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ISL97516
Data Sheet March 16, 2007 FN9261.2
600kHz/1.2MHz PWM Step-Up Regulator
The ISL97516 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. When shut down, it draws <1A of current and can operate down to 2.3V input supply. These features along with 1.2MHz switching frequency makes it an ideal device for portable equipment and TFT-LCD displays. The ISL97516 is available in an 8 Ld MSOP package with a maximum height of 1.1mm. The device is specified for operation over the full -40C to +85C temperature range.
Features
* >90% Efficiency * 2.0A, 200m Power MOSFET * 2.3V to 5.5V Input * Up to 25V Output * 600kHz/1.2MHz Switching Frequency Selection * Adjustable Soft-Start * Internal Thermal Protection * 1.1mm Max Height 8 Ld MSOP Package * Pb-free Plus Anneal Available (RoHS compliant)
Applications
* TFT-LCD displays * DSL modems * PCMCIA cards
Pinout
ISL97516 (8 LD MSOP) TOP VIEW
COMP 1 FB 2 EN 3 GND 4 8 SS 7 FSEL 6 VDD 5 LX
* Digital cameras * GSM/CDMA phones * Portable equipment * Handheld devices
Ordering Information
PART NUMBER (Note) ISL97516IUZ ISL97516IUZ-T PART MARKING TAPE AND REEL 7516Z 7516Z bulk pack (tubes) PACKAGE (Pb-Free) 8 Ld MSOP PKG. DWG. # MDP0043 MDP0043 MDP0043
13" (2,500 pieces) 8 Ld MSOP 13" (1k pieces) 8 Ld MSOP
ISL97516IUZ-TK 7516Z
NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are 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.
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CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL or 1-888-468-3774 | Intersil (and design) is a registered trademark of Intersil Americas Inc. Copyright Intersil Americas Inc. 2006, 2007. All Rights Reserved All other trademarks mentioned are the property of their respective owners.
ISL97516
Absolute Maximum Ratings (TA = +25C)
LX to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27V VDD to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6V COMP, FB, EN, SS, FSEL to GND . . . . . . . . . -0.3V to (VDD +0.3V) Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65C to +150C Operating Ambient Temperature . . . . . . . . . . . . . . . .-40C to +85C Operating Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +135C Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Curves
CAUTION: Stresses above those listed in "Absolute Maximum Ratings" may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. 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
PARAMETER IQ1 IQ2 IQ3 VFB IB-FB VDD DMAX-600kHz DMAX-1.2MHz ILIM IEN rDS(ON) ILX-LEAK VOUT/VIN VOUT/IOUT FOSC1 FOSC2 VIL VIH GM VDD-ON HYS ISS OTP
VIN = 3.3V, VOUT = 12V, IOUT = 0mA, FSEL = GND, TA = -40C to +85C unless otherwise specified. CONDITIONS EN = 0V EN= VDD, FB = 1.3V EN = VDD, FB = 1.0V 1.272 MIN TYP 1 0.7 3 1.294 0.01 2.3 FSEL = 0V FSEL = VDD 85 85 1.5 EN = 0V VDD = 2.7V, ILX = 1A VSW = 27V 3V < VIN < 5.5V, VOUT = 12V VIN = 3.3V, VOUT = 12V, IO = 30mA to 200mA FSEL = 0V FSEL = VDD 500 1000 92 90 2.0 0.01 0.2 0.01 0.2 0.3 620 1250 740 1500 0.5 1.5 I = 5A 70 2.1 130 2.2 100 4 6 150 8 150 2.3 3 0.5 4 1.309 0.5 5.5 MAX 5 UNIT A mA mA V A V % % A A A % % kHz kHz V V 1/ V mV A C
DESCRIPTION Quiescent Current - Shutdown Quiescent Current - Not Switching Quiescent Current - Switching Feedback Voltage Feedback Input Bias Current Input Voltage Range Maximum Duty Cycle Maximum Duty Cycle Current Limit - Max Peak Input Current Shutdown Input Bias Current Switch ON Resistance Switch Leakage Current Line Regulation Load Regulation Switching Frequency Accuracy Switching Frequency Accuracy EN, FSEL Input Low Level EN, FSEL Input High Level Error Amp Tranconductance VDD UVLO On Threshold VDD UVLO hyeteresis Soft-Start Charge Current Over Temperature Protection
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FN9261.2 March 16, 2007
Block Diagram
FSEL EN SS
VDD
REFERENCE GENERATOR
OSCILLATOR
SHUTDOWN & START-UP CONTROL
LX PWM LOGIC CONTROLLER COMPARATOR FET DRIVER
CURRENT SENSE
GND
FB GM AMPLIFIER
COMP
Pin Descriptions
PIN NUMBER 1 2 PIN NAME COMP FB DESCRIPTION Compensation pin. Output of the internal error amplifier. Capacitor and resistor from COMP pin to ground. 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. Shutdown control pin. Pull EN low to turn off the device. Analog and power ground. Power switch pin. Connected to the drain of the internal power MOSFET. Analog power supply input pin. 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. Soft-start control pin. Connect a capacitor to control the converter start-up.
3 4 5 6 7
EN GND LX VDD FSEL
8
SS
Typical Application Circuit
R3 3.9k C5 4.7nF 1 COMP R1 85.2k 2 FB R2 10k 3 EN 4 GND S1 FSEL 7 VDD 6 LX 5 SS 8 C3 27nF 2.3V TO 5.5V 10H 12V
C4
+ C1 22F
0.1F
D1
+ C2 22F
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FN9261.2 March 16, 2007
Typical Performance Curves
95 90 EFFICIENCY(%) 85 EFFICIENCY(%) VIN = 5V, VO = 12V, fs = 1.25 MHz 80 75 70 65 60 0 200 400 600 800 1000 IOUT (mA) VIN = 5V, VO = 9V, fs = 620 kHz VIN = 5V, VO = 9V, fs = 1.25MHz VIN = 5V, VO = 12V, fs = 620 kHz 92 90 88 86 84 82 80 78 76 74 0 100 200 300 IOUT (mA) 400 500 VIN = 3.3V, VO = 12V, fs = 620kHz VIN = 3.3V, VO = 12V, fs = 1.25MHz VIN = 3.3V, VO = 9V, fs = 1.25MHz VIN = 3.3V, VO = 9V, fs = 620kHz
FIGURE 1. BOOST EFFICIENCY vs IOUT
FIGURE 2. BOOST EFFICIENCY vs IOUT
0.9 0.8 0.7 LOAD REGULATION(%) 0.6 0.5 0.4 0.3 0.2 0.1 0 0 200 400 600 800 1000 IOUT (mA) VIN = 5V, VO = 12V, fs = 620kHz LOAD REGULATION (%) VIN = 5V, VO = 12V, fs = 1.25MHz VIN = 5V, VO = 9V, fs = 1.25MHz
0.7 VIN = 3.3V, VO = 12V, 0.6 0.5 VIN = 3.3, VO = 9V, 0.4 0.3 0.2 0.1 0 0 100 200 fs = 1.25kHz fs = 1.25MHz VIN = 3.3V, VO = 9V, fs = 1.25MHz
VIN = 5V, VO = 9V, fs = 620kHz
VIN = 3.3, VO = 12V, fs = 620kHz 300 400 500
IOUT (mA)
FIGURE 3. LOAD REGULATION vs IOUT
FIGURE 4. LOAD REGULATION vs IOUT
0.6 0.5 0.4 0.3 VO = 12V, IO = 80mA 0.2 0.1 0 -0.1 2 3 fs = 1.25MHz VO = 9V, IO = 80mA fs = 1.25MHz LINE REGULATION (%) VO = 9V, IO = 100mA fs = 620kHz VIN = 3.3V fs = 600kHz VO = 12V IO = 50mA to 300mA
VO = 12V, IO = 80mA fs = 620kHz 4 VIN (V) 5 6
FIGURE 5. LINE REGULATION vs VIN
FIGURE 6. TRANSIENT RESPONSE
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FN9261.2 March 16, 2007
Typical Performance Curves
(Continued)
JEDEC JESD51-7 HIGH EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD 1.0 0.9 POWER DISSIPATION (W) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0 25 50 75 85 100 125 AMBIENT TEMPERATURE (C) 870mW
JA
IO = 50mA to 300mA VO = 12V
VIN = 3.3V
fs = 1.2MHz
=
M SO +1 P8 15 C /W
FIGURE 7. TRANSIENT RESPONSE
FIGURE 8. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE
JEDEC JESD51-3 LOW EFFECTIVE THERMAL CONDUCTIVITY TEST BOARD 0.6 POWER DISSIPATION (W) 0.5 486mW 0.4 0.3 0.2 0.1 0.0 0 25 50 75 85 100 125 AMBIENT TEMPERATURE (C)
JA =
M SO +2 P8 06 C /W
FIGURE 9. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE
Applications Information
The ISL97516 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 deliver it to a higher output voltage. The input voltage range is 2.3V to 5.5V and 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 external CSS capacitor. The EN pin allows the user to completely shutdown the device.
the boost converter operates in two cycles. During the first cycle, 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:
V IN I L1 = T1 x --------L D T1 = ----------F SW D = Duty Cycle I OUT V O = --------------- x T 1 C OUT
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,
(EQ. 1)
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FN9261.2 March 16, 2007
During the second cycle, the power FET turns off and the Schottky diode is forward biased, (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 clamp 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:
V IN - V OUT I L = T2 x ------------------------------L 1-D T2 = -----------F SW
L VIN CIN ISL97516
D VOUT COUT
IL2 T2
IL VO
(EQ. 2)
FIGURE 12. BOOST CONVERTER - CYCLE 2, POWER SWITCH OPEN
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 ----------- x --------- + ------------ x ------------------------------- = 0 L F SW L F SW V OUT 1 --------------- = -----------1-D V IN
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:
R 1 V OUT = V FB x 1 + ------ R 2
(EQ. 3)
(EQ. 4)
L VIN CIN ISL97516
D VOUT COUT
The nominal VFB voltage is 1.294V.
Inductor Selection
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 2H to 33H. 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:
:
FIGURE 10. BOOST CONVERTER
L VIN CIN ISL97516 COUT VOUT
I OUT x V OUT V IN x ( V OUT - V IN ) I L ( PEAK ) = ----------------------------------- + 1 2 x ---------------------------------------------------V IN L x V OUT x FREQ (EQ. 5)
Output Capacitor
IL T1 VO IL1
FIGURE 11. BOOST CONVERTER - CYCLE 1, POWER SWITCH CLOSED
Low ESR capacitors should be used to minimized 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 as:
I OUT x D V O = -------------------------- + I OUT x ESR F SW x C O
(EQ. 6)
For noise sensitive application, a 0.1F placed in parallel with the larger output capacitor is recommended to reduce the switching noise coupled from the LX switching node. 6
FN9261.2 March 16, 2007
Schottky Diode
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 ISL97516. 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.
Maximum Output Current
The MOSFET current limit is nominally 2.0A and guaranteed 1.7A. This restricts the maximum output current, IOMAX, based on the following formula:
I L = I L-AVG + ( 1 2 x I L ) (EQ. 7)
where: IL = MOSFET current limit IL-AVG = average inductor current IL = inductor ripple current
V IN x [ ( V O + V DIODE ) - V IN ] I L = -----------------------------------------------------------------------------L x ( V O + V DIODE ) x F S
Input Capacitor
The value of the input capacitor depends 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 10F is required. For applications that run close to the maximum output current limit, input capacitor in the range of 22F to 47F is recommended. The ISL97516 is powered from the VIN. A High frequency 0.1F bypass cap is recommended to be close to the VIN pin to reduce supply line noise and ensure stable operation.
(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)
Loop Compensation
The ISL97516 incorporates a transconductance amplifier in its feedback path to allow the user some adjustment on the transient response and better regulation. The ISL97516 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 in the range of 2k to 7.5k and the compensation capacitor in the range of 3nF to 10nF.
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 10H inductor.
TABLE 1. VIN (V) 2.5 2.5 2.5 3.3 3.3 3.3 5 5 VOUT (V) 5 9 12 5 9 12 9 12 IOMAX (mA) 870 500 380 1150 655 500 990 750
Soft-Start
The soft-start is provided by an internal 6A current source 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.
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 12. The voltage rating of the external MOSFET should be greater than AVDD.
Frequency Selection
The ISL97516 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.
Shutdown Control
When the EN pin is pulled down, the ISL97516 is shutdown reducing the supply current to <1A.
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FN9261.2 March 16, 2007
DC PATH BLOCK APPLICATION
VIN AVDD
LX FB INTERSIL ISL97516
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
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FN9261.2 March 16, 2007
Mini SO Package Family (MSOP)
0.25 M C A B D N A (N/2)+1
MDP0043
MINI SO PACKAGE FAMILY MILLIMETERS SYMBOL A A1 MSOP8 1.10 0.10 0.86 0.33 0.18 3.00 4.90 3.00 0.65 0.55 0.95 8 MSOP10 1.10 0.10 0.86 0.23 0.18 3.00 4.90 3.00 0.50 0.55 0.95 10 TOLERANCE Max. 0.05 0.09 +0.07/-0.08 0.05 0.10 0.15 0.10 Basic 0.15 Basic Reference NOTES 1, 3 2, 3 Rev. D 2/07 NOTES: 1. Plastic or metal protrusions of 0.15mm maximum per side are not included.
E
E1
PIN #1 I.D.
A2 b c
B
1 (N/2)
D E E1
e C SEATING PLANE 0.10 C N LEADS b
H
e L L1 N
0.08 M C A B
L1 A c SEE DETAIL "X"
2. Plastic interlead protrusions of 0.25mm maximum per side are not included. 3. Dimensions "D" and "E1" are measured at Datum Plane "H". 4. Dimensioning and tolerancing per ASME Y14.5M-1994.
A2 GAUGE PLANE L DETAIL X
0.25
A1
3 3
All Intersil U.S. products are manufactured, assembled and tested utilizing ISO9000 quality systems. Intersil Corporation's quality certifications can be viewed 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 9
FN9261.2 March 16, 2007

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