CS2516 CS2516 Pulse-Load Battery Monitor Description The CS2516 is designed for use in battery powered medical, security, or environmental systems where prior notification of impending power source failure is a requirement. The IC effectively provides continuous monitoring of battery condition by pulsesampling the system voltage at predetermined intervals. Low standby current permits unswitched connection to the battery with minimal impact on operating life. The ability to load the battery during the test pulse provides assurance that sufficient reserve capacity exists to operate critical system components. The CS2516 contains an internal timer that generates a 1.0 millisecond test pulse once each 33 seconds (both times are typical). The load switch transistor conducts only during the test pulse, and can sink up to 50mA directly. An Features external transistor can be added to increase the load current capability. Should, during the test pulse, the sense terminal voltage fall below the threshold level determined by the internal (synthesized) temperature compensated zener diode, the comparator will permit a charging current to flow out of PW. This pin is also the input of a Schmitt trigger that in turn drives the output transistor. Collectively, the charge current and trigger, in conjunction with an external RC network, operate as a Òpulse-stretcherÓ to provide output ÒONÓ times that are a multiple of the sampling time. This feature permits low battery alarm devices or visible annunciators to be driven directly by the IC. The maximum permissible output current is 30mA. Block Diagram ■ Adjustable Battery Sense from 7 to 12 Volts ■ Pulse Loads Battery at up to 50mA ■ Standby Current Under 10µA ■ Test Period, Rate and Load Adjustable ■ On Chip 15mA Output Driver Package Options 8L PDIP and 8L SO Rp VCC SENSE PW CT RP 1 8 VCC SENSE 2 7 PW CT 3 6 OUT 5 Load Switch COM 4 OUT Cycle Timer COM Load Switch Cherry Semiconductor Corporation 2000 South County Trail, East Greenwich, RI 02818 Tel: (401)885-3600 Fax: (401)885-5786 Email: [email protected] Web Site: www.cherry-semi.com Rev. 1/17/95 1 A ¨ Company CS2516 Absolute Maximum Ratings Supply Voltage (VCC).........................................................................................................................................................0 to 14V Rp Input Voltage ............................................................................................................................................................-0.5 to VCC SENSE, CT, PW, Output and Load Switch....................................................................................................................-0.5 to 8V Load Current...........................................................................................................................................................................50mA Output Current ......................................................................................................................................................................30mA Storage Temperature.................................................................................................................................................-40 to +150ûC Lead Temperature Soldering: Wave Solder (through hole styles only)..........................................10 sec. max, 260¡C peak Reflow (SMD styles only) ..........................................60 sec. max above 183¡C, 230¡C peak Electrical Characteristics: VCC = 9V, Rp = 9.1 M½, CT = 4.7µF, Cpw = 0.1µF, Rpw = 10M½, 0¡ ² TA ² 85¡ unless otherwise specified. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Operating Voltage 9 12 V Standby Current 4 10 µA ■ VCC ■ Cycle Timer Charge Current VCT=0V, 6V²VCC²12V 2V ² VCT < 7.5V -1.70 -0.77 -1.20 -0.74 -0.48 -0.71 µA µA Discharge Current VCT= 8.8V VCT= 2.0V 8.0 1.1 20.0 3.0 25.0 3.6 mA mA Discharge Impedance 4.6V < VCT< 8.0V Upper Charge Threshold -0.48µA < ICT < -1.70µA 7.0 440 8.0 9.0 ½ V Lower Charge Threshold -0.48µA < IC < -1.70µA 0.5 1.0 3.0 V Lower Discharge Threshold 1.1mA < IC< 25mA 2.0 4.6 6.0 V ■ Load Switch ÒONÓ Voltage ILoad Switch = 50mA ÒOFFÓ Current VLoad Switch = 12V 0.3 0.5 V 1.0 µA 7.1 V ■ Sense Input Threshold Voltage Threshold Temp Coefficient 6.3 0¡C < TA < 85¡C 6.7 150 Active Impedance ppm/¡C 5.0 8.5 12.0 k½ -950 -300 -550 -250 -250 -200 µA µA Schmitt Upper Threshold 2.25 2.50 2.75 V Hysteresis 0.60 1.00 1.40 V 1.00 µA 0.5 V 1.0 µA ■ Pulse Stretcher Source Current Input Bias Current VSENSE = 6.3V, VPW = 0V VCC=VSENSE=6.3V, VPW = 0V VSENSE=7.1V, VPW=1.2V ■ Output Switch ÒONÓ Voltage VPW = 3V; IOUT = 15mA ÒOFFÓ Current VPW = 0V; VOUT = 12V 0.1 2 PARAMETER TEST CONDITIONS MIN TYP MAX UNIT ■ Recommended Component Values Rp Program Resistor 1.0 9.1 M½ CT Cycle Timer Capacitor 4.7 22.0 µF CPW Pulse Stretcher Capacitor 0.01 0.10 µF RPW Pulse Stretcher Resistor 1 10 M½ Package Pin Description PACKAGE PIN # PIN SYMBOL FUNCTION 8L PDIP & SO Narrow 1 RP Test period programming resistor. 2 SENSE Voltage sense comparator input. 3 CT Test period, duration programming capacitor. 4 COM Common negative 5 Load Switch Collector of pulse loading NPN transistor. 6 OUT Alarm Pulse width-stretcher output 7 PW Output pulse-width programming RC. 8 VCC Power source. Typical Performance Characteristics CT Discharge Impedance vs CT Voltage (Typ +25¡C) 1000 Impedance, W 900 800 700 600 500 400 8.8 8.0 7.0 6.0 5.0 4.0 CT Voltage 3.0 2.0 1.0 Timing Diagram VCC 7.1V 8V CT Load Switch 4.6V 1V VCC Tp 1V 1.14ms 1V VCC Vsat Td PW OUT VCC 6.7V 33S Tt 0V Tpw VCC 1ms 2.5V 1.5V 510ms VCC Vsat BATT. OK BATT. LOW 3 0V CS2516 Electrical Characteristics: VCC = 9V, RP = 9.1 M½, CT = 4.7µF, Cpw = 0.1µF, Rpw = 10M½, 0¡ ² TA ² 85¡ unless otherwise specified CS2516 Applications Formulae and Typical Values Program and Standby Currents: IP = Cycle Timer Period: Tt = VCC = RP 9V 9.1m½ Å 1µA Standby Current = 4IP = 4µA (typ.) VTCT 7CT 7 x 4.7µF = = Å 33sec., IP 1µA 1µA where Vt = Upper Charge Threshold - Lower Charge Threshold (7V typ.) Test Pulse Width: Tp = RdCT x ln(VP) Å 242CTÅ 242 x 4.7µF Å 1.14ms where Rd is the dynamic cycle timer discharge impedance (440½ typ.) and VP = Pulse Stretcher: Delay Time: TD = Upper Charge Threshold Lower Discharge Threshold [1n(VP) = 0.55 typ.] VdCPW 2.5CPW 2.5 x 0.1µF = = Å 1ms 250µA Isrc 250µA where Vd = Schmitt Trigger Upper Threshold (2.5V typ.) and Isrc = Typical source current at the PW pin at the nominal low battery sense threshold of 6.7V. Pulse Width: Tp = CPWRPW ln(VS) Å 0.51 x 0.1µF x 10m½ Å 510ms. and VS = Schmitt Trigger Upper Threshold Schmitt Trigger Hysteresis [ln(VS) = 0.51 typ.] Applications Information The value of Rp affects standby current, operating current, and the test cycle period. The recommended value is (V+/1µA) where V+ is the fresh battery voltage. Higher values of Rp are not recommended. Minimum recommended value is (V+/10µA) which will increase both the standby and operating currents by 10X and reduce the test cycle period by the same factor; the test pulse width will be unaffected. The value of Ct affects both the test cycle period and the test pulse width. Of critical importance is the selection of a low leakage type capacitor; if leakage current exceeds the cycle timer charge current, the timer will not operate. The pulse stretcher components RPW and CPW should be selected such that the delay timer to charge CPW is shorter than the test pulse width programmed by Ct to guarantee operation of the Output. The output is an open-collector transistor which may be used to drive an indicator device directly or to interface to logic family devices. The SENSE input typical 8.5k½ input impedance appears only during the test pulse; otherwise the SENSE input is in a high impedance state. The effective low battery threshold voltage can be modified (increased only) by means of a voltage divider placed across the load resistor. This technique can also be used to effectively reduce the threshold tolerance band. Typical Application Circuit Rp 9.1MW Rp VCC VCC Cpw 0.1mF PW SENSE Rpw CT CS2516 + CT 10MW OUT 510W 4.7mF COM Load Switch 220W + 9V 4 CS2516 Increased Pulse-Load Current Capability Rp + 9.1MW VCC Rp 9V Cpw SENSE 0.1mF PW Rpw CT CS2516 + CT 10MW OUT OUT 4.7mF 820W COM Load Switch 220W RL 12V Battery Application with 9V Threshold Rp + 51W 9.1MW Rp VCC 12V Cpw SENSE 0.1mF PW Rpw CT CS2516 + CT 10MW OUT OUT 150W 4.7mF COM Load Switch Adjustable Sense Threshold 200W Rp + 9.1MW Rp VCC 9V Cpw SENSE 0.1mF PW Rpw CT CS-2516 + CT 10MW OUT OUT 1.8kW 4.7mF COM Load Switch 5 RL 220W CS2516 Package Specification PACKAGE DIMENSIONS IN mm (INCHES) PACKAGE THERMAL DATA D Lead Count Metric Max Min 10.16 9.02 5.00 4.80 8L PDIP 8L SOIC Thermal Data English Max Min .400 .355 .197 .189 RQJC RQJA 8L PDIP 8L SO 52 100 45 165 typ typ ûC/W ûC/W Surface Mount Narrow Body (D); 150 mil wide 4.00 (.157) 3.80 (.150) 6.20 (.244) 5.80 (.228) 0.51 (.020) 0.33 (.013) 1.27 (.050) BSC 1.75 (.069) MAX 1.57 (.062) 1.37 (.054) 1.27 (.050) 0.40 (.016) 0.25 (.010) 0.19 (.008) 0.25 (0.10) 0.10 (.004) D REF: JEDEC MS-012 Plastic DIP (N); 300 mil wide 7.11 (.280) 6.10 (.240) 8.26 (.325) 7.62 (.300) 1.77 (.070) 1.14 (.045) 2.54 (.100) BSC 3.68 (.145) 2.92 (.115) .356 (.014) .203 (.008) 0.39 (.015) MIN. .558 (.022) .356 (.014) REF: JEDEC MS-001 D Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same. Ordering Information Part Number CS2516KN8 CS2516KD8 CS2516KDR8 Rev. 1/17/95 Description 8 Lead PDIP 8 Lead SOIC 8 Lead SOIC (tape & reel) Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information. 6 © 1999 Cherry Semiconductor Corporation