CHERRY CS8371ET7

CS8371
CS8371
8V/1A, 5V/250mA Dual Regulator with
Independent Output Enables and NoCapª
Description
The CS8371 is a 8V/5V dual output
linear regulator. The 8V ±5% output
sources 1A, while the 5V ±5% output sources 250mA. Each output is
controlled by its own ENABLE
lead. Setting the ENABLE input
high turns on the associated regulator output. Holding both ENABLE
inputs low puts the IC into sleep
mode where current consumption
is less than 10µA.
The regulator is protected against
overvoltage, short-circuit and ther-
Features
mal runaway conditions. The
device can withstand 45V load
dump transients making suitable
for use in automotive environments. CherryÕs proprietary
NoCapª solution is the first technology which allows the output to
be stable without the use of an
external capacitor.
■ Two Regulated Outputs
8V ±5%, 1A
5V ±5%, 250mA
The CS8371 is available in a 7 lead
TO-220 package with copper tab.
The tab can be connected to a
heatsink if necessary.
■ <10µA Sleep Mode Current
■ Independent ENABLE for
each Output
■ Separate Sense Feedback
Lead for 8V Output
■ Fault Protection
Overvoltage Shutdown
+45V Peak Transient
Voltage
Short Circuit
Thermal Shutdown
■ CMOS Compatible, LowCurrent ENABLE Inputs
Block Diagram
VCC
Overvoltage
Shutdown
Package Options
-
ENABLE1
VOUT1
Current Limit
+
-
Trimmed Bandgap
Voltage Reference
Sense
TO-220 7 Lead
+
1.2V
Pre-Regulator/
Bias Generator
Tab (Gnd)
VIA
Thermal
Shutdown
-
ENABLE2
+
-
1.2V
+
Gnd
1 ENABLE 1
2 ENABLE 2
3 VOUT2
4 Gnd
5 Sense
6 VCC
7 VOUT1
VOUT2
Current Limit
1
NoCap is a trademark of Cherry Semiconductor Corporation, and is patented.
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. 6/9/99
1
A
¨
Company
CS8371
Absolute Maximum Ratings
Power Dissipation .............................................................................................................................................Internally Limited
ENABLE Input Voltage Range .............................................................................................................................-0.6V to +10.0V
Load Current (8V Regulator)...........................................................................................................................Internally Limited
Load Current (5V Regulator)...........................................................................................................................Internally Limited
Transient Peak Voltage (31V load dump @ 14V VCC) ...........................................................................................................45V
Storage Temperature Range ................................................................................................................................-65¡C to +150¡C
Junction Temperature Range...............................................................................................................................-40¡C to +150¡C
Lead Temperature Soldering: Wave Solder (through hole styles only) ..........................................10 sec. max, 260¡C peak
Electrical Characteristics: -40¡C ² TA ² +85¡C, 10.5V ² VCC ² 16.0V, ENABLE 1 = ENABLE 2 = 5.0V,
IOUT1 = IOUT2 = 5.0mA, unless otherwise stated.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
7.60
8.00
8.40
V
■ Primary Output (VOUT1)
Output Voltage
IOUT1 = 1.0A
Line Regulation
10.5V ² VCC ² 26V
50
mV
Load Regulation
5mA ² IOUT1 ² 1.0A
150
mV
Sleep Mode Quiescent
Current
VCC = 14V, ENABLE 1 = ENABLE 2 = 0V
10.0
µA
0
0.2
Quiescent Current
VCC = 14V, IOUT1 = 1.0A, IOUT2 = 250mA
30
mA
Dropout Voltage
IOUT1 = 250mA
1.2
V
Dropout Voltage
IOUT1 = 1.0A
1.5
V
Quiescent Bias Current
IOUT1 = 5mA, ENABLE2 = 0V, VCC = 14V
IQ = ICC - IOUT1
10
mA
Quiescent Bias Current
IOUT1 = 1.0A, ENABLE2 = 0V, VCC = 14V
IQ = ICC - IOUT1
22
mA
Ripple Rejection
f = 120Hz, VCC = 14V with 1.0VPP AC,
COUT = 0µF
f = 10kHz, VCC = 14V with 1.0VPP AC,
COUT = 0µF
f = 20kHz, VCC = 14V with 1.0VPP AC,
COUT = 0µF
Current Limit
VCC = 16V
Overshoot Voltage
5mA ² IREG1 ² 1.0A
Output Noise
10Hz-100kHz
90
dB
74
dB
68
dB
1.1
2.5
A
6.0
V
300
µVrms
■ Secondary Output (VOUT2)
Output Voltage
IOUT2 = 250mA
Line Regulation
Load Regulation
4.75
5.25
V
7V ² VCC ² 26V
40
mV
5mA ² IOUT2 ² 250mA
100
mV
Dropout Voltage
IOUT2 = 5.0mA
2.2
V
Dropout Voltage
IOUT2 = 250mA
2.5
V
Quiescent Bias Current
IOUT2 = 5mA, ENABLE1 = 0V, VCC = 14V
IQ = ICC - IOUT2
7
mA
Quiescent Bias Current
IOUT2 = 250mA, ENABLE1 = 0V, VCC = 14V
IQ = ICC - IOUT2
8
mA
Ripple Rejection
f = 120Hz, VCC = 14V with 1.0 VPP AC,
COUT = 0µF
f= 10kHz, VCC = 14V with 1.0VPP AC,
COUT = 0µF
f = 20kHz, VCC = 14V with 1.0VPP AC,
COUT = 0µF
2
5.00
90
dB
75
dB
67
dB
CS8371
Electrical Characteristics: -40¡C ² TA ² +85¡C, 10.5V ² VCC ² 16.0V, ENABLE 1 = ENABLE 2 = 5.0V,
IOUT1 = IOUT2 = 5.0mA, unless otherwise stated.
PARAMETER
TEST CONDITIONS
MIN
■ Secondary Output (VOUT2): continued
Current Limit
VCC = 16V
270
Overshoot Voltage
5mA ² IREG2 ² 250mA
Output Noise
10Hz-100kHz
■ Protection Circuitry
ESD Threshold
UNIT
600
mA
4.3
V
µVrms
-150
150
µA
Low
High
0
2.0
0.8
5.0
V
V
Human Body Model
±2.0
Overvoltage Shutdown
±4.0
kV
24
Thermal Shutdown
MAX
170
■ ENABLE Function (ENABLE)
Input Current
VCC = 14V, 0V ² ENABLE ² 5.5V
Input Voltage
TYP
Guaranteed by Design
30
150
V
180
¡C
30
¡C
Thermal Hysteresis
Package Pin Description
PACKAGE PIN #
PIN SYMBOL
7 Lead TO-220
1
2
3
4
5
6
7
FUNCTION
ENABLE1
ENABLE 2
VOUT2
Gnd
Sense
VCC
VOUT1
ENABLE control for the 8V, 1A output
ENABLE control for the 5V, 250mA output
5V ±5%, 250mA regulated output
Ground
Sense feedback for the primary 8V output
Supply voltage, usually from battery
8V ±5%, 1A regulated output
Typical Performance Characteristics
8.05
8.04
2.0
VIN = 14V
IOUT = 1A
5.00
VIN = 14V
IOUT = 250A
1.8
8.02
8.01
8.00
7.99
7.98
Dropout Voltage (V)
1.6
Output Voltage (V)
Output Voltage (V)
8.03
4.95
4.90
1.2
-40°C
25°C
1.0
0.8
85°C
0.6
7.97
0.4
7.96
7.95
-40
1.4
0.2
-20
0
20
40
60
80
Ambient Temperature (°C)
Regulator 1 Output Voltage
100
120
140
4.85
-40
-20
0
20
40
60
80
Ambient Temperature (°C)
Regulator 2 Output Voltage
3
100
120
140
0
0
100
200
300
400
500
600
700
Output Current (mA)
Regulator 1 Dropout Voltage
800
900 1000
CS8371
Typical Performance Characteristics: continued
10
2.5
10
VIN = 14V
TA = 25°C
-40°C
25°C
1.5
85°C
1.0
8
7
6
5
4
3
0.5
0
0
50
100
150
1
6.0
5.5
0.5
0.4
0.3
0.2
0.1
40
60
-20
0
20
40
60
IOUT = 1A
IOUT = 5mA
4.0
-20
0
20
5.01
8.010
5.00
3.0
2.8
2.6
Output Voltage (V)
Output Voltage (V)
Quiescent Current (mA)
IOUT = 250mA
IOUT = 5mA
8.005
8.000
-40°C
25°C
7.995
85°C
25°C
85°C
4.99
4.98
4.97
7.990
4.96
7.985
4.95
2.4
2.2
-20
0
20
40
60
7.980
80
0
100
200
300
Ambient Temperature (°C)
0
1
2
3
4
5
6
7
8
9
10
11
12
8
7
6
5
4
3
2
1
0
700
800
4.94
900 1000
0
50
5
4
3
2
1
0
0
1
2
3
4
5
6
7
Time (ms)
Regulator 2 Startup
100
150
200
Regulator 2 Load Regulation
8
9
10
11
12
COUT = 0mF
TA = 25°C
2
1
0
-1
-2
16
14
12
10
0
100
200
300
400
Time (ns)
Regulator 1 Line Transient Response
4
250
Output Current (mA)
COUT = 0mF
TA = 25°C
IOUT = 5mA
Time (ms)
Regulator 1 Startup
600
Output Voltage Deviation (V)
COUT = 0mF
TA = 25°C
IOUT = 5mA
Reg 2 Output Voltage (V)
5
4
3
2
1
0
500
Regulator 1 Load Regulation
Enable 2 (V)
Reg 1 Output Voltage (V)
Enable 1 (V)
Regulator 2 Quiescent Current
8
7
6
5
4
3
2
1
0
400
-40°C
Output Current (mA)
Input Voltage (V)
2.0
-40
80
VIN = 14V
8.015
3.6
3.2
60
5.02
VIN = 14V
3.4
40
Regulator 1 Quiescent Current
8.020
Enable 1 = 0V
Enable 2 = 5V
VIN = 14V
4.5
Ambient Temperature (°C)
Quiescent Current
4.0
5.0
3.0
-40
80
Ambient Temperature (°C)
Ambient Temperature (°C)
Quiescent Current
500
3.5
0
-40
80
400
Enable 1 = 5V
Enable 2 = 0V
VIN = 14V
5.5
0.6
4.5
300
200
6.0
0.7
5.0
3.8
100
Regulator 2 Current Limit
Quiescent Current (mA)
Quiescent Current (mA)
Quiescent Current (mA)
6.5
20
0
Reg 2 Output Current (mA)
0.8
0
3
0
3
2
Enable 1 = 0V
Enable 2 = 0V
VIN = 14V
0.9
7.0
-20
4
2
1.0
Enable 1 = 5V
Enable 2 = 5V
VIN = 14V
IOUT 1 = 1A
IOUT 2 = 250mA
4.0
-40
5
1
Regulator 1 Current Limit
9.0
7.5
6
Reg 1 Output Current (A)
Regulator 2 Dropout Voltage
8.0
7
1
Output Current (mA)
8.5
8
2
00
250
200
VIN = 14V
TA = 25°C
9
Reg 2 Output Voltage (V)
Dropout Voltage (V)
2.0
Reg 1 Output Voltage (V)
9
500
600
CS8371
0.2
0
-0.2
-0.4
-0.6
16
14
12
10
0
100
200
300
400
500
600
VIN = 14V
COUT = 0mF
TA = 25°C
3
2
1
0
-1
-2
-3
1000
5
0
5
10
Time (ns)
25
30
250
5
0
5
10
15
20
25
30
Regulator 2 Load Transient Response
TA = 25°C
VIN = 14V
COUT = 0mF
Ripple Rejection (dB)
80
60
Output Capacitor ESR (W)
100
80
60
40
40
10
0
-500
5
100
1
+500
Time (ms)
Regulator 1 Load Transient Response
TA = 25°C
VIN = 14V
COUT = 0mF
Ripple Rejection (dB)
20
VIN = 14V
COUT = 0mF
TA = 25°C
Time (ms)
Regulator 2 Line Transient Response
20
15
Load Current (mA) Output Voltage Deviation (mV)
COUT = 0mF
TA = 25°C
0.6
0.4
Load Current (mA) Output Voltage Deviation (V)
Input Voltage (V)
Output Voltage Deviation (V)
Typical Performance Characteristics: continued
100
1k
10k
100k
1M
20
1
10
100
Frequency (Hz)
Regulator 1 Ripple Rejection
1k
10k
Frequency (Hz)
Regulator 2 Ripple Rejection
100k
1M
TA = 25°C
VIN = 14V
RESR £ 1.6W
IOUT = 5ma to 1A
1
Unstable
Region
0.1
.01
0.1
1
10
100
1000
Output Capacitor Size (mF)
Regulator 1 Stability
Definition of Terms
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.
Load Regulation: The change in output voltage for a change in
load current at constant chip 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.
Current Limit: Peak current that can be delivered to the output.
Input Voltage: The DC voltage applied to the input terminals
with respect to ground.
Quiescent Current: The part of the positive input current that
does not contribute to the positive load current. 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.
5
CS8371
Applications Circuit
C 1*
0.1 mF
DISPLAY
VIN
VOUT1
8V
CS8371
Control
ENABLE1
ENABLE2
VOUT2
Gnd
5V
Tuner IC
*C1 is required if regulator is far from power source filter.
Application Notes
With separate control of each output channel, the CS8371
is ideal for applications where each load must be switched
independently. In an automotive radio, the 8V output
drives the displays and tape drive motors while the 5V
output supplies the Tuner IC and memory.
over temperature, load and line variations without the
need for an expensive external capacitor. It incorporates
high gain (>80dB) and large unity gain bandwidth
(>100kHz) while maintaining many of the characteristics
of a single-pole amplifier (large phase margin and no
overshoot).
NoCapª is ideally suited for slow switching or steady
loads. If the load displays large transient current requirements, such as with high frequency microprocessors, an
output storage capacitor may be needed. Some large
capacitor and small capacitor ESR values at the output
may cause small signal oscillations at the output. This will
depend on the load conditions. With these types of loads,
a traditional output stage may be better suited for proper
operation.
Output 1 employs NoCapª. Refer to the plots in the
Typical Performance Characteristics section for appropriate output capacitor selections for stability if an external
capacitor is required by the switching characteristics of the
load. Output 2 has a Darlington NPN-type output structure and is inherently stable with any type of capacitive
load or no capacitor at all.
Stability Considerations/NoCapª
Normally a low dropout or quasi-low dropout regulator
(or any type requiring a slow lateral PNP in the control
loop) necessitates a large external compensation capacitor
at the output of the IC. The external capacitor is also used
to curtail overshoot, determine startup delay time and
load transient response.
Traditional LDO regulators typically have low unity gain
bandwidth, display overshoot and poor ripple rejection.
Compensation is also an issue because the high frequency
load capacitor value, ESR (Equivalent Series Resistance)
and board layout parasitics all can create oscillations if not
properly accounted for.
NoCapª is a Cherry Semiconductor exclusive output
stage which internally compensates the LDO regulator
6
CS8371
Applications Notes: continued
Calculating Power Dissipation
in a Dual Output Linear Regulator
IIN
The maximum power dissipation for a dual output regulator (Figure 1) is
Smart
Regulator
VIN
IOUT1
VOUT1
IOUT2
PD(max) = {VIN(max) Ð VOUT1(min)}IOUT1(max) +
{VIN(max) Ð VOUT2(min)}IOUT2(max) + VIN(max)IQ,
VOUT2
}
(1)
where
VIN(max) is the maximum input voltage,
Control
Features
IQ
VOUT1(min) is the minimum output voltage from VOUT1,
VOUT2(min) is the minimum output voltage from VOUT2,
Figure 1: Dual output regulator with key performance parameters
labeled.
IOUT1(max) is the maximum output current, for the application,
IOUT2(max) is the maximum output current, for the application,
Heatsinks
IQ is the quiescent current the regulator consumes at
IOUT(max).
A heatsink effectively increases the surface area of the
package to improve the flow of heat away from the IC and
into the surrounding air.
Once the value of PD(max) is known, the maximum permissible value of RQJA can be calculated:
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 =
150¡C - TA
PD
(2)
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 heatsink data
sheets of heatsink manufacturers.
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.
7
CS8371
Package Specification
PACKAGE DIMENSIONS IN mm (INCHES)
PACKAGE THERMAL DATA
Thermal Data
RQJC
typ
RQJA
typ
TO-220
2.4
50
ûC/W
ûC/W
7 Lead TO-220 (T) Straight
7 Lead TO-220 (TVA) Vertical
4.83 (.190)
4.06 (.160)
10.54 (.415)
9.78 (.385)
10.54 (.415)
9.78 (.385)
1.40 (.055)
1.14 (.045)
1.40 (.055)
1.14 (.045)
3.96 (.156)
3.71 (.146)
2.87 (.113)
2.62 (.103)
2.87 (.113)
2.62 (.103)
6.55 (.258)
5.94 (.234)
14.99 (.590)
14.22 (.560)
3.96 (.156)
3.71 (.146)
14.99 (.590)
14.22 (.560)
6.55 (.258)
5.94 (.234)
11.86 (.467)
2.03 (.080)
14.22 (.560)
13.72 (.540)
0.81
(.030)
0.94 (.037)
0.58 (.023)
1.40 (.055)
1.14 (.045)
7.62 (.300)
0.64 (.025)
0.38 (.015)
4.34
(.171)
7.52 (.296)
4.83 (.190)
4.06 (.160)
2.92 (.115)
2.29 (.090)
Cherry Semiconductor Corporation reserves the right to
make changes to the specifications without notice. Please
contact Cherry Semiconductor Corporation for the latest
available information.
Ordering Information
Rev. 6/9/99
0.56 (.022)
0.36 (.014)
1.27
(.050)
TYP
0.56 (.022)
0.36 (.014)
7.75 (.305)
7.49 (.295)
Part Number
CS8371ET7
CS8371ETVA7
2.92 (.115)
2.29 (.090)
2.92
(.115)
8.26
(.325)
Description
7 Lead TO-220 Straight
7 Lead TO-220 Vertical
8
© 1999 Cherry Semiconductor Corporation