ISL97701 ® Data Sheet February 22, 2008 Boost Regulator with Integrated Schottky and Input Disconnect Switch The ISL97701 represents a high efficiency boost converter with integrated boost FET, boost diode and input disconnect FET. With an input voltage of 2.3V to 5.5V the ISL97701 has an output capability of up to 50mA at 18V using integrated 500mA switches. Efficiencies are up to 87%. The integrated protection FET is used to disconnect the boost inductor from the input supply whenever an output fault condition is detected, or when the device is disabled. This gives 0 output current in the disabled mode, compared to standard boost converters where current can still flow when the device is disabled. The ISL97701 comes in the 10 Ld 3x3 DFN package and is specified for operation over the -40°C to +85°C temperature range. FN6474.1 Features • Up to 87% efficiency • 2.3V to 5.5V input • Up to 28V output • 50mA at 18V • Integrated boost Schottky diode • Input voltage disconnect switch • Synchronization input • Chip enable • 10 Ld 3x3 DFN package • Pb-free (RoHS compliant) Applications • OLED display power • LED display power Ordering Information • Adjustable power supplies PART NUMBER (Note) PART MARKING PACKAGE (Pb-free) PKG. DWG. # Typical Application Diagram ISL97701IRZ 977 01IRZ 10 Ld 3x3 DFN MDP0047 L1 ISL97701IRZ-T7* 977 01IRZ 10 Ld 3x3 DFN MDP0047 6.8µH ISL97701IRZ-T13* 977 01IRZ 10 Ld 3x3 DFN MDP0047 2.3V TO 5.5V NOTE: 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. LX VDD C0 5µF NEN OSCILLATOR AND CONTROL *Please refer to TB347 for details on reel specifications. VDDOUT VOUT VDD+2V TO 30V C1 3.3µF R1 390kΩ NSYNC GND FB R2 39kΩ Pinout ISL97701 (10 LD 3X3 DFN) TOP VIEW GND 1 10 LX 9 VOUT VDDOUT 2 VDD 3 NOTE: VOUT = (390k + 39k)/39k*1.15V = 12.65V THERMAL PAD NSYNC 4 8 NEN 7 GND FB 5 6 NC 1 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. 2007, 2008. All Rights Reserved All other trademarks mentioned are the property of their respective owners. ISL97701 Block Diagram VDD SYNCHRONIZATION SIGNAL DETECTOR UNDERVOLTAGE DETECTOR OVER-TEMPERATURE DETECTOR 1 NSYNC OVERCURRENT DETECTOR (DC) MUX 0 OSCILLATOR VDD CLK NEN START GND RESTART DISABLE AND WAIT STATE MACHINE (DEFAULT SEQUENCE) 1. SOFT INRUSH 2. VDDOUT ENABLE 3. SOFT BOOST 25 4. SOFT BOOST 50 5. SOFT BOOST 75 6. NORMAL SLOPE COMPENSATION RAMP-GENERATOR ERROR AMP + FB VDD CCOMP CLAMP + As + Av Σ - S2 VDDOUT OVERVOLTAGE DETECTOR 2 LX EN =0 + Ai - VOLTAGE REFERENCE CONTROL LOGIC -PWM TIMING -CURRENT LIMIT -PULSE SKIPPING VOUT GATE DRIVER CURRENT LIMIT COMPARATOR RSENSE GND ISL97701 FIGURE 1. ISL97701 BLOCK DIAGRAM 2 FN6474.1 February 22, 2008 ISL97701 Absolute Maximum Ratings (TA = +25°C) Thermal Information VDD to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 6V VOUT to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to 31V LX to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VOUT + 1V VDDOUT, NSYNC, FB, NEN to GND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to VDD + 0.3V Continuous Current in VDD, GND, VDDOUT, LX . . . . . . . . . 650mA Continuous Current in NSYNC, FB, NEN . . . . . . . . . . . . . . . . 10mA Thermal Resistance (Typical, Notes 1, 2) θJA (°C/W) θJC (°C/W) 10 Ld 3x3 DFN Package . . . . . . . . . . . 48 7 Storage Temperature . . . . . . . . . . . . . . . . . . . . . . . .-65°C to +150°C Ambient Operating Temperature (TA) . . . . . . . . . . . .-40°C to +85°C Operating Junction Temperature (TJ) . . . . . . . . . . . . . . . . . . +125°C Maximum Junction Temperature . . . . . . . . . . . . . . . . . . . . . . +130°C 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. NOTES: 1. 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. 2. For θJC, the “case temp” location is the center of the exposed metal pad on the package underside. Electrical Specifications PARAMETER VDD = 3.6V, GND = NEN = 0V, NSYNC = VDD, R1 = 390kΩ, R2 = 39kΩ, L = 10µH, TA = -40°C to +85°C unless otherwise stated. DESCRIPTION CONDITION MIN TYP MAX UNIT 5.5 V 0.1 3 µA 250 350 kΩ 1 µA SUPPLY VDD Supply Operating Voltage Range IDIS Supply Current when Disabled 2.3 NEN = VDD LOGIC INPUTS – NEN, NSYNC RUP Pull-up Resistor Enabled, Input at GND 150 IIL Leakage Current when Disabled Disabled, Input at GND -1 VHI Logic High Threshold VLO Logic Low Threshold 1.8 V 0.7 V 2.3 V POWER-ON RESET – VDD VRES_ON Power-On Reset Threshold VDD rising VRES_OFF Power-Off Threshold VDD falling 2.2 1.9 2 0.9 1 V LX OUTPUT DRIVER fOSC LX Switching Frequency with Internal Oscillator fSYNC LX Switching Frequency when Externally Synchronized at NSYNC tON-MIN Minimum On-Time FB = 0V, I(LX) > Ilim(LX) 60 ns tOFF-MIN Minimum Off-time (≥ Maximum Duty Cycle) FB = 0V, I(LX) < Ilim(LX) 60 ns rON LX ON-Resistance I(LX) = 100mA 0.4 Ω ILEAK LX Leakage Current NEN = VDD, V(LX) = 30V IPEAK LX Peak Current Limit t > 8.32ms (end of soft-start) 1.1 MHz f (NSYNC) 1 5 1200 µA mA SCHOTTKY DIODE – LX, VOUT VDIODE Forward Voltage from LX to VOUT 3 I = 10mA, TA = +25°C 0.4 0.5 0.6 V I = 10mA, TA = -40°C to +85°C 0.3 0.5 0.7 V FN6474.1 February 22, 2008 ISL97701 Electrical Specifications PARAMETER VDD = 3.6V, GND = NEN = 0V, NSYNC = VDD, R1 = 390kΩ, R2 = 39kΩ, L = 10µH, TA = -40°C to +85°C unless otherwise stated. (Continued) DESCRIPTION CONDITION MIN TYP MAX UNIT TA = +25°C 1.13 1.15 1.17 V TA = -40°C to +85°C 1.12 1.15 1.18 V -0.2 0.2 µA 25 Ω 1400 kHz 100 ns FEEDBACK INPUTS VrefFB Input Reference Voltage on FB IFB Input Current in FB FB = 1.3V RFB FB Pull-Down Switch Resistance IFB = 10mA 15 SYNCHRONIZATION INPUT – NSYNC fNSYNC External Sync Frequency Range tdNSYNC NSYNC Falling Edge to LX Falling Edge Delay 600 fNSYNC = 600kHz 80 OVERVOLTAGE DETECTOR - VOUT VOUT Overvoltage Threshold FB = GND 31 35 V t > 2.048ms, DC current 800 mA OVERCURRENT DETECTOR IOCTVDDOUT Overcurrent Threshold OVER-TEMPERATURE DETECTOR tOFF Shut-Down Temperature Threshold T rising 135 °C tON Turn-On Temperature Threshold T falling 100 °C Ω FAULT SWITCH – VDD, VDDOUT rONFS ON-Resistance from VDD to VDDOUT IOUT = 50mA, t > 2.048ms 0.2 IleakVDDOUT Leakage Current VDDOUT = 0V 0.01 ISS_VDDOUT Soft Inrush Current Source at VDDOUT VDD - VDDOUT = 0.5V, tON < 2.048ms Output Voltage Accuracy, Assuming Resistor Divider Tolerances of 0.1% or Better IOUT = 10mA, TA = +25°C -1.5 1.5 % IOUT = 10mA, TA = -40°C to +85°C -2.5 2.5 % ΔVOUT/ΔIOUT Load Regulation IOUT = 0mA to 50mA 0.05 % ΔVOUT/ΔVDD Line Regulation VDD = 3.6V to 2.6V, IOUT = 30mA 0.1 %/V 3 50 µA mA REGULATION ACC 4 FN6474.1 February 22, 2008 ISL97701 Typical Performance Curves 90 90 4.2V 4.2V 85 80 EFFICIENCY (%) EFFICIENCY (%) 85 3.6V 2.7V 75 3.6V 80 2.7V 75 70 70 65 65 0 50 100 0 150 50 100 150 IOUT (mA) LOAD CURRENT (mA) FIGURE 2. EFFICIENCY vs LOAD CURRENT (VOUT = 18.3V) L = 10µH (CDRH4D28C-100NC) C = 6.6µF FIGURE 3. EFFICIENCY vs IOUT (VOUT = 18.3V) L = 6.8µH (TDK RLF7030) C = 6.6µF 90 90 4.2V 4.2V 85 EFFICIENCY (%) EFFICIENCY (%) 85 3.6V 80 2.7V 75 70 3.6V 80 2.7V 75 70 65 65 0 50 100 150 200 0 50 FIGURE 4. EFFICIENCY vs IOUT (VOUT = 12.6V) L = 6.8µH (TDK RLF7030) C = 6.6µF V(NEN) 100 150 200 IOUT (mA) IOUT (mA) FIGURE 5. EFFICIENCY vs IOUT (VOUT = 12.7V) L = 10µH (CDRH4D28C-100NC) C = 6.6µF V(NEN) V(VOUT) V(VOUT) I(VDD) I(VDD) FIGURE 6. START-UP TO 12V (VDD = 3.6V, RL = 360Ω) 5 FIGURE 7. START-UP TO 18V (VDD = 3.6V, RL = 360Ω) FN6474.1 February 22, 2008 ISL97701 Typical Performance Curves (Continued) V(NEN) 18.20 18.19 18.18 18.17 VOUT (V) V(VOUT) 18.16 18.15 18.14 18.13 18.12 18.11 18.10 18.09 I(VDD) 0 50 100 150 LOAD CURRENT (mA) FIGURE 9. LOAD REGULATION (VIN = 3.6V) FIGURE 8. SHUTDOWN (VDD = 3.6V, RL = 360Ω) 18.29 QUIESCENT CURRENT (µA) 1200 18.28 VOUT (V) 18.27 18.26 18.25 18.24 18.23 2.6 3.1 3.6 4.1 4.6 1000 800 600 400 200 0 5.1 0 1 2 VIN (V) 3 4 5 6 VIN (V) FIGURE 11. QUIESCENT CURRENT vs VIN FIGURE 10. LINE REGULATION (IOUT = 30mA) 3.2 2.9 2.6 POUT (W) 2.3 2.0 1.7 1.4 1.1 0.8 0.5 2.3 (CH1 = VOUT; CH4 = iL; CH2 = IOUT) FIGURE 12. TRANSIENT RESPONSE (VIN = 3.3V; VOUT = 18.3V; STEP LOAD CURRENT FROM 2.6mA TO 70mA) 6 2.7 3.1 3.5 3.9 VIN (V) 4.3 4.7 5.1 5.5 FIGURE 13. RECOMMENDED MAXIMUM OUTPUT POWER vs INPUT VOLTAGE FN6474.1 February 22, 2008 ISL97701 When NEN is driven low the ISL97701 begins with the start-up sequence. Pin Descriptions PIN NUMBER PIN NAME 1 GND 2 VDDOUT 3 VDD 4 NSYNC 5 FB Feedback Input 6 NC Do Not Connect 7 GND Ground 8 NEN Enable Input (Active Low) SOFT INRUSH: STATE DURATION ~2.048ms 9 VOUT Boost Output Voltage 10 LX The switch at VDDOUT is configured as current source and provides a limited current through the inductor to pre-charge the capacitor at VOUT. Start-Up Sequence PIN FUNCTION Ground Protection Switch Output Supply Input Synchronization Input (Falling Edge) After pin NEN is pulled low or a restart is triggered from Fault Control during operation, the ISL97701 goes through a startup sequence with the following six states: Soft Inrush -> VDDOUT Enable -> Soft Boost 25 -> Soft Boost 50 -> Soft Boost 75 -> Normal. If the sequence has completed, the ISL97701 stays in the “Normal” state until NEN is high again or any fault is detected. Boost FET Function Overview VDDOUT ENABLE: STATE DURATION ~128µs The ISL97701 is a high frequency, high efficiency boost regulator which operates in constant frequency PWM mode. The boost converter generates a stable, higher output voltage from a variable, low voltage input source (e.g. Li-ion battery). The output voltage level is defined from the feedback resistor network in Equation 1. V OUT = V refFB • ( R 1 + R 2 ) ⁄ R 2 (EQ. 1) The switching frequency is either generated from the fixed 1MHz internal oscillator or provided externally at the synchronization pin in the range from 600kHz to 1.4MHz. The compensation network and soft-start functions are built in with fixed parameters without any need for further external components. To stop battery discharge into the output load when disabled, the inductor is disconnected from the input supply with a low ON-resistance power switch. The switch at VDDOUT is fully enabled and connects the inductor to VDD with a low ON-resistance. SOFT BOOST 25 -> 50 -> 75: STATE DURATION 3x ~2.048ms The boost regulator begins to switch at LX. The LX current limit increases in three steps representing 25%, 50% and 75% of its final value. NORMAL If no fault was detected Normal state is entered ~8.256ms after NEN is pulled low. The LX current limit steps up to 100%. In all states Fault Control can force the sequence to restart or even to shutdown (see Table 1). V(NEN) Built-in fault protection monitors inductor current and output voltage as well as junction temperature in order to interrupt the high current circuit path through the inductor and diode in the event of a load failure. V(VOUT) Low logic input thresholds allow the ISL97701 to interface directly to microcontrollers with lower supply voltage. Alternatively, the internal pull-up resistors on all logic inputs provide level shifting when driven from open collector outputs. Description of Operation NORMAL 75 SOFT INRUSH Enable Pin (Active Low) - NEN If NEN is high, the ISL97701 shuts down all its internal functions and deactivates its I/So. Only the internal pull-up resistor at NEN remains active. If NEN is high, the input disconnect switch between VDD and VDDOUT interrupts the circuit path from the input voltage VDD through inductor and diode to the output load at VOUT. If shutdown, the total supply current in VDD is typically less than 0.1µA. 7 I(VDD) 50 25 VDDOUT ENABLE FIGURE 14. FAULT CONTROL SEQUENCE Fault Control The input voltage at VDD, current in the VDDOUT switch, voltage at VOUT and junction temperature TJ are continuously monitored and can either restart the start-up FN6474.1 February 22, 2008 ISL97701 sequence or in some cases disable the ISL97701 boost function as long as the fault is present. TABLE 1. FAULT PROTECTION FAULT DESCRIPTION FAULT CONDITION ISL97701 FAULT REACTION Undervoltage at VDD V(VDD) < V(VDD)off Overcurrent drawn from VDDOUT I(VDDOUT) > Disables VDDOUT switch and It(VDDOUT)err LX driver and immediately restarts the start-up sequence Overvoltage at VOUT V(VOUT) > Vt(VOUT)err Disables I/Os and waits until V(VDD) reaches V(VDD)on to begin with the start-up sequence pin is, for example, static high, the internal oscillator defines the LX output frequency and phase. When externally synchronized, all falling edges at LX are timed from the falling edge of the clock signal applied at NSYNC. The timing of the rising edge at LX is defined by the boost controller. V(NSYNC) Disables VDDOUT switch and LX driver and waits until output voltage V(VOUT) drops to Vt(VOUT) to restart the start-up sequence Over-Temperature Tj > Toff on chip V(LX) Disables VDDOUT switch and LX driver and waits until junction temp drops to “Ton” to restart the start-up sequence FIGURE 15. NSYNC TO LX SYNCHRONIZATION DELAY Maximum Duty Cycle – LX The maximum duty cycle Dmax, at which the power FET can operate defines the upper limit of the regulator output to input voltage ratio according to Equation 2: V OUT 1 ---------------- = -------------------------1 – DMAX V IN V(NSYNC) (EQ. 2) In the ISL97701, DMAX is defined from the minimum off-time tOFF(LX)min and the switching frequency. V(LX) If NSYNC is tied to VDD the internal oscillator defines DMAX according to Equation 3: D MAX ( f OSC ) = 1 – t OFF ( LX )min • f OSC (EQ. 3) With external synchronization at pin NSYNC: D MAX ( NSYNC ) = 1 – t OFF ( LX )min • f ( NSYNC ) (EQ. 4) The duty cycle at LX can be 0% (pulse skipping), if the output voltage exceeds the target voltage set with the feedback resistors. FIGURE 16. LX SYNCHRONIZATION WITH f(SYNC) = 600kHz V(NSYNC) Internal Schottky Diode – LX, VOUT The inductor node LX internally connects to the power FET and to the anode of the integrated power Schottky diode. The cathode of the diode is pin VOUT. An overvoltage detector at VOUT continuously monitors the cathode voltage and immediately disables the boost regulator if the voltage exceeds the maximum allowable voltage. V(LX) External Synchronization Pin - NSYNC Pin NSYNC can be used to synchronize the LX output pin with an external clock signal in the range from 600kHz to 1.4MHz. A frequency detector monitoring NSYNC enables external synchronization if f(NSYNC) is higher than ~300kHz. If the 8 FIGURE 17. LX SYNCHRONIZATION WITH f(SYNC) = 1.4MHz FN6474.1 February 22, 2008 ISL97701 C7 3.3µF/50V R1 390kΩ J7 VOUT C6 1nF/50V C8 100nF L1 J2 J3 6.8µH U1 2 VDD J1 3 VDD_IN J4 C1 VDD 100nF C2 10µF 4 C9 4.7µF/10V 5 R6 39kΩ LX 10 VDDOUT 9 VOUT VDD 8 NEN NSYNC 7 GND FB 6 NC GND R3 OPEN GND_OUT VDD 1 1 J6 J1 2 NEN 3 GND_IN ISL97701 JP3 NSYNC FIGURE 18. ISL97701 APPLICATION BOARD Typical Application Typical applications are passive- or active-matrix organic light emitting diode displays (PMOLED, AMOLED) in handheld devices. Applications with low power or screen saver mode is directly supported. TABLE 2. OPTIMAL COMBINATION OF BOOST INDUCTOR L AND OUTPUT CAPACITOR COUT CAPACITOR (µF) INDUCTOR (µH) MIN MAX 4.7 2.2 10 6.8 3.3 10 10 4.7 10 15 6.8 10 Components Selection The input capacitance is normally 10µf~15µF and the output capacitor is 3.3µf to 6.6µF. X5R or X7R type of ceramic capacitor with correct voltage rating is recommended. The output capacitor value will affect the output voltage ripple. The higher the value of the output capacitor, the lower the ripple of the output voltage. When choosing an inductor, make sure the inductor can handle the average and peak currents given by Equations 5, 6 and 7 (80% efficiency assumed): I OUT ⋅ V OUT I LAVG = ---------------------------------0.8 ⋅ V IN Recommended inductor and ceramic capacitor manufacturers are listed in Table 3: TABLE 3. RECOMMENDED INDUCTOR AND CERAMIC CAPACITOR MANUFACTURERS INDUCTOR CERAMIC CAPACITOR Sumida: www.sumida.com Taiyo Yuden: www.t-yuden.com TDK: www.tdk.co.jp AVX: www.avxcorp.com Toko: www.tokoam.com Murata: www.murata.com (EQ. 5) 1 I LPK = I LAVG + --- ⋅ ΔI L 2 (EQ. 6) V IN ⋅ ( V OUT – V IN ) ΔI L = --------------------------------------------------L ⋅ V OUT ⋅ f OSC (EQ. 7) Where: • ΔIL is the peak-to-peak inductor current ripple in Amperes • L is the inductance in H • fOSC is the switching frequency, typically 1.0MHz Optimal combinations of the boost inductor L and the output capacitor COUT are listed in Table 2: 9 PCB Layout Considerations The layout is very important for the converter to function properly. To ensure the high pulse current in the power ground does not interfere with the sensitive feedback signals, the current loops (VIN-L1-LX-GND, and VIN-L1VOUT-COUT-GND) should be as short as possible. For the DFN package, there is no separated GND. All return GNDs should be connected in GND pin but with no sharing branch. The heat of the IC is mainly dissipated through the thermal pad. Maximizing the copper area connected to the thermal pad is preferable. In addition, a solid ground plane is helpful for the EMI performance. FN6474.1 February 22, 2008 ISL97701 Dual Flat No-Lead Package Family (DFN) MDP0047 A DUAL FLAT NO-LEAD PACKAGE FAMILY (JEDEC REG: MO-229) D MILLIMETERS N N-1 0.075 C 2X PIN #1 I.D. E 1 DFN8 DFN10 TOLERANCE A 0.85 0.90 ±0.10 A1 0.02 0.02 +0.03/-0.02 b 0.30 0.25 ±0.05 c 0.20 0.20 Reference D 4.00 3.00 Basic D2 3.00 2.25 Reference E 4.00 3.00 Basic E2 2.20 1.50 Reference e 0.80 0.50 Basic L 0.50 0.50 ±0.10 L1 0.10 0 Maximum 2 0.075 C B 2X TOP VIEW (D2) 4 SYMBOL L1 N-1 N L (N LEADS) Rev. 2 2/07 NOTES: (E2) 1. Dimensioning and tolerancing per ASME Y14.5M-1994. 2. Exposed lead at side of package is a non-functional feature. PIN #1 I.D. 1 2 5 3 e b 0.10 M C A B 4. Exposed leads may extend to the edge of the package or be pulled back. See dimension “L1”. 5. Inward end of lead may be square or circular in shape with radius (b/2) as shown. BOTTOM VIEW 0.10 3. Bottom-side pin #1 I.D. may be a diepad chamfer, an extended tiebar tab, or a small square as shown. 6. N is the total number of leads on the device. C C SEATING PLANE 0.08 C SEE DETAIL "X" (N LEADS & EXPOSED PAD) 2 C A (c) A1 DETAIL X 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 10 FN6474.1 February 22, 2008