AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Features General Description - Precision Monitoring of +3V, +3.3V, and +5V Power-Supply Voltages - Fully Specified Over Temperature - Available in Three Output Configurations - Push-Pull RESET Low Output (AP1701/3) - Push-Pull RESET High Output (AP1702/4) - 140ms min Power-On Reset Pulse Width - 12µA Supply Current - Guaranteed Reset Valid to VCC = +1V - Power Supply Transient Immunity - No External Components - 3-pin SOT23 package - Computers - Controllers - Intelligent Instruments - Critical µP and µC Power Monitoring - Portable/Battery Powered Equipment - Automotive The AP1701/2/3/4 are used for microprocessor (µP) supervisory circuits to monitor the power supplies in µP and digital systems. They provide excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V, +3.3V, +3.0V powered circuits. These circuits perform a single function: they assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. Reset thresholds suitable for operation with a variety of supply voltages are available. The AP1701/2/3/4 have push pull outputs. The AP1701/3 have an active low RESET output, while the AP1702/4 has an active high RESET output. The reset comparator is designed to ignore fast transients on VCC, and the outputs are guaranteed to be in the correct logic state for VCC down to 1V. Low supply current makes the AP1701/2/3/4 ideal for use in portable equipment. The AP1701/2/3/4 is available in a 3-pin SOT23 package. Pin Assignments Pin Descriptions Applications (Top View) GND GND 1 AP1701 AP1702 RESET (RESET) Name RESET (RESET) 3 VCC VCC 2 Description Ground Reset output pin L: for AP1701/3 H: for AP1702/4 Operating voltage input SOT-23 (Top View) RESET (RESET) GND 1 AP1703 AP1704 3 VCC 2 SOT-23 This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this product. No rights under any patent accompany the sale of the product. Rev.1.0 1/8 May. 7, 2004 AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Ordering Information AP170X X X X Enable Voltage Package Lead Free 1: Active-Low 2: Active-High 3: Active-Low 4: Active-High A: 4.63 B: 4.38 C: 4.00 D: 3.08 E: 2.93 F: 2.63 W:SOT23 Blank : Normal L : Lead Free Package Absolute Maximum Ratings Symbol VCC VRESET Parameter Terminal Voltage (with respect to GND) RESET, RESET (push-pull) Rating Unit -0.3 to +6.0 V -0.3 to (VCC + 0.3) V ICC Input Current, VCC 20 mA IO Output Current, RESET, RESET 20 mA VR 100 V/µS 320 mW TOP Rate of Rise, VCC Continuous Power Dissipation (TA = +70°C), de-rate 4mW/°C above +70°C Operating Temperature Range -40 to +105 °C TST Storage Temperature Range -65 to +150 °C +300 °C PD TLEAD Lead Temperature (soldering, 10s) Anachip Corp. www.anachip.com.tw Rev.1.0 May.7, 2004 2/8 AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Electrical Characteristics Symbol Parameter VCC VCC Range ICC Supply Current (TA=25ºC) Conditions o Min. o TA = 0 C to +70 C 1.0 VTH TDELAY VOL VOH RESET Output Voltage-Low VOH RESET Output Voltage-High Unit 5.5 V VCC < 5.5V 19 60 µA 17 50 µA 4.63 4.72 4.54 AP1701/2/3/4B 4.29 4.38 4.47 AP1701/2/3/4C 3.92 4.00 4.08 AP1701/2/3/4D 3.02 3.08 3.14 AP1701/2/3/4E 2.87 2.93 2.99 AP1701/2/3/4F 2.57 2.63 2.68 Reset Threshold Tempco VCC to Reset Delay VCC = VTH to (VTH – 100mV) Reset Active TA = 0oC to +70oC 100 Timeout Period VCC = VTH min, ISINK = 1.2mA, AP1701/3 RESET Output VCC = VTH min, ISINK = 3.2mA Voltage Low VCC > 1.0V, ISINK = 50uA VCC > VTH max, ISOURCE = 500uA, 0.8VCC RESET Output AP1701/3 Voltage-High VCC –1.5 VCC > VTH max, ISOURCE = 800uA VOL Max. VCC < 3.6V AP1701/2/3/4A Reset Threshold TA=25ºC Typ. 30 ppm/oC 20 µs 240 380 ms 0.3 0.4 V 0.3 V VCC = VTH max, ISINK = 1.2mA, AP1702/4 0.3 VCC = VTH max, ISINK = 3.2mA 1.8V < VCC < VTH min, ISOURCE = 150uA, AP1702/4 0.4 0.8 VCC V V V Application Circuit VCC VCC VCC Microprocessor AP170X RESET INPUT RESET (RESET) GND GND Anachip Corp. www.anachip.com.tw Rev.1.0 May.7, 2004 3/8 AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Function Description When VCC falls below 1V, the AP1701/3 RESET output no longer sinks current—it becomes an open circuit. Therefore, high-impedance CMOS logic inputs connected to RESET can drift to undetermined voltages. This presents no problem in most applications since most µP and other circuitry is inoperative with VCC below 1V. However, in applications where RESET must be valid down to 0V, adding a pull down resistor to RESET causes any stray leakage currents to flow to ground, holding RESET low. R1’s value is not critical; 100k is large enough not to load RESET and small enough to pull RESET to ground. For the AP1702/4 if RESET is required to remain valid for VCC < 1V. A microprocessor’s (µP’s) reset input starts the µP in a known state. The AP1701/2/3/4 assert reset to prevent code-execution errors during power-up, power-down, or brownout conditions. They assert a reset signal whenever the VCC supply voltage declines below a preset threshold, keeping it asserted for at least 140ms after VCC has risen above the reset threshold. The AP1701/2/3/4 have a push-pull output stage. Applications Information Negative-Going VCC Transients In addition to issuing a reset to the µP during power-up, power-down, and brownout conditions, the AP1701/2/3/4 are relatively immune to short-duration negative-going VCC transients (glitches). The AP1701/2/3/4 do not generate a reset pulse. The graph was generated using a negative going pulse applied to VCC, starting 0.5V above the actual reset threshold and ending below it by the magnitude indicated (reset comparator overdrive). The graph indicates the maximum pulse width a negative going VCC transient can have without causing a reset pulse. As the magnitude of the transient increases (goes farther below the reset threshold), the maximum allowable pulse width decreases. Typically, a VCC transient that goes 100mV below the reset threshold and lasts 20µs or less will not cause a reset pulse. A 0.1µF bypass capacitor mounted as close as possible to the VCC pin provides additional transient immunity. Benefits of Highly Accurate Reset Threshold Most µP supervisor ICs have reset threshold voltages between 5% and 10% below the value of nominal sup-ply voltages. This ensures a reset will not occur within 5% of the nominal supply, but will occur when the supply is 10% below nominal. When using ICs rated at only the nominal supply ±5%, this leaves a zone of uncertainty where the supply is between 5% and 10% low, and where the reset may or may not be asserted. Ensuring a Valid Reset Output Down to VCC = 0 RESET is guaranteed to be a logic low for VCC > 1V. Once VCC exceeds the reset threshold, an internal timer keeps RESET low for the reset timeout period; after this interval, RESET goes high. If a brownout condition occurs (VCC dips below the reset threshold), RESET goes low. Any time VCC goes below the reset threshold, the internal timer resets to zero, and RESET goes low. The internal timer starts after VCC returns above the reset threshold, and RESET remains low for the reset timeout period. Anachip Corp. www.anachip.com.tw Rev.1.0 May.7, 2004 4/8 AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Function Block Driver RESET / RESET Delay Circuit VREF Performance Characteristics Threshold 2.928 24 20 2.926 16 2.924 Iq 12 8 2.922 4 2.92 0 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 100 110 120 Temp ( C ) Iq v.s Temp -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90 Temp Threshold v.s. Temp Anachip Corp. www.anachip.com.tw Rev.1.0 May.7, 2004 5/8 AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Timing Diagram VTH VCC t1 t1 Active Low t1 Active High t1 Giltch Immunity Maximum Transient Duration(us) 3500 3000 3000 2500 2000 1500 1000 500 900 270 0 0 100 200 140 300 90 400 70 500 58 600 50 700 50 800 48 48 900 1000 1100 RESET COMPARATOR OVERDRIVE(mV) Anachip Corp. www.anachip.com.tw Rev.1.0 May.7, 2004 6/8 AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Marking Information (Top View) 3 Identification code ( See appendix ) XX Y M X 1 2 Blank: normal L: Lead Free Package Month: A~L Year:0~9 SOT23-3L Appendix Part Identification Part Number Code Number AP1701A EA AP1703A AP1701B EB AP1703B AP1701C EC AP1703C AP1701D ED AP1703D AP1701E EE AP1703E AP1701F EF AP1703F AP1702A E0 AP1704A AP1702B E2 AP1704B AP1702C E3 AP1704C AP1702D E4 AP1704D AP1702E E5 AP1704E AP1702F E6 AP1704F Anachip Corp. www.anachip.com.tw Identification Code EG EH EI EJ EK EL E7 E8 E9 EM EN EP Rev.1.0 May.7, 2004 7/8 AP1701/2/3/4 3-Pin Microprocessor Reset Circuits Package Information HE E Package Type: SOT23-3L e A A1 A2 b C D E e HE L Dimensions In Millimeters Min. 1.00 0.00 1.00 0.35 0.10 2.70 1.40 1.70 2.40 0.30 Nom. 1.20 1.15 0.175 2.90 1.60 2.00 2.70 - L C A1 b Symbol A A2 D Max. 1.40 0.10 1.30 0.50 0.25 3.10 1.80 2.30 3.00 0.55 Anachip Corp. www.anachip.com.tw Dimensions In Inches Min. 0.039 0.000 0.039 0.014 0.004 0.106 0.055 0.067 0.094 0.012 Nom. 0.047 0.045 0.007 0.114 0.063 0.079 0.106 - Max. 0.055 0.004 0.051 0.020 0.010 0.122 0.071 0.091 0.118 0.022 Rev.1.0 May.7, 2004 8/8