CHERRY CS2516KN8

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