DATASHEET

DATASHEET
Dual LDO with Low Noise, Very High PSRR and Low IQ
ISL78302A
Features
ISL78302A is a high-performance dual LDO capable of
sourcing 300mA current from each output. It has a low
standby current and very high PSRR and is stable with output
capacitance of 1µF to 10µF with ESR of up to 200mΩ.
• Integrates Two 300mA High-performance LDOs
• Excellent Transient Response to Large Current Steps
• ±1.8% Accuracy Over All Operating Conditions
• Excellent Load Regulation: < 0.1% Voltage Change Across
Full Range of Load Current
The device integrates an individual Power-On Reset (POR)
function for each output. The POR delay for VO2 can be
externally programmed by connecting a timing capacitor to the
CPOR pin. The POR delay for VO1 is internally fixed at
approximately 2ms. A reference bypass pin is also provided for
connecting a noise-filtering capacitor for low noise and
high-PSRR applications.
• Low Output Noise: Typically 30µVRMS at 100µA (1.5V)
• Very High PSRR: 90dB at 1kHz
• Extremely Low Quiescent Current: 47µA (Both LDOs Active)
• Wide Input Voltage Capability: 2.3V to 6.5V
• Low Dropout Voltage: Typically 230mV at 300mA
The quiescent current is typically only 47µA with both LDOs
enabled and active. Separate Enable pins control each
individual LDO output. When both Enable pins are low, the
device is in shutdown, typically drawing less than 0.3µA.
• Stable with 1µF to 10µF Ceramic Capacitors
• Separate Enable and POR Pins for Each LDO
• Soft-start and Staged Turn-on to Limit Input Current Surge
During Enable
The ISL78302A is AEC-Q100 qualified. The ISL78302A is rated
for the automotive temperature range (-40°C to +105°C).
• Current Limit and Overheat Protection
• Tiny 10 Ld 3mmx3mm DFN Package
• -40°C to +105°C Operating Temperature Range
• Pb-free (RoHS Compliant)
• AEC-Q100 Qualified
Applications
• Radio Receivers
• Camera Modules
• GPS/Navigation
• Infotainment Systems
ISL78302A
VIN (2.3 TO 6.5V)
1
ON
2
ENABLE1
OFF ON
ENABLE2
OFF
3
4
5
C1
C2
VIN
EN1
VO1
VO2
EN2
POR2
CBYP
POR1
CPOR
GND
10
VOUT1
9
VOUT2 OK
8
7
VOUT2 TOO LOW
VOUT1 OK
6
C3
C4
C5
VOUT1 TOO LOW
VOUT2
RESET2
(200ms DELAY,
C3 = 0.01µF)
RESET1
(2ms DELAY)
C1, C4, C5: 1µF X5R CERAMIC CAPACITOR
C2: 0.1µF X7R CERAMIC CAPACITOR
C3: 0.01µF X7R CERAMIC CAPACITOR
FIGURE 1. TYPICAL APPLICATION
December 22, 2015
FN7932.2
1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2012, 2013, 2015. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
ISL78302A
Block Diagram
VIN
VO1
VO2
LDO
VO1
ERROR
AMPLIFIER
~1.0V
VO2
VREF
TRIM
IS1
POR
COMPARATOR
QEN1
VOK1
1V
POR1
LDO-1
POR2
QEN2
VO2
100k
QEN1
IS2
LDO-2
IS1
VOK2
EN1
CONTROL
LOGIC
EN2
POR2
VOK2
POR2
DELAY
CBYP
VO1
BANDGAP AND
TEMPERATURE
SENSOR
VOLTAGE
REFERENCE
GENERATOR
100k
UVLO
1.00V
VOK1
0.94V
2
POR1
0.90V
CPOR
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POR1
DELAY
GND
FN7932.2
December 22, 2015
ISL78302A
Pin Configuration
ISL78302A
(10 LD 3X3 DFN)
TOP VIEW
VIN 1
10 VO1
EN1 2
9
VO2
EN2 3
8
POR2
CBYP 4
7
POR1
CPOR 5
6
GND
Pin Descriptions
PIN NUMBER PIN NAME
TYPE
DESCRIPTION
1
VIN
Analog I/O
Supply Voltage/LDO Input. Connect a 1µF capacitor to GND.
2
EN1
Low Voltage Compatible CMOS Input LDO-1 Enable
3
EN2
Low Voltage Compatible CMOS Input LDO-2 Enable
4
CBYP
Analog I/O
Reference Bypass Capacitor Pin. Optionally connect capacitor of value 0.01µF to 1µF
between this pin and GND to tune in the desired noise and PSRR performance.
5
CPOR
Analog I/O
POR2 Delay Setting Capacitor Pin. Connect a capacitor between this pin and GND to
delay the POR2 output release after LDO-2 output reaches 94% of its specified
voltage level (200ms delay per 0.01µF).
6
GND
Ground
7
POR1
Open Drain Output (1mA)
Open-drain POR Output for LDO-1 (active-low). Internally connected to VO1 through
100kΩ resistor.
8
POR2
Open Drain Output (1mA)
Open-drain POR Output for LDO-2 (active-low). Internally connected to VO2 through
100kΩ resistor.
9
VO2
Analog I/O
LDO-2 Output. Connect capacitor of value 1µF to 10µF to GND
(1µF recommended).
10
VO1
Analog I/O
LDO-1 Output. Connect capacitor of value 1µF to 10µF to GND
(1µF recommended).
Connection to system ground. Connect to PCB Ground plane.
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
ISL78302AARMMZ
PART
MARKING
DNAL
VO1 VOLTAGE
(V)
VO2 VOLTAGE
(V)
TEMP RANGE
(°C)
3.0
3.0
-40 to +105
PACKAGE
(RoHS Compliant)
10 Ld 3x3 DFN
PKG DWG. #
L10.3x3C
ISL78302AARLLZ
DNAM
2.9
2.9
-40 to +105
10 Ld 3x3 DFN
L10.3x3C
ISL78302AARJMZ
DNAN
2.8
3.0
-40 to +105
10 Ld 3x3 DFN
L10.3x3C
ISL78302AARJRZ
DNAP
2.8
2.6
-40 to +105
10 Ld 3x3 DFN
L10.3x3C
ISL78302AARJCZ
DNAK
2.8
1.8
-40 to +105
10 Ld 3x3 DFN
L10.3x3C
ISL78302AARGCZ
DNAR
2.7
1.8
-40 to +105
10 Ld 3x3 DFN
L10.3x3C
ISL78302AARPLZ
DNAS
1.85
2.9
-40 to +105
10 Ld 3x3 DFN
L10.3x3C
ISL78302AARBJZ
DNAT
1.5
2.8
-40 to +105
10 Ld 3x3 DFN
L10.3x3C
NOTES:
1. Add “-T” suffix for tape and reel. Please refer to TB347 for details on reel specifications.
2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte
tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil
Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), please see device information page for ISL78302A. For more information on MSL, please see Tech Brief TB363.
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FN7932.2
December 22, 2015
ISL78302A
Absolute Maximum Ratings
Thermal Information
Supply Voltage (VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+7.1V
VO1, VO2 Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +3.6V
All Other Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3 to (VIN + 0.3)V
Thermal Resistance
JA (°C/W) JC (°C/W)
10 Ld 3x3 DFN Package (Notes 4, 5). . . . .
59
18.5
Junction Temperature Range . . . . . . . . . . . . . . . . . . . . . . .-40°C to +125°C
Storage Temperature Range. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Pb-free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see TB493
ESD Ratings
Human Body Model (Tested per JESD22-A114E) . . . . . . . . . . . . . . . . 3000V
Machine Model (Tested per JESD-A115-A) . . . . . . . . . . . . . . . . . . . . . . 200V
Charge Device Model (Tested per AEC-Q100-011) . . . . . . . . . . . . . . 1500V
Recommended Operating Conditions
Ambient Temperature Range (TA) . . . . . . . . . . . . . . . . . . .-40°C to +105°C
Operating Temperature Range . . . . . . . . . . . . . . . . . . . . .-40°C to +105°C
Supply Voltage (VIN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3V to 6.5V
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product
reliability and result in failures not covered by warranty.
NOTES:
4. JA is measured in free air with the component mounted on a high effective thermal conductivity test board with “direct attach” features. See Tech
Brief TB379.
5. For JC, the “case temp” location is the center of the exposed metal pad on the package underside.
Electrical Specifications
Unless otherwise noted, all parameters are guaranteed over the operational supply voltage and temperature
range of the device as follows: TA = -40°C to 105°C; VIN = (VO + 0.5V) to 6.5V with a minimum VIN of 2.3V; CIN = 1µF; CO = 1µF; CBYP = 0.01µF;
CPOR = 0.01µF. Boldface limits apply over the operating temperature range, -40°C to +105°C.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
(Note 6) TYP
MAX
(Note 6)
UNITS
6.5
V
DC CHARACTERISTICS
Supply Voltage
2.3
VIN
Quiescent condition: IO1 = 0µA; IO2 = 0µA
Ground Current
IDD1
One LDO active
30
36
µA
IDD2
Both LDO active
47
55
µA
0.3
2.1
µA
Shutdown Current
IDDS
UVLO Threshold
VUV+
1.9
2.1
2.3
V
VUV-
1.6
1.8
2.0
V
Regulation Voltage Accuracy
Maximum Output Current
IMAX
Internal Current Limit
ILIM
Dropout Voltage (Note 7)
VDO1
VDO2
VDO3
Thermal Shutdown Temperature
VIN = VO + 0.5V to 5.5V, IO = 10µA to 300mA, TJ = +25°C
-0.8
+0.8
%
VIN = VO + 0.5V to 5.5V, IO = 10µA to 300mA, TJ = -40°C to +125°C
-1.8
+1.8
%
650
mA
Continuous
300
320
mA
475
IO = 300mA; VO  2.5V
450
IO = 150mA; VO  2.5V
225
IO = 300mA; 2.5V  VO  2.8V
250
IO = 150mA; 2.5V  VO  2.8V
125
IO = 300mA; VO > 2.8V
230
IO = 150mA; VO > 2.8V
115
mV
250
mV
160
mV
mV
145
mV
TSD+
145
°C
TSD-
110
°C
AC CHARACTERISTICS
IO = 10mA, VIN = 2.8V(min), VO = 1.8V, CBYP = 0.1µF
Ripple Rejection
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4
@ 1kHz
90
dB
@ 10kHz
70
dB
@ 100kHz
50
dB
FN7932.2
December 22, 2015
ISL78302A
Electrical Specifications
Unless otherwise noted, all parameters are guaranteed over the operational supply voltage and temperature
range of the device as follows: TA = -40°C to 105°C; VIN = (VO + 0.5V) to 6.5V with a minimum VIN of 2.3V; CIN = 1µF; CO = 1µF; CBYP = 0.01µF;
CPOR = 0.01µF. Boldface limits apply over the operating temperature range, -40°C to +105°C. (Continued) (Continued)
PARAMETER
SYMBOL
Output Noise Voltage
MIN
(Note 6) TYP
TEST CONDITIONS
MAX
(Note 6)
UNITS
IO = 100µA, VO = 1.5V, TA = +25°C, CBYP = 0.1µF
BW = 10Hz to 100kHz
30
µVRMS
250
500
µs
30
60
µs/V
DEVICE START-UP CHARACTERISTICS
Device Enable Time
tEN
Time from assertion of the ENx pin to when the output voltage
reaches 95% of the VO (nom)
LDO Soft-Start Ramp Rate
tSSR
Slope of linear portion of LDO output voltage ramp during start-up
EN1, EN2 PIN CHARACTERISTICS
Input Low Voltage
VIL
-0.3
0.5
V
Input High Voltage
VIH
1.35
VIN +
0.3
V
0.1
µA
Input Leakage Current
IIL, IIH
Pin Capacitance
CPIN
Informative
5
pF
POR1, POR2 PIN CHARACTERISTICS
POR1, POR2 Thresholds
VPOR+
POR1 Delay
91
94
97
%
VPOR-
As a percentage of nominal output voltage
87
90
93
%
tP1LH
0.5
2.0
3.2
ms
25
tP1HL
POR2 Delay
tP2LH
CPOR = 0.01µF
100
VOL
POR1, POR2 Pin Internal Pull-Up
Resistance
300
25
tP2HL
POR1, POR2 Pin Output Low
Voltage
200
µs
@ IOL = 1.0mA
RPOR
78
100
ms
µs
0.2
V
180
kΩ
NOTES:
6. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.
7. VOx = 0.98*VOx(NOM); valid for VOx greater than 1.85V.
EN1
EN2
tEN
VPOR+
VPOR-
VPOR+
VPOR-
<tP1HL
VO1
VO2
<tP2HL
tP1LH
tP1HL
tP2LH
tP2HL
POR1
POR2
FIGURE 2. TIMING PARAMETER DEFINITION
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FN7932.2
December 22, 2015
ISL78302A
Typical Performance Curves
0.10
0.8
VO = 3.3V
ILOAD = 0mA
0.4
0.2
-40°C
0.0
+25°C
-0.2
+85°C
-0.4
VIN = 3.8V
VO = 3.3V
0.08
OUTPUT VOLTAGE CHANGE (%)
OUTPUT VOLTAGE, VO (%)
0.6
-0.6
0.06
0.04
-40°C
0.02
+25°C
0.00
-0.02
+85°C
-0.04
-0.06
-0.08
-0.8
3.4
3.8
4.6
4.2
5.0
5.4
5.8
6.2
-0.10
6.6
0
50
200
250
300
350
400
LOAD CURRENT - IO (mA)
FIGURE 3. OUTPUT VOLTAGE vs INPUT VOLTAGE (3.3V OUTPUT)
FIGURE 4. OUTPUT VOLTAGE CHANGE vs LOAD CURRENT
0.10
3.4
VIN = 3.8V
VO = 3.3V
ILOAD = 0mA
0.08
0.06
0.04
0.02
0.00
-0.02
-0.04
-0.06
VO = 3.3V
IO = 0mA
3.3
OUTPUT VOLTAGE, VO (V)
OUTPUT VOLTAGE CHANGE (%)
150
100
INPUT VOLTAGE (V)
3.2
IO = 150mA
3.1
IO = 300mA
3.0
2.9
-0.08
-0.10
-40
2.8
-25
5
-10
20 35 50 65
TEMPERATURE (°C)
80
95
110 125
3.6
4.1
4.6
5.1
5.6
6.1
6.5
INPUT VOLTAGE (V)
FIGURE 5. OUTPUT VOLTAGE CHANGE vs TEMPERATURE
FIGURE 6. OUTPUT VOLTAGE vs INPUT VOLTAGE (3.3V OUTPUT)
2.9
350
VO = 2.8V
IO = 0mA
DROPOUT VOLTAGE, VDO (mV)
2.8
OUTPUT VOLTAGE, VO (V)
3.1
2.7
IO = 150mA
2.6
IO = 300mA
2.5
2.4
2.3
2.6
300
250
VO = 2.8V
200
VO = 3.3V
150
100
50
0
3.1
3.6
4.1
4.6
5.1
5.6
6.1
6.5
INPUT VOLTAGE (V)
FIGURE 7. OUTPUT VOLTAGE vs INPUT VOLTAGE (2.8V OUTPUT)
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0
50
100
150
200
250
OUTPUT LOAD (mA)
300
350
400
FIGURE 8. DROPOUT VOLTAGE vs LOAD CURRENT
FN7932.2
December 22, 2015
ISL78302A
Typical Performance Curves
(Continued)
55
350
VO = 3.3V
50
GROUND CURRENT (µA)
DROPOUT VOLTAGE, VDO (mV)
300
250
+85°C
+25°C
-40°C
200
150
100
+125°C
+25°C
45
-40°C
40
35
VO1 = 3.3V
VO2 = 2.8V
30
50
IO (BOTH CHANNELS) = 0µA
0
0
50
100
150
200
250
OUTPUT LOAD (mA)
300
350
25
400
3.0
3.5
4.0
4.58
5.5
5.0
6.0
6.5
INPUT VOLTAGE (V)
FIGURE 9. DROPOUT VOLTAGE vs LOAD CURRENT
FIGURE 10. GROUND CURRENT vs INPUT VOLTAGE
55
200
180
50
140
GROUND CURRENT (µA)
GROUND CURRENT (µA)
160
+85°C
+25°C
120
100
-40°C
80
60
40
VIN = 3.8V
VO1 = 3.3V
VO2 = 2.8V
20
0
0
50
100
150
200
250
300
45
40
35
VIN = 3.8V
VO = 3.3V
ILOAD = 0µA
30
BOTH OUTPUTS ON
25
-40
400
350
-25
-10
5
LOAD CURRENT (mA)
FIGURE 11. GROUND CURRENT vs LOAD
5
3.5
IL2 = 300mA
V O1
95
110 125
VO2
VO1 = 3.3V
VO2 = 2.8V
IL1 = 300mA
IL2 = 300mA
2.5
3
2
POR1
3.0
VOLTAGE (V)
VOLTAGE (V)
4
80
FIGURE 12. GROUND CURRENT vs TEMPERATURE
VO1 = 3.3V
VO2 = 2.8V
IL1 = 300mA
VIN
20 35 50 65
TEMPERATURE (°C)
POR2
CPOR = 0.1µF
2.0
VO1
1.5
1
1.0
0
0.5
V O2
0
0
1
2
3
4
5
TIME (s)
6
7
8
FIGURE 13. POWER-UP/POWER-DOWN
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7
9
10
0
0.5
1.0
1.5
2.0
2.5
3.0
TIME (s)
3.5
4.0
4.5
5.0
FIGURE 14. POWER-UP/POWER-DOWN WITH POR SIGNALS
FN7932.2
December 22, 2015
ISL78302A
Typical Performance Curves
(Continued)
VO = 3.3V
ILOAD = 300mA
VO2 (10mV/DIV)
VO1 (V)
CLOAD = 1µF
CBYP = 0.01µF
VIN = 5.0V
VO1 = 3.3V
VO2 = 2.8V
IL1 = 300mA
IL2 = 300mA
CL1, CL2 = 1µF
CBYP = 0.01µF
3
2
1
4.3V
3.6V
VEN (V)
0
5
10mV/DIV
0
0
100
200
300
400
500
600
700
800
900 1000
400µs/DIV
TIME (µs)
FIGURE 16. LINE TRANSIENT RESPONSE (3.3V OUTPUT)
FIGURE 15. TURN-ON/TURN-OFF RESPONSE
VO = 2.8V
ILOAD = 300mA
CLOAD = 1µF
CBYP = 0.01µF
VO (25mV/DIV)
4.2V
3.5V
VO = 1.8V
VIN = 2.8V
300mA
10mV/DIV
ILOAD
100µA
100µs/DIV
400µs/DIV
FIGURE 17. LINE TRANSIENT RESPONSE (2.8V OUTPUT)
FIGURE 18. LOAD TRANSIENT RESPONSE
100
1000
90
80
CBYP = 0.1µF
70
PSRR (dB)
SPECTRAL NOISE DENSITY (nV/Hz)
VIN = 3.6V
VO = 1.8V
IO = 10mA
CLOAD = 1µF
60
50
40
30
20
10
0
0.1
1k
10k
FREQUENCY (Hz)
100k
FIGURE 19. PSRR vs FREQUENCY
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1M
100
10
1
VIN = 3.6V
VO = 1.8V
ILOAD = 10mA
CBYP = 0.1µF
CIN = 1µF
CLOAD = 1µF
0.1
10
100
1k
10k
FREQUENCY (Hz)
100k
1M
FIGURE 20. SPECTRAL NOISE DENSITY vs FREQUENCY
FN7932.2
December 22, 2015
ISL78302A
Functional Description
The ISL78302A contains two high-performance LDOs. High
performance is achieved through a circuit that delivers fast
transient response to varying load conditions. In a quiescent
condition, the ISL78302A adjusts its biasing to achieve the
lowest standby current consumption.
The device also integrates current limit protection, smart thermal
shutdown protection, staged turn-on, and soft-start. Smart
thermal shutdown protects the device against overheating.
Staged turn-on and soft-start minimize start-up input current
surges without causing excessive device turn-on time.
Power Control
The ISL78302A has two separate enable pins (EN1 and EN2) to
individually control power to each of the LDO outputs. When both
EN1 and EN2 are low, the device is in shutdown mode. During
this condition, all on-chip circuits are off, and the device draws
minimum current, typically less than 0.3µA.
When one or both of the enable pins are asserted, the device first
polls the output of the UVLO detector to ensure that VIN voltage is
at least about 2.1V. Once verified, the device initiates a start-up
sequence. During the start-up sequence, trim settings are first
read and latched. Then, sequentially, the bandgap, reference
voltage, and current generation circuitry power up. Once the
references are stable, a fast-start circuit quickly charges the
external reference bypass capacitor (connected to the CBYP pin)
to the proper operating voltage. After the bypass capacitor has
been charged, the LDOs power up in their specified sequence.
Soft-start circuitry integrated into each LDO limits the initial
ramp-up rate to about 30µs/V to minimize current surge.
If EN1 is brought high, and EN2 goes high before the VO1 output
stabilizes, the ISL78302A delays the VO2 turn-on until the VO1
output reaches its target level.
If EN2 is brought high, and EN1 goes high before VO2 starts its
output ramp, then VO1 turns on first, and the ISL78302A delays
the VO2 turn-on until the VO1 output reaches its target level.
If EN2 is brought high, and EN1 goes high after VO2 starts its
output ramp, then the ISL78302A immediately starts to ramp up
the VO1 output.
If both EN1 and EN2 are brought high at the same time, the VO1
output has priority, and is always powered up first.
During operation, whenever the VIN voltage drops below about
1.8V, the ISL78302A immediately disables both LDO outputs.
When VIN rises back above 2.1V, the device re-initiates its
start-up sequence, and LDO operation resumes automatically.
Reference Generation
The reference generation circuitry includes a trimmed bandgap,
a trimmed voltage reference divider, a trimmed current reference
generator, and an RC noise filter. The filter includes the external
capacitor connected to the CBYP pin. A 0.01µF capacitor
connected to CBYP implements a 100Hz lowpass filter and is
recommended for most high-performance applications. For the
lowest noise application, a 0.1µF or greater CBYP capacitor
should be used. This filters the reference noise below the 10Hz to
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9
1kHz frequency band, which is crucial in many noise-sensitive
applications.
The bandgap generates a zero temperature coefficient (TC)
voltage for the reference divider. The reference divider provides
the regulation reference, POR detection thresholds, and other
voltage references required for current generation and
over-temperature detection.
The current generator provides the references required for
adaptive biasing as well as references for LDO output current
limit and thermal shutdown determination.
LDO Regulation and Programmable Output
Divider
The LDO regulator is implemented with a high-gain operational
amplifier driving a PMOS pass transistor. The design of the
ISL78302A provides a regulator that has low quiescent current,
fast transient response, and overall stability across all operating
and load current conditions. LDO stability is guaranteed for a 1µF
to 10µF output capacitor that has a tolerance better than 20%
and ESR less than 200mΩ. The design is performance-optimized
for a 1µF capacitor. Unless limited by the application, use of an
output capacitor value above 4.7µF is not normally needed as
LDO performance improvement is minimal.
Each LDO uses an independently trimmed 1V reference. An
internal resistor divider drops the LDO output voltage down to 1V.
This is compared to the 1V reference for regulation.
Power-On Reset Generation
Each LDO has a separate power-on reset (POR) signal generation
circuit that outputs to the respective POR pins. The POR signal is
generated as follows.
A POR comparator continuously monitors the output of each
LDO. The LDO enters a power-good state when the output voltage
is above 94% of the expected output voltage for a period
exceeding the LDO PGOOD entry delay time. In the power-good
state, the open-drain PORx output is in a high-impedance state.
An internal 100kΩ pull-up resistor pulls the pin up to the
respective LDO output voltage. An external resistor can be added
between the PORx output and the LDO output for a faster rise
time; however, the PORx output should not connect through an
external resistor to a supply greater than the associated LDO
voltage.
For the 1.5V regulated output option, it has been found that the
internal pull-ups on POR output does not always function correctly
above VIN = 6V. For this reason, it is recommended to use an
external 100k pull-up resistor for the POR pin that is associated
to the 1.5V output. For outputs higher than 1.5V, no external
resistor is required over the full input range from 2.3V to 6.5V.
The power-good state is exited when the LDO output falls below
90% of the expected output voltage for a period longer than the
PGOOD exit delay time. While power-good is false, the
ISL78302A pulls the respective POR pin low.
For LDO-1, the PGOOD entry delay time is fixed at about 2ms
while the PGOOD exit delay is about 25µs. For LDO-2, the PGOOD
entry and exit delays are determined by the value of the external
capacitor connected to the CPOR pin. For a 0.01µF capacitor, the
FN7932.2
December 22, 2015
ISL78302A
entry and exit delays are 200ms and 25µs, respectively. Larger
or smaller capacitor values yield proportionately longer or shorter
delay times. The POR exit delay should never be allowed to be
less than 10µs to ensure sufficient immunity against transient
induced false POR triggering.
Overheat Detection
The bandgap provides a proportional-to-temperature current that
is indicative of the temperature of the silicon. This current is
compared with references to determine if the device is in danger
of damage due to overheating. When the die temperature
reaches about +145°C, one or both of the LDOs momentarily
shuts down until the die cools sufficiently. In the overheat
condition, only the LDO sourcing more than 50mA is shut off.
This does not affect the operation of the other LDO. If both LDOs
source more than 50mA and an overheat condition occurs, both
LDO outputs are disabled. Once the die temperature falls back
below about +110°C, the disabled LDOs are re-enabled, and
soft-start automatically takes place.
The ISL78302A provides short-circuit protection by limiting the
output current to about 475mA. If short circuited, an output
current of 475mA will cause die heating. If the short circuit lasts
long enough, the overheat detection circuit will turn off the output.
Revision History
The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to web to make sure you
have the latest revision.
DATE
REVISION
CHANGE
December 22, 2015
FN7932.2
On page 4, updated Charged Device Model test method from “JESD22-C101C” to “AEC-Q100-011”.
Updated POD L10.3x3C to current version with changes as follows:
Removed package outline and included center to center distance between lands on recommended land
pattern.
Removed Note 4 “Dimension b applies to the metallized terminal and is measured between 0.18mm and
0.30mm from the terminal tip.” since it is not applicable to this package. Renumbered notes accordingly.
Tiebar Note 4 updated
From: Tiebar shown (if present) is a non-functional feature.
To: Tiebar shown (if present) is a non-functional feature and may be located on any of the 4 sides (or ends).
December 23, 2013
FN7932.1
Page 10
- 2nd line of the disclaimer changed from:
"Intersil products are manufactured, assembled and tested utilizing ISO9001 quality systems as noted"
to:
"Intersil Automotive Qualified products are manufactured, assembled and tested utilizing TS16949 quality
systems as noted"
May 21, 2012
FN7932.0
Initial Release
About Intersil
ntersil Corporation is a leading provider of innovative power management and precision analog solutions. The company's products
address some of the largest markets within the industrial and infrastructure, mobile computing and high-end consumer markets.
For the most updated datasheet, application notes, related documentation and related parts, please see the respective product
information page found at www.intersil.com.
You may report errors or suggestions for improving this datasheet by visiting www.intersil.com/ask.
Reliability reports are also available from our website at www.intersil.com/support.
For additional products, see www.intersil.com/en/products.html
Intersil Automotive Qualified products are manufactured, assembled and tested utilizing TS16949 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time
without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be
accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
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10
FN7932.2
December 22, 2015
ISL78302A
Package Outline Drawing
L10.3x3C
10 LEAD DUAL FLAT PACKAGE (DFN)
Rev 4, 3/15
3.00
5
PIN #1 INDEX AREA
A
B
10
5
PIN 1
INDEX AREA
1
2.38
3.00
0.50
2
10 x 0.25
6
(4X)
0.10 C B
1.64
TOP VIEW
10x 0.40
BOTTOM VIEW
(4X)
0.10 M C B
SEE DETAIL "X"
(10 x 0.60)
(10x 0.25)
0.90
MAX
0.10 C
BASE PLANE
2.38
0.20
C
SEATING PLANE
0.08 C
SIDE VIEW
(8x 0.50)
1.64
2.80 TYP
C
TYPICAL RECOMMENDED LAND PATTERN
0.20 REF
4
0.05
DETAIL "X"
NOTES:
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11
1.
Dimensions are in millimeters.
Dimensions in ( ) for Reference Only.
2.
Dimensioning and tolerancing conform to AMSE Y14.5m-1994.
3.
Unless otherwise specified, tolerance : Decimal ± 0.05
4.
Tiebar shown (if present) is a non-functional feature and may be
located on any of the 4 sides (or ends).
5.
The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 identifier may be
either a mold or mark feature.
6.
Compliant to JEDEC MO-229-WEED-3 except for E-PAD
dimensions.
FN7932.2
December 22, 2015
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