DATASHEET

DUCT
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ISL9751
1% Output Accuracy 600kHz/1.2MHz PWM Step-Up
Regulator
ISL97519
Features
The ISL97519 is a high frequency, high efficiency step-up
voltage regulator operated at constant frequency PWM mode.
With an internal 2.0A, 200m MOSFET, it can deliver up to 1A
output current at over 90% efficiency. The selectable 600kHz
and 1.2MHz allows smaller inductors and faster transient
response. An external compensation pin gives the user greater
flexibility in setting frequency compensation allowing the use
of low ESR ceramic output capacitors.
• 1% Output Accuracy
When shut down, it draws <1µA of current and can operate
down to 2.3V input supply. These features, along with 1.2MHz
switching frequency, make it an ideal device for portable
equipment and TFT-LCD displays.
• Adjustable Soft-Start
The ISL97519 is available in an 8 Ld MSOP package with a
maximum height of 1.1mm. The device is specified for
operation over the full -40°C to +105°C temperature range.
Pin Configuration
• >90% Efficiency
• 2.0A, 200m Power MOSFET
• 2.3V to 5.5V Input
• 1.1*VIN to 25V Output
• 600kHz/1.2MHz Switching Frequency Selection
• Internal Thermal Protection
• 1.1mm Max Height 8 Ld MSOP Package
• Pb-Free (RoHS compliant)
• Halogen Free
Applications
• TFT-LCD displays
ISL97519
(8 LD MSOP)
TOP VIEW
• DSL modems
• PCMCIA cards
• Digital cameras
COMP 1
8 SS
• GSM/CDMA phones
FB 2
7 FSEL
• Portable equipment
EN 3
6 VDD
• Handheld devices
GND 4
5 LX
Ordering Information
PART
NUMBER
(Notes 2, 3)
PART
MARKING
PACKAGE
(Pb-free)
PKG.
DWG. #
ISL97519IUZ
7519Z
8 Ld MSOP
M8.118A
ISL97519IUZ-T
7519Z
8 Ld MSOP
M8.118A
ISL97519IUZ-TK
7519Z
8 Ld MSOP
M8.118A
NOTES:
1. Please refer to TB347 for details on reel specifications.
2. These Intersil Pb-free plastic packaged products employ special Pbfree 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 Pbfree requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), please see device information
page for ISL97519. For more information on MSL please see
techbrief TB363.
February 16, 2012
FN6454.4
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 2007-2009, 2012. 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.
ISL97519
Absolute Maximum Ratings (TA = +25°C)
Thermal Information
LX to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27V
VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6.5V
COMP, FB, EN, SS, FSEL to GND . . . . . . . . . . . . . . . . . .-0.3V to (VDD + 0.3V)
Thermal Resistance (Typical, Note 4)
JA (°C/W)
8 Lead MSOP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
160
Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C
Operating Ambient Temperature . . . . . . . . . . . . . . . . . . . .-40°C to +105°C
Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . .+135°C
Power Dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Curves
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
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.
NOTE:
4. JA is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
IMPORTANT NOTE: All parameters having Min/Max specifications are guaranteed. Typical values are for information purposes only. Unless otherwise
noted, all tests are at the specified temperature and are pulsed tests, therefore: TJ = TC = TA
Electrical Specifications
VIN = 3.3V, VOUT = 12V, IOUT = 0mA, FSEL = GND, TA = -40°C to +105°C Unless Otherwise Specified.
Boldface limits apply over the operating temperature range, -40°C to +105°C.
PARAMETER
DESCRIPTION
CONDITIONS
MIN
(Note 5)
TYP
MAX
(Note 5)
UNIT
1
5
µA
IQ1
Quiescent Current - Shutdown
EN = 0V
IQ2
Quiescent Current - Not Switching
EN = VDD, FB = 1.3V
0.7
IQ3
Quiescent Current - Switching
EN = VDD, FB = 1.0V
3
4
mA
VFB
Feedback Voltage
TA = -40°C to +85°C
1.281
1.294
1.307
V
TA = -40°C to +105°C
1.276
1.294
1.307
V
0.5
µA
5.5
V
0.01
mA
IB-FB
Feedback Input Bias Current
VDD
Input Voltage Range
DMAX - 600kHz
Maximum Duty Cycle
FSEL = 0V
85
92
%
DMAX - 1.2MHz
Maximum Duty Cycle
FSEL = VDD
85
90
%
2.3
ILIM
Current Limit - Max Peak Input Current
IEN
Shutdown Input Bias Current
EN = 0V
0.01
rDS(ON)
Switch ON-Resistance
VDD = 2.7V, ILX = 1A
0.2
ILX-LEAK
Switch Leakage Current
VSW = 27V
0.01
VOUT/VIN
Line Regulation
3V < VIN < 5.5V, VOUT = 12V
0.2
%
VOUT/IOUT
Load Regulation
VIN = 3.3V, VOUT = 12V, IO = 30mA to 200mA
0.3
%
fOSC1
Switching Frequency Accuracy
FSEL = 0V
500
620
740
kHz
fOSC2
Switching Frequency Accuracy
FSEL = VDD
1000
1250
1500
kHz
VIL
EN, FSEL Input Low Level
VIH
EN, FSEL Input High Level
GM
Error Amp Tranconductance
VDD-ON
VDD UVLO On Threshold
HYS
VDD UVLO Hysteresis
ISS
Soft-Start Charge Current
OTP
Over-Temperature Protection
1.5
2.0
A
0.5

3
0.5
1.5
I = 5µA
µA
µA
V
V
70
130
150
1µ/
2.1
2.2
2.3
V
100
4
6
150
mV
8
µA
°C
NOTE:
5. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified. Temperature limits established by characterization
and are not production tested.
2
FN6454.4
February 16, 2012
ISL97519
Block Diagram
EN
FSEL
REFERENCE
GENERATOR
VDD
OSCILLATOR
SS
SHUTDOWN
AND START-UP
CONTROL
LX
PWM LOGIC
CONTROLLER
FET
DRIVER
COMPARATOR
CURRENT
SENSE
GND
FB
GM
AMPLIFIER
COMP
Pin Descriptions
PIN NUMBER
PIN NAME
DESCRIPTION
1
COMP
2
FB
Voltage feedback pin. Internal reference is 1.294V nominal. Connect a resistor divider from VOUT.
VOUT = 1.294V (1 + R1/R2). See “Typical Application Circuit”.
3
EN
Shut-down control pin. Pull EN low to turn off the device.
4
GND
5
LX
6
VDD
Analog power supply input pin.
7
FSEL
Frequency select pin. When FSEL is set low, switching frequency is set to 620kHz. When connected to high or
VDD, switching frequency is set to 1.25MHz.
8
SS
Compensation pin. Output of the internal error amplifier. Capacitor and resistor from COMP pin to ground.
Analog and power ground.
Power switch pin. Connected to the drain of the internal power MOSFET.
Soft-start control pin. Connect a capacitor to control the converter start-up.
Typical Application Circuit
R3
3.9k
C5
4.7nF
1 COMP
R1
85.2k
R2
10k
2 FB
FSEL 7
3 EN
VDD 6
4 GND
S1
3
SS 8
LX 5
C3
27nF
+ C1
0.1µF 22µF
2.3V TO 5.5V
C4
10µH
D1
+ C2
22µF
12V
FN6454.4
February 16, 2012
ISL97519
95
92
90
90
VIN = 3.3V, VO = 9V,
fs = 620kHz
88
85
EFFICIENCY (%)
EFFICIENCY (%)
Typical Performance Curves
VIN = 5V, VO = 12V, fs = 1.25MHz
80
VIN = 5V, VO = 12V, fs = 620kHz
75
VIN = 5V, VO = 9V, fs = 620kHz
70
86
84
82
VIN = 3.3V, VO = 12V,
fs = 620kHz
VIN = 3.3V, VO = 12V,
80
78
65
VIN = 5V, VO = 9V, fs = 1.25MHz
200
400
600
800
VIN = 3.3V, VO = 9V,
fs = 1.25MHz
76
60
0
fs = 1.25MHz
74
1000
0
100
FIGURE 1. BOOST EFFICIENCY vs IOUT
300
0.7
0.8
VIN = 5V, VO = 12V,
VIN = 5V, VO = 9V,
fs = 1.25MHz
fs = 1.25MHz
VIN = 5V, VO = 9V,
0.5
fs = 620kHz
LOAD REGULATION (%)
0.6
0.4
0.3
0.2
400
VIN = 3.3, VO = 9V,
fs = 1.25MHz
0.4
0.3
0.2
VIN = 3.3, VO = 12V,
fs = 620kHz
0
0
200
0.5
0.1
VIN = 5V, VO = 12V,
fs = 620kHz
0
500
VIN = 3.3V, VO = 9V,
fs = 1.25MHz
VIN = 3.3V, VO = 12V,
fs = 1.25MHz
0.6
0.7
0.1
400
FIGURE 2. BOOST EFFICIENCY vs IOUT
0.9
LOAD REGULATION (%)
200
IOUT (mA)
IOUT (mA)
600
800
1000
0
100
200
300
400
500
IOUT (mA)
IOUT (mA)
FIGURE 4. LOAD REGULATION vs IOUT
FIGURE 3. LOAD REGULATION vs IOUT
0.6
VO = 12V
LINE REGULATION (%)
0.5
IO = 50mA TO 300mA
VO = 9V, IO = 100mA
0.4
fs = 620kHz
VO = 9V, IO = 80mA
fs = 1.25MHz
0.3
VIN = 3.3V
VO = 12V, IO = 80mA
fs = 600kHz
fs = 1.25MHz
0.2
0.1
0
-0.1
VO = 12V, IO = 80mA
fs = 620kHz
2
3
4
5
6
VIN (V)
FIGURE 5. LINE REGULATION vs VIN
4
FIGURE 6. TRANSIENT RESPONSE
FN6454.4
February 16, 2012
ISL97519
Typical Performance Curves
(Continued)
IO = 50mA TO 300mA
1.0
VO = 12V
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
VIN = 3.3V
POWER DISSIPATION (W)
0.9
fs = 1.2MHz
870mW
0.8
0.7

JA
=
0.6
0.5
0.4
M
SO
+1 P8
60
°C
/W
0.3
0.2
0.1
0
0
25
50
75 85
100
125
AMBIENT TEMPERATURE (°C)
FIGURE 7. TRANSIENT RESPONSE
FIGURE 8. PACKAGE POWER DISSIPATION vs AMBIENT
TEMPERATURE
JEDEC JESD51-3 LOW EFFECTIVE THERMAL
CONDUCTIVITY TEST BOARD
POWER DISSIPATION (W)
0.6
0.5
486mW
0.4

JA
=
0.3
M
SO
+2 P8
06
°C
/W
0.2
0.1
0.0
0
25
50
75 85
100
125
AMBIENT TEMPERATURE (°C)
FIGURE 9. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE
Applications Information
The ISL97519 is a high frequency, high efficiency boost
regulator operated at constant frequency PWM mode. The
boost converter stores energy from an input voltage source
and delivers it to a higher output voltage. The input voltage
range is 2.3V to 5.5V and the output voltage range is 5V to
25V. The switching frequency is selectable between 600kHz
and 1.2MHz allowing smaller inductors and faster transient
response. An external compensation pin gives the user greater
flexibility in setting output transient response and tighter load
regulation. The converter soft-start characteristic can also be
controlled by the external CSS capacitor. The EN pin allows the
user to completely shut-down the device.
Boost Converter Operations
Figure 10 shows a boost converter with all the key
components. In steady-state operating and continuous
conduction mode where the inductor current is continuous, the
boost converter operates in two cycles. During the first cycle,
5
as shown in Figure 11, the internal power FET turns on and the
Schottky diode is reverse biased and cuts off the current flow
to the output. The output current is supplied from the output
capacitor. The voltage across the inductor is VIN and the
inductor current ramps up in a rate of VIN/L, L is the
inductance. The inductance is magnetized and energy is stored
in the inductor. The change in inductor current is shown in
Equation 1:
V IN
I L1 = t1  -------L
D
t1 = ---------f SW
D = Duty Cycle
I OUT
V O = -------------  t 1
C OUT
(EQ. 1)
FN6454.4
February 16, 2012
ISL97519
During the second cycle, the power FET turns off and the
Schottky diode is forward biased, (see Figure 12). The energy
stored in the inductor is pumped to the output supplying
output current and charging the output capacitor. The Schottky
diode side of the inductor is clamped to a Schottky diode
above the output voltage. So the voltage drop across the
inductor is VIN - VOUT. The change in inductor current during the
second cycle is shown in Equation 2:
L
D
VOUT
VIN
COUT
CIN
ISL97519
IL
IL2
V IN – V OUT
I L = t2  ---------------------------L
t2
VO
1–D
t2 = ------------f SW
(EQ. 2)
For stable operation, the same amount of energy stored in the
inductor must be taken out. The change in inductor current
during the two cycles must be the same.
I1 + I2 = 0
V IN 1 – D V IN – V OUT
D
----------  ------- + -------------  ---------------------------- = 0
L
f SW
L
f SW
V OUT
1
------------- = ------------1–D
V IN
(EQ. 3)
L
FIGURE 12. BOOST CONVERTER - CYCLE 2, POWER SWITCH
OPEN
Output Voltage
An external feedback resistor divider is required to divide the
output voltage down to the nominal 1.294V reference voltage.
The current drawn by the resistor network should be limited to
maintain the overall converter efficiency. The maximum value
of the resistor network is limited by the feedback input bias
current and the potential for noise being coupled into the
feedback pin. A resistor network less than 100k is
recommended. The boost converter output voltage is
determined by the relationship in Equation 4:
R 1

V OUT = V FB   1 + -------
R 2

D
VOUT
VIN
COUT
CIN
(EQ. 4)
The nominal VFB voltage is 1.294V.
Inductor Selection
ISL97519
FIGURE 10. BOOST CONVERTER
L
VOUT
VIN
COUT
CIN
ISL97519
The inductor selection determines the output ripple voltage,
transient response, output current capability, and efficiency. Its
selection depends on the input voltage, output voltage,
switching frequency, and maximum output current. For most
applications, the inductance should be in the range of 2µH to
33µH. The inductor maximum DC current specification must
be greater than the peak inductor current required by the
regulator. The peak inductor current can be calculated using
Equation 5:
I OUT  V OUT
V IN   V OUT – V IN 
I L  PEAK  = ------------------------------- + 1  2  ----------------------------------------------V IN
L  V OUT  FREQ
(EQ. 5)
IL
IL1
t1
VO
FIGURE 11. BOOST CONVERTER - CYCLE 1, POWER SWITCH
CLOSED
Output Capacitor
Low ESR capacitors should be used to minimize the output
voltage ripple. Multilayer ceramic capacitors (X5R and X7R)
are preferred for the output capacitors because of their lower
ESR and small packages. Tantalum capacitors with higher ESR
can also be used. The output ripple can be calculated in
Equation 6:
I OUT  D
V O = ----------------------- + I OUT  ESR
f SW  C O
(EQ. 6)
For noise sensitive applications, a 0.1µF placed in parallel with
the larger output capacitor is recommended to reduce the
switching noise coupled from the LX switching node.
6
FN6454.4
February 16, 2012
ISL97519
Schottky Diode
Maximum Output Current
In selecting the Schottky diode, the reverse break down
voltage, forward current and forward voltage drop must be
considered for optimum converter performance. The diode
must be rated to handle 2.0A, the current limit of the
ISL97519. The breakdown voltage must exceed the maximum
output voltage. Low forward voltage drop, low leakage current,
and fast reverse recovery will help the converter to achieve the
maximum efficiency.
The MOSFET current limit is nominally 2.0A and guaranteed
1.7A. This restricts the maximum output current, IOMAX, based
on Equation 7:
Input Capacitor
The value of the input capacitor depends upon the input and
output voltages, the maximum output current, the inductor
value and the noise allowed to put back on the input line. For
most applications, a minimum 10µF is required. For
applications that run close to the maximum output current
limit, an input capacitor in the range of 22µF to 47µF is
recommended.
The ISL97519 is powered from the VIN. A High frequency
0.1µF bypass cap is recommended to be close to the VIN pin to
reduce supply line noise and ensure stable operation.
Loop Compensation
The ISL97519 incorporates a transconductance amplifier in its
feedback path to allow the user some adjustment on the
transient response and better regulation. The ISL97519 uses
current mode control architecture, which has a fast current
sense loop and a slow voltage feedback loop. The fast current
feedback loop does not require any compensation. The slow
voltage loop must be compensated for stable operation. The
compensation network is a series RC network from COMP pin
to ground. The resistor sets the high frequency integrator gain
for fast transient response and the capacitor sets the
integrator zero to ensure loop stability. For most applications,
the compensation resistor is in the range of 2k to 7.5k and the
compensation capacitor is in the range of 3nF to 10nF.
Soft-Start
The soft-start is provided by an internal 6µA current source,
which charges the external CSS; the peak MOSFET current is
limited by the voltage on the capacitor. This in turn controls the
rising rate of the output voltage. The regulator goes through
the start-up sequence as well, after the EN pin is pulled to HI.
Frequency Selection
The ISL97519 switching frequency can be user selected to
operate at either constant 620kHz or 1.25MHz. Connecting
FSEL pin to ground sets the PWM switching frequency to
620kHz. When connecting FSEL high or VDD, the switching
frequency is set to 1.25MHz.
Shut-down Control
(EQ. 7)
I L = I L-AVG +  1  2  I L 
where:
IL = MOSFET current limit
IL-AVG = average inductor current
IL = inductor ripple current
V IN    V O + V DIODE  – V IN 
I L = -----------------------------------------------------------------------L   V O + V DIODE   f S
(EQ. 8)
VDIODE = Schottky diode forward voltage, typically, 0.6V
fS = switching frequency, 600kHz or 1.2MHz
I OUT
I L-AVG = ------------1–D
(EQ. 9)
D = MOSFET turn-on ratio:
V IN
D = 1 – --------------------------------------V OUT + V DIODE
(EQ. 10)
Table 1 gives typical maximum IOUT values for 1.2MHz
switching frequency and 10µH inductor.
TABLE 1. MAXIMUM IOUT VALUES
VIN (V)
VOUT (V)
IOMAX (mA)
2.5
5
870
2.5
9
500
2.5
12
380
3.3
5
1150
3.3
9
655
3.3
12
500
5
9
990
5
12
750
Cascaded MOSFET Application
An 25V N-Channel MOSFET is integrated in the boost regulator.
For the applications where the output voltage is greater than
25V, an external cascaded MOSFET is needed, as shown in
Figure 13. The voltage rating of the external MOSFET should be
greater than AVDD.
When the EN pin is pulled down, the ISL97519 is shut down
reducing the supply current to <1µA.
7
FN6454.4
February 16, 2012
ISL97519
AVDD
VIN
LX
FB
INTERSIL
ISL97519
DC Path Block Application
Note that there is a DC path in the boost converter from the
input to the output through the inductor and diode, hence the
input voltage will be seen at output with a forward voltage drop
of diode before the part is enabled. If this voltage is not
desired, the following circuit can be inserted between input
and inductor to disconnect the DC path when the part is
disabled.
TO INDUCTOR
INPUT
EN
FIGURE 13. CASCADED MOSFET TOPOLOGY FOR HIGH OUTPUT
VOLTAGE APPLICATIONS
FIGURE 14. CIRCUIT TO DISCONNECT THE DC PATH OF BOOST
CONVERTER
For additional products, see www.intersil.com/product_tree
Intersil products are manufactured, assembled and tested utilizing ISO9001 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
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
8
FN6454.4
February 16, 2012
ISL97519
Package Outline Drawing
M8.118A
8 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE (MSOP)
Rev 0, 9/09
3.0±0.1
8
A
0.25
CAB
3.0±0.1
4.9±0.15
DETAIL "X"
1.10 Max
PIN# 1 ID
B
SIDE VIEW 2
1
0.18 ± 0.05
2
0.65 BSC
TOP VIEW
0.95 BSC
0.86±0.09
H
GAUGE
PLANE
C
0.25
SEATING PLANE
0.33 +0.07/ -0.08
0.08 C A B
0.10 ± 0.05
3°±3°
0.10 C
0.55 ± 0.15
DETAIL "X"
SIDE VIEW 1
5.80
NOTES:
4.40
3.00
1.
Dimensions are in millimeters.
2.
Dimensioning and tolerancing conform to JEDEC MO-187-AA
and AMSE Y14.5m-1994.
3.
Plastic or metal protrusions of 0.15mm max per side are not
included.
4.
Plastic interlead protrusions of 0.25mm max per side are not
included.
5.
Dimensions “D” and “E1” are measured at Datum Plane “H”.
6.
This replaces existing drawing # MDP0043 MSOP 8L.
0.65
0.40
1.40
TYPICAL RECOMMENDED LAND PATTERN
9
FN6454.4
February 16, 2012