AAT3520/2/4 MicroPower Microprocessor Reset Circuit Features The AAT3520 Series of PowerManagerTM products is a member of AATI's Total Power Management ICTM (TPMICTM) product family. These microprocessor reset circuits are ideal for monitoring voltage supplies in portable systems, where extended battery life is critical. They provide a low cost, reliable solution by eliminating external components. The AAT3520 series operates by monitoring the system power supply voltage. When the input voltage drops below a fixed threshold, the device asserts a reset signal for a fixed time period after VCC has risen back above the fixed threshold; 30ms and 150ms minimum periods are available. The AAT3520 product series is guaranteed to operate down to 1.2V and designed to ignore fast line transients appearing on VCC. The AAT3520 series is available with three output stage versions: AAT3520 push-pull active high output, AAT3522 push-pull active low output and AAT3524 open drain active low output. The quiescent supply current is extremely low, typically 1A, making it ideal for portable battery operated equipment. * * * * * * * The AAT3520/2/4 are available in a 3 pin SOT23 package and are specified over -40 to 85C operating temperature range. PowerManagerTM 1.2V to 5.5V Input voltage range Operation down to 1.2V Extremely low quiescent current: less than 2A High accuracy detection threshold: 1.5% Monitor Power Supply Voltages Fixed thresholds from 2.2V to 4.6V Reset pulse width options * Minimum 30 ms or 150ms * Fast propagation delay <20s Available output configurations: * Open-drain output * CMOS active high output * CMOS active low output Temp range -40 to 85C 3 pin SOT23 package * * * Applications * * * * * Notebook Computers Cell Phones Portable Electronics Embedded Systems Intelligent Instruments Typical Application VCC VCC VCC * 100k (nominal) AAT3520 AAT3522 RESET AAT3524 (RESET) GND RESET uP INPUT GND *AAT3524 Only 3520.2002.2.0.9 1 Preliminary Information General Description AAT3520/2/4 MicroPower Microprocessor Reset Circuit Pin Descriptions AAT3520, 3522, 3524 (SOT23-3) Pin # Symbol 1 GND Ground connection RESET (AAT3520) RESET output remains high while VCC is below the reset threshold and remains so for a fixed time period after VCC raises above the reset threshold. RESET (AAT3522, AAT3524) RESET output remains low while VCC is below the reset threshold and remains so for a fixed time period after VCC raises above the reset threshold 2 3 Function Vcc Supply Voltage (+1.2V to +5.5V) Part Number Descriptions SOT23-3 Part Number Part Description AAT3520 Reset Output Push Pull Active High with Delay AAT3522 Reset Output Push Pull Active Low with Delay AAT3524 Reset Output Open Drain Active Low with Delay Pin Configuration SOT-23 (Top View) GND 1 3 (RESET) RESET 2 VCC 2 3520.2002.2.0.9 AAT3520/2/4 MicroPower Microprocessor Reset Circuit Absolute Maximum Ratings Symbol VCC VRESET IMAX IRESET dVcc/dt TJ TLEAD (TA=25C unless otherwise noted) Description VCC to GND RESET to GND (Push-Pull Output) RESET to GND (Open Drain Output) Maximum Continuous Input Current RESET/RESET Current Rate of rise of Vcc Operating Junction Temperature Range Maximum Soldering Temperature (at Leads) for 10s Value Units -0.3 to 5.5 -0.3 to VCC+0.3 -0.3 to 5.5 20 20 100 -40 to 150 300 V V mA mA V/s C C Note: Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum rating should be applied at any one time. Thermal Information Symbol JA PD Description Value Units 200 320 C/W mW Maximum Thermal Resistance (SOT23-3)1 Maximum Power Dissipation (SOT23-3)1 Note 1: Mounted on an FR4 board. Electrical Characteristics (VIN = 5V, TA = -40 to 85C unless otherwise noted. Typical values are at TA=25C, VCC = 5V for 4.63/4.38V versions, VCC = 3.3V for 3.08/2.93V versions, VCC = 3.0V for 2.63V version and VCC = 2.5V for 2.32/2.2V versions ) Symbol Description VCC Operation Voltage IQ Quiescent Current VTH RESET Threshold (Table 1) VTH/C tP RESET Threshold Tempco RESET Propagation Delay tRDY RESET Active Timeout Period VOL RESET Low Output Voltage AAT3522, AAT3524 VOH RESET High Output Voltage AAT3522 VOL RESET Low Output Voltage AAT3520 VOH RESET High Output Voltage AAT3520 IDOFF RESET leakage current, AAT3524 3520.2002.2.0.9 Conditions Min Typ TA = 0C to +70C TA = -40C to +85C VCC = 5.5V VCC = 3V TA = 25C TA = -40C to +85C 1.0 1.2 5.5 V 5.5 1.05 3 A 0.85 2 VTH VTH +1.5% V VTH VTH +2.5% 40 ppm/C 15 s 50 100 ms 250 400 0.3 VCC = VTH to (VTH -100mV) -50 option -200 option ISINK =1.6mA, VCC > 2.1V, RESET asserted ISINK =100A, VCC >1.2V, RESET asserted ISOURCE = 800 A ISINK =1.2mA, VCC > 1.2V, RESET not asserted ISINK = 3.2mA, VCC > 4.5V, RESET not asserted ISOURCE = 500A, VCC > 2.1V, RESET asserted ISOURCE = 50A, VCC > 1.2V, RESET asserted VCC > VTH VTH -1.5% VTH -2.5% 30 150 Max 0.4 VCC -1.5 Units V V 0.3 0.4 V 0.8VCC V 0.8VCC 1 A 3 AAT3520/2/4 MicroPower Microprocessor Reset Circuit Typical Characteristics Normalized Reset Threshold vs. Temperature Supply Current vs. Temperature 1.20 VCC=5V 1.00 0.80 VCC=3V 0.60 0.40 0.20 0.00 -40 -20 0 20 40 60 80 Normalized Threshold Supply Current (A) 1.40 1.003 1.002 1.001 1.000 0.999 0.998 0.997 -40 Temperature (C) 20 40 60 80 100 Normalized Power-Up Reset Timeout (ms) Temperature (C) Reset Propagation Delay (s) 0 20 40 60 80 Power-Down Reset Propagation Delay vs. Temperature 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 -20 0 Temperature (C) Normalized Power-Up Reset Timeout vs. Temperature -40 -20 30 25 VOD=10mV 20 15 10 VOD=100mV 5 0 -40 -20 0 20 40 60 80 Temperature (C) Maximum Transient Duration vs. Reset Threshold Overdrive Maximum Transient Duration (S) 400 350 300 250 200 150 100 50 0 1 10 100 1000 Reset Threshold Overdrive, VTH-VCC (mV) 4 3520.2002.2.0.9 AAT3520/2/4 MicroPower Microprocessor Reset Circuit Functional Block Diagram VCC Reset Generator + Timer RESET (RESET) Oscillator VREF GND Functional Description General During start-up, the reset pin on a microprocessor ensures that it is fully reset and starts up in a known condition. The AAT3520 series of microprocessor reset devices monitor the supply voltage to a microprocessor and assert a reset signal whenever the VCC RESET VTH VTH tRDY VCC voltage falls below a factory programmed threshold. This threshold is accurate within +/-1.5% at 25C and within +/- 2.5% over the entire operating temperature range. The reset signal remains asserted for a fixed time period (tRDY) after VCC has risen above the threshold as shown in Figure 1. See Ordering Information for available RESET active timeout periods VTH tRDY Figure 1: Reset Timing Diagram (AAT3522, AAT3524) 3520.2002.2.0.9 5 AAT3520/2/4 MicroPower Microprocessor Reset Circuit Supply Voltage Transient Behavior Applications Information In some cases fast negative transients of short duration can appear on the VCC power supply. The AAT3520 series devices provide some immunity to line transients which can generate invalid reset pulses. Figure 1 shows typical behavior to short duration pulses verses RESET comparator overdrive. As shown in the Maximum Transient Duration vs. Reset Threshold Overdrive graph, when the transient voltage becomes larger, the time allowed before asserting a reset becomes shorter. e.g. typically a transient of 100mV below the reset threshold would have to present for more than 50s to cause a reset. Immunity can be increased by the addition of a small by-pass capacitor of 0.1F connected as close to the VCC pin as possible. Reset Output Options The AAT3524 has an active low open drain output and the AAT3520/2 have a push-pull output. The AAT3524 may be used in multiple voltage systems, with an external pull-up resistor. This allows the AAT3524 to interface to microprocessors with higher supply voltages up to 5.5V (Figure 2). In the event of a power down or brown-out condition the reset signal remains valid until the VCC drops below 1.2V. To ensure validity down to ground an external 100k resistor should be connected between the RESET output and GND. +3.3V +5.0V VCC VCC 100k AAT3524 RESET GND RESET INPUT 5V System GND Figure 2: Using AAT3524 Open Drain Output with Multiple Supplies 6 3520.2002.2.0.9 AAT3520/2/4 MicroPower Microprocessor Reset Circuit Factory Trimmed Reset Thresholds* and Ordering Information Table 1 Reset Threshold Voltage, VTH (V) Ordering Part Number Minimum Marking Reset Active (ms) TA = 25C TA = 40 to 85C Min Typ Max Min Max AAT3520IGY-2.32-200-T1 AAT3522IGY-2.32-200-T1 AAT3524IGY-2.32-200-T1 150 150 150 2.285 2.320 2.355 2.262 2.378 AAT3520IGY-2.63-200-T1 AAT3522IGY-2.63-200-T1 AAT3524IGY-2.63-200-T1 150 150 150 2.591 2.630 2.669 2.564 2.696 AAT3520IGY-2.93-200-T1 AAT3522IGY-2.93-200-T1 AAT3524IGY-2.93-200-T1 150 150 150 2.886 2.930 2.974 2.857 3.003 AAT3520IGY-3.08-50-T1 AAT3520IGY-3.08-200-T1 AAT3522IGY-3.08-50-T1 AAT3522IGY-3.08-200-T1 AAT3524IGY-3.08-200-T1 30 150 30 150 150 3.034 3.080 3.126 3.003 3.157 AAT3520IGY-4.38-200-T1 AAT3522IGY-4.38-200-T1 AAT3524IGY-4.38-200-T1 150 150 150 4.314 4.380 4.446 4.271 4.490 AAT3520IGY-4.63-200-T1 AAT3522IGY-4.63-200-T1 AAT3524IGY-4.63-200-T1 150 150 150 4.561 4.630 4.699 4.514 4.746 *Contact Local Sales Office for custom trimmed options 3520.2002.2.0.9 7 AAT3520/2/4 MicroPower Microprocessor Reset Circuit Package Information SOT23-3 D Dim S1 E A A1 A2 b C D E e H L S S1 1 H S e A A2 A1 b 1 C L Millimeters Min Max .887 1.02 .013 0.10 0.37 0.51 0.085 0.180 2.80 3.04 1.20 1.40 1.78 2.05 2.10 2.64 0.69 0.45 0.60 0.89 1.03 0 8 Inches Min Max 0.034 .040 0.0005 .004 0.015 0.020 0.003 0.007 0.110 0.120 0.047 0.055 0.070 0.080 0.083 0.104 0.027 0.018 0.024 0.035 0.040 0 8 Note: 1. PACKAGE BODY SIZE EXCLUDE MOLD FLASH PROTRUSIONS OR GATE BURRS. 2. TOLERANCE 0.1000 mm (4mi) UNLESS OTHERWISE SPECIFIED 3. COPLANARITY: 0.1000 4. DIMENSION L IS MEASURED IN GAGE PLANE Advanced Analogic Technologies, Inc. 1250 Oakmead Parkway, Suite 310, Sunnyvale, CA 94086 Phone (408) 524-9684 Fax (408) 524-9689 8 3520.2002.2.0.9