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| HT7022A 2.2V Voltage Detector Features * Low detectable voltage 2.2V * Low power consumption * Low temperature coefficient * Built-in high-stability reference source * Built-in hysteresis characteristic * TO-92 and SOT-89 package Applications * Battery checkers * Power failure detectors * Microcomputer reset * Battery memory backup * Non-volatile RAM signal storage protectors General Description The HT7022A is a three-terminal low power voltage detector implemented in CMOS technology. It detects a particular fixed voltage 2.2V. The voltage detector consists of a high-precision and low power consumption standard voltage source, a comparator, hysteresis circuit, and an output driver. CMOS technology ensures low power consumption. Although designed primarily as fixed voltage detectors, these devices can be used with external components to detect user specified threshold voltages (NMOS open drain type only). Output Type Selection Table VDD Type VOUT A VDD>VDET(+) Hi-Z VDDVDET(-) VSS Rev. 1.10 1 April 20, 2004 HT7022A Block Diagram N Channel Open Drain Output (Normal Open; Active Low) VDD VOUT V REF GND A Type V OUT D a s h lin e S o lid lin e V V IN IN fro m fro m H L O I (R) (R) L H I O V DET V V HYS DET 1 .0 5 V IN Pin Assignment T O -9 2 S O T -8 9 H T7022A F r o n t V ie w H T7022A OUTVDD VSS B o tto m V ie w OUT VDD VSS Rev. 1.10 2 April 20, 2004 HT7022A Pad Assignment OUT VDD VSS 1 2 3 (0 ,0 ) Chip size: 2032 1321 (mm)2 * The IC substrate should be connected to VDD in the PCB layout artwork. Pad Coordinates Pad No. 1 2 3 X -434.34 120.65 774.70 Y Unit: mm 394.97 461.01 412.75 Absolute Maximum Ratings Supply Voltage ............................VSS-0.3V to VSS+13V Output Current......................................................50mA Power Consumption ..........................................200mW Output Voltage...........................VSS-0.3V to VDD+0.3V Storage Temperature ............................-50C to 125C Operating Temperature...........................-40C to 85C Note: These are stress ratings only. Stresses exceeding the range specified under Absolute Maximum Ratings may cause substantial damage to the device. Functional operation of this device at other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability. Electrical Characteristics Symbol Parameter Hi(R)Lo Detectable Voltage Lo(R)Hi Detectable Voltage VHYS IDD VDD IOL DVDET DTa Hysteresis Width Operating Current Operating Voltage Output Sink Current Temperature Coefficient Test Conditions VDD 3/4 3/4 3/4 3.2V No load 3/4 2V 3/4 3/4 VOUT=0.2V 0C VDET Rev. 1.10 3 April 20, 2004 HT7022A Functional Description The HT7022A is a voltage detector equipped with a high stability voltage reference which is connected to the negative input of a comparator3/4 denoted as VREF in the following figure for NMOS output voltage detector. When the voltage drop to the positive input of the comparator (i,e,VB) is higher than VREF, VOUT goes high, M1 turns off, and VB is expressed as VBH=VDD (RB+RC) / (RA+RB+RC). If VDD is decreased so that VB falls to a value less than VREF, the comparator output inverts from high to low, VOUT goes low, VC is high, M1 turns on, RC is bypassed, and V B becomes: VBL=VDDRB / (RA+RB), which is less than VBH. By so doing, the comparator output will stay low to prevent the circuit from oscillating when VB VREF. V The hysteresis width is: VHYS = VDET (+) - VDET (-) The figure demonstrates the NMOS output type with positive output polarity (VOUT is normally open, active low). V DD R A C o m p a ra to r R V B REF L V C V MN OUT R B If VDD falls below the minimum operating voltage, the output becomes undefined. When VDD goes from low to VDD RB / (RA+RB) > VREF, the comparator output and VOUT goes high. R M1 C The detectable voltage is defined as: VDET (-) = RA + RB + RC VREF RB + RC NMOS Output Voltage Detector V SS The release voltage is defined as: VDET (+) = RA + RB VREF RB Application Circuits Microcomputer Reset Circuit Normally a reset circuit is required to protect the microcomputer system from malfunctions due to power line interruptions. The following examples show how different output configurations perform a reset function in various systems. * NMOS open drain output application for separate * NMOS open drain output application with R-C delay V R DD H T7022A V OUT M ic r o c o m p u te r power supply V DD1 V V OUT C DD2 V SS H T7022A RESET M ic r o c o m p u te r V SS Rev. 1.10 4 April 20, 2004 HT7022A Power-on Reset Circuit With several external components, the HT7022A can be used to perform a power-on reset function as shown: V * Varying the detectable voltage with a diode IN V V f1 IN V f2 R D V DD V C V DD OUT V OUT H T7022A V OUT V H T7022A SS V SS V SS V SS V Detectable Voltage = Vf1+Vf2+VDET Malfunction Analysis The following circuit demonstrates the way a circuit analyzes malfunctions by monitoring the variation or spike noise of power supply voltage. V DD DD t V OUT V OUT H T7022A V SS V SS Charge Monitoring Circuit t Change of Detectable Voltage If the required voltage is not found in the standard product selection table, it is possible to change it by using external resistance dividers or diodes. * Varying the detectable voltage with a resistance di- The following circuit shows a charged monitor for protection against battery deterioration by overcharging. When the voltage of the battery is higher than the set detectable voltage, the transistor turns on to bypass the charge current, protecting the battery from overcharging. V S o la r C e ll V Tr OUT DD vider V IN BATT Load R A V DD V R B OUT V SS H T7022A H T7022A V SS V SS Detectable voltage = Hysteresis width = RA + RB VDET RB RA + RB VHYS RB Rev. 1.10 5 April 20, 2004 HT7022A Package Information 3-pin TO-92 Outline Dimensions A B D C E F G H Symbol A B C D E F G H I a Dimensions in mil Min. 170 170 500 11 90 45 45 130 8 4 Nom. 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 3/4 Max. 200 200 3/4 20 110 55 65 160 18 6 Rev. 1.10 6 April 20, 2004 HT7022A 3-pin SOT-89 Outline Dimensions A B I J E C D G F H Symbol A B C D E F G H I J Dimensions in mil Min. 173 64 90 35 155 14 17 3/4 55 14 Nom. 3/4 3/4 3/4 3/4 3/4 3/4 3/4 59 3/4 3/4 Max. 181 72 102 47 167 19 22 3/4 63 17 Rev. 1.10 7 April 20, 2004 HT7022A Product Tape and Reel Specifications TO-92 Reel Dimensions (Unit: mm) P ackage U p, 30 F la t S id e U p P ackage U p, F la t S id e D o w n 58 88 360 43 Rev. 1.10 8 April 20, 2004 HT7022A SOT-89 Reel Dimensions T2 D A B C T1 SOT-89 Symbol A B C D T1 T2 Description Reel Outer Diameter Reel Inner Diameter Spindle Hole Diameter Key Slit Width Space Between Flange Reel Thickness Dimensions in mm 1801.0 621.5 12.75+0.15 1.90.15 12.4+0.2 17-0.4 Rev. 1.10 9 April 20, 2004 HT7022A TO-92 Carrier Tape Dimensions P Dh H1 H H0 l1 W2 W0 t W1 W F1 P2 P0 F2 D0 TO-92 Symbol I1 P P0 P2 F1 F2 Dh W W0 W1 W2 H0 H1 D0 t H Note: Description Taped Lead Length Component Pitch Perforation Pitch Component to Perforation (Length Direction) Lead Spread Lead Spread Component Alignment Carrier Tape Width Hold-down Tape Width Perforation Position Hold-down Tape Position Lead Clinch Height Component Height Perforation Diameter Taped Lead Thickness Component Base Height Dimensions in mm (2.5) 12.71.0 12.70.3 6.350.4 2.5+0.4 -0.1 2.5+0.4 -0.1 00.1 18.0+1.0 -0.5 6.00.5 9.00.5 (0.5) 16.00.5 Less than 24.7 4.00.2 0.70.2 19.00.5 Thickness less than 0.380.05mm~0.5mm P0 Accumulated pitch tolerance: 1mm/20pitches. ( ) Bracketed figures are for consultation only Rev. 1.10 10 April 20, 2004 HT7022A SOT-89 Carrier Tape Dimensions D E F W C P0 P1 t B0 D1 P K0 A0 SOT-89 Symbol W P E F D D1 P0 P1 A0 B0 K0 t C Description Carrier Tape Width Cavity Pitch Perforation Position Cavity to Perforation (Width Direction) Perforation Diameter Cavity Hole Diameter Perforation Pitch Cavity to Perforation (Length Direction) Cavity Length Cavity Width Cavity Depth Carrier Tape Thickness Cover Tape Width Dimensions in mm 12.0+0.3 -0.1 8.00.1 1.750.1 5.50.05 1.5+0.1 1.5+0.1 4.00.1 2.00.10 4.80.1 4.50.1 1.80.1 0.300.013 9.3 Rev. 1.10 11 April 20, 2004 HT7022A Holtek Semiconductor Inc. (Headquarters) No.3, Creation Rd. II, Science Park, Hsinchu, Taiwan Tel: 886-3-563-1999 Fax: 886-3-563-1189 http://www.holtek.com.tw Holtek Semiconductor Inc. (Taipei Sales Office) 4F-2, No. 3-2, YuanQu St., Nankang Software Park, Taipei 115, Taiwan Tel: 886-2-2655-7070 Fax: 886-2-2655-7373 Fax: 886-2-2655-7383 (International sales hotline) Holtek Semiconductor Inc. (Shanghai Sales Office) 7th Floor, Building 2, No.889, Yi Shan Rd., Shanghai, China 200233 Tel: 021-6485-5560 Fax: 021-6485-0313 http://www.holtek.com.cn Holtek Semiconductor Inc. (Shenzhen Sales Office) 43F, SEG Plaza, Shen Nan Zhong Road, Shenzhen, China 518031 Tel: 0755-8346-5589 Fax: 0755-8346-5590 ISDN: 0755-8346-5591 Holtek Semiconductor Inc. (Beijing Sales Office) Suite 1721, Jinyu Tower, A129 West Xuan Wu Men Street, Xicheng District, Beijing, China 100031 Tel: 010-6641-0030, 6641-7751, 6641-7752 Fax: 010-6641-0125 Holmate Semiconductor, Inc. (North America Sales Office) 46712 Fremont Blvd., Fremont, CA 94538 Tel: 510-252-9880 Fax: 510-252-9885 http://www.holmate.com Copyright O 2004 by HOLTEK SEMICONDUCTOR INC. The information appearing in this Data Sheet is believed to be accurate at the time of publication. However, Holtek assumes no responsibility arising from the use of the specifications described. The applications mentioned herein are used solely for the purpose of illustration and Holtek makes no warranty or representation that such applications will be suitable without further modification, nor recommends the use of its products for application that may present a risk to human life due to malfunction or otherwise. Holteks products are not authorized for use as critical components in life support devices or systems. Holtek reserves the right to alter its products without prior notification. For the most up-to-date information, please visit our web site at http://www.holtek.com.tw. Rev. 1.10 12 April 20, 2004 |
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