.102 (.118 ± .004) (NOTE 3) 0.65 (.0256) BSC 8 7 6 5 RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) 3.00 ± 0.102 (.118 ± .004) (NOTE 4) 4.90 ± 0.152 (.193 ± .006) DETAIL “A” 0.52 (.0205) REF 0° – 6° TYP GAUGE PLANE 0.53 ± 0.152 (.021 ± .006) DETAIL “A” 1 2 3 4 1.10 (.043) MAX 0.86 (.034) REF 0.18 (.007) SEATING PLANE 0.22 – 0.38 (.009 – .015) TYP 0.65 (.0256) BSC NOTE: 1. DIMENSIONS IN MILLIMETER/(INCH) 2. DRAWING NOT TO SCALE 3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS. MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS. INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE 5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX 0.127 ± 0.076 (.005 ± .003) MSOP (MS8) 0204 144012fc 14 LTC1440/LTC1441/LTC1442 U PACKAGE DESCRIPTION N8 Package 8-Lead PDIP (Narrow 0.300) (LTC DWG # 05-08-1510) .400* (10.160) MAX 8 7 6 5 1 2 3 4 .255 ± .015* (6.477 ± 0.381) .300 – .325 (7.620 – 8.255) .065 (1.651) TYP .008 – .015 (0.203 – 0.381) ( +.035 .325 –.015 8.255 +0.889 –0.381 .130 ± .005 (3.302 ± 0.127) .045 – .065 (1.143 – 1.651) ) .120 (3.048) .020 MIN (0.508) MIN .018 ± .003 .100 (2.54) BSC (0.457 ± 0.076) N8 1002 NOTE: 1. DIMENSIONS ARE INCHES MILLIMETERS *THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .010 INCH (0.254mm) S8 Package 8-Lead Plastic Small Outline (Narrow 0.150) (LTC DWG # 05-08-1610) .189 – .197 (4.801 – 5.004) NOTE 3 .045 ±.005 .050 BSC 8 .245 MIN 7 6 5 .160 ±.005 .150 – .157 (3.810 – 3.988) NOTE 3 .228 – .244 (5.791 – 6.197) .030 ±.005 TYP 1 RECOMMENDED SOLDER PAD LAYOUT .010 – .020 × 45° (0.254 – 0.508) .008 – .010 (0.203 – 0.254) 0°– 8° TYP .016 – .050 (0.406 – 1.270) NOTE: 1. DIMENSIONS IN .053 – .069 (1.346 – 1.752) .014 – .019 (0.355 – 0.483) TYP INCHES (MILLIMETERS) 2. DRAWING NOT TO SCALE 3. THESE DIMENSIONS DO NOT INCLUDE MOLD FLASH OR PROTRUSIONS. MOLD FLASH OR PROTRUSIONS SHALL NOT EXCEED .006" (0.15mm) 2 3 4 .004 – .010 (0.101 – 0.254) .050 (1.270) BSC SO8 0303 144012fc Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LTC1440/LTC1441/LTC1442 U TYPICAL APPLICATION 10kHz V/F Converter +V 6.2V TO 12V LM334 2k* INPUT 0V TO 5V 1.2M* Q8 Q1 + LT1034-1.2 2.2µF 10kHz TRIM 200k C1 1/2 LTC1441 0.01µF + LT1034-1.2 – 0.47µF Q2 + 50pF Q3 100k Q4 2M TYP 100Hz TRIM = HP5082-2810 15k = 1N4148 Q7 Q5 = 2N2222 100pF** fOUT 0kHz TO 10kHz * = 1% METAL FILM ** = POLYSTYRENE Q6 74C14 10M 2.7M 0.1µF – C2 1/2 LTC1441 + 1440/1/2 TA04 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1443 1.182V Reference with Micropower Quad Comparators 1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF LTC1444/LTC1445 1.2V Reference with Quad Comparator with Adjustable Hysteresis 1% Accuracy, 8.5µA Maximum Current, Ref Output Drives 0.01µF LTC1540 1.182V Reference with Nanopower Comparator with Adjustable Hysteresis DFN Package 0.3µA Quiescent Current (Typical), Reference Drives 0.01µF LTC1541 1.2V Reference with Micropower Amplifier and Comparator DFN Package 1.25% Accuracy, Rail-to-Rail Out, Low Offset Amplifier LTC1842/LTC1843 1.82V Reference with Dual Comparators with Adjustable Hysteresis 1% Accuracy, Open-Drain Out, Reference Drives 0.01µF LTC1998 1.2 Reference with Comparator with Adjustable Thesholds Li-Ion Low Battery Monitor, SOT23, 1% Accuracy LT6700-1 0.4 Reference with Low Voltage Dual Comparators LT6700-2/LT6700-3 SOT23, 1.4V to 18.5V Supply Range, ±2% Over Temperature 144012fc 16 Linear Technology Corporation LT 0106 REV C • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 1996