INTERSIL ISL78310

High Performance 1A LDO
ISL78310
Features
The ISL78310 is a low dropout voltage, high-current, single
output LDO specified for 1A output current. This part operates
from input voltages down to 2.2V and up to 6V. The part offers
fixed and external resistor adjustable output voltages from 0.8V
to 5V. Custom voltage options are available upon request.
• 2.2V to 6V Input Supply
For applications that desire to set the in-rush current to less than
the current limit of the part, or for applications that require
turn-on time control, an external capacitor can be placed on the
soft-start pin for maximum control. A supply-independent
ENABLE signal allows the part to be placed into a low quiescent
current shutdown mode. Sub-micron CMOS process is used for
this product family to deliver best-in-class analog performance
and overall value.
• Adjustable In-Rush Current Limiting
• 130mV Dropout Voltage Typical (at 1A)
• Fast Load Transient Response
• ±0.2% Initial VOUT Accuracy
• 58dB Typical PSRR
• 63µVRMS Output Noise at VOUT = 1.8V
• Power-Good Feature
• 500mV Feedback Voltage
• Supply-Independent 1V Enable Input Threshold
• Short-Circuit Current Protection
This CMOS LDO consumes significant lower quiescent (ground
pin) current as a function of load over bipolar LDOs, which
translates into higher efficiency and packages with smaller
footprints. Quiescent current is optimized to achieve a very fast
load transient response.
• 1A Peak Reverse Current
• Over-Temperature Shutdown
• Any Cap Stable with Minimum 10µF Ceramic
• ±1.8% Guaranteed VOUT Accuracy for Junction Temperature
Range from -40°C to +125°C
The ISL78310 is both AEC-Q100 rated and fully TS16949
compliant. The ISL78310 is rated for the automotive
temperature range (-40°C to +125°C).
• Available in a 10 Lead DFN Package
• Pb-Free (RoHS Compliant)
Applications
• AEC-Q100 Tested
• Core & I/O Power
• TS16949 Compliant
• Camera Modules
• Post Regulation of Switched Supplies
• Radio Systems
• Infotainment Systems
Pin Configuration
ISL78310
(10 LD 3x3 DFN)
TOP VIEW
February 17, 2011
FN7810.0
1
VOUT
1
10 VIN
VOUT
2
9 VIN
SENSE/ADJ
3
PG
4
7 ENABLE
GND
5
6 SS
PAD
8 NC
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas Inc. 2011. 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.
ISL78310
Pin Descriptions
PIN
NUMBER
PIN NAME
1, 2
VOUT
3
SENSE/ADJ
For internally fixed VOUT option, this pin provides output voltage feedback. By connecting this pin to the output rail
at the load, small voltage drops caused by PCB trace resistance can be eliminated.
For the adjustable output voltage option, this pin is connected to the feedback resistor divider and provides voltage
feedback signals for the LDO to set the outpt voltage.
4
PG
This is an open drain logic output used to indicate the status of the output voltage. Logic low indicates VOUT is not
in regulation. Must be grounded if not used.
5
GND
6
SS
7
ENABLE
8
NC
Do not connect this pin to ground or supply. Leave floating.
9, 10
VIN
Input supply pin. A minimum 10µF X5R/X7R input capacitor is required for stability. See “External Capacitor
Requirements” on page 9 for more details.
DESCRIPTION
Regulated output voltage. A minimum 10µF X5R/X7R output capacitor is required for stability. See “External
Capacitor Requirements” on page 9 for more details.
Ground.
External capacitor on this pin adjusts startup ramp and controls in-rush current.
VIN independent chip enable. TTL and CMOS compatible.
EPAD
EPAD at ground potential. Soldering it directly to GND plane is required for thermal considerations. See “Heatsinking
the DFN Package” on page 11 for more details.
Ordering Information
PART NUMBER
(Notes 1, 3, 4)
PART MARKING
VOUT VOLTAGE
(Note 2)
TEMP RANGE (°C)
PACKAGE
(Pb-Free)
PKG DWG. #
ISL78310ARAJZ
DZAE
ADJ
-40 to +125
10 Ld 3x3 DFN
L10.3x3
ISL78310ARAJZ-TR5303
DZAE
ADJ
-40 to +125
10 Ld 3x3 DFN
L10.3x3
NOTES:
1. Add “-T*” suffix for tape and reel. Please refer to TB347 for details on reel specifications.
2. For other output voltages, contact Intersil Marketing.
3. 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.
4. For Moisture Sensitivity Level (MSL), please see device information page for ISL78310. For more information on MSL please see techbrief TB363.
2
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ISL78310
Typical Application Diagrams
9
2.5V ± 10%
10µF
10
V OUT
VIN
V OUT
VIN
SENSE/ADJ
1
2
3
1.8V ± 1.8%
10µF
100k
10k
ISL78310
7
6
ENABLE
PG
4
SS
(NOTE 5)
GND
5
FIGURE 1. FIXED TYPICAL APPLICATION DIAGRAM
9
2.5V ± 10%
10µF
10
VIN
VIN
VOUT
ISL78310
VOUT
1
2
1.8V ± 1.8%
10µF
2.6k
10k
100k
SENSE/ADJ
1k
7
6
ENABLE
PG
4
SS
GND
(NOTE 5)
5
FIGURE 2. ADJUSTABLE TYPICAL APPLICATION DIAGRAM
NOTE:
5. Used when large bulk capacitance required on VOUT for application.
3
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February 17, 2011
ISL78310
ISL78310 Schematic Block Diagram
VIN
VOUT
4
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February 17, 2011
ISL78310
Absolute Maximum Ratings
Thermal Information
VIN relative to GND (Note 6) . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6.5V
VOUT relative to GND (Note 6). . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6.5V
PG, ENABLE, SENSE/ADJ, SS
Relative to GND (Note 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +6.5V
Thermal Resistance . . . . . . . . . . . . . . . . . . . . θJA (°C/W) θJC (°C/W)
10 Ld DFN Package (Notes 7, 8) . . . . . . . .
48
7
Storage Temperature Range. . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+150°C
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions (Notes 9, 10)
Junction Temperature Range (TJ) (Note 9) . . . . . . . . . . . .-40°C to +125°C
VIN relative to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2.2V to 6V
VOUT range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800mV to 5V
PG, ENABLE, SENSE/ADJ, SS relative to GND . . . . . . . . . . . . . . . 0V to +6V
PG Sink Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <10mA
ESD Rating
Human Body Model (Tested per JESD22-A114E) . . . . . . . . . . . . . . . . 2500V
Machine Model (Tested per JESD-A115-A) . . . . . . . . . . . . . . . . . . . . . 250V
Charge Device Model (Tested per JESD22-C101C). . . . . . . . . . . . . . 1000V
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:
6. Absolute maximum voltage rating is defined as the voltage applied for a lifetime average duty cycle above 6V of 1%.
7. θJA 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.
8. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside.
9. Extended operation at these conditions may compromise reliability. Exceeding these limits will result in damage. Recommended operating conditions
define limits where specifications are guaranteed.
10. Electromigration specification defined as lifetime average junction temperature of +110°C where max rated DC current = lifetime average current.
Electrical Specifications
Unless otherwise noted, VIN = VOUT + 0.4V, VOUT = 1.8V, CIN = COUT = 10µF, TJ = +25°C, ILOAD = 0A.
Applications must follow thermal guidelines of the package to determine worst case junction temperature. Please refer to “ISL78310 Schematic
Block Diagram” on page 4 and Tech Brief TB379. Boldface limits apply over the operating temperature range, -40°C to +125°C.
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
(Note 11)
TYP
MAX
(Note 11)
UNITS
-1.8
0.2
1.8
%
-1.8
0.2
1.8
%
491
500
509
mV
1
%
DC CHARACTERISTICS
DC Output Voltage Accuracy
VOUT
VOUT Options: 0.8V, 1.2V, 1.5V and 1.8V
2.2V ≤ VIN < 3.6V; 0A < ILOAD ≤ 1A
VOUT Options: 2.5V, 3.3V and 5.0V
VOUT + 0.4V ≤ VIN ≤ 6V; 0A < ILOAD < 1A
Feedback Pin (ADJ Option Only)
VADJ
2.2V ≤VIN ≤ 6V, 0A < ILOAD < 1A
DC Input Line Regulation
ΔVOUT/
ΔVIN
VOUT + 0.5V < VIN < 5V
DC Output Load Regulation
ΔVOUT/
ΔIOUT
0A < ILOAD < 1A, All voltage options
Feedback Input Current
VADJ = 0.5V
Ground Pin Current
IQ
-1
%
0.01
1
µA
ILOAD = 0A, 2.2V < VIN < 6V
3
5
mA
ILOAD = 1A, 2.2V < VIN < 6V
5
7
mA
ENABLE Pin = 0V, VIN = 6V
0.2
12
µA
Dropout Voltage (Note 12)
VDO
ILOAD = 1A, VOUT = 2.5V
130
212
mV
Output Short Circuit Current
OCP
VOUT = 0V, 2.2V < VIN < 6V
1.75
A
Thermal Shutdown Temperature
TSD
2.2V < VIN < 6V
160
°C
Thermal Shutdown Hysteresis
(Rising Threshold)
TSDn
2.2V < VIN < 6V
30
°C
PSRR
f = 1kHz, ILOAD = 1A; VIN = 2.2V
58
dB
Ground Pin Current in Shutdown
ISHDN
AC CHARACTERISTICS
Input Supply Ripple Rejection
Output Noise Voltage
5
f = 120Hz, ILOAD = 1A; VIN = 2.2V
72
dB
ILOAD = 1A, BW = 10Hz < f < 100kHz
63
µVRMS
FN7810.0
February 17, 2011
ISL78310
Electrical Specifications
Unless otherwise noted, VIN = VOUT + 0.4V, VOUT = 1.8V, CIN = COUT = 10µF, TJ = +25°C, ILOAD = 0A.
Applications must follow thermal guidelines of the package to determine worst case junction temperature. Please refer to “ISL78310 Schematic
Block Diagram” on page 4 and Tech Brief TB379. Boldface limits apply over the operating temperature range, -40°C to +125°C. (Continued)
PARAMETER
SYMBOL
TEST CONDITIONS
MIN
(Note 11)
TYP
MAX
(Note 11)
UNITS
ENABLE PIN CHARACTERISTICS
Turn-on Threshold
2.2V < VIN < 6V
0.3
0.8
1
V
Hysteresis (Rising Threshold)
2.2V < VOUT + 0.4V < 6V
10
80
200
mV
Enable Pin Turn-on Delay
COUT = 10µF, ILOAD = 1A
Enable Pin Leakage Current
VIN = 6V, EN = 3V
100
µs
1
µA
ADJUSTABLE INRUSH CURRENT LIMIT CHARACTERISTICS
Current limit adjust
IPD
VIN = 3.5V, EN = 0V, SS = 1V
ICHG
0.5
1
1.3
mA
-3.3
-2
-0.8
µA
75
85
92
%VOUT
PG PIN CHARACTERISTICS
VOUT PG Flag Threshold
VOUT PG Flag Hysteresis
4
PG Flag Low Voltage
VIN = 2.5V, ISINK = 500µA
PG Flag Leakage Current
VIN = 6V, PG = 6V
%
100
mV
1
µA
NOTES:
11. Compliance to datasheet limits is assured by one or more methods: production test, characterization and/or design.
12. Dropout is defined by the difference in supply VIN and VOUT when the supply produces a 2% drop in VOUT from its nominal value.
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ISL78310
Typical Operating Performance
Unless otherwise noted: VIN = 2.2V, VOUT = 1.8V, CIN = COUT = 10µF, TJ = +25°C, IL = 0A.
1.8
2.0
1.8
1.6
1.4
0.6
1.2
0
+125°C
1.0
VOUT (V)
ΔVOUT (%)
1.2
-0.6
-1.2
0.8
-40°C
+25°C
0.6
0.4
0.2
-1.8
-50
-25
0
25
50
75
100
125
0
150
0
1
3
2
4
SUPPLY VOLTAGE (V)
JUNCTION TEMPERATURE (°C)
FIGURE 3. VOUT vs TEMPERATURE
5
0.6
GROUND CURRENT (mA)
ΔVOUT (%)
1.2
+25°C
0
-0.6
-40°C
+125°C
-1.2
0
0.25
0.50
0.75
4
3
2
1
0
1.00
2
4
3
FIGURE 5. VOUT vs LOAD CURRENT
200
180
DROPOUT VOLTAGE (mV)
+125°C
3.00
2.75
+25°C
-40°C
2.50
2.25
2.00
1.75
1.50
0
6
FIGURE 6. GROUND CURRENT vs SUPPLY VOLTAGE
3.50
3.25
5
INPUT VOLTAGE (V)
LOAD CURRENT (A)
GROUND CURRENT (mA)
6
FIGURE 4. VOUT vs SUPPLY VOLTAGE
1.8
-1.8
5
VOUT = 2.5V
ILOAD = 1A
160
140
120
ILOAD = 500mA
100
80
ILOAD = 100mA
60
40
20
0.25
0.50
0.75
LOAD CURRENT (A)
FIGURE 7. GROUND CURRENT vs LOAD CURRENT
7
1.00
0
-40 -25 -10
5
20
35
50
65
80
95 110 125
TEMPERATURE (°C)
FIGURE 8. DROPOUT VOLTAGE vs TEMPERATURE
FN7810.0
February 17, 2011
ISL78310
Typical Operating Performance
Unless otherwise noted: VIN = 2.2V, VOUT = 1.8V, CIN = COUT = 10µF, TJ = +25°C, IL = 0A. (Continued)
ENABLE
(2V/DIV)
VOLTAGE RAILS AT 50mV/DIV
VOUT (1V/DIV)
VIN = 3.7V, VOUT = 3.3V, COUT = 10µF, CPB = 100pF
SS (1V/DIV)
VIN = 2.9V, VOUT = 2.5V, COUT = 10µF, CPB = 82pF
(500µs/DIV)
PG (1V/DIV)
VIN = 2.5V, VOUT = 1.8V, COUT = 10µF, CPB = 82pF
FIGURE 10. ENABLE START-UP
VIN = 2.5V, VOUT = 1.5V, COUT = 22µF, CPB = 150pF
90
80
VIN = 2.5V, VOUT = 1.2V, COUT = 47µF, CPB = 270pF
500mA
70
1A
PSRR (dB)
60
VIN = 2.5V, VOUT = 1.0V, COUT = 47µF, CPB = 220pF
1A
di/dt = 4A/µs
20µs/DIV
0mA
100mA
40
30
20
FIGURE 9. LOAD TRANSIENT RESPONSE
10
VIN = 2.5V, VOUT = 1.8V, COUT = 10µF, CPB = 82pF
0
100
1k
10k
100k
1M
FREQUENCY (Hz)
FIGURE 11. PSRR vs FREQUENCY
10
SPECTRAL NOISE DENSITY (µV/√Hz)
1mA
50
1
0.1
0.01
ILOAD = 1A
0.001
10
100
1k
10k
100k
1M
10M
FREQUENCY (Hz)
FIGURE 12. SPECTRAL NOISE DENSITY vs FREQUENCY
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ISL78310
Applications Information
This zero increases the crossover frequency of the LDO and
provides additional phase resulting in faster load transient
response.
Input Voltage Requirements
ISL78310 is capable of delivering output voltages from 0.8V to
5.0V. Due to the nature of an LDO, VIN must be some margin
higher than the output voltage plus dropout at the maximum
rated current of the application if active filtering (PSRR) is
expected from VIN to VOUT. The generous dropout specification of
this family of LDOs allows applications to design for a level of
efficiency that can accommodate profiles smaller than the
TO220/263.
VIN
VOUT
PG
EN
ISL78310
CPB
RTOP
ADJ
CIN
COUT
RBOTTOM
SS
External Capacitor Requirements
GENERAL GUIDELINE
External capacitors are required for proper operation. Careful
attention must be paid to layout guidelines and selection of
capacitor type and value to ensure optimal performance.
OUTPUT CAPACITOR
The ISL78310 applies state-of-the-art internal compensation to
keep the selection of the output capacitor simple for the
customer. Stable operation over full temperation, VIN range, VOUT
range and load extremes are guaranteed for all capacitor types
and values assuming a minimum of 10µF X5R/X7R is used for
local bypass on VOUT. This output capacitor must be connected to
the VOUT and GND pins of the LDO with PCB traces no longer than
0.5cm. Additional capacitors of any value in ceramic, POSCAP,
alum/tantalum electrolytic types may be placed in parallel to
improve PSRR at higher frequencies and/or load transient AC
output voltage tolerances.
INPUT CAPACITOR
For proper operation, a minimum capacitance of 10µF X5R/X7R
is required at the input. This ceramic input capacitor must be
connected to VIN and GND pins of the LDO with PCB traces no
longer than 0.5cm.
FIGURE 13.
It is also important to note that the LDO stability and load transient
are affected by the type of output capacitor used. For optimal
result, empirical tuning of CPB is suggested for each specific
application. It is recommended to not use CPB when high ESR
capacitors such as Aluminum Electrolytic or Tantalum are used.
Table 1 shows the recommended CPB, RTOP, RBOTTOM and CPB
values for different output voltage rails.
TABLE 1.
VOUT
(V)
RTOP
(kΩ)
RBOTTOM
(Ω)
CPB
(pF)
COUT
(µF)
5.0
2.61
287
100
10
3.3
2.61
464
100
10
2.5
2.61
649
82
10
1.8
2.61
1.0k
82
10
1.5*
2.61
1.3k
68
10
Phase Boost Capacitor (CPB)
1.5
2.61
1.3k
150
22
A small phase boost capacitor, CPB, can be placed across the top
resistor in the feedback resistor divider network (Figure 13
below) in order to place a zero at:
1.2*
2.61
1.87k
120
22
1.2*
2.61
1.87k
270
47
1.0
2.61
2.61k
220
47
0.8
2.61
4.32k
220
47
F Z = 1 ⁄ ( 2 • pi • R TOP • C PB )
(EQ. 1)
*Either option could be used, depending on cost/performance
requirements.
Thermal Fault Protection
In the event the die temperature exceeds typically +160°C, then
the output of the LDO shuts down until the die temperature cools
down to typically +130°C. The level of power, combined with the
thermal resistance of the package (+48°C/W for DFN),
determines whether the junction temperature exceeds the
thermal shutdown temperature specified in the “Electrical
Specifications” table on page 5 (see thermal packaging
guidelines).
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ISL78310
Current Limit Protection
The ISL78310 LDO incorporates protection against overcurrent
due to any short or overload condition applied to the output pin.
The current limit circuit performs as a constant current source
when the output current exceeds the current limit threshold
noted in the “Electrical Specifications” table on page 5. If the
short or overload condition is removed from VOUT, then the
output returns to normal voltage mode regulation. In the event of
an overload condition on the DFN package, the LDO will begin to
cycle on and off due to the die temperature exceeding thermal
fault condition.
Functional Description
Enable Operation
The Enable turn-on threshold is typically 0.8V with a hysteresis of
80mV. The Enable pin does not have an internal pull-up or
pull-down resistor. As a result, this pin must not be left floating.
This pin must be tied to VIN if it is not used. A pull-up resistor
(typically 1kΩ to 10kΩ) will be required for applications that use
open collector or open drain outputs to control the Enable pin.
FIGURE 14. IN-RUSH CURRENT WITH NO CSS,
COUT = 1000µF, IN-RUSH CURRENT = 1.8A
The Enable pin may be connected directly to VIN for applications
that are always on.
Soft-Start Operation
The soft-start circuit controls the rate at which the output voltage
rises up to regulation at power-up or LDO enable. This start-up
ramp time can be set by adding an external capacitor from the
SS pin to GND. An internal 2µA current source charges up this
CSS and the feedback reference voltage is clamped to the
voltage across it. The startup time of the regulator output voltage
for a given CSS value can be calculated using Equation 2.
C SS x0.5V
t RAMP = ------------------------2μA
(EQ. 2)
The soft-start function also effectively limits the amount of inrush current to less than the programmed current limit during
start-up or an enable sequence, to avoid an over current fault
condition. This can be an issue for applications that require large,
external bulk capacitances on VOUT where high levels of charging
current can be seen for a significant period of time. High in-rush
currents can cause VIN to drop below minimum, which could
cause VOUT to shutdown.
FIGURE 15. IN-RUSH CURRENT WITH CSS = 15nF, COUT = 1000µF,
IN-RUSH CURRENT = 0.5A
FIGURE 16. IN-RUSH CURRENT WITH CSS = 33nF, COUT = 1000µF, IN-RUSH CURRENT = 0.2A
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ISL78310
Equation 3 can be used to calculate CSS for a desired in-rush
current, where VOUT is the output voltage, COUT is the total
capacitance on the output, and IINRUSH is the desired in-rush
current.
( V OUT xC OUT x2μA )
C SS = -------------------------------------------------I INRUSH x0.5V
(EQ. 3)
Heatsinking the DFN Package
The DFN package uses the copper area on the PCB as a heat-sink.
The EPAD of this package must be soldered to the copper plane
(GND plane) for heat sinking. Figure 17 shows a curve for the θJA of
the DFN package for different copper area sizes.
46
The scopes in Figure 14 to 33 capture the response for the softstart function. The output voltage is set to 1.8V.
Power-Good Operation
The PGOOD is a logic output that indicates the status of VOUT.
The PGOOD flag is an open-drain NMOS that can sink 10mA
during a fault condition. The PGOOD pin requires an external pullup resistor, which is typically connected to the VOUT pin. The
PGOOD pin should not be pulled up to a voltage source greater
than VIN. PGOOD goes low when the output voltage drops below
84% of the nominal output voltage or if the part is disabled. The
PGOOD comparator fuctions during current limit and thermal
shutdown. For applications not using this feature, connect this
pin to ground.
Output Voltage Selection
An external resistor divider is used to scale the output voltage
relative to the internal reference voltage. This voltage is then fed
back to the error amplifier. The output voltage can be
programmed to any level between 0.8V and 5V. An external
resistor divider, R1 and R2, is used to set the output voltage as
shown in Equation 4. The recommended value for R2 is 500Ω to
1kΩ. R1 is then chosen according to Equation 5.
⎛ R1
⎞
V OUT = 0.5V × ⎜ ------- + 1⎟
⎝ R2
⎠
(EQ. 4)
V OUT
R 1 = R 2 × ⎛ ------------- – 1⎞
⎝ 0.5V
⎠
(EQ. 5)
42
θJA (°C/W)
The external capacitor is always discharged to ground at the
beginning of start-up or enabling.
44
40
38
36
34
2
4
6
8
10
12
14
16
18
20
22
24
EPAD-MOUNT COPPER LAND AREA ON PCB, mm2
FIGURE 17. 3mmx3mm 10 LD DFN ON 4-LAYER PCB WITH
THERMAL VIAS θJA vs EPAD-MOUNT COPPER LAND
AREA ON PCB
General PowerPAD Design
Considerations
Figure 18 shows the recommended use of vias on the thermal
pad to remove heat from the IC. This typical array populates the
thermal pad footprint with vias spaced three times the radius
distance from the center of each via. Small via size is advisable,
but not to the extent that solder reflow becomes difficult.
All vias should be connected to the pad potential, with low
thermal resistance for efficient heat transfer. Complete
connection of the plated-through hole to each plane is important.
It is not recommended to use “thermal relief” patterns to connect
the vias.
Power Dissipation
The junction temperature must not exceed the range specified in
the “Recommended Operating Conditions” on page 5. The power
dissipation can be calculated by using Equation 6:
P D = ( V IN – V OUT ) × I OUT + V IN × I GND
(EQ. 6)
The maximum allowed junction temperature, TJ(MAX), and the
maximum expected ambient temperature, TA(MAX), will
determine the maximum allowable power dissipation, as shown
in Equation 7:
(EQ. 7)
P D ( MAX ) = ( T J ( MAX ) – T A ) ⁄ θ JA
θJA is the junction-to-ambient thermal resistance.
FIGURE 18. PCB VIA PATTERN
For safe operation, ensure that the power disspiation PD,
calculated from Equation 6, is less than the maximum allowable
power dissipation PD(MAX).
11
FN7810.0
February 17, 2011
ISL78310
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 Rev.
DATE
REVISION
2/17/11
FN7810.0
CHANGE
Initial Release.
Products
Intersil Corporation is a leader in the design and manufacture of high-performance analog semiconductors. The Company's products
address some of the industry's fastest growing markets, such as, flat panel displays, cell phones, handheld products, and notebooks.
Intersil's product families address power management and analog signal processing functions. Go to www.intersil.com/products for a
complete list of Intersil product families.
*For a complete listing of Applications, Related Documentation and Related Parts, please see the respective device information page
on intersil.com: ISL78310
To report errors or suggestions for this datasheet, please go to: www.intersil.com/askourstaff
FITs are available from our website at: http://rel.intersil.com/reports/sear
For additional products, see www.intersil.com/product_tree
Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted
in the quality certifications found at www.intersil.com/design/quality
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
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For information regarding Intersil Corporation and its products, see www.intersil.com
12
FN7810.0
February 17, 2011
ISL78310
Package Outline Drawing
L10.3x3
10 LEAD DUAL FLAT PACKAGE (DFN)
Rev 6, 09/09
3.00
6
PIN #1 INDEX AREA
A
B
1
6
PIN 1
INDEX AREA
(4X)
3.00
2.00
8x 0.50
2
10 x 0.23
4
0.10
1.60
TOP VIEW
10x 0.35
BOTTOM VIEW
4
(4X)
0.10 M C A B
0.415
PACKAGE
OUTLINE
0.200
0.23
0.35
(10 x 0.55)
SEE DETAIL "X"
(10x 0.23)
1.00
MAX
0.10 C
BASE PLANE
2.00
0.20
C
SEATING PLANE
0.08 C
SIDE VIEW
(8x 0.50)
C
0.20 REF
5
1.60
0.05
TYPICAL RECOMMENDED LAND PATTERN
DETAIL "X"
NOTES:
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.
Lead width applies to the metallized terminal and is measured
between 0.18mm and 0.30mm from the terminal tip.
5.
Tiebar shown (if present) is a non-functional feature.
6.
The configuration of the pin #1 identifier is optional, but must be
located within the zone indicated. The pin #1 indentifier may be
either a mold or mark feature.
13
FN7810.0
February 17, 2011