CHERRY CS8391

CS8391
CS8391
5V/250mA, 5V/100mA Micropower
Low Dropout Regulator with ENABLE
Description
The CS8391 is a precision, dual 5V
micropower linear voltage regulator. The switched primary output
(VOUT1) supplies up to 250mA
while the secondary (VOUT2) is
capable of supplying 100mA. Both
outputs have a maximum dropout
voltage of 600mV and low reverse
current. Quiescent current drain is
typically 150µA when supplying
100µA from each output.
The ENABLE input provides logic
Features
level control of the primary output.
With the primary output disabled,
quiescent current drain is typically
100µA when supplying 100µA from
the secondary output.
The CS8391 is extremely robust
with protection provided for
reverse battery, short circuit, and
overtemperature on both outputs.
The CS8391 is available in a 5-lead
D2PAK.
Absolute Maximum Ratings
Input Voltage.....................................................................................-15V to 45V
Power Dissipation .................................................................Internally Limited
Operating Temperature Range................................................-40¡C to +125¡C
Maximum Junction Temperature ...........................................-40¡C to +150¡C
Storage Temperature Range ....................................................-55¡C to +150¡C
Electrostatic Discharge (Human Body Model) ..........................................4kV
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
■ 5V, 250mA Primary Output
■ 5V, 100mA Secondary
Output
■ 3% Tolerance, Both
Outputs
■ ON/OFF Control for
Primary Output
■ Low Quiescent Current
Drain (100µA VOUT2)
■ Low Reverse Current
■ Protection Features
Reverse Battery (-15V)
Short Circuit
Overtemperature
Package Options
5 Lead D2PAK
Tab (Gnd)
Block Diagram
Primary Output
VOUT1
VIN
*
Current
Limit
+
ENABLE
VOUT1Sense
+
Bandgap
Reference
*Note: Internally
connected on 5 leaded
package.
Thermal
Shutdown
1
1. VIN
2. VOUT1
3. Gnd
4. VOUT2
5. ENABLE
Secondary Output
VOUT2
*
Current
Limit
VOUT2Sense
+
-
Consult factory for 8L and 16L SO, 8L and
16L PDIP, 7L D2PAK and 5L TO-220.
Gnd
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. 1/12/98
1
A
¨
Company
CS8391
Electrical Characteristics: 6V ² VIN ² 26V, IOUT1 = IOUT2 = 100µA, -40¡C ² TC ² 125ûC, -40¡C ² TJ ² 150ûC unless otherwise specified
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
4.85
5.00
400
100
5.15
600
150
V
mV
mV
■ Primary Output Stage (VOUT1)
Output Voltage, VOUT1
Dropout Voltage
100µA ² IOUT1 ² 250mA
IOUT1 = 250mA
IOUT1 = 100µA
Line Regulation
6V ² VIN ² 26V
5
50
mV
Load Regulation
1mA ² IOUT1 ² 250mA, VIN = 14V
5
50
mV
Quiescent Current
ENABLE = HIGH, VIN = 16V,
IOUT1 = 250mA
f = 120Hz, IOUT1 = 125mA, 7V ² VIN ² 17V
22
50
mA
Ripple Rejection
Current Limit
Short Circuit Current Limit
VOUT1 = 0V, VIN = 16V
Reverse Current
VOUT1 = 5V, VIN = 0V
60
70
dB
260
400
mA
25
mA
100
1500
µA
5.00
5.15
V
■ Secondary Output (VOUT2)
Output Voltage, VOUT2
100µA ² IOUT2 ² 100mA
Dropout Voltage
IOUT2 = 100mA
IOUT2 = 100µA
400
100
600
150
mV
mV
Line Regulation
6V ² VIN ² 26V
5
50
mV
Load Regulation
100µA ² IOUT2 ² 100mA, VIN = 14V
5
50
mV
Quiescent Current
ENABLE = LOW, VIN = 12.8V
ENABLE = HIGH, VIN = 16V,
IOUT2 = 100mA
100
8
150
25
µA
mA
Ripple Rejection
f = 120Hz, IOUT2 = 50mA, 7V ² VIN ² 17V
4.85
Current Limit
Short Circuit Current Limit
VOUT2 = 0V, VIN = 16V, IOUT1 = 0A
Reverse Current
VOUT2 = 5V, VIN = 0V
60
70
dB
105
200
mA
25
mA
100
250
µA
0.8
V
V
µA
■ Enable Function (ENABLE)
Input Threshold
Input Bias Current
ENABLE = LOW, 7V ² VIN ² 26V
ENABLE = HIGH, 7V ² VIN ² 26V
0V ² VENABLE ² 5V
2.0
-2
1.2
1.2
0
(Guaranteed by Design)
150
180
2
■ Protection Circuits
Overtemperature Threshold
2
¡C
CS8391
Package Lead Description
PACKAGE LEAD #
LEAD SYMBOL
FUNCTION
5 Lead D2PAK
1
2
VIN
VOUT1
Supply voltage to IC, usually direct from battery.
5V regulated output which is activated by ENABLE input.
3
Gnd
Ground connection.
4
VOUT2
Standby output 5V, 100mA capability; always on.
5
ENABLE
CMOS compatible input lead; switches VOUT1. When ENABLE is
high, VOUT1 is active.
Definition of Terms
Current Limit
Peak current that can be delivered to the output.
Load Regulation
The change in output voltage for a change in load current
at constant chip temperature.
Dropout Voltage
The input-output voltage differential at which the circuit
ceases to regulate against further reduction in input voltage. Measured when the output voltage has dropped
100mV from the nominal value obtained at 14V input,
dropout voltage is dependent upon load current and junction temperature.
Long Term Stability
Output voltage stability under accelerated life-test conditions after 1000 hours with maximum rated voltage and
junction temperature.
Quiescent Current
The part of the positive input current that does not contribute to the positive load current. i.e., the regulator
ground lead current.
Input Output Differential
The voltage difference between the unregulated input voltage and the regulated output voltage for which the regulator will operate.
Ripple Rejection
The ratio of the peak-to-peak input ripple voltage to the
peak-to-peak output ripple voltage.
Input Voltage
The DC voltage applied to the input terminals with respect
to ground.
Short Circuit Current Limit
Peak current that can be delivered by the output when
forced to 0V.
Line Regulation
The change in output voltage for a change in the input
voltage. The measurement is made under conditions of
low dissipation or by using pulse techniques such that the
average chip temperature is not significantly affected.
Temperature Stability of VOUT
The percentage change in output voltage for a thermal variation from room temperature to either temperature extreme.
Typical Circuit Waveform
45V
VIN
14V
ENABLE
2.0V
0.8V
26V
31V
14V
3V
5V
5V
5V
5V
5V
5V
2.4V
0V
0V
VOUT1
0V
VOUT2
5V
5V
5V
5V
5V
5V
0V
5V
2.4V
0V
System
Condition
Turn
On
Load
Dump
Low VIN
Line Noise, Etc.
3
VOUT
1
Short
Circuit
VOUT2
Short
Circuit
Thermal
Shutdown
Turn
Off
CS8391
Application Notes
IOUT2(max) is the maximum output current for the application, and
General
The CS8391 is a micropower dual 5V regulator. All bias
required to operate the internal circuitry is derived from
the standby output, VOUT2. If this output experiences an
over current situation and collapses, then VOUT1 will also
collapse (see timing diagrams).
IQ is the quiescent current the regulator consumes at both
IOUT1(max) and IOUT2(max).
Once the value of PD(max) is known, the maximum permissible value of RQJA can be calculated:
If there is critical circuitry that must remain active under
most conditions it should be connected to VOUT2. Any circuitry that is likely to be subjected to a short circuit, e.g.,
circuitry outside the module, should be connected to VOUT1.
150¡C - TA
(2)
PD
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.
RQJA =
External Capacitors
Output capacitors are required for stability with the CS8391.
Without them, the regulator outputs will oscillate. Actual
size and type may vary depending upon the application
load and temperature range. Capacitor effective series
resistance (ESR) is also a factor in the IC stability. Worstcase is determined at the minimum ambient temperature
and maximum load expected.
In some cases, none of the packages will be sufficient to
dissipate the heat generated by the IC, and an external heat
sink will be required.
IIN
Smart
Regulator
VIN
Output capacitors can be increased in size to any desired
value above the minimum. One possible purpose of this
would be to maintain the output voltages during brief conditions of negative input transients that might be characteristic of a particular system.
IOUT1
VOUT1
IOUT2
VOUT2
}
Capacitors must also be rated at all ambient temperatures
expected in the system. To maintain regulator stability
down to -40ûC, capacitors rated at that temperature must be
used.
Control
Features
IQ
More information on capacitor selection for Smart
Regulatorsª is available in the Smart Regulator application note, Compensation for Linear Regulators.
Figure 1: Dual output regulator with key performance parameters
labeled.
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.
ENABLE
The ENABLE function controls VOUT1. When ENABLE is
high, VOUT1 is on. When ENABLE is low, VOUT1 is off.
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:
Calculating Power Dissipation
in a Dual Output Linear Regulator
RQJA = RQJC + RQCS + RQSA
The maximum power dissipation for a dual output regulator (Figure 1) is:
(3)
where:
RQJC = the junctionÐtoÐcase thermal resistance,
PD(max) = {VIN(max)ÐVOUT1(min)}IOUT1(max)+
{VIN(max)ÐVOUT2(min)}IOUT2(max)+VIN(max)IQ (1)
RQCS = the caseÐtoÐheat sink thermal resistance, and
RQSA = the heat sinkÐtoÐambient thermal resistance.
where:
VIN(max) is the maximum input voltage,
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, heat sink and the interface
between them. These values appear in heat sink data sheets
of heat sink manufacturers.
VOUT1(min) is the minimum output voltage from VOUT1,
VOUT2(min) is the minimum output voltage from VOUT2,
IOUT1(max) is the maximum output current for the application,
4
CS8391
Test & Application Circuit
VIN
0.1mF
C1
VBATT
VOUT2
CS8391
VCC
C2
22mF
ESR<8W
mP
VOUT1
22mF
ESR<8W
Load
C3
ENABLE
I/O
Gnd
Gnd
* C1 required if regulator is located far from power supply filter.
** C2 and C3 required for stability. Capacitor must operate at minimum temperature expected during system operations.
5
CS8391
Package Specification
PACKAGE DIMENSIONS IN MM(INCHES)
PACKAGE THERMAL DATA
Thermal Data
5 Lead D2 PAK
RQJC
typ
2.4
¡C/W
RQJA
typ
10-50*
¡C/W
* Depending on thermal properties of substrate. RQJA = RQJC + RQCA
5 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)
0.91 (.036)
0.66 (.026)
2.79 (.110)
2.29 (.090)
1.70 (.067) REF
4.57 (.180)
4.31 (.170)
.254 (.010) REF
0.10 (.004)
0.00 (.000)
Ordering Information
Part Number
CS8391YDP5
CS8391YDPR5
Rev. 1/12/98
Cherry Semiconductor Corporation reserves the right to
make changes to the specifications without notice. Please
contact Cherry Semiconductor Corporation for the latest
available information.
Description
5 Lead D2PAK
5 Lead D2PAK (tape & reel)
6
© 1999 Cherry Semiconductor Corporation