LTC2930CDD-TRPBF

FEATURES ■ ■ LTC2930 Configurable Six Supply Monitor with Adjustable Reset Timer, Manual Reset DESCRIPTION The LTC®2930 is a configurable supply monitor for systems with up to six supply voltages. One of 16 preset or adjustable voltage monitor combinations can be selected using an external resistive divider connected to the mode select pin. The preset voltage thresholds are accurate to ±1.5% over temperature. The LTC2930 also features adjustable inputs with a 0.5V nominal threshold. The reset timeout period is adjustable using an external capacitor. A reset event may be generated with a manual reset button on the manual reset input. Tight voltage threshold accuracy and glitch immunity ensure reliable reset operation without false triggering. The RST output is guaranteed to be in the correct state for VCC down to 1V and may be externally pulled up to an external voltage. The 52μA supply current makes the LTC2930 ideal for power conscious systems and it may be configured to monitor fewer than six inputs. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 6967591, 7119714, 7239251. ■ ■ ■ ■ ■ ■ ■ ■ Simultaneously Monitors Six Supplies 16 User Selectable Combinations of 5V, 3.3V, 3V, 2.5V, 1.8V, 1.5V and ± Adjustable Voltage Thresholds Guaranteed ±1.5% Threshold Accuracy Adjustable Reset Timeout Low Supply Current: 52μA Manual Reset Pin Power Supply Glitch Immunity Guaranteed RST for VCC ≥ 1V High Temperature Operation to 125°C 12-Lead 3mm × 3mm DFN Package APPLICATIONS ■ ■ ■ ■ ■ ■ Desktop and Notebook Computers Multivoltage Systems Telecom Equipment Portable Battery-Powered Equipment Network Servers Automotive TYPICAL APPLICATION Six Supply Monitor, 5% Threshold 12V, 5V, 3.3V, 1.8V, 1.2V, –5.2V 12V 5V 3.3V 1.8V 1.2V –5.2V 2150k 1% 487k 1% Voltage Threshold Configuration Table V1 (V) 5.0 SYSTEM LOGIC V2 (V) 3.3 3.3 3.3 3.3 3.3 3.3 3.3 3.0 3.0 3.0 2.5 2.5 2.5 2.5 2.5 2.5 V3 (V) 2.5 2.5 2.5 1.8 1.8 ADJ ADJ 2.5 1.8 ADJ 1.8 1.8 1.8 1.5 ADJ ADJ V4 (V) 1.8 1.5 ADJ ADJ –ADJ ADJ –ADJ ADJ ADJ ADJ 1.5 ADJ –ADJ ADJ ADJ –ADJ V5 (V) ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ V6 (V) ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ ADJ 2930fa 5.0 5.0 5.0 5.0 V1 V2 V3 V4 V5 V6 MR VREF VPG GND CRT MANUAL RESET CRT 47nF 2930 TA01 5.0 RST LTC2930 5.0 5.0 5.0 5.0 3.3 3.3 3.3 3.3 3.3 3.3 0.1μF 124k 1% 121k 1% 100k 1% 100k 1% 16.2k 1% 86.6k 1% tRST = 94ms 1 LTC2930 ABSOLUTE MAXIMUM RATINGS (Notes 1, 2, 3) PIN CONFIGURATION TOP VIEW V5 V3 V1 CRT RST MR 1 2 3 4 5 6 13 12 V6 11 V2 10 V4 9 VREF 8 VPG 7 GND V1, V2, V3, V4, V5, V6, VPG, RST................ –0.3V to 7V CRT, VREF MR...............................–0.3V to (VCC + 0.3V) , Reference Load Current (IVREF) ..............................±1mA V4 Input Current (–ADJ Mode) ..............................–1mA RST Current .........................................................±10mA Operating Temperature Range LTC2930C ................................................ 0°C to 70°C LTC2930I.............................................. –40°C to 85°C LTC2930H .......................................... –40°C to 125°C Storage Temperature Range................... –65°C to 150°C DD PACKAGE 12-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 130°C, θJA = 43°C/W EXPOSED PAD (PIN 13) IS GND (PCB CONNECTION OPTIONAL) ORDER INFORMATION LEAD FREE FINISH LTC2930CDD#PBF LTC2930IDD#PBF LTC2930HDD#PBF TAPE AND REEL LTC2930CDD#TRPBF LTC2930IDD#TRPBF LTC2930HDD#TRPBF PART MARKING* LDMJ LDMJ LDMJ PACKAGE DESCRIPTION 12-Lead 3mm × 3mm DFN 12-Lead 3mm × 3mm DFN 12-Lead 3mm × 3mm DFN TEMPERATURE RANGE 0°C to 70°C –40°C to 85°C –40°C to 125°C *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ This product is only offered in trays. For more information go to: http://www.linear.com/packaging/ ELECTRICAL CHARACTERISTICS SYMBOL VCC VCCMINP VRT50 VRT33 VRT30 VRT25 VRT18 VRT15 VRTA VRTAN VREF VPG IVPG PARAMETER Minimum Internal Operating Voltage Minimum Required for Mode Selection 5V, 5% Reset Threshold 3.3V, 5% Reset Threshold 3V, 5% Reset Threshold 2.5V, 5% Reset Threshold 1.8V, 5% Reset Threshold 1.5V, 5% Reset Threshold ADJ Reset Threshold –ADJ Reset Threshold Reference Voltage Mode Selection Voltage Range VPG Input Current The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise specified. (Note 3) CONDITIONS RST in Correct Logic State VCC Rising V1 Input Threshold V1, V2 Input Threshold V2 Input Threshold V2, V3 Input Threshold V3, V4 Input Threshold V3, V4 Input Threshold V3, V4, V5, V6 Input Threshold V4 Input Threshold VCC ≥ 2.3V, IVREF = ±1mA, CREF ≤ 1000pF VCC ≥ VCCMINP VPG = VREF ● ● ● ● ● ● ● ● ● ● ● ● ● MIN TYP MAX 1 2.4 UNITS V V V V V V V V mV mV V V nA 4.600 3.036 2.760 2.300 1.656 1.380 492.5 –18 1.192 0 4.675 3.086 2.805 2.338 1.683 1.403 500 0 1.210 4.750 3.135 2.850 2.375 1.710 1.425 507.5 18 1.228 VREF ±20 2930fa 2 LTC2930 ELECTRICAL CHARACTERISTICS SYMBOL IV1 IV2 IV3 IV4 PARAMETER V1 Input Current V2 Input Current V3 Input Current V4 Input Current The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VCC = 5V, unless otherwise specified. (Note 3) CONDITIONS V1 = 5V, IVREF = 12μA (Note 4) V2 = 3.3V V3 = 2.5V V3 = 0.55V (ADJ Mode) V4 = 1.8V V4 = 0.55V (ADJ Mode) V4 = –0.02V (–ADJ Mode) V5, V6 = 0.55V VCRT = GND VCRT = 1.3V CRT = 1500pF Vn Less Than Reset Threshold by More than 1% ISINK = 3mA, VCC = 3V ISINK = 100μA, VCC = 1V ISOURCE = –1μA VCC = 3.3V to 5.5V VCC = 3.3V to 5.5V VCC = 3.3V VCC = 3.3V, VMR Falling VMR = 1V ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● MIN TYP 52 0.8 0.52 0.34 MAX 75 2 1.2 ±15 0.8 ±15 ±15 ±15 –2.6 30 4 UNITS μA μA μA nA μA nA nA nA μA μA ms μs IV5, IV6 ICRT(UP) ICRT(DN) tRST tUV VOL VOH VIL VIH tMRW tMRD IMR V5, V6 Input Current CRT Pull-Up Current CRT Pull-Down Current Reset Timeout Period Vn Undervoltage Detect to RST Voltage Output Low RST Voltage Output High RST (Note 5) MR Input Threshold Low MR Input Threshold High MR Input Pulse Width Manual Reset Propagation Delay MR Pull-Up Current –1.4 10 2 –2 20 3 150 0.15 0.05 0.4 0.3 0.4 V V V V V ns V2-1 1.6 150 0.1 –4 –10 1 –16 μs μA 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. Note 2: All currents into pins are positive, all voltages are referenced to GND unless otherwise noted. Note 3: The greater of V1, V2 is the internal supply voltage (VCC). Note 4: Under static no-fault conditions, V1 will necessarily supply quiescent current. If at any time V2 is larger than V1, V2 must be capable of supplying the quiescent current, programming (transient) current and reference load current. Note 5: The output pin RST has a diode protected internal pull-up to V2 of typically 6μA. However, an external pull-up resistor may be used when faster rise times are required or for VOH voltages greater than V2. TIMING DIAGRAM Vn Monitor Timing Vn VRT tUV RST tRST tMRD tRST 2930 TD MR tMRW 2930fa 3 LTC2930 TYPICAL PERFORMANCE CHARACTERISTICS Normalized Threshold Voltages vs Temperature NORMALIZED THRESHOLD VOLTAGES (V/V) 1.015 1.010 1.005 1.000 0.995 0.990 0.985 –50 –25 THRESHOLD VOLTAGE, VRTAN (mV) 18 12 6 0 –6 –12 –18 –50 –25 VREF (V) –ADJ Threshold Voltage vs Temperature 1.228 1.222 1.216 1.210 1.204 1.198 VREF vs Temperature 50 25 75 0 TEMPERATURE (°C) 100 125 50 25 75 0 TEMPERATURE (°C) 100 125 1.192 –50 –25 50 25 75 0 TEMPERATURE (°C) 100 125 2930 G01 2930 G02 2930 G03 Supply Current vs Temperature 70 V1 = 5V V2 = 3.3V 65 V3 = 2.5V V4 = 1.8V V5 = V6 = 1V 60 IV4 (A) 55 50 45 40 –50 –25 –100μ –10μ –1μ –100n –10n –1n I(V4) vs V4 in Negative Adjust Mode 300 TYPICAL TRANSIENT DURATION (μs) 250 200 Transient Duration vs Comparator Overdrive (V1,V2) TA = 25°C SUPPLY CURRENT, IV1 (μA) 125°C RESET OCCURS ABOVE CURVE 150 100 50 0 0.1 1 10 100 RESET COMPARATOR OVERDRIVE (% OF VRTX) 2930 G06 90°C 25°C 50 25 75 0 TEMPERATURE (°C) 100 125 –100p –300 –250 –200 –150 –100 V4 (mV) –50 0 2930 G05 2930 G04 Transient Duration vs Comparator Overdrive (V3, V4, V5, V6) 450 TYPICAL TRANSIENT DURATION (μs) 375 RST OUTPUT VOLTAGE (V) 300 RESET OCCURS ABOVE CURVE 225 150 75 0 0.1 1 10 100 RESET COMPARATOR OVERDRIVE (% OF VRTX) 2930 G07 RST Output Voltage vs V1, VPG = GND 6 5 4 3 2 1 0 0 1 2 V1 (V) 2930 G08 Reset Timeout Period vs Temperature 5 RESET TIMEOUT PERIOD, tRST (ms) 4 5 CRT = 1500pF (SILVER MICA) TA = 25°C TA = 25°C 10k PULL-UP FROM RST TO V1 4 3 2 3 1 –50 –25 75 0 25 50 TEMPERATURE (°C) 100 125 2930 G09 2930fa 4 LTC2930 TYPICAL PERFORMANCE CHARACTERISTICS Reset Timeout Period vs CRT 10 RESET TIMEOUT PERIOD tRST (s) 1 100m 10m 1m 100μ 10μ 10p 3 ISINK (mA) 9 VOL = 0.2V 6 TA = 25°C 15 ISINK vs Supply Voltage (RST) TA = 25°C 12 VOL = 0.4V 100p 1n 10n CRT (F) 100n 1μ 2930 G10 0 0 1 3 2 V1 OR V2 (V) 4 5 2930 G11 Voltage Output Low vs Output Sink Current (RST) 500 V1 = 5V V2 = 3V 18 125°C 85°C VOL (mV) 300 25°C 200 –40°C 100 PULL-UP CURRENT (μA) 15 12 9 6 RST Pull-Up Current vs V2 TA = 25°C 400 VRT33 VRT30 3 VRT25 0 0 2 6 4 ISINK (mA) 8 10 0 2.0 2.5 3.0 3.5 V2 (V) 4.0 4.5 5.0 2930 G13 2930 G12 PIN FUNCTIONS V5 (Pin 1): Adjustable Voltage Input 5. High impedance comparator input with 0.5V typical threshold. See Applications Information for details. Tie to V1 if unused. V3 (Pin 2): Voltage Input 3. Select from 2.5V, 1.8V, 1.5V, or ADJ. See Applications Information for details. Tie to V1 if unused. V1 (Pin 3): Voltage Input 1. Select from 5V or 3.3V. See Applications Information for details. The greater of V1 or V2 is also VCC for the device. Bypass this pin to ground with a 0.1μF (or greater) capacitor. CRT (Pin 4): Reset Timeout Capacitor. Attach an external . capacitor (CRT) to GND to set a reset timeout of 2ms/nF Leaving the pin open generates a minimum delay of approximately 25μs. A 47nF capacitor generates a 94ms reset delay time. RST (Pin 5): Reset Output. Logic output with weak 6μA pull-up to V2. Pulls low when any voltage input is below the reset threshold and held low for the configured delay time after all voltage inputs are above threshold. Use an external pull-up to pull greater than V2. Leave open if unused. 2930fa 5 LTC2930 PIN FUNCTIONS MR (Pin 6): Manual Reset Input. A logic low on this pin pulls RST low. When the MR pin returns high, RST returns high after the configured reset timeout if all six voltage inputs are above threshold. A weak internal pull-up allows the pin to be left open for normal monitor operation. When using a switch, the switch is debounced through the reset circuitry using the delay provided by the CRT timing capacitor. GND (Pin 7): Ground. VPG (Pin 8): Threshold Select Input. Connect to an external 1% resistive divider between VREF and GND to select 1 of 16 combinations and/or ±adjustable voltage thresholds (See Table 1). Do not add capacitance on the VPG pin. VREF (Pin 9): Buffered Reference Voltage Output. A 1.210V nominal reference used for the mode selection voltage (VPG) and for the offset of negative adjustable applications. The buffered reference can source and sink up to 1mA. The reference can drive a bypass capacitor of up to 1000pF without oscillation. V4 (Pin 10): Voltage Input 4. Select from 1.8V, 1.5V, ADJ or –ADJ. See Applications Information for details. Tie to V1 if unused. V2 (Pin 11): Voltage Input 2. Select from 3.3V, 3V or 2.5V. See Applications Information for details. The greater of V1, V2 is also VCC for the device. Bypass this pin to ground with a 0.1μF (or greater) capacitor. RST is weakly pulled up to V2. V6 (Pin 12): Adjustable Voltage Input 6. High impedance comparator input with 0.5V typical threshold. See Applications Information for details. Tie to V1 if unused. Exposed Pad (Pin 13): Exposed pad may be left open or connected to device ground. BLOCK DIAGRAM BUFFER VREF 9 1.210V BANDGAP REFERENCE VPG 8 A/D V1 V1 3 V2 11 V3 2 V4 10 V5 1 RESISTIVE DIVIDER MATRIX 4 POWER DETECT VCC V2 CMP1-4 0.5V V6 12 – GND 7 VCC 6 + + – CMP5 V2 6μA RST 4 – + CMP6 4 10μA 22μA 6 MR ADJUSTABLE RESET PULSE GENERATOR 5 VCC 2μA 4 CRT CRT 2931 BD 2930fa LTC2930 APPLICATIONS INFORMATION Supply Monitoring The LTC2930 is a low power, high accuracy configurable six supply monitoring circuit with a common reset output. An external capacitor sets the reset timeout period. An external resistive divider between VREF VPG and GND selects 1 of , 16 possible input voltage monitor combinations. All six voltage inputs must be above their predetermined thresholds for the reset not to be activated. The LTC2930 asserts the reset output during power-up, power-down and brownout conditions on any one of the voltage inputs. Power-Up The greater of V1 and V2 serves as the internal supply voltage (VCC). On power-up, VCC powers the drive circuits for the RST pin. This ensures that the RST output will be low as soon as either V1 or V2 reaches 1V. The RST output remains low until the part is configured. Once voltage thresholds are set, if any of the supply monitor inputs is below its configured threshold, RST will be a logic low. Once all the monitor inputs rise above their thresholds, an internal timer is started and RST is released after the delay time. If VCC < (V3 – 1.0V) and VCC < 2.4V, the V3 input impedance will be low (10kΩ typical). Threshold Accuracy Consider a 5V system with ±5% tolerance. The 5V supply may vary between 4.75V to 5.25V. System ICs powered by this supply must operate reliably within this band (and a little more as explained below). A perfectly accurate su5V SUPPLY TOLERANCE NOMINAL SUPPLY VOLTAGE Table 1. Voltage Threshold Modes* MODE V1 (V) V2 (V) V3 (V) V4 (V) R1 (kΩ) R2 (kΩ) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 5.0 5.0 3.3 3.3 3.3 5.0 5.0 5.0 5.0 5.0 3.3 3.3 3.3 5.0 5.0 5.0 3.3 3.3 2.5 2.5 2.5 3.3 3.3 3.3 3.0 3.0 2.5 2.5 2.5 3.3 3.3 3.0 ADJ ADJ ADJ ADJ 1.5 2.5 2.5 2.5 2.5 ADJ 1.8 1.8 1.8 1.8 1.8 1.8 ADJ –ADJ ADJ –ADJ ADJ ADJ 1.8 1.5 ADJ ADJ 1.5 ADJ –ADJ –ADJ ADJ ADJ Open 93.1 86.6 78.7 71.5 66.5 59.0 53.6 47.5 40.2 34.8 28.0 22.1 16.2 9.53 Short Short 9.53 16.2 22.1 28.0 34.8 40.2 47.5 53.6 59.0 66.5 71.5 78.7 86.6 93.1 Open VPG VREF 0.000 0.094 0.156 0.219 0.281 0.344 0.406 0.469 0.531 0.594 0.656 0.719 0.781 0.844 0.906 1.000 *V5 and V6 are always adjustable (ADJ). pervisor for this supply generates a reset at exactly 4.75V, however no supervisor is this perfect. The actual reset threshold of a supervisor varies over a specified band; the LTC2930 varies ±1.5% around its nominal threshold voltage (see Figure 1) over temperature. The reset threshold band and the power supply tolerance bands should not overlap. This prevents false or nuisance resets when the power supply is actually within its specified tolerance band. The LTC2930 has a ±1.5% reset threshold accuracy, so a “5%” threshold is typically set to 6.5% below the nominal input voltage. Therefore, a typical 5V, “5%” threshold is 4.675V. The threshold is guaranteed to lie in the band between 4.750V and 4.600V over temperature. The powered system must work reliably down to the low end of the threshold band, or risk malfunction before a reset signal is properly issued. A less accurate supervisor increases the required system voltage margin and increases the probability of system malfunction. The LTC2930 ±1.5% specification improves the reliability of the system over supervisors with wider threshold tolerances. MINIMUM RELIABLE SYSTEM VOLTAGE IDEAL SUPERVISOR THRESHOLD 4.75V ±1.5% THRESHOLD BAND 4.675V 4.6V REGION OF POTENTIAL MALFUNCTION –5% –6.5% –8% Figure 1. 1.5% Threshold Accuracy Improves System Reliability 2930fa 7 LTC2930 APPLICATIONS INFORMATION LTC2930 VREF VPG GND R1 1% R2 1% 2930 F02 Table 2. Suggested 1% Resistor Values for the ADJ Inputs VSUPPLY (V) 12 10 8 7.5 6 5 3.3 3 2.5 1.8 1.5 1.2 1 0.9 *See Figure 3. VTRIP (V) 11.25 9.4 7.5 7 5.6 4.725 3.055 2.82 2.325 1.685 1.410 1.120 0.933 0.840 R3 (kΩ) 2150 1780 1400 1300 1020 845 511 464 365 237 182 124 86.6 68.1 R4 (kΩ) 100 100 100 100 100 100 100 100 100 100 100 100 100 100 Figure 2. Mode Selection Monitor Configuration Select the LTC2930 input voltage combination by placing the recommended resistive divider from VREF to GND and connecting the tap point to VPG, as shown in Figure 2. Table 1 offers recommended 1% resistor values for each of the 16 modes. The last column in Table 1 specifies optimum VPG/VREF ratios (± 0.01), when configuring with a ratiometric DAC. At power-up, once V1 or V2 reaches 2.4V, the monitor enters a setup period of approximately 150μs. During the setup time, the voltage on the VPG pin is sampled and the monitor is configured to the desired input combination. The comparators are enabled and supply monitoring begins. Do not add capacitance to the VPG pin. VTRIP R3 1% V3, V4, V5 OR V6 R4 1% LTC2930 Table 3. Suggested 1% Resistor Values for the –ADJ Inputs VSUPPLY (V) –2 –5 –5.2 –10 –12 *See Figure 4. VTRIP (V) –1.87 –4.64 –4.87 –9.31 –11.30 R3 (kΩ) 187 464 487 931 1130 R4 (kΩ) 121 121 121 121 121 + – 0.5V VTRIP = 0.5V • 1+ 2930 F03 R3 R4 Figure 3. Setting the Positive Adjustable Trip Point Using The Adjustable Thresholds The reference inputs on the V3 and/or V4 comparators are set to 0.5V when the positive adjustable modes are selected (Figure 3). The reference inputs on the V5 and V6 comparators are always set to 0.5V. The tap point on an external resistive divider, connected between the positive voltage being sensed and ground, is connected to the high impedance, adjustable inputs (V3, V4, V5, V6). Calculate the trip voltage from: In the negative adjustable mode, the reference level on the V4 comparator is connected to ground (Figure 4). The tap point on an external resistive divider, connected between the negative voltage being sensed and the VREF pin, is VREF R4 1% V4 R3 1% VTRIP LTC2930 2930 F04 Figure 4. Setting the Negative Adjustable Trip Point 2930fa 8 LTC2930 APPLICATIONS INFORMATION connected to the high impedance adjustable input (V4). VREF provides the necessary level shift required to operate at ground. The negative trip voltage is calculated from: VTRIP = − VREF • R3 ;V = 1.210 V Nominal R4 REF Leaving the CRT pin unconnected generates a minimum reset timeout of approximately 25μs. Maximum reset timeout is limited by the largest available low leakage capacitor. The accuracy of the timeout period is affected by capacitor leakage (the nominal charging current is 2μA) and capacitor tolerance. A low leakage ceramic capacitor is recommended. OR-ed System Reset In Figure 5, two LTC2930s are configured to monitor 11 supply voltages simultaneously. The unused adjustable input pin is tied to the V1 input. The open-drain RST outputs are OR-tied and pulled up to 5V through a 10kΩ resistor. RST pulls high 94ms after all the inputs are above the threshold voltages. Should a reset event occur on either LTC2930, both RST outputs pull low. Similarly, if the manual reset pushbutton is pressed, both RST outputs also pull low. Using a Pushbutton On/Off Controller with the LTC2930 In Figure 6, the LTC2950-1 pushbutton controller powers a system on and off. The system starts after the pushbutton is pressed, which brings the LTM4600’s RUN pin high. Subsequently, the LTM4600 generates a 5V output which applies power to each of the four DC/DC converters. The LTC2930 is configured to mode 13 (see Table 1). The voltages monitored are 5V, 3.3V, 1.8V, –5.2V, 2.5V and 12V. If the KILL input is not driven high within 512ms of a valid turn-on event, EN pulls low shutting down the system. If the external 12V supply drops below 9.6V, EN pulls low, powering down the LTM4600 and subsequent circuitry. An external 4.7nF capacitor sets the 9.4ms reset timeout period. Therefore, 9.4ms after the last supply is above threshold, RST pulls high. The reset timing capacitor must be chosen to keep the reset timeout period below 512ms. Otherwise, the KILL timer will expire and shut down the system. Pressing the pushbutton after the system is powered initiates the power off sequence. An interrupt is set, bringing EN low immediately and disabling the LTM4600. 2930fa In a negative adjustable application, the minimum value for R4 is limited by the sourcing capability of VREF (±1mA). With no other load on VREF R4 (minimum) is: , 1.210V = 1.210k 1mA Tables 2 and 3 offer suggested 1% resistor values for various positive and negative supply adjustable applications assuming 5% monitor thresholds. Although all six supply monitor comparators have builtin glitch immunity, bypass capacitors on V1 and V2 are recommended because the greater of V1 or V2 is also the VCC for the device. Filter capacitors on the V3, V4, V5 and V6 inputs are allowed. Power-Down On power-down, once any of the monitor inputs drops below its threshold, RST is held at a logic low. A logic low of 0.4V is guaranteed until both V1 and V2 drop below 1V. If the bandgap reference becomes invalid (VCC < 2V typical), the LTC2930 will enter the 150μs setup period when VCC rises above 2.4V max. Selecting the Reset Timing Capacitor The reset timeout period is adjustable in order to accommodate a variety of microprocessor applications. The reset timeout period, tRST, is adjusted by connecting a capacitor, CRT, between the CRT pin and ground. The value of this capacitor is determined by: CRT = tRST = 500 [pF / ms] • tRST 2MΩ 9 LTC2930 APPLICATIONS INFORMATION 5V 10k 5V 3V 12V 8V 6V V1 68.1k 1% 0.1μF 86.6k 1% 487k 1% V2 V3 V4 V5 V6 121k 1% 100k 1% 100k 1% R1A 16.2k 1% R2A 86.6k 1% VREF VPG GND MR 10k** CRT CRT 47nF MANUAL RESET PUSHBUTTON tRST = 94ms **OPTIONAL FOR EXTENDED ESD TOLERANCE 100k 1% 100k 1% R1B 100k40.2k 1% 1% R2B 59k 1% 2930 F05 3.3V 1.8V –5.2V 1V 0.9V 1020k 1% RST LTC2930 0.1μF 1400k 1% 2150k 1% V1 V2 V3 V4 V5 V6 MR VREF VPG GND CRT CRT 47nF LTC2930 RST RESET Figure 5. OR-ed System Reset 12V (9.6V THRESHOLD) LTM4600 VIN VOUT RUN 5V LT3028 VOUT 3.3V SHDN 10k 5V VIN 3.3V EN LTC2950-1 VIN INT PB KILL VIN LT3028 VOUT 1.8V SHDN 1.8V SYSTEM LOGIC LTC3704 VIN VOUT –5.2V RUN/UVLO –5.2V VIN LT3028 VOUT 2.5V SHDN 10k 2.5V 2930 F06 V1 365k 1% 1500k 1% 487k 1% V2 V3 V4 V5 V6 MR 100k 1% 0.1μF 100k 1% 121k 1% VREF R1 16.2k 1% R2 86.6k 1% VPG CRT GND LTC2930 RST SYSTEM RESET 4.7nF tRST = 9.4ms Figure 6. Using a Pushbutton On/Off Controller with the LTC2930 2930fa 10 LTC2930 PACKAGE DESCRIPTION DD Package 12-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1725 Rev A) 0.70 0.05 3.50 0.05 2.10 0.05 2.38 0.05 1.65 0.05 PACKAGE OUTLINE 0.25 0.05 2.25 REF 0.45 BSC RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED R = 0.115 TYP 7 0.40 12 0.10 3.00 0.10 (4 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF 0.75 0.05 2.38 0.10 1.65 0.10 PIN 1 NOTCH R = 0.20 OR 0.25 45 CHAMFER 0.05 6 2.25 REF 1 0.23 0.45 BSC (DD12) DFN 0106 REV A 0.00 – 0.05 BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING IS NOT A JEDEC PACKAGE OUTLINE 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 AND TIE BARS SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE 2930fa 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. 11 LTC2930 TYPICAL APPLICATION Five Supply Monitor, 5% Threshold (3.3V, 1.5V, 1.2V, 1V, 0.9V) 3.3V 1.5V 1.2V 1V 0.9V 68.1k 1% 86.6k 1% 124k 1% V1 V2 V3 V4 V5 V6 MR VREF VPG LTC2930 0.1μF RST SYSTEM RESET 100k 1% 100k 1% 100k 1% R1 71.5k 1% R2 28k 1% GND CRT CRT 47nF PUSHBUTTON RESET 2930 TA02 tRST = 94ms RELATED PARTS PART NUMBER LTC1326 LTC1728 LTC2900 LTC2901 LTC2902 LTC2903 LTC2904-LTC2907 LTC2908 LTC2909 LTC2910 LTC2912-LTC2914 LTC2915-LTC2918 LTC2928 LTC2931 LTC2932 DESCRIPTION Micropower Triple Supply Monitor for 5V/2.5V, 3.3V and ADJ Micropower Triple Supply Monitor with Open-Drain Reset Programmable Quad Supply Monitor Programmable Quad Supply Monitor Programmable Quad Supply Monitor Precision Quad Supply Monitor Three-State Programmable Precision Dual Supply Monitor Precision Six Supply Monitor (Four Fixed & Two Adjustable) Precision Triple/Dual Input UV, OV and Negative Voltage Monitor Precision Octal Positive/Negative Voltage Supply Monitor Single/Dual/Quad UV and OV Voltage Monitors Single Supply Monitor with 27 Pin-Selectable Thresholds Quad Power Supply Sequencer and Supervisor Configurable Six Supply Monitor with Individual Comparator Outputs Configurable Six Supply Monitor with Individual Comparator Outputs COMMENTS 4.725V, 3.118V, 1V Threshold (±0.75%) and ADJ 5-Lead SOT-23 Package Adjustable Reset, 10-Lead MSOP and DFN Packages Adjustable Reset and Watchdog Timer Adjustable Reset and Tolerance (5%, 7.5%, 10%, or 12.5%) 6-Lead SOT-23 Package 8-Lead SOT-23 and DFN Packages 8-Lead TSOT-23 and DFN Packages Shunt Regulated VCC Pin, Adjustable Threshold and Reset, 8-Lead SOT-23 and DFN Packages 16-Lead SSOP and 5mm × 3mm DFN Packages, H-Grade Temperature Range Separate VCC Pin, Adjustable Reset Timer, H-Grade Temperature Range Manual Reset, Watchdog, TSOT-8/MSOP-10 and 3mm × 2mm DFN Packages, H-Grade Temperature Range Easily Configure Power Management without Software, 36-Lead 5mm × 7mm QFN and SSOP Packages Adjustable Reset and Watchdog Timers, TSSOP-20 Package Adjustable Reset Timer and Tolerance, TSSOP-20 Package, Pin-Selectable Tolerance (5%, 7.5%, 10%, or 12.5%), Reset Disable for Margining 2930fa 12 Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● LT 0308 REV A • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 www.linear.com © LINEAR TECHNOLOGY CORPORATION 2008