CS2516

CS2516 CHERRY | Alldatasheet

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Technical content

Features

n Adjustable Battery Sense from 7 to 12 Volts n Pulse Loads Battery at up to 50mA n Standby Current Under 10µA n Test Period, Rate and Load Adjustable n On Chip 15mA Output Driver Package Options 8L PDIP and 8L SO CS2516 Pulse-Load Battery Monitor 1RP SENSE CT COM VCC PW OUT Load Switch CS2516

Description

The CS2516 is designed for use in bat- tery powered medical, security, or environmental systems where prior notification of impending power source failure is a requirement. The IC effectively provides continuous moni- toring of battery condition by pulse- sampling the system voltage at prede- termined intervals. Low standby cur- rent 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 capac- ity 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 external transistor can be added to in- crease the load current capability. Should, during the test pulse, the sense terminal voltage fall below the thresh- old level determined by the internal (synthesized) temperature compensat- ed 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 conjunc- tion with an external RC network, operate as a Òpulse-stretcherÓ to pro- vide 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 maxi- mum permissible output current is 30mA. Block Diagram Cherry Semiconductor Corporation

2000 South County Trail, East Greenwich, RI 02818

Tel: (401)885-3600 Fax: (401)885-5786 Email: info@cherry-semi.com Web Site: www.cherry-semi.com A Company ¨ Rev. 1/17/95

Electrical Characteristics: VCC = 9V, Rp = 9.1 M½, CT = 4.7µF, Cpw = 0.1µF, Rpw = 10M½, 0 ¡²T A ² 85¡ unless otherwise specified. PARAMETER TEST CONDITIONS MIN TYP MAX UNIT Absolute Maximum Ratings CS2516 n VCC Operating Voltage 9 12 V Standby Current 4 10 µA n Cycle Timer Charge Current V CT=0V, 6V²VCC²12V -1.70 -1.20 -0.48 µA 2V ² VCT < 7.5V -0.77 -0.74 -0.71 µA Discharge Current V CT= 8.8V 8.0 20.0 25.0 mA VCT= 2.0V 1.1 3.0 3.6 mA Discharge Impedance 4.6V < V CT< 8.0V 440 ½ Lower Discharge Threshold 1.1mA < I C< 25mA 2.0 4.6 6.0 V n Load Switch ÒONÓ Voltage I Load Switch = 50mA 0.3 0.5 V ÒOFFÓ Current V Load Switch = 12V 1.0 µA n Sense Input Threshold Voltage 6.3 6.7 7.1 V Threshold Temp Coefficient 0¡C < T A < 85¡C 150 ppm/¡C Active Impedance 5.0 8.5 12.0 k½ n Pulse Stretcher Source Current V SENSE = 6.3V, VPW = 0V -950 -550 -250 µA VCC=VSENSE=6.3V, VPW = 0V -300 -250 -200 µA Schmitt Upper Threshold 2.25 2.50 2.75 V Hysteresis 0.60 1.00 1.40 V Input Bias Current V SENSE=7.1V, VPW=1.2V 1.00 µA n Output Switch ÒONÓ Voltage V PW = 3V; IOUT = 15mA 0.1 0.5 V ÒOFFÓ Current V PW = 0V; VOUT = 12V 1.0 µA

PACKAGE PIN # PIN SYMBOL FUNCTION Typical Performance Characteristics Timing Diagram CT Discharge Impedance vs CT Voltage (Typ +25¡C) Electrical Characteristics: VCC = 9V, RP = 9.1 M½, CT = 4.7µF, Cpw = 0.1µF, Rpw = 10M½, 0 ¡²T A ² 85¡ unless otherwise specified PARAMETER TEST CONDITIONS MIN TYP MAX UNIT 400 500 600 700 800 900 1000 CT Voltage Impedance, W VCC CT Load Switch PW OUT BATT. OK BATT. LOW Vsat Vsat Tpw 510ms 1.5V 2.5V Td 1ms Tp 1.14ms 4.6V4.6V 7.1V 6.7V33S Tt VCC VCC VCC VCC VCC CS2516 8L PDIP & SO Narrow 1R P Test period programming resistor. 2 SENSE Voltage sense comparator input. T 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. CC Power source. n Recommended Component Values Rp Program Resistor 1.0 9.1 M½ C T Cycle Timer Capacitor 4.7 22.0 µF CPW Pulse Stretcher Capacitor 0.01 0.10 µF RPW Pulse Stretcher Resistor 1 10 M½

Program and Standby Currents: IP = = Å 1µA Standby Current = 4I P = 4µA (typ.)9V 9.1m½ VCC RP 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 = [1n(VP) = 0.55 typ.] Pulse Stretcher: Delay Time: TD = = = Å 1ms 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 = [ln(V S) = 0.51 typ.]Schmitt Trigger Upper Threshold Schmitt Trigger Hysteresis 2.5 x 0.1µF 250µA 2.5CPW 250µA VdCPW Isrc Upper Charge Threshold Lower Discharge Threshold VCC 220W CT CS2516 Rp 4.7mF 9.1MW PW OUT Load Switch Rp SENSE CT COM Cpw Rpw 10MW 0.1mF 510W VCC Applications Information Typical Application Circuit 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 R p are not recommended. Minimum recom- mended 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 C t 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 R PW 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 thresh- old voltage can be modified (increased only) by means of a voltage divider placed across the load resistor. This tech- nique can also be used to effectively reduce the threshold tolerance band. Applications Formulae and Typical Values CS2516 Cycle Timer Period: Tt === Å 33sec., where Vt = Upper Charge Threshold - Lower Charge Threshold (7V typ.) 7 x 4.7µF 1µA 7CT 1µA VTCT IP

4.7mF 9.1MW RL 220W PW OUT Load Switch Rp SENSE CT COM Cpw Rpw 10MW 0.1mF 200W 1.8kW Adjustable Sense Threshold VCC OUT CT CS2516 Rp 4.7mF 9.1MW 150W 12V PW OUT Load Switch Rp SENSE CT COM Cpw Rpw 10MW 0.1mF +51W 12V Battery Application with 9V Threshold VCC OUT 220W CT CS2516 Rp 4.7mF 9.1MW 820W RL PW OUT Load Switch Rp SENSE CT COM Cpw Rpw 10MW 0.1mF Increased Pulse-Load Current Capability CS2516

CS2516KDR8 8 Lead SOIC (tape & reel) D Lead Count Metric English Max Min Max Min 8L PDIP 10.16 9.02 .400 .355 8L SOIC 5.00 4.80 .197 .189 Thermal Data 8L PDIP 8L SO RQJC typ 52 45 ûC/W RQJA typ 100 165 ûC/W Package Specification PACKAGE DIMENSIONS IN mm (INCHES)

Ordering Information

Rev. 1/17/95 CS2516 © 1999 Cherry Semiconductor Corporation Cherry Semiconductor Corporation reserves the right to make changes to the specifications without notice. Please contact Cherry Semiconductor Corporation for the latest available information. 0.33 (.013) 6.20 (.244) 5.80 (.228) 4.00 (.157) 3.80 (.150) 1.57 (.062) 1.37 (.054) D 0.25 (0.10) 0.10 (.004) 1.75 (.069) MAX 1.27 (.050) 0.40 (.016) REF: JEDEC MS-012 0.25 (.010) 0.19 (.008) Surface Mount Narrow Body (D); 150 mil wide Plastic DIP (N); 300 mil wide 0.39 (.015) MIN. 1.14 (.045) D Some 8 and 16 lead packages may have 1/2 lead at the end of the package. All specs are the same. .203 (.008) .356 (.014) REF: JEDEC MS-001 3.68 (.145) 2.92 (.115) 8.26 (.325) 7.62 (.300) 7.11 (.280) 6.10 (.240) .356 (.014) .558 (.022)