CS8135
CS8135
5V, 5V Low Dropout Dual Regulator
with RESET /ENABLE
Description
Features
transients, such as a 60V load dump,
the 500mA output will automatically
shut down the primary output to protect both internal circuits and the load.
The standby regulator will continue to
power any standby load.
The CS8135 is a low dropout, high current, dual 5V linear regulator. The secondary 5V/10mA output is often used
for powering systems with standby
memory. Quiescent current drain is
less than 3mA when supplying 10mA
loads from the standby regulator.
The CS8135 is packaged in a 5 lead
TO-220.
In automotive applications, the CS8135
and all regulated circuits are protected
from reverse battery installations, as
well as two-battery jumps. During line
NOTE: The CS8135 is compatible with
the LM2935.
Absolute Maximum Ratings
Input Voltage
Operating Range .....................................................................-0.5V to 26V
Load Dump ............................................................................................60V
Internal Power Dissipation ..................................................Internally Limited
Junction Temperature Range (TJ)............................................-40°C to +150°C
Storage Temperature Range ....................................................-65°C to +150°C
Lead Temperature Soldering
Wave Solder (through hole styles only)..........10 sec. max, 260°C peak
Electrostatic Discharge (Human Body Model) ..........................................2kV
■ Two Regulated Outputs
Primary Output 5V
± 5%; 500mA
Secondary Standby 5V
±5%; 10mA
■ Low Dropout Voltage
(0.6V at 0.5A)
■ ON/OFF Control
Option
■ Low Quiescent Drain
(<3mA)
■ RESET Option
■ Protection Features
Reverse Battery
60V Load Dump
-50V Reverse Transient
Short Circuit
Thermal Shutdown
Overvoltage Shutdown
Package Option
Block Diagram
5 Lead TO-220
Standby Output
V IN
V OUT2
Bandgap
Reference
Output
Current
Limit
+
-
Primary Output
Gnd
Thermal
Shutdown
RESET/
ENABLE
Tab (Gnd)
V OUT1
Over Voltage
Shutdown
+
+
-
-
Output
Current
Limit
1
+
-
1 VIN
2 VOUT1
3 Gnd
4 RESET /
ENABLE
5 VOUT2
ON Semiconductor
2000 South County Trail, East Greenwich, RI 02818
Tel: (401)885–3600 Fax: (401)885–5786
N. American Technical Support: 800-282-9855
Web Site: www.cherry–semi.com
June, 1999 - Rev. 2
1
CS8135
Electrical Characteristics : VIN = 14V, IOUT1 = 5mA, IOUT2 = 1mA, -40°C ≤ TA ≤ 125°C, -40°C ≤ TJ ≤ 150°C unless otherwise specified
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
4.75
5.00
5.25
V
0.35
0.50
0.60
V
V
mV
■ Output Stage (VOUT1)
Output Voltage, VOUT1
6V ≤ VIN ≤ 26V, 5mA ≤ IOUT1 ≤ 500mA
Dropout Voltage
IOUT = 500mA
IOUT = 750mA
Line Regulation
6V ≤ VIN ≤ 26V, IOUT1 = 5mA
10
50
Load Regulation
5mA ≤ IOUT ≤ 500mA
10
50
mV
Quiescent Current
IOUT1 ≤ 10mA, No Load on Standby
IOUT1 = 500mA, No Load on Standby
IOUT1 = 750mA, No Load on Standby
3
30
60
7
100
150
mA
mA
mA
Ripple Rejection
f = 120Hz
66
dB
Current Limit
1.40
A
Maximum Line Transient
VOUT1 ≤ 5.5V
0.75
90
V
Reverse Polarity
Input Voltage, DC
VOUT1 ≥ -0.6V, 10Ω Load
-50
V
Reverse Polarity Input
Voltage, Transient
1% Duty Cycle, t = 100ms, VOUT1 ≥ -6V,
10Ω Load
-80
V
Output Noise Voltage
10Hz-100kHz
100
µVrms
20
mV/khr
200
mΩ
30
V
Long Term Stability
Output Impedance
500mA DC and 10mA rms,
100Hz-10kHz
Overvoltage Shutdown
■ Standby Output (VOUT2)
Output Voltage (VOUT2)
6V ≤ VIN ≤ 26V, 1mA ≤ IOUT1 ≤ 10mA
Dropout Voltage
5.00
5.25
V
IOUT2 = 10mA
0.3
0.7
V
Tracking
VOUT1 - VOUT2
50
200
mV
Line Regulation
6V ≤ VIN ≤ 26V
4
50
mV
Load Regulation
1mA ≤ IOUT1 ≤ 10mA
10
50
mV
Quiescent Current
IOUT ≤ 10mA, VOUT OFF
2
3
mA
Ripple Rejection
f = 120Hz
66
dB
70
mA
Current Limit
Output Noise Voltage
4.75
25
10Hz-100kHz
Long Term Stability
Output Impedance
10mA DC and 1mA rms, 100Hz-10kHz
300
µV
20
mV/khr
1
Ω
■ RESET Function
RESET Output Voltage
Low R1 = 20kΩ, VIN = 4.5V
High R1 = 20kΩ, VIN = 14V
See Test & Application Circuit
(page 6)
RESET Output Current
VIN = 4.5V, RESET in Low State
5
ON/OFF Resistor
R1 (±10% Tolerance)
20
2
4.5
0.8
5.0
1.1
6.0
V
V
mA
30
kΩ
CS8135
Package Lead Description
PACKAGE LEAD #
LEAD SYMBOL
FUNCTION
TO-220
Supply voltage to IC, usually direct from battery.
1
VIN
2
VOUT1
3
Gnd
4
RESET/ENABLE
5
VOUT2
Regulated output voltage 5V, 500mA (typ) switched.
Ground connection.
CMOS compatible output lead, RESET goes low whenever
VOUT1 becomes unregulated. To use the ENABLE option, connect the lead via a resistor to VIN (see app. notes).
STANDBY output 5V, 10mA typ, always on.
1.0
7
0.9
6
0.8
5
OUTPUT VOLTAGE (V)
INPUT-OUTPUT DIFFERENTIAL VOLTAGE (V)
Typical Performance Characteristics
0.7
0.6
0.5
0.4
0.3
RL=500Ω
4
3
2
1
0
0.2
-1
0.1
-2
0.0
0
200
400
600
-40
800
-20
20
40
60
Standby Output Voltage vs. Input Voltage
Dropout Voltage vs. Output Current
20
OUTPUT VOLTAGE
DEVIATION (mV)
1.0
INPUT-OUTPUT DIFFERENTIAL VOLTAGE (V)
0
INPUT VOLTAGE (V)
OUTPUT CURRENT (mA)
0.9
0.8
0.7
0.6
INPUT VOLTAGE
CHANGE (V)
0.5
0.4
0.3
0.2
0.1
IOUT1=500mA
10
0
-10
-20
3
2
1
0
0.0
0
5
10
15
0
20
10
20
OUTPUT CURRENT (mA)
OUTPUT VOLTAGE
DEVIATION (mV)
7
RL=10Ω
5
4
3
50
40
50
60
10
5
0
-5
-10
2
INPUT VOLTAGE
CHANGE (V)
OUTPUT VOLTAGE (V)
40
Line Transient Response (VOUT1)
Standby Dropout Voltage vs. Output Current
6
30
TIME (µs)
1
0
-1
-2
-40
-20
0
20
40
60
3
2
1
0
0
10
INPUT VOLTAGE (V)
20
30
TIME (µs)
Output Voltage vs. Input Voltage
Line Transient Response (VOUT2)
3
60
CS8135
Typical Performance Characteristics: continued
OUTPUT VOLTAGE
DEVIATION (mV)
150
5
SWITCH OPEN
VO OFF
100
QUIESCENT CURRENT (mA)
50
0
-50
-100
-150
LOAD
CURRENT (A)
0.8
0.6
0.4
4
3
2
1
0.2
0
0
0
10
20
30
40
50
0
60
20
100
18
50
16
POWER DISSIPATION (W)
150
0
-50
-100
-150
20
15
10
INFINITE
HEAT SINK
14
12
10
8
10° C/W HEAT SINK
6
4
NO HEAT SINK
2
5
0
0
0
10
20
30
40
50
0
60
10
20
30
40
50
60
AMBIENT TEMPERATURE (°C)
TIME (µs)
Maximum Power Dissipation (TO-220)
Load Transient Response (VOUT2)
120
QUIESCENT CURRENT (mA)
IOUT2=10mA
100
80
60
40
20
0
0
25
Quiescent Current vs. Standby Output Current
Load Transient Response (VOUT1)
STANDBY
OUTPUT VOLTAGE
DEVIATION (mV)
20
STANDBY OUTPUT CURRENT (mA)
TIME (µs)
STANDBY LOAD
CURRENT (mA)
15
10
5
200
400
600
800
OUTPUT CURRENT (mA)
Quiescent Current vs. Output Current
4
70
80
90
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.
Output Noise Voltage
The rms AC voltage at the output, with constant load and
no input ripple, measured over a specified frequency
range.
Input Voltage
The DC voltage applied to the input with respect to ground.
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.
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.
Load Regulation
The change in output voltage for a change in load current
at constant chip temperature.
Current Limit
Peak current that can be delivered to the output.
Typical Circuit Waveform
60V
SWITCH
26V
31V
VIN 14V
14V
3V
CLOSED
OPEN
5V
OPEN
5V
5V
5V
2.4V
VOUT1
0V
0V
0V
5V
RESET
0V
VOUT
5V
2
System
Condition
5V
5V
2.4V
Turn
On
Load
Dump
Low VIN
Line, Noise, Etc.
VOUT1
Short
Circuit
Thermal
Shutdown
Turn
Off
*Reference Test & Application Circuit
Circuit Description
In applications where the standby output is not needed, it
may be disabled by connecting a resistor from the standby
output to the supply voltage. This eliminates the need for
a capacitor on the output to prevent unwanted oscillations. The value of the resistor depends upon the minimum input voltage expected for a given system. Since the
standby output is shunted with an internal diode zener,
the current through the external resistor should be sufficient to bias VOUT2 up to this point. Approximately 60µA
will suffice, resulting in a 10kΩ external resistor for most
applications.
Standby Output
The CS8135 is equipped with two outputs. The second output is intended for use in systems requiring standby memory circuits. While the high current regulator output can be
controlled with the RESET lead described below, the standby output remains on under all conditions as long as sufficient input voltage is applied to the IC. Thus, memory and
other circuits powered by this output remain unaffected by
positive line transients, thermal shutdown, etc.
The standby regulator circuit is designed so that the quiescent current to the IC is very low (<3mA) when the other
regulator output is off.
5
CS8135
Definition of Terms
CS8135
Circuit Description: continued
output voltage of this lead is high (5V). This is set by an
internal clamp. If the high current output becomes unregulated for any reason (line transients, short circuit, thermal
shutdown, low input voltage, etc.) the lead switches to the
active low state, and is capable of sinking several milliamps. This output signal can be used to initiate any reset
or start-up procedure that may be required of the system.
VIN
RD
10kΩ
VOUT2
VOUT2
+
The RESET lead can also be driven directly from logic circuits. The only requirement is that the 20kΩ pull-up resistor remain in place. This will not affect the logic gate since
the voltage on this lead is limited by the internal clamp to
5V. The RESET signal is sacrificed in this arrangement
since the maximum sink capability of the lead in the active
low state (approximately 5mA), is usually not sufficient to
pull down the active high logic gate. The flag can be
retained if the driving gate is open collector logic.
C3
Disabling VOUT2 when it is not needed. C3 is no longer needed.
High Current Output
VIN
Unlike the standby regulated output, which must remain
on whenever possible, the high current regulated output is
fault protected against overvoltage and also incorporates
thermal shutdown. If the input voltage rises above approximately 30V (e.g., load dump), this output will automatically shutdown. This protects the internal circuitry and
enables the IC to survive higher voltage transients than
would otherwise be expected. Thermal shutdown is effective against die overheating since the high current output
is the dominant source of power dissipation in the IC.
R1
20kΩ
CS8135
RESET/
ENABLE
Controlling ON/OFF Terminal with a typical CMOS or TTL Logic Gate
R1
20kΩ
RESET Function
The RESET function has the ability to serve a dual purpose
if desired. When controlled in the manner shown in the
test circuit (common in automotive systems where
RESET /ENABLE is connected to the ignition switch), the
lead also serves as an output flag that is active low whenever a fault condition is detected with the high current
regulated output. Under normal operating conditions, the
CMOS MM 74CO4
or Equivalent
Delayed
Reset
Out
R2
100kΩ
CS8135
RESET/
ENABLE
Gnd
4.7 µF
Reset Pulse on Power-Up (with approximately 300ms delay)
Application Notes
Test & Application Circuit
C1*
0.1 µF
S1
ON/OFF
VIN
Stability Considerations
VOUT1
+
R1
20kΩ
RESET
FLAG
RESET/
ENABLE
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 output capacitor C2 shown in the test and
applications circuit should work for most applications,
however it is not necessarily the optimized solution.
To determine acceptable values for C2 and C3 for a particular application, start with a tantalum capacitor of the rec-
C2 **
10µF
CS8135
VOUT2
Gnd
+
C3**
10µF
NOTES:
* C1 required if regulator is located far from power supply filter.
** C2, C3 required for stability.
6
VOUT2(min) is the minimum output voltage from VOUT2,
ommended value and work towards a less expensive
alternative part for each output.
Step 1: Place the completed circuit with the tantalum
capacitors of the recommended values in an environmental chamber at the lowest specified operating temperature
and monitor the outputs with an oscilloscope. A decade
box connected in series with capacitor C2 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 on
the output under observation and look for oscillations on
the output. 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 output 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 capacitor 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.
Repeat steps 1 through 7 with the capacitor on the other
output, C3.
IOUT1(max) is the maximum output current for the
application,
IOUT2(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 RΘJA can be calculated:
RΘJA =
(2)
The value of RΘJA can then be compared with those in
the package section of the data sheet. Those packages
with RΘJA'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.
IIN
VIN
Smart
Regulator
}
IOUT1
VOUT1
IOUT2
VOUT2
Control
Features
IQ
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.
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 RΘJA.
RΘJA = RΘJC + RΘCS + RΘSA
(3)
where
RΘJC = the junction-to-case thermal resistance,
RΘCS = the case-to-heatsink thermal resistance, and
RΘSA = the heatsink-to-ambient thermal resistance.
RΘJC appears in the package section of the data sheet. Like
RΘJA, it too is a function of package type. RΘCS and RΘSA
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 Dual Output Linear Regulator
The maximum power dissipation for a dual output regulator (Figure 1) is:
PD(max) = {VIN(max)-VOUT1(min)}IOUT1(max)+
{VIN(max)-VOUT2(min)}IOUT2(max)+VIN(max)IQ
150°C - TA
PD
(1)
Where
VIN(max) is the maximum input voltage,
VOUT1(min) is the minimum output voltage from VOUT1,
7
CS8135
Application Notes: continued
CS8135
Package Specification
Package Dimensions in MM (Inches)
PACKAGE THERMAL DATA
Thermal Data
RΘJC
typ
5 Lead TO-220 (T) Straight
RΘJA
10.54 (.415)
9.78 (.385)
2.87 (.113)
6.55 (.258) 2.62 (.103)
5.94 (.234)
1.40 (.055)
1.14 (.045)
4.83 (.190)
4.06 (.160)
5 Lead TO-220
2.3
typ
50
°C/W
°C/W
5 Lead TO-220 (THA) Horizontal
3.96 (.156)
3.71 (.146)
4.83 (.190)
10.54 (.415)
9.78 (.385)
2.87 (.113)
2.62 (.103)
14.99 (.590)
14.22 (.560)
1.40 (.055)
4.06 (.160)
1.14 (.045)
3.96 (.156)
3.71 (.146)
14.99 (.590)
14.22 (.560)
6.55 (.258)
5.94 (.234)
14.22 (.560)
13.72 (.540)
2.77 (.109)
6.83 (.269)
1.02 (.040)
0.76 (.030)
1.83(.072)
1.57(.062)
1.02(.040)
0.63(.025)
1.68
(.066)
TYP
1.70 (.067)
0.81(.032)
0.56 (.022)
0.36 (.014)
2.92 (.115)
2.29 (.090)
0.56 (.022)
0.36 (.014)
6.60 (.260)
5.84 (.230)
6.81(.268)
6.93(.273)
6.68(.263)
2.92 (.115)
2.29 (.090)
5 Lead TO-220 (TVA) Vertical
4.83 (.190)
4.06 (.160)
10.54 (.415)
9.78 (.385)
3.96 (.156)
3.71 (.146)
1.40 (.055)
1.14 (.045)
6.55 (.258)
5.94 (.234)
2.87 (.113)
2.62 (.103)
14.99 (.590)
14.22 (.560)
1.78 (.070)
2.92 (.115)
2.29 (.090)
8.64 (.340)
7.87 (.310)
4.34 (.171)
1.68
(.066) typ
1.70 (.067)
0.56 (.022)
0.36 (.014)
7.51 (.296)
6.80 (.268)
.94 (.037)
.69 (.027)
Ordering Information
Part Number
CS8135YT5
CS8135YTVA5
CS8135YTHA5
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further notice to any products herein. For additional information and the latest available information, please contact
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Description
5 Lead TO-220 Straight
5 Lead TO-220 Vertical
5 Lead TO-220 Horizontal
8
© Semiconductor Components Industries, LLC, 2000