CHERRY CS8221YDP3

CS8221
CS8221
Micropower 5V, 100mA
Low Dropout Linear Regulator
Description
The CS8221 is a precision 5V,
100mA micropower voltage regulator with very low quiescent current
(60µA typical at 100µA load). The
5V output is accurate within ±2%
and supplies 100mA of load current
with a maximum dropout voltage
of only 600mV.
Features
The regulator is protected against
reverse battery, short circuit, over
voltage, and over temperature conditions. The device can withstand
74V load dump transients making it
suitable for use in automotive environments.
Absolute Maximum Ratings
Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Internally Limited
Transient Peak Voltage (60V Load Dump) . . . . . . . . . . . . . . . . . . . .-15V, 74V
Output Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Internally Limited
ESD Susceptibility (Human Body Model) . . . . . . . . . . . . . . . . . . . . . . . . . .2kV
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40¡C to 150¡C
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-55¡C to 150¡C
Lead Temperature Soldering
Reflow (SMD styles only) . . . . . .60 sec. max above 183¡C, 230¡C peak
■ Low Quiescent Current
(60µA @ 100µA load)
■ 5V, ±2% Output
■ 100mA Output Current
Capability
■ Fault Protection
+74V Peak Transient
Voltage
-15V Reverse Voltage
Short Circuit
Thermal Shutdown
Low Reverse Current
(Output to Input)
Package Options
Block Diagram
VOUT
VIN
8L SO Narrow
(Internally Fused Leads)
VIN
Current Source
(Circuit Bias)
Gnd
Gnd
1
VOUT
Over
Voltage
Shutdown
D2PAK
Current Limit
Sense
Gnd
NC
Sense
Gnd
Sense*
3L D2PAK
Tab (Gnd)
+
Thermal
Shutdown
- Error
Amplifier
Bandgap
Reference
1
1. VIN
2. Gnd
3. VOUT
Gnd
Consult factory for TO-92.
* 8 Lead SO Narrow
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
Rev. 12/28/98
1
A
¨
Company
CS8221
Electrical Characteristics: 6V ² VIN ² 26V, IOUT = 1mA, -40¡ ² TA ² 125¡C, -40¡ ² TJ ² 150¡C; unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
4.90
4.85
5.00
5.00
5.10
5.15
V
V
mV
■ Output Stage
Output Voltage, VOUT
9V<VIN<16V, 100µA ² IOUT ² 100mA
6V ² VIN ² 26V, 100µA ² IOUT ² 100mA
Dropout Voltage (VIN-VOUT)
IOUT = 100mA
400
600
IOUT = 100µA
100
150
mV
Load Regulation
VIN = 14V
100µA ² IOUT ² 100mA
5
50
mV
Line Regulation
6V<V<26V
5
50
mV
60
4
12
120
6
20
µA
mA
mA
IOUT = 1mA
Quiescent Current, (IQ)
IOUT = 100µA, VIN = 6V
IOUT ² 50mA
IOUT ² 100mA
Ripple Rejection
7V ² VIN ² 17V, IOUT = 100mA,
f = 120Hz
Current Limit
Short Circuit Output Current
VOUT = 0V
Thermal Shutdown (Note 1)
Overvoltage Shutdown
VOUT ² 1V
Reverse Current
VOUT = 5V, VIN = 0V
60
75
dB
125
200
mA
40
125
µA
150
180
¡C
30
34
38
V
100
500
µA
Note 1: This parameter is guaranteed by design, but not parametrically tested in production.
Package Lead Description
PACKAGE LEAD #
8L SO Narrow
(Internally Fused Leads)
1
LEAD SYMBOL
FUNCTION
3L
D2PAK
1
VIN
Input voltage.
2
3
VOUT
5V, ±2%, 100mA output.
3
Ð
NC
No connection.
4
Ð
Sense
Kelvin connection which allows remote sensing of the output
voltage for improved regulation. If remote sensing is not
required, connect to VOUT.
5,6,7,8
2
Gnd
Ground.
2
CS8221
Circuit Description
Voltage Reference and Output Circuitry
> 30V
Output Stage Protection
The output stage is protected against overvoltage, short
circuit and thermal runaway conditions (Figure 1).
If the input voltage rises above 34V (typ), the output shuts
down. This response protects the internal circuitry and
enables the IC to survive unexpected voltage transients.
Should the junction temperature of the power device
exceed 180ûC (typ) the power transistor is turned off.
Thermal shutdown is an effective means to prevent die
overheating since the power transistor is the principle heat
source in the IC.
VIN
VOUT
IOUT
Load
Dump
Thermal
Shutdown
Short
Circuit
Figure 1. Typical Circuit Waveforms for Output Stage Protection.
Application & Test Diagram
VOUT
VIN
C1**
0.1mF
CS8221
C2***
10mF
Sense*
Gnd
* 8 Lead SO Narrow only
**C1 is required if regulator is distant from power source filter.
***C2 is required for stability.
Application Notes
ber at the lowest specified operating temperature and
monitor the outputs with an oscilloscope. A decade box
connected in series with the capacitor will simulate the
higher ESR of an aluminum capacitor. Leave the decade
box outside the chamber, the small resistance added by
the longer leads is negligible.
Step 2: With the input voltage at its maximum value,
increase the load current slowly from zero to full load
while observing the output for any oscillations. If no oscillations are observed, the capacitor is large enough to
ensure a stable design under steady state conditions.
Step 3: Increase the ESR of the capacitor from zero using
the decade box and vary the load current until oscillations
appear. Record the values of load current and ESR that
cause the greatest oscillation. This represents the worst
case load conditions for the regulator at low temperature.
Step 4: Maintain the worst case load conditions set in step
3 and vary the input voltage until the oscillations increase.
This point represents the worst case input voltage conditions.
Step 5: If the capacitor is adequate, repeat steps 3 and 4
with the next smaller valued capacitor. A smaller capaci-
Stability Considerations
The output or compensation capacitor helps determine
three main characteristics of a linear regulator: start-up
delay, load transient response and loop stability.
The capacitor value and type should be based on cost,
availability, size and temperature constraints. A tantalum
or aluminum electrolytic capacitor is best, since a film or
ceramic capacitor with almost zero ESR can cause instability. The aluminum electrolytic capacitor is the least expensive solution, but, if the circuit operates at low temperatures (-25¡C to -40¡C), both the value and ESR of the
capacitor will vary considerably. The capacitor manufacturers data sheet usually provides this information.
The value for the output capacitor COUT shown in the test
and applications circuit should work for most applications, however it is not necessarily the optimized solution.
To determine an acceptable value for COUT for a particular
application, start with a tantalum capacitor of the recommended value and work towards a less expensive alternative part.
Step 1: Place the completed circuit with a tantalum capacitor of the recommended value in an environmental cham3
CS8221
Application Notes: continued
tor will usually cost less and occupy less board space. If
the output oscillates within the range of expected operating conditions, repeat steps 3 and 4 with the next larger
standard capacitor value.
Step 6: Test the load transient response by switching in
various loads at several frequencies to simulate its real
working environment. Vary the ESR to reduce ringing.
Step 7: Remove the unit from the environmental chamber
and heat the IC with a heat gun. Vary the load current as
instructed in step 5 to test for any oscillations.
Once the minimum capacitor value with the maximum
ESR is found, a safety factor should be added to allow for
the tolerance of the capacitor and any variations in regulator performance. Most good quality aluminum electrolytic
capacitors have a tolerance of ±20% so the minimum value
found should be increased by at least 50% to allow for this
tolerance plus the variation which will occur at low temperatures. The ESR of the capacitor should be less than
50% of the maximum allowable ESR found in step 3
above.
The value of RQJA can then be compared with those in
the package section of the data sheet. Those packages
with RQJA's less than the calculated value in equation 2
will keep the die temperature below 150¡C.
In some cases, none of the packages will be sufficient to
dissipate the heat generated by the IC, and an external
heatsink will be required.
Heat Sinks
A heat sink effectively increases the surface area of the
package to improve the flow of heat away from the IC and
into the surrounding air.
Each material in the heat flow path between the IC and the
outside environment will have a thermal resistance. Like
series electrical resistances, these resistances are summed
to determine the value of RQJA:
RQJA = RQJC + RQCS + RQSA
(3)
where:
RQJC = the junctionÐtoÐcase thermal resistance,
RQCS = the caseÐtoÐheatsink thermal resistance, and
RQSA = the heatsinkÐtoÐambient thermal resistance.
RQJC appears in the package section of the data sheet. Like
RQJA, it too is a function of package type. RQCS and RQSA
are functions of the package type, heatsink and the interface between them. These values appear in heat sink data
sheets of heat sink manufacturers.
Calculating Power Dissipation
in a Single Output Linear Regulator
The maximum power dissipation for a single output regulator (Figure 2) is:
PD(max) = {VIN(max)ÐVOUT(min)}IOUT(max)+VIN(max)IQ
(1)
where:
VIN(max) is the maximum input voltage,
VOUT(min) is the minimum output voltage,
IOUT(max) is the maximum output current for the application, and
IQ is the quiescent current the regulator consumes at
IOUT(max).
Once the value of PD(max) is known, the maximum permissible value of RQJA can be calculated:
RQJA =
150¡C - TA
PD
IIN
(2)
IOUT
VIN
CS8221
VOUT
IQ
Figure 2. Single output regulator with key performance parameters
labeled.
4
CS8221
Package Specification
PACKAGE DIMENSIONS IN mm (INCHES)
PACKAGE THERMAL DATA
D
Lead Count
8L SO Narrow
(internally fused leads)
Metric
Max
Min
5.00
4.80
Thermal Data
English
Max Min
.197 .189
RQJC
RQJA
typ
typ
8 Lead
SO Narrow
(internally fused leads)
25
110
3 Lead
D2PAK
4.2
10-50*
ûC/W
ûC/W
*Depending on thermal properties of substrate. RQJA = RQJC + RQCA
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)
D
REF: JEDEC MS-012
5
0.25 (0.10)
0.10 (.004)
CS8221
Package Specification
3 Lead D2PAK (DP)
10.31 (.406)
10.05 (.396)
1.40 (.055)
1.14 (.045)
1.68 (.066)
1.40 (.055)
8.53 (.336)
8.28 (.326)
15.75 (.620)
14.73 (.580)
2.74(.108)
2.49(.098)
1.40 (.055)
1.14 (.045)
2.79 (.110)
2.29 (.090)
0.91 (.036)
0.66 (.026)
2.54 (.100) REF
.254 (.010) REF
0.10 (.004)
0.00 (.000)
4.57 (.180)
4.31 (.170)
Ordering Information
Part Number
CS8221YDF8
CS8221YDFR8
CS8221YDP3
CS8221YDPR3
Rev. 12/28/98
Description
8L SO Narrow (internally fused leads)
8L SO Narrow (internally fused leads)
(tape & reel)
3L D2PAK
3L D2PAK (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