LIN D O C #: 3546 SG3546 3 . 3 V U N D E R V O LTA G E S E N S I N G C I R C U I T T H E I P N F I N I T E O W E R O F I P N N O VA T I O N R O D U C T I O N DESCRIPTION The SG3546 is an undervoltage sensing circuit specifically designed for use as a reset controller in 3.3V microprocessor-based applications. Its micropower operation makes this device ideal for portable applications where extended battery life is required. The device offers a 1.2V temperature compensated bandgap reference, a A T A S H E E T K E Y F E AT U R E S precision comparator with hysteresis and a high-current open collector output. This device operates from 1 to 10V input supply and drains <10µA in the non-fault condition. The SG3546 is available in an 8-pin 150mil SOIC package or a 3-pin TO-92 package and is rated for an ambient temperature of 0°C to 70°C. PRODUCT HIGHLIGHT ■ LOW STANDBY CURRENT ■ INTERNAL VOLTAGE THRESHOLD AT 2.95V ■ TEMPERATURE COMPENSATED BANDGAP REFERENCE ■ PRECISION COMPARATOR WITH 40MV OF HYSTERESIS ■ CLAMP DIODE FOR DISCHARGING DELAY CAPACITOR ■ OUTPUT CURRENT SINK CAPABILITY (typ 5mA) ■ 1-10V INPUT SUPPLY RANGE ■ AVAILABLE IN 150MIL, 8-PIN SOIC AND 3-PIN TO-92 PACKAGES L OW -V OLTAGE M ICROPROCESSOR R ESET 2 D R 1 POWER SUPPLY RESET CDLY MICROPROCESSOR CIRCUIT 1.2 VREF 3 PA C K A G E O R D E R I N F O R M AT I O N T A (°C) 0 to 70 SOIC DM Plastic 8-pin SG3546DM TO-92 LP Plastic 3-pin SG3546LP Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. SG3546DMT) F O R F U R T H E R I N F O R M AT I O N C A L L ( 7 1 4 ) 8 9 8 - 8 1 2 1 Copyright © 1994 Rev. 1.3 1/96 11861 W ESTERN A VENUE , G ARDEN G ROVE , CA. 92841 1 PRODUCT DATABOOK 1996/1997 SG3546 3 . 3 V U N D E R V O LT A G E S E N S I N G C I R C U I T P R O D U C T I O N A B S O L U T E M A X I M U M R AT I N G S D A T A S H E E T PACKAGE PIN OUTS (Note 1) Input Supply Voltage (VIN)............................................................................... -1V to 12V RESET Output Voltage (VOUT) .......................................................................... -1V to 12V Clamp Diode Forward Current .............................................................................. 100mA Operating Junction Temperature Plastic (DM - Package) ......................................................................................... 150°C Storage Temperature Range ...................................................................... -65°C to 150°C Lead Temperature (Soldering, 10 seconds) ............................................................ 300°C RESET INPUT N.C. GROUND 1 2 3 4 N.C. N.C. N.C. N.C. 8 7 6 5 DM PACKAGE (Top View) Note 1. Values beyond which damage may occur. All voltages are specified with respect to ground, and all currents are positive into the specified terminal. 3. GROUND T H E R M A L D ATA 2. INPUT 1. RESET DM PACKAGE: THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ JA 165°C/W LP PACKAGE (Top View) LP PACKAGE: THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ JA 156°C/W Junction Temperature Calculation: TJ = T A + (PD x θJA). The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. BLOCK DIAGRAM INPUT 2 RESET 1 1.2 VREF 4 GROUND 2 Copyright © 1994 Rev. 1.3 2/96 PRODUCT DATABOOK 1996/1997 SG3546 3 . 3 V U N D E R V O LTA G E S E N S I N G C I R C U I T P R O D U C T I O N D A T A S H E E T R E C O M M E N D E D O P E R AT I N G C O N D I T I O N S Parameter Symbol Input Supply Voltage RESET Output Voltage Clamp Diode Forward Current Operating Ambient Temperature Range: SG3546 TA (Note 2) Recommended Operating Conditions Min. Typ. Max. Units 1 10 10 50 V V mA 0 70 °C Note 2. Range over which the device is guaranteed functional. ELECTRICAL CHARACTERISTICS (Unless otherwise specified, these specifications apply over the operating ambient temperatures of 0°C ≤ T A ≤ 70°C for the SG3546. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.) Parameter Symbol Test Conditions Min. SG3546 Typ. Max. Units Total Device Operating Input Voltage Range Quiescent Input Current VIN IIN 1.0 10 20 50 V µA µA 2.81 2.86 40 3.0 3.0 V V mV 0.05 0.06 0.40 0.30 20 0.5 2.0 1.2 V V mA µA µA V 10 19 VIN = 3.3V VIN = 10V Comparator Section Threshold Voltage High-State Output Low-State Output Hysteresis VIH VIL VH VIN Increasing VIN Decreasing Output Sink Saturation VOL Output Sink Current Output Off-State Leakage ISINK VIN = 2.6V, ISINK = 1mA VIN = 1.0V, ISINK = 100µA VIN , RESET = 2.6V VIN , RESET = 3.6V VIN , RESET = 10V Pin 1 to pin 2, (IF = 5.0mA) 2.75 2.75 RESET Output Section Clamp Diode Forward Voltage Copyright © 1994 Rev. 1.3 2/96 VF 0.5 3 PRODUCT DATABOOK 1996/1997 SG3546 3 . 3 V U N D E R V O LT A G E S E N S I N G C I R C U I T P R O D U C T I O N D A T A S GRAPH / CURVE INDEX FIGURE INDEX Characteristic Curves 4 H E E T Application Circuits FIGURE # FIGURE # 1. COMPARATOR THRESHOLD VOLTAGE vs. TEMPERATURE 7. SWITCHING THE LOAD OFF WHEN BATTERY REACHES BELOW VTH 2. RESET OUTPUT VOLTAGE vs. INPUT VOLTAGE 8. LOW VOLTAGE MICROPROCESSOR RESET 3. RESET OUTPUT SATURATION vs. SINK CURRENT 9. VOLTAGE MONITOR 4. INPUT CURRENT vs. INPUT VOLTAGE 5. RESET DELAY TIME (LOW to HIGH) 6. RESET DELAY TIME (HIGH to LOW) Copyright © 1994 Rev. 1.3 2/96 PRODUCT DATABOOK 1996/1997 SG3546 3 . 3 V U N D E R V O LTA G E S E N S I N G C I R C U I T P R O D U C T I O N D A T A S H E E T C H A R A C T E R I S T I C C U RV E S FIGURE 1. — COMPARATOR THRESHOLD VOLTAGE vs. TEMPERATURE FIGURE 2. — RESET OUTPUT VOLTAGE vs. INPUT VOLTAGE RL = 43K to VIN 3.050 RL = 82K to VIN TA = 25°C Output Voltage - (V) Threshold Voltage - (V) 4 3.000 2.950 2.900 2.850 2.800 3 2 1 2.750 0 -50 -25 0 25 50 75 100 0 125 2 1 3 FIGURE 3. — RESET OUTPUT SATURATION vs. SINK CURRENT FIGURE 4. — INPUT CURRENT vs. INPUT VOLTAGE RL = ¥ TA = 25°C 70 VIN = 3V TA = 25°C 60 Input Current - (µA) (VOL) Output Saturation - (mV) 5 Input Voltage - (V) Junction Temperature - (°C) 300 4 200 100 50 40 30 20 10 0 0 0 3 6 9 12 (ISINK) Sink Current - (mA) Copyright © 1994 Rev. 1.3 2/96 14 0 0.5 1 1.5 2 2.5 3 3.5 4 Input Voltage - (V) 5 PRODUCT DATABOOK 1996/1997 SG3546 3 . 3 V U N D E R V O LT A G E S E N S I N G C I R C U I T P R O D U C T I O N D A T A S H E E T CHARACTERISTIC CURVES FIGURE 5. — RESET DELAY TIME (LOW TO HIGH) FIGURE 6. — RESET DELAY TIME (HIGH TO LOW) VIN VIN 43K 3.3V 2.7V 2.7V RESET REF 100% 3.3V 3.3V 2.7V 2.7V VIN = 3.3V to 2.6V RL = 43K TA = 25°C 2µs/DIV. 6 RESET REF 100% 0% 43K 3.3V 0% VIN = 4.0V to 5.0V RL = 43K TA = 25°C 0.5µs/DIV. Copyright © 1994 Rev. 1.3 2/96 PRODUCT DATABOOK 1996/1997 SG3546 3 . 3 V U N D E R V O LTA G E S E N S I N G C I R C U I T P R O D U C T I O N D A T A S H E E T T Y P I C A L A P P L I C AT I O N C I R C U I T S 2 R 1 POWER SUPPLY RESET CDLY MICROPROCESSOR CIRCUIT LOAD 2 1 RESET 1.2 VREF 3 1.2 VREF A time-delayed reset can be accomplished with the addition of C DLY. For systems with extremely fast power supply rise times (< 500ns), it is recommended that the RCDLY time constant be greater than 5.0µs. VTH(MPU) is the microprocessor reset input threshold. 4 tDLY = R CDLY In FIGURE 7. — SWITCHING THE LOAD OFF WHEN BATTERY VOLTAGE REACHES BELOW VTH 1 VTH(MPU) 1- V IN FIGURE 8. — LOW VOLTAGE MICROPROCESSOR RESET 1.0k 2 1 POWER SUPPLY RESET 1.2 VREF 3 FIGURE 9. — VOLTAGE MONITOR Copyright © 1994 Rev. 1.3 2/96 7