a FEATURES Simultaneous Monitoring of 9 V, and two 3.3 V Supplies Low Power: 10 A Typical Internal Comparator Hysteresis Power Supply Glitch Immunity VCC from 2.5 V to 3.6 V Guaranteed from 10 oC to +60oC No External Components 8-Pin SOIC Package APPLICATIONS Pagers Portable Instruments Triple- Power Supply Monitor ADM9261 FUNCTIONAL BLOCK DIAGRAM GND 1 +C1 - 8 ERR1 SU1 2 +C2 - 7 ERR2 SU2 3 + -C3 6 ERR3 SU3 4 VREF 5 VCC ADM9261 GENERAL DESCRIPTION The ADM9261 is a Multi-Supply Monitor IC which simultaneously monitors the three power supply voltages of a pager system and outputs error signals if any of the supply voltages falls below an acceptable minimum value. Analog Devices experience in the design of power supply supervisory circuits is used to provide an optimum solution for the overall circuit in terms of cost, performance and power consumption. Key features of the design include the incorporation of hysteresis and glitch immunity into the comparators, which minimizes the possibility of spurious triggering by noise spikes on the supplies being monitored. Power supply voltages outside V CC can be monitored without the need for input attenuators or other components, and the current drain (including input currents of the monitoring circuits) is typically only 10A, which imposes very little additional burden on the pager's battery. The ADM9261 is manufactured on one of Analog Devices proprietary BiCMOS processes, which also includes high performance thin film resistors to achieve the accuracy required for the precision voltage reference and comparator trip points. The ADM9261 is packaged in a space-saving SOIC package. REV. 0 Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 617/329-4700 World Wide Web Site: http://www.analog.com Fax: 617/326-8703 (c) Analog Devices, Inc., 1997 ADM9261SPECIFICATIONS Parameter Min OPERATING TEMPERATURE RANGE V CC SUPPLY VOLTAGE (VCC = Full Operating Range, TA = TMIN to TMAX unless otherwise noted) Typ Max Units 10 60 C 2.5 3.6 V Test Conditions/Comments TOTAL SUPPLY CURRENT 10 20 A Total Current into VCC and SU1 - SU3. Typ. is measured with VCC = 3.3 V, SU1 = 6 V, SU2 = SU3 = 3.3 V. Max is measured with VCC=3.6V, SU1 = 9 V, SU2= SU3 = 3.6 V V CC SUPPLY CURRENT 4 10 A Current from SU1 - SU3 not included SU1 INPUT RESISTANCE 3 M IIN ~ 2 A when SU1 = 6 V SU2 INPUT RESISTANCE 1.65 M IIN ~ 2 A when SU2 = 3.3 V SU3 INPUT RESISTANCE 1.65 M IIN ~ 2 A when SU3 = 3.3 V SU1 LOW TRIP POINT 3.808 3.904 4.00 V Measured with SU1 Falling SU2 LOW TRIP POINT 2.856 2.928 3.00 V Measured with SU2 Falling SU3 LOW TRIP POINT 2.666 2.733 2.80 V Measured with SU3 Falling HYSTERESIS 3 % GLITCH IMMUNITY 20 s 100 mV Glitch on VCC or SU1-3 PROPAGATION DELAY 20 s Delay from Supply Going Out side Tolerance until Output Changes V 10 k External to Positive Supply V CC V 10 k External to Positive Supply V CC OPEN DRAIN OUTPUT LOW OPEN DRAIN OUTPUT HIGH 0.4 V+ 0.25 Specifications subject to change without notice. 2 REV. 0 ADM9261 ABSOLUTE MAXIMUM RATINGS* ORDERING GUIDE (TA = +25C unless otherwise noted) V CC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +6 V SU1, SU2, SU3 . . . . . . . . . . . . . . . . . . . . 0.3 V to +15 V All Other Inputs . . . . . . . . . . . . . . . 0.3 V to VCC + 0.3 V All Outputs . . . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +6 V Output Sink Current ERR1-3, . . . . . . . . . . . . . . . . 20 mA Operating Temperature Range Industrial (A Version) . . . . . . . . . . . . . 40C to +85C Power Dissipation, RM-8 . . . . . . . . . . . . . . . TBD mW JA Thermal Impedance . . . . . . . . . . . . . . . TBDC/W Lead Temperature (Soldering, 10 secs) . . . . . . . +300C Vapor Phase (60 secs) . . . . . . . . . . . . . . . . . . . . +215C Infrared (15 secs) . . . . . . . . . . . . . . . . . . . . . . . . +220C Storage Temperature Range . . . . . . . . . 65C to +150C Model Temperature Range Package Option 1 ADM9261ARM ADM9261ARM-REEL 2 ADM9261ARM-REEL7 3 40C to +85C 40C to +85C 40C to +85C RM-8 RM-8 RM-8 NOTES 1 RM = Thin Small Outline IC. 2 2500 devices per reel. 3 1000 devices per reel. *Stresses above those listed under Absolute Maximum Ratings may cause permanent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum ratings for extended periods of time may affect device reliability. CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the ADM9261 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality. REV. 0 3 ADM9261 PIN CONFIGURATION GND 1 SU1 2 SU2 3 SU3 4 8 ADM9261 TOP VIEW (Not to Scale) ERR1 7 ERR2 6 ERR3 5 VCC PIN FUNCTION DESCRIPTIONS Pin No. Mnemonic Function 1 2 GND SU1 3 SU2 4 SU3 5 V CC Ground. Supply to Be Monitored. 9 V battery supply - comparator trips when supply voltage falls below 4 V. Supply to Be Monitored. 3.3 V supply - comparator trips when supply voltage falls below 3.0V Supply to Be Monitored. 3.3 V supply. - comparator trips when supply voltage falls below 2.8V. Supply Monitor IC Power Supply. Can be powered from any power supply between 2.5 V and 3.6 V including supplies being monitored (except for SU1). Open Drain Output. Low when SU3 is below its minimum value. Otherwise pulls high through an 10k resistor to a positive supply. Open Drain Output. Low when SU2 is below its minimum value. Otherwise pulls high through an 10k resistor to a positive supply. Open Drain Output. Low when SU1 is below its minimum value. Otherwise pulls high through an 10k resistor to a positive supply. 6 7 8 ERR3 ERR2 ERR1 4 one of the external external external REV. 0 ADM9261 CIRCUIT INFORMATION Monitor Inputs SU1 to SU3 The ADM9621 is provided with three analog inputs, SU1 to SU3, to monitor supply voltages of +9 V and two +3.3V supplies. Each input is connected to a voltage comparator whose trip point is set by an on-chip voltage reference and on-chip precision thin-film resistors. Onchip attenuators reduce the input voltage to the comparators, so that voltages greater than the supply voltage can be monitored without the need for external resistors. As the ADM9261 is intended for battery-powered systems, the input attenuators are high resistance to minimise current drawn from the supplies. This, coupled with the lowpwer design of the comparators themselves, gives a typical current consumption of 10A, including the input currents of SU1 to SU3. The logic outputs are open-drain and take their output high level from the voltage connected to the pull-up resistor. They will normally be connected to VCC, but can be connected to any voltage up to 15V if a different logic swing is required. Error Outputs Error outputs ERR1 to ERR3 are open-drain outputs that are OFF when the corresponding supply voltage SU1 to SU3 is greater than its minimum value and ON when the corresponding supply voltage falls below its minimum value. Each output requires a 10k pullup resistor to a positive supply, which is normally the system logic supply, but can be different if required. The open-drain construction allows two or more of these outputs to be wire ANDed together if required, as shown in figure 1. VCC SU1 VCC SU2 10kW ERR1 ERR2 SU3 ERR3 OUTPUT GND Truth Table for Wired AND SU1 < < < < > > > > min min min min min min min min SU2 < < > > < < > > min min min min min min min min SU3 < > < > < > < > min min min min min min min min Output 0 0 0 0 0 0 0 1 Power Supply VCC The ADM9261 can be powered from any supply voltage between 2.5 V and 6 V. This includes any of the supply voltages apart from that connected to SU1, since this is greater than 6 V. It will usually be powered from one of the 3.3 V supplies. REV. 0 5 ADM9261 APPLICATIONS interfaced to this. In either case the ADM9261 is very simple to use. Inputs SU1 to SU3 are simply connected to the supplies to be monitored and the outputs are connected to the devices logic system, either separately or to a single input using wired AND. The ADM9261 will derive its power supply from one of the 3.3V supplies. The ADM9261 is designed for use in pagers and other portable devices that use 3.3V logic systems derived from a 9V battery. Interfacing of the ADM9261 to the system will vary with the application, if a microcontroller is used, the outputs of the ADM9261 may be connected to one or more I/O lines. If a microprocessor is used with a separate ASIC or other chip for I/O then the ADM9261 can be Figure 14 shows a typical application of the ADM9261. VCC PSU #1 9V SU1 PSU #2 3.3V SU2 VCC 10kW ERR1 VCC 10kW ERR2 ADM9261 PSU #3 3.3V SU3 VCC 10kW PAGER ASIC MICROPROCESSOR ERR3 GND Figure 14. Typical Application of ADM9261 8 REV. 0 ADM9261 OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 8-Lead Micro SOIC (R-8A) 0.122 (3.10) 0.114 (2.90) 8 0.122 (3.10) 0.114 (2.90) 1 5 0.199 (5.05) 0.187 (4.75) 4 PIN 1 0.0256 (0.65) BSC 0.120 (3.05) 0.112 (2.84) 0.006 (0.15) 0.002 (0.05) 0.120 (3.05) 0.112 (2.84) 0.043 (1.09) 0.037 (0.94) 0.018 (0.46) SEATING 0.008 (0.20) PLANE REV. 0 0.011 (0.28) 0.003 (0.08) 9 33 27 0.028 (0.71) 0.016 (0.41)