LTC2965 100V Micropower Single Voltage Monitor Features Description Wide Operating Range: 3.5V to 100V n Wide Monitoring Range: 3.5V to 98V n Quiescent Current: 7µA n Adjustable Threshold Range n Internal High Value Resistive Dividers n ±1.4% (Max) Threshold Accuracy Over Temperature n Polarity Selection n100V Rated Outputs n Selectable Built-In Hysteresis n16-Lead MS and 8-Lead 3mm × 3mm DFN Packages The LTC®2965 is a low current, high voltage single channel voltage monitor. Internal high value resistors sense the input monitor pin providing a compact and low power solution for voltage monitoring. Two comparator reference inputs (INH and INL) are included to allow configuration of a high and low threshold using an external resistive divider biased from the on-chip reference. A range selection pin is provided to set the internal resistive divider for 10x or 40x scaling. The thresholds are scaled according to the range selection settings. Additionally, either INH or INL can be grounded to enable built-in hysteresis. Polarity selection pin allows the output to be inverted. The output is 100V capable and includes a 500k pull-up resistor to an internal supply. n Applications n n n n Portable Equipment Battery-Powered Equipment Telecom Systems Automotive/Industrial Electronics L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application Undervoltage Monitor 24V 5V VIN OUT INH 91k 3.5V to 24.5V 10x 14V to 98V 40x 24V UNDERVOLTAGE 5V SYS LTC2965 INL Supply Current vs VIN 12 909k 10 PS RS GND 8 2965 TA01a POLARITY AND RANGE SELECTION IVIN (µA) THRESHOLD CONFIGURATION RANGE SELECTION 100k REF 200k VIN MONITOR RANGE 6 4 RISING THRESHOLD FALLING THRESHOLD HYSTERESIS RANGE 20.0V 18.2V 1.8V 10x 0 –45°C 25°C 90°C 125°C RANGE = 40x OUT = LOW IREF = 0µA 2 0 20 40 60 VIN (V) 80 100 2965 TA01b 2965fb For more information www.linear.com/LTC2965 1 LTC2965 Absolute Maximum Ratings (Notes 1, 2) Input Voltages VIN........................................................ –0.3V to 140V PS, RS...................................................... –0.3V to 6V INH, INL.................................................... –0.3V to 6V Output Voltages OUT...................................................... –0.3V to 140V Average Currents VIN....................................................................–20mA OUT....................................................................±5mA REF.....................................................................±5mA INH, INL..............................................................–1mA Operating Ambient Temperature Range LTC2965C................................................. 0°C to 70°C LTC2965I..............................................–40°C to 85°C LTC2965H........................................... –40°C to 125°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec).................... 300°C Pin Configuration TOP VIEW VIN 1 REF 2 INH 3 9 GND INL 4 TOP VIEW 8 OUT 7 GND 6 RS 5 PS VIN NC NC NC NC REF INH INL OUT NC NC NC NC GND RS PS 16 15 14 13 12 11 10 9 MS PACKAGE 16-LEAD PLASTIC MSOP DD PACKAGE 8-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 150°C, θJA = 120°C/W TJMAX = 150°C, θJA = 43°C/W EXPOSED PAD (PIN 9) PCB GND CONNECTION OPTIONAL Order Information 1 2 3 4 5 6 7 8 (http://www.linear.com/product/LTC2965#orderinfo) Lead Free Finish TUBE TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LTC2965CDD#PBF LTC2965CDD#TRPBF LGMK 8-Lead (3mm × 3mm) Plastic DFN 0°C to 70°C LTC2965IDD#PBF LTC2965IDD#TRPBF LGMK 8-Lead (3mm × 3mm) Plastic DFN –40°C to 85°C LTC2965HDD#PBF LTC2965HDD#TRPBF LGMK 8-Lead (3mm × 3mm) Plastic DFN –40°C to 125°C LTC2965CMS#PBF LTC2965CMS#TRPBF 2965 16-Lead Plastic MSOP 0°C to 70°C LTC2965IMS#PBF LTC2965IMS#TRPBF 2965 16-Lead Plastic MSOP –40°C to 85°C LTC2965HMS#PBF LTC2965HMS#TRPBF 2965 16-Lead Plastic MSOP –40°C to 125°C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. Consult LTC Marketing for information on nonstandard lead based finish parts. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/ 2 2965fb For more information www.linear.com/LTC2965 LTC2965 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, RS = GND, PS = GND, INH = 1.2V, INL = GND (Notes 1, 2). SYMBOL VIN VMON IVIN VUVLO PARAMETER Input Supply Operating Range VIN Monitor Range VIN Input Supply Current Undervoltage Lockout Undervoltage Lockout Hysteresis Comparator Reference Input: INH, INL Comparator Common Mode Voltage VCM VIN Error Voltage at 96V VERR VIN Error Voltage at 24V VOS AVERR VHYS Comparator Offset Voltage Internal Resistive Divider Range Error Comparator Built-in Hysteresis VHYTH tPD Built-in Hysteresis Enable Threshold VIN to OUT Comparator Propagation Delay IIN(LKG) Input Leakage Current (INH, INL) Reference: REF Reference Output Voltage VREF Noise Reference Output Noise Control Inputs: RS, PS Select Input Threshold VTH Input Leakage Current ILKG Status Outputs: OUT Voltage Output Low VOL VOH Voltage Output High IOH IO(LKG) Output Current High Leakage Current, Output High CONDITIONS VIN l VIN = 100V, 40x VIN Rising VIN Falling l MIN 3.5 3.5 3 TYP 7 l MAX 100 98 15 3 UNITS V V µA V mV V mV mV mV mV mV % mV mV mV µs nA nA 70 Overdrive = 10%, OUT Falling,10x INH = GND, INL = 1.2V V = 1.2V, I-Grade V = 1.2V, H-Grade l 40 2.45 ±1360 ±400 ±315 ±75 ±3 ±0.4 30 –14 175 80 l l ±0.1 ±0.1 ±1 ±10 IREF ≤ 100µA, VIN ≥ 3.5V 100Hz to 100kHz l 2.378 2.402 140 2.426 V µVRMS l 0.4 1.4 ±100 V nA 100 400 2.75 4 –5 ±250 mV mV V V µA nA l INH = VREF, 40x 0.35V ≤ INH ≤ 2.4V, 40x INH = VREF, 10x 0.35V ≤ INH ≤ 2.4V, 10x INH = 0.35V, 10x INH = 2.4V, Range = 10x, 40x INH = GND, INL Rising, VIN = 24V INL = GND , INH Falling, VIN = 24V ±250 ±250 ±35 ±35 ±1.9 l l l l l l l V = 2.4V l VIN = 1.25V, I = 10µA VIN = 3.5V, I = 500µA VIN = 3.5V, I = –1µA VIN ≥ 4.5V, I = –1µA V = GND, VIN = 3.5V V = 100V, VIN = 6V l l 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. 0.35 l l l l l l 14 –30 100 2 2.8 –15 22 –22 2.375 3 –7.5 Note 2: All currents into pins are positive; all voltages are referenced to GND unless otherwise noted. 2965fb For more information www.linear.com/LTC2965 3 LTC2965 Typical Performance Characteristics Supply Current vs VIN VREF vs Temperature 12 2.412 10 2.408 8 2.404 2.450 I = –10µA VREF vs Load Current VIN = 3.5V 6 2.400 –45°C 25°C 90°C 125°C RANGE = 40x OUT = LOW IREF = 0µA 2 0 20 40 60 VIN (V) 100 80 2.375 –45°C 25°C 90°C 125°C 2.392 2.388 –50 –25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2965 G01 2.450 2.400 2.396 4 0 VREF (V) VREF (V) IVIN (µA) 2.425 2.350 0.4 0 1.2 1.6 0.8 LOAD CURRENT (mA) 2965 G02 VREF vs VIN 2965 G03 Comparator VOS vs Temperature % Range Error vs Temperature 1500 0.4 25°C 2.0 VINH(L) = 1.2V 1000 2.400 2.375 2.350 2.7 0.2 500 VOS (µV) RANGE ERROR, AVERR (%) VREF (V) 2.425 0 –500 –0.2 1µA 100µA 1mA 3.0 3.5 3.2 VIN (V) 3.7 –0.4 –50 –25 4.0 0 25 50 75 100 125 150 TEMPERATURE (°C) 50 –45°C 25°C 90°C 125°C 0 0.1 1 10 % OVERDRIVE (%) 100 28 |BUILT-IN HYSTERESIS| VHYS (mV) PROPAGATION DELAY, tPD (µs) 75 25 0 25 50 75 100 125 150 TEMPERATURE (°C) 2965 G06 Built-In Hysteresis vs Temperature VINL = 1.2V VINH = GND VIN = 12V 100 –1500 –50 –25 2965 G05 VIN Falling Propagation Delay vs % Overdrive 125 –1000 10x 40x 2965 G04 VINH(L) = 1.2V 26 24 22 20 18 16 –50 2965 G10 4 0 0 50 100 TEMPERATURE (°C) 150 2965 G08 2965fb For more information www.linear.com/LTC2965 LTC2965 Typical Performance Characteristics Voltage Output High vs Pull-Down Current (OUT) 4 Voltage Output Low vs Pull-Up Current (OUT) 1.50 VIN = 12V Voltage Output High vs Input Voltage 3.5 –45°C 25°C 90°C 125°C 1.25 3 3.2 1 0 –45°C 25°C 90°C 125°C 0 –6 –9 –3 PULL-DOWN CURRENT (µA) –12 2.9 VOH (V) VOL (V) VOH (V) 1.00 2 0.75 2.6 0.50 2.3 0.25 2.0 0 I = –1µA 0 1 5 2 3 4 PULL-UP CURRENT (mA) 3 4 5 6 7 8 VIN (V) 2965 G10 2965 G09 1.7 2965 G11 Pin Functions Exposed Pad (DD8 Only): Exposed pad may be left floating or connected to device ground. GND: Device Ground. INH: High Comparator Reference Input. Voltage on this pin is multiplied by the configured range setting to set the VIN high or rising threshold. Keep within valid voltage range, VCM, or tie to GND to configure built-in hysteresis where high threshold for VIN becomes INL + VHYS scaled according to the RS pin configuration. INL: Low Comparator Reference Input. Voltage on this pin is multiplied by the configured range setting to set the VIN low or falling threshold. Keep within valid voltage range, VCM, or tie to GND to configure built-in hysteresis where low threshold becomes INH – VHYS scaled according to the RS pin configuration. Otherwise, INH-INL sets the hysteresis of the comparator. Oscillation will occur if INL > INH unless built-in hysteresis is enabled. OUT: Comparator Output. OUT consists of a high voltage active pull-down and a gated, resistive (500kΩ) pull-up to an internally generated supply between 3.5V and 5V depending on input supply voltage. Blocking circuitry at the pin allows the pin to be resistively pulled up to voltages as high as 100V without back conducting onto the internal supply of the part. Polarity with respect to the VIN pin is configured using the polarity select pin, PS. OUT pulls low when the part is in UVLO. PS: Polarity Selection. Connect to REF or a voltage >VTH to configure comparator output to be inverting with respect to VIN. Otherwise connect pin to GND to configure comparator output to be noninverting with respect to VIN. REF: Reference Output. VREF with respect to GND. Use a maximum of 1nF to bypass unless damping resistor is used. RS: Range Select Input. RS selects 10x or 40x range. Connect to REF or GND to configure pin. (See Table 1) VIN: Voltage Monitor and Supply Input. An internal high value resistive divider is connected to the pin. If VIN falls below the UVLO threshold minus hysteresis, the output is pulled low. If VIN < 1.2V, the logic state of the outputs cannot be guaranteed. 2965fb For more information www.linear.com/LTC2965 5 LTC2965 Block Diagrams REF 1X VIN VREF INTERNAL REGULATOR GND 70M VINT + – VHYTH INH –+ + VHYS VHYS VINT – +– OUT INL VHYTH 500k – + PS 10x/40x RS 2965 BD 6 2965fb For more information www.linear.com/LTC2965 LTC2965 Operation A built-in buffered reference gives the monitor flexibility to operate independently from a high voltage supply without the requirement of additional low voltage biasing. The reference provides an accurate voltage from which a resistive divider to ground configures the threshold voltage for the internal comparator. In addition, the REF pin can be used as a logic high voltage for the range and polarity select pins. The input voltage threshold at VIN is determined by the voltage on the INH and INL pins which are scaled by the internal resistive divider. The LTC2965 offers two range settings to select from, 10x and 40x, using the RS pin. Use Table 1 to determine the correct configuration for a desired range setting. The polarity select pin, (PS), configures the OUT pin to be inverting or noninverting with respect to VIN allowing the part to be configured for monitoring overvoltage and undervoltage conditions with either polarity output. Table 1. VIN MONITOR RANGE RANGE SELECTION RS 3.5V to 24.5V 10x L 14V to 98V 40x H The INH pin determines the high or rising edge threshold for VIN. If the monitored voltage connected to VIN rises to the scaled INH voltage then the OUT pin is pulled high assuming PS is ground. Likewise, the INL pin determines the low or falling edge threshold for VIN in each channel. If VIN falls to the scaled INL voltage then the OUT pin is pulled low assuming PS is ground. The amount of hysteresis referred to VIN is the difference in voltage between INH and INL scaled according to the RS pin configuration. INH and INL have an allowable voltage range, VCM. Figure 1 shows the allowable monitor voltage at VIN for each range as a function of comparator reference input voltage (INL/INH). Typically, an external resistive divider biased from REF is used to generate the INH and INL pin voltages. A built-in hysteresis feature requiring only two resistors can be enabled on either the VIN rising edge by grounding INH or on the falling edge by grounding INL. For example, it is appropriate to ground INH to activate rising edge hysteresis if an accurate falling voltage threshold is required for undervoltage detection. Conversely, it is appropriate to ground INL for falling edge built-in hysteresis if an accurate overvoltage threshold is required. Do not ground both INH and INL. Oscillation occurs if VINL > VINH unless INH built-in hysteresis is enabled. The high voltage OUT pins have the capability to be pulled up to a user defined voltage as high as 100V with an external resistor. The LTC2965 also includes an internal 500k pull-up resistor to an internal voltage between 3.5V and 5V depending on input voltage. (See VOH in Electrical Characteristics). If the VIN pin falls below the UVLO threshold then the OUT pin is pulled low regardless of the PS pin state. 100 MONITOR THRESHOLD, VIN (V) The LTC2965 is a micropower single channel voltage monitor with a 100V maximum operating voltage. Its channel is comprised of an internal high value resistive divider and a comparator with a high voltage output. A reference voltage is provided to allow the thresholds to be set independently. This configuration has the advantage of being able to monitor very high voltages with very little current draw while threshold programming is done using low value resistors at low voltages. Integration of a resistive divider for high voltage sensing makes the LTC2965 a compact and low power solution for generating voltage status signals to a monitoring system. 40x 10x 10 1 0.5 1 1.5 2 2.5 COMPARATOR REFERENCE INPUT (INL, INH) (V) 2965 F01 Figure 1. Monitor Threshold vs Comparator Reference Inputs 2965fb For more information www.linear.com/LTC2965 7 LTC2965 Applications Information Threshold Configuration The closest 1% value is 909kΩ. R2 can be determined from: The LTC2965 channel monitors the voltage applied to the VIN input. A comparator senses the VIN pin on one of its inputs through the internal resistive divider. The other input is connected to INH/INL that is in turn biased with external resistive dividers off of the REF pin as shown in Figure 2a and 2b. The VIN rising and falling thresholds are determined by: VIN(RISE) = RANGE • VINH Where RANGE is the configured range of the internal resistive divider. In order to set the threshold for the LTC2965, choose an appropriate range setting for the desired VIN voltage threshold such that the INH and INL voltages are within the specified common mode range, VCM. For example, if a falling threshold of 18V is desired for monitoring a 24V power supply then a range greater than 10x is allowed. However, to maximize the accuracy of the VIN threshold the smallest acceptable range is used, 10x in this case. To implement 2V of hysteresis referred to VIN this means: VINH = 2V, VINL = 1.8V With 10x range the VIN thresholds are: VIN(RISE) = 20V, VIN(FALL) = 18V One possible way to configure the thresholds is by using three resistors to set the voltages on INH and INL. See Figure 2a. The solution for R1, R2 and R3 provides three equations and three unknowns. Maximum resistor size is governed by maximum input leakage current. The maximum input leakage current below 85°C is 1nA. For a maximum error of 1% due to both input currents, the resistive divider current should be at least 100 times the sum of the leakage currents, or 0.2µA. If in this example, a leakage current error of 0.1% is desired then the total divider resistance is 1.2MΩ which results in a current of 2µA through this network. For RSUM = 1.2MΩ RSUM =R1+R2+R3 8 = ( VINH •RSUM ) –R1 VREF (2V •1.2MΩ) – 909kΩ = 90.2kΩ 2.402V The closest 1% value is 90.9kΩ. R3 can be determined from RSUM: R3 = RSUM – R1 – R2 = 1.2MΩ – 909kΩ – 90.9kΩ = 200.1kΩ VIN(FALL) = RANGE • VINL R1= R2 = The closest 1% value is 200kΩ. Plugging the standard values back into the equations yields the design values for the VINH and VINL voltages: VINH = 2.002V, VINL = 1.819V The corresponding threshold voltages are: VIN(RISE) = 20.01V, VIN(FALL) = 18.19V Another possible way to configure the thresholds is with independent dividers using two resistors per threshold to set the voltages on INH and INL. See Figure 2b. Care must be taken such that the thresholds are not set too close to each other, otherwise the mismatch of the resistors may cause the voltage at INL to be greater than the voltage at INH which may cause the comparator to oscillate. As in the previous example, if RSUM = 1.2MΩ is chosen and the target for VINL is 1.8V: RSUM =R1+R2 R1= ( VINL •RSUM ) = (1.8V •1.2MΩ) = 899.5kΩ VREF 2.402V The closest 1% value is 909kΩ. R2 can be determined by: R1 VINL (909kΩ) = 304kΩ = (2.402V – 1.8V ) • 1.8V R2 = ( VREF – VINL ) • ( VINL •RSUM ) = (1.8V •1.2MΩ) = 899.5kΩ VREF 2.402V 2965fb For more information www.linear.com/LTC2965 LTC2965 Applications Information The closest 1% value is 301kΩ. Plugging the standard values back into the equation for VINL yields the design voltage for VINL: (R1• VREF ) = (909kΩ • 2.402V ) =1.804V VINL = (R1+R2) (301kΩ+909kΩ) At this point in the independent divider example only the values required to set the voltage at INL have been found. Repeat the process for the INH input by substituting the above equations with VINH for VINL, R3 for R1, R4 for R2 and VINH = 2.0V. VIN REF VIN LTC2965 R3 INH R1 R2 GND VIN LTC2965 R4 INH PS R2 INL RS REF INL R1 R3 VIN(FALL) = RANGE • INL Figure 3b introduces built-in hysteresis on the falling edge because INL is pulled to ground. Similarly, a two-resistor network, R3 and R4, is used to set the voltage on INH using: R4 VREF = –1 R3 VINH Using built-in hysteresis the VIN thresholds are: VIN(FALL) = RANGE • (INH – VHYS) OUT RS PS GND 2965 F02ab Figure 2a. Three-Resistor Threshold Configuration VIN(RISE) = RANGE • (INL + VHYS) VIN(RISE) = RANGE • INH VIN OUT Using built-in hysteresis, the VINA thresholds are: Figure 2b.Two-Resistor Threshold Configuration Consider VINH = 2V with built-in hysteresis activated on the falling edge. For 10x range, 1.1% falling hysteresis is obtained. If a larger percentage of hysteresis is desired then VINH is alternatively set to 0.5V and the range is selected to be 40x to obtain the same VIN threshold but with 4.4% falling hysteresis. The amount of built-in hysteresis is scaled according to Table 2. If more hysteresis is needed then it is implemented in the external resistive divider as described in the Threshold Configuration section. Using Built-In Hysteresis VIN The LTC2965 has the capability of simplifying the threshold configuration such that only two resistors are required. The device pins can be configured to select a built-in hysteresis voltage, VHYS, which can be applied to either the rising or falling threshold depending on whether the INH or INL pin is grounded. Note that the hysteresis voltage at each range setting remains at a fixed value. Figure 3 introduces examples of each configuration. For example, if INH is biased from an external divider and the INL pin is grounded, then hysteresis is enabled on the low or falling threshold. The low threshold is then –VHYS relative to the high threshold determined by INH. Figure 3a introduces built-in hysteresis on the rising edge because INH is pulled to ground. A two-resistor network, R1 and R2, is used to set the voltage on INL using: REF R2 VIN OUT LTC2965 INH INL R1 VIN REF R4 OUT LTC2965 INH INL RS GND VIN R3 PS RS GND PS 2965 F03ab Figure 3a. Rising Edge Built-In Hysteresis Figure 3b. Falling Edge Built-In Hysteresis Table 2. Built-In Hysteresis Voltage vs Range RANGE VIN REFERRED BUILT-IN HYSTERESIS 10x 220mV 40x 880mV R2 VREF = –1 R1 V INL 2965fb For more information www.linear.com/LTC2965 9 LTC2965 Applications Information Error Analysis The actual VIN falling threshold has an error tolerance of ±267mV or ±1.48%. VIN thresholds are subject to the following errors: • REF Voltage Variation (∆VREF) Improving Threshold Accuracy • Comparator Offset (VOS) The biggest threshold error terms are: • Internal Divider Range Error (AVERR) • External Resistive Divider Accuracy • External Resistive Divider Error (AXERR) • REF Voltage Variation The effect these errors have on the VIN threshold is expressed by: Even using 1% tolerance resistors, external resistive divider accuracy still accounts for as much as ±2% threshold error while REF voltage variation accounts for ±1% threshold error. In order to minimize these threshold error terms, an external reference can be used to set the thresholds for INH/INL as shown in Figure 4. An LT6656-2.048 has an initial accuracy of 0.05% and provides bias via the 0.1% resistive divider network for INH and INL. It is biased off of the LTC2965 REF pin. The threshold error tolerance is calculated using the method described in the Typical Applications section with ∆VREF = ±1.024mV given the initial accuracy of the LT6656 2.048V output and using 0.1% tolerance resistors for the external divider. ⎡ ⎤ VINH(L) VERR =RANGE • ⎢±VOS ±∆VREF • ± VINH(L) • A XERR ⎥ VREF ⎣ ⎦ ±RANGE • A VERR • VINH(L) A XERR = 2 • TOLERANCE ⎛ VINH(L) ⎞ • ⎜1– ⎟ VREF ⎠ 100 ⎝ External divider error is determined by the percentage tolerance values of the resistors. If 1% tolerance resistors are used in the external divider then there is a 2% worst-case voltage error associated with it. The effects of comparator offset and VREF voltage are uncorrelated with each other. Therefore, a Root-Sum-Square can be applied to the error voltage referred to VIN. Using the example from Threshold Configuration and assuming 1% resistors implement the external resistive divider, the falling VIN threshold of approximately 18V has an error tolerance of: ⎛ V ⎞ VERR(REF) = (RANGE) ⎜±∆VREF • INL ⎟ VREF ⎠ ⎝ ⎛ 1.8V ⎞ = (10) • ⎜±24mV • ⎟ =±180mV ⎝ 2.402V ⎠ ⎛ ⎛ V ⎞⎞ VERR(EXT) = (RANGE) ⎜±VINL • 2 • 0.01• ⎜1– INL ⎟⎟ ⎝ VREF ⎠⎠ ⎝ = (10) • (±1.8V • 0.0005) =±9mV VERR(VOS) = (RANGE) (±∆VOS ) = (10) • (±1.6mV ) =±16mV VERR(RS) = (RANGE) (±A VERR ) (±VINL ) = (10) • (±0.004) • (1.8V ) =±72mV = (10) • (±1.8V • 0.005) =±90mV VERR(VOS) = (RANGE) (±∆VOS ) = (10) • (±16mV ) =±160mV 2 (±180mV ) + (±90mV ) + (±160mV ) + (±72mV ) 2 2 2 =±267mV 10 2 The resulting VIN threshold error is reduced to ±0.42% from ±1.48% in the previous error analysis example. 2 2 2 2 + VERR(EXT) + VERR(VOS) + VERR(RS) VERR = VERR(REF) 2 2 (±9mV ) + (±9mV ) + (±16mV ) + (±72mV ) =±75mV = (10) • (±0.004) • (1.8V ) =±72mV 2 2 2 2 2 + VERR(EXT) + VERR(VOS) + VERR(RS) VERR = VERR(REF) = VERR(RS) = (RANGE) (±A VERR ) (±VINL ) = ⎛ V ⎞ VERR(REF) = (RANGE) ⎜±∆VREF • INL ⎟ VREF ⎠ ⎝ ⎛ 1.8V ⎞ = (10) • ⎜±1.024mV • ⎟ =±9mV ⎝ 2.048V ⎠ ⎛ ⎛ V ⎞⎞ VERR(EXT) = (RANGE) ⎜±VINL • 2 • 0.001• ⎜1– INL ⎟⎟ ⎝ VREF ⎠⎠ ⎝ 2965fb For more information www.linear.com/LTC2965 LTC2965 Applications Information VIN 1µF R3 47.5k 0.1% R2 200k 0.1% R1 1.8M 0.1% LT6656-2.048 OUT IN GND R4 10k REF VIN LTC2965 INH INL GND 2965 F04 Figure 4. Reducing VIN Threshold Error Output Configuration with Polarity Selection The OUT pin may be used with a wide range of user-defined voltages up to 100V with an external resistor. Select a resistor compatible with desired output rise time and load current specifications. When the status outputs are low, power is dissipated in the pull-up resistors. An internal pull-up is present if the OUT pins are left floating or if low power consumption is required. The internal pull-up resistor does not draw current if an external resistor pulls OUT up to a voltage greater than VOH. If PS is connected to ground, the comparator output is noninverting. This means that OUT pulls low when VIN falls below the scaled INL voltages. OUT is released after VIN rises above the scaled INH voltage. Likewise, if PS is connected up to REF or a voltage > VTH, the comparator output is inverting. This means that OUT pulls low when VIN rises above the scaled INH voltage and is released when VIN falls below the scaled INL voltage. If the VIN pin falls below the UVLO threshold minus hysteresis, the output is pulled to ground. The output is guaranteed to stay low for VIN ≥ 1.25V regardless of the output logic configuration. It is recommended that circuit board traces associated with the OUT pin be located on a different layer than those associated with the INH/INL and REF pins where possible to avoid capacitive coupling. Hot Swap™ Events connected to the input resonant ringing can occur as a result of series inductance. The peak voltage could rise to 2x the input supply, but in practice can reach 2.5x if a capacitor with a strong voltage coefficient is present. Circuit board trace inductances of as little as 10nH can produce significant ringing. Ringing beyond the absolute maximum specification can be destructive to the part and should be avoided whenever possible. One effective means to eliminate ringing seen at the VIN pins and to protect the part is to include a 1kΩ to 5kΩ resistance between the monitored voltage and the VIN pin as shown in Figure 5. This provides damping for the resonant circuit. If there is a decoupling capacitor on the VIN pins the time constant formed by the RC network should be considered. VIN RS 1k VINA/VINB LTC2965 GND 2965 F05 Figure 5. Hot Swap Protection High Voltage Pin Creepage/Clearance Options Appropriate spacing between component lead traces is critical to avoid flashover between conductors. There are multiple industry and safety standards that have different spacing requirements depending on factors such as operating voltage, presence of conformal coat, elevation, etc. The LTC2965 is available in a 16-lead MSOP package which offers landing clearance of at least 0.79mm (0.031in). The package incorporates unconnected pins between all adjacent high voltage and low voltage pins to maximize PC board trace clearance. For voltages >30V the MSOP should be used, otherwise the smaller or DFN is sufficient when clearance is not an issue. For more information, refer to the printed circuit board design standards described in IPC2221 and UL60950. The LTC2965 can withstand high voltage transients up to 140V. However, when a supply voltage is abruptly 2965fb For more information www.linear.com/LTC2965 11 LTC2965 Applications Information Voltage Reference The REF pin is a buffered reference with a voltage of VREF referenced to GND. A bypass capacitor up to 1000pF in value can be driven by the REF pin directly. Larger capacitances require a series resistance to dampen the transient response as shown in Figure 6A. If a resistive divider is already present then the bypass capacitor can be connected to the INH or INL pin as shown in Figure 6B. Figure 6C 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 the INH/INL pins. Figure 7 shows the reference load transient response. Figure 8 shows the reference line transient response. If there is a decoupling capacitor on the INH/INL pin the time constant formed by the RC network should be considered. Use a capacitor with a compatible voltage rating. REF CREF INL GND INL 2965 F07 100µs/DIV Figure 7. VREF Load Transient 1nF 1µF + 600Ω VIN 1V/DIV 3.5V 6b 2965 F08 10µs/DIV Figure 8. VREF Line Transient 100 RESISTANCE VALUE (kΩ) VREF GND 2965 F06ab 6a LOAD CURRENT 10µA 8V INH CREF 100µA VREF LTC2965 RS INH 2.4V 50mV/DIV 2.4V 10mV/DIV REF LTC2965 RS 1nF 10nF + 4.3kΩ 0.1µF + 1.5kΩ 1µF + 600Ω 10 1 0.1 0.001 0.01 0.1 CAPACITANCE VALUE (µF) 1 2965 F06c 6c Figure 6. Using Series Resistance to Dampen REF Transient Response 12 2965fb For more information www.linear.com/LTC2965 LTC2965 Typical Applications Negative Voltage Monitor with Output Level Shift Current Sink/Source Figure 9 illustrates an LTC2965 configured to monitor a –15V supply with a level-shifted output to a 5V supply. Q1 buffers the digital input of the 5V system from the –15V supply and prevents UV from going below GND. The OUT pin drives the base of Q1 through a resistor network comprised of R3 and R4. Keep R4/R3 ≥0.4 to ensure there is proper base current to pull UV to ground. If an exposed pad is present it should be tied to the LTC2965 GND pin or left open. The LTC2965 can be used as a high voltage current source or a current sink as shown in Figure 10. The current is determined by placing a resistive load, RSET, on the REF pin. The total current is then VREF/RSET + IVA because the bias current of the part adds a small error term. Part of the bias current is the internal resistive divider which is approximately 78MΩ with the RS pin configured to 10x. 5V –15V MONITOR WITH LEVEL SHIFT RISING THRESHOLD FALLING THRESHOLD HYSTERESIS RANGE SETTING R4 510k –14.5V –14.2V –0.3V 10X R3 1M LTC2965 INH R2 976k DIGITAL INPUT UV Q1 MMBT2907 FAIRCHILD VIN REF R5 200k OUT INL R1 1.43M PS RS GND –15V 2965 F09 Figure 9. Negative Voltage Monitor with Output Level Shift to a 5V Digital Input Current Sink ISET = VREF/RSET Current Source ISET = VREF/RSET VIN ISINK = 1mA LOAD VIN VIN VIN REF REF LTC2965 LTC2965 RSET 2.4k INH OUT OPEN INL PS RS GND RSET 2.4k INH OUT OPEN INL PS RS GND IERROR = (VREF/RSET) – ISUPPLY LOAD ISRC = 1mA 2965 F10 Figure 10. LTC2965 Configured as High Voltage Current Source 2965fb For more information www.linear.com/LTC2965 13 LTC2965 Typical Applications Configure the current to be no greater than 1mA to ensure that the REF voltage stays within ±1% tolerance. Current values larger than 1mA exceed the REF buffer’s load regulation capability and cause the REF voltage to drop out of regulation. Shunt Mode Hysteretic Regulator Figure 11 shows the LTC2965 used as the controller for a shunt mode hysteretic regulator to manage a battery-based solar power system. When the battery voltage reaches a 14 lower float limit of 13.7V Q1 turns off and the solar panel current passes through to the battery and load. Once the battery voltage rises to the upper charging limit of 14.7V, Q1 turns on shorting the solar panel to ground with D1 isolating the battery from the shunt path. The upper and lower thresholds are generated from the onchip reference as a separate external divider to set INH and INL and scaled by 10x. The charging thresholds are temperature compensated by an NTC thermistor over a 0°C to 50°C range. 2965fb For more information www.linear.com/LTC2965 LTC2965 Package Description Please refer to http://www.linear.com/product/LTC2965#packaging for the most recent package drawings. DD Package 8-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1698 Rev C) 0.70 ±0.05 3.5 ±0.05 1.65 ±0.05 2.10 ±0.05 (2 SIDES) PACKAGE OUTLINE 0.25 ±0.05 0.50 BSC 2.38 ±0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED PIN 1 TOP MARK (NOTE 6) 0.200 REF 3.00 ±0.10 (4 SIDES) R = 0.125 TYP 5 0.40 ±0.10 8 1.65 ±0.10 (2 SIDES) 0.75 ±0.05 4 0.25 ±0.05 1 (DD8) DFN 0509 REV C 0.50 BSC 2.38 ±0.10 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD 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 2965fb For more information www.linear.com/LTC2965 15 LTC2965 Package Description Please refer to http://www.linear.com/product/LTC2965#packaging for the most recent package drawings. MS Package 16-Lead Plastic MSOP (Reference LTC DWG # 05-08-1669 Rev A) 0.889 ±0.127 (.035 ±.005) 5.10 (.201) MIN 3.20 – 3.45 (.126 – .136) 4.039 ±0.102 (.159 ±.004) (NOTE 3) 0.50 (.0197) BSC 0.305 ±0.038 (.0120 ±.0015) TYP RECOMMENDED SOLDER PAD LAYOUT 0.254 (.010) DETAIL “A” 3.00 ±0.102 (.118 ±.004) (NOTE 4) 4.90 ±0.152 (.193 ±.006) 0° – 6° TYP 0.280 ±0.076 (.011 ±.003) REF 16151413121110 9 GAUGE PLANE 0.53 ±0.152 (.021 ±.006) DETAIL “A” 0.18 (.007) SEATING PLANE 1.10 (.043) MAX 0.17 – 0.27 (.007 – .011) TYP 1234567 8 0.50 (.0197) 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 16 0.86 (.034) REF 0.1016 ±0.0508 (.004 ±.002) MSOP (MS16) 0213 REV A 2965fb For more information www.linear.com/LTC2965 LTC2965 Revision History REV DATE DESCRIPTION A 09/15 Fixed typos PAGE NUMBER B 03/16 Added Absolute Maximum Rating for INH and INL Pins 3, 4, 10 – 12 2 2965fb 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. For more information www.linear.com/LTC2965 17 LTC2965 Typical Application D1 B130** 25V 100µF 1A SOLAR PANEL FUSE 2A 1M LC-P127R2P*** (12V, 7.2Ah) VIN REF Q1 BUK7640-100A* 46.4k LTC2965 OUT INH 150k 6.81k 47nF INL 95.3k *NXP **DIODES INC ***PANASONIC ****MURATA NCP18WF104JO3RB 100mA MAXIMUM 24 HOUR AVERAGE LOAD CURRENT GND RS PS NTC**** 100k 2965 F11 Figure 11. Shunt Mode Hysteretic Regulator Related Parts PART NUMBER DESCRIPTION COMMENTS LTC1326 Micropower Triple Supply Monitor for 5V/2.5V, 3.3V and ADJ 4.725V, 3.118V, 1V Threshold (±0.75%) and ADJ LTC1440/LTC1441/ Ultralow Power Single/Dual Comparator with Reference LTC1442 Adjustable Hysteresis, 3mm × 3mm × 0.75mm DFN Package LTC1726/LTC1727/ Micropower Triple Supply Monitor LTC1728 Adjustable Reset and Watchdog Timeouts LTC1985 5-Lead SOT-23 Package Micropower Triple Supply Monitor with Push-Pull Reset Output LTC2900/LTC2901/ Programmable Quad Supply Monitor LTC2902 Adjustable Reset, Watchdog Timer and Tolerance, 10-Lead MSOP and DFN Packages LTC2903 Precision Quad Supply Monitor 6-Lead SOT-23 and DFN Packages LTC2904/LTC2905 LTC2906/LTC2907 Three-State Programmable Precision Dual Supply Monitor 8-Lead SOT-23 and DFN Packages LTC2908 Precision Six-Supply Monitor (Four Fixed and Two Adjustable) 8-Lead TSOT-23 and DFN Packages LTC2909/LTC2919 Precision Triple/Dual Input UV, OV and Negative Voltage Monitor Shunt Regulated VCC Pin, Adjustable Threshold and Reset LTC2910 Octal Positive/Negative Voltage Monitor Separate VCC Pin, Eight Inputs, Up to Two Negative Monitors Adjustable Reset Timer, 16-Lead SSOP and DFN Packages LTC2912/LTC2913/ Single/Dual/Quad UV and OV Voltage Monitors LTC2914 Separate VCC Pin, Adjustable Reset Timer LTC2915/LTC2916 LTC2917/LTC2918 Single Voltage Supervisors with 27 Pin-Selectable Thresholds Manual Reset and Watchdog Functions, 8- and 10-Lead TSOT-23, MSOP and DFN Packages LTC2966 100V Micropower Dual Voltage Monitor 1.75V to 98V Monitoring Range, 3.5V to 100V Operating Range, 7µA Quiescent Current LTC2960 36V Nano-Current Two Input Voltage Monitor 36V, 850nA Quiescent Current, 2mm × 2mm 8-Lead DFN and TSOT-23 Packages LT6700 Micropower Dual Comparator with 400mV Reference SOT-23, 2mm × 3mm DFN Package 18 Linear Technology Corporation 1630 McCarthy Blvd., Milpitas, CA 95035-7417 For more information www.linear.com/LTC2965 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com/LTC2965 2965fb LT 0316 REV B • PRINTED IN USA LINEAR TECHNOLOGY CORPORATION 2015