Cherry Semiconductor CS2516KD8, CS2516KN8, CS2516KDR8 Datasheet
Features
■
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
CS2516
Pulse-Load Battery Monitor
CS2516
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
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
1
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
R
SENSE
C
COM
V
CC
PW
OUT
Load Switch
1
R
P
SENSE
2
3
C
T
4
COM
8
7
6
5
V
CC
PW
OUT
Load
Switch
p
T
Cycle
Timer
2
Electrical Characteristics: VCC= 9V, Rp= 9.1 M½, CT= 4.7µF, Cpw = 0.1µF, Rpw = 10M½,
0¡²TA² 85¡ unless otherwise specified.
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
Absolute Maximum Ratings
Supply Voltage (VCC).........................................................................................................................................................0 to 14V
RpInput Voltage ............................................................................................................................................................-0.5 to V
CC
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
CS2516
■ V
CC
Operating Voltage 9 12 V
Standby Current 4 10 µA
■ Cycle Timer
Charge Current V
C
T
=0V, 6V²VCC²12V -1.70 -1.20 -0.48 µA
2V ² V
C
T
< 7.5V -0.77 -0.74 -0.71 µA
Discharge Current V
C
T
= 8.8V 8.0 20.0 25.0 mA
V
C
T
= 2.0V 1.1 3.0 3.6 mA
Discharge Impedance 4.6V < V
C
T
< 8.0V 440 ½
Upper Charge Threshold -0.48µA < I
C
T
< -1.70µA 7.0 8.0 9.0 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 I
Load Switch
= 50mA 0.3 0.5 V
ÒOFFÓ Current V
Load Switch
= 12V 1.0 µA
■ Sense Input
Threshold Voltage 6.3 6.7 7.1 V
Threshold Temp Coefficient 0¡C < TA< 85¡C 150 ppm/¡C
Active Impedance 5.0 8.5 12.0 k½
■ Pulse Stretcher
Source Current V
SENSE
= 6.3V, VPW= 0V -950 -550 -250 µA
V
CC=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
■ Output Switch
ÒONÓ Voltage VPW= 3V; I
OUT
= 15mA 0.1 0.5 V
ÒOFFÓ Current V
PW
= 0V; V
OUT
= 12V 1.0 µA
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