LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION KEY FEATURES DESCRIPTION The input voltage ranges from 1.6V to 6.0V, allowing for a wide selection of system battery voltages. Start-up operation is guaranteed at 1.6V input The LX1742 is capable of achieving output voltages as high as 25V and the output voltage is easily programmed using two external resistors in conjunction with the feedback pin. The LX1742 has an additional feature for simple dynamic adjustment of the output voltage (i.e., up to ±15% of the nominal output voltage). Voltage adjustment is achieved via an analog reference signal or a direct PWM input signal applied to the ADJ pin. Any PWM amplitude is easily accommodated with a single external resistor. 80% Typical Efficiency 80µA Typical Quiescent Supply Current Externally Programmable Peak Inductor Current Limit For Maximum Efficiency Logic Controlled Shutdown < 1.0 µA Shutdown Current (typ) Dynamic Output Voltage Adjustment Via Analog Reference Or Direct PWM Input 8-Pin MSOP Package WWW . Microsemi .C OM The LX1742 is a compact high efficiency step-up boost controller. Featuring a pseudo-hysteretic pulse frequency modulation topology, the LX1742 was designed for maximum efficiency, reduced board size, and minimal cost. Utilizing an internal N-Channel MOSFET, the LX1742 offers designers maximum flexibility with respect to efficiency and cost. The LX1742 provides several design enhancements that improve overall performance under very light load currents by implementing control circuitry that is optimized for portable systems - thus providing a quiescent supply current of only 80µA (typ) and a shutdown current of less than 1µA. APPLICATIONS/BENEFITS Pagers Wireless Phones PDAs Handheld Computers General LCD Bias Applications LED Driver IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com PRODUCT HIGHLIGHT VBAT = (1.6V to 6.0V) UPS530 L1 47µH VOUT = 18V ± 15% (For Contrast Adjustment) SW IN OUT SHDN LX1742 R1 1MΩ C2 * 1nF C1 4.7µF FB ADJ CS GND RCS 1kΩ R2 72kΩ RPWM 625kΩ LX1742 100kHz VPWM = 3.0V PACKAGE ORDER INFO Plastic MSOP TA (°C) DU 8-Pin 0 to 70 LX1742CDU Note: Available in Tape & Reel. Append the letter “T” to the part number. (i.e. LX1742CDUT) Copyright 2000 Rev. 1.0, 2002-08-23 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 1 LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION ABSOLUTE MAXIMUM RATINGS PACKAGE PIN OUT SW 1 8 OUT IN 2 7 GND FB 3 6 CS SHDN 4 5 ADJ DU PACKAGE (Top View) Note: Exceeding these ratings could cause damage to the device. All voltages are with respect to Ground. Currents are positive into, negative out of specified terminal. WWW . Microsemi .C OM Supply Voltage (VIN) ..................................................................................... -0.3V to 7.0V Output Voltage (OUT) ................................................................................................25.0V Feedback Input Voltage (VFB) ..............................................................-0.3V to VIN + 0.3V Shutdown Input Voltage (V SHDN ) ........................................................-0.3V to VIN + 0.3V PWM Input Amplitude .........................................................................-0.3V to VIN + 0.3V Analog Adjust Input Voltage (VADJ).................................................................-0.3V to VIN Source Input Current (ISRC)................................................................................. 500mARMS Operating Junction Temperature................................................................................ 150°C Storage Temperature Range.........................................................................-65°C to 150°C Lead Temperature (Soldering 180 seconds)............................................................... 235°C THERMAL DATA DU Plastic MSOP 8-Pin THERMAL RESISTANCE-JUNCTION TO AMBIENT, θJA THERMAL RESISTANCE-JUNCTION TO CASE, θJC 206°C/W 39°C/W Junction Temperature Calculation: TJ = TA + (PD x θJC). The θJA numbers are guidelines for the thermal performance of the device/pc-board system. All of the above assume no ambient airflow. FUNCTIONAL PIN DESCRIPTION NAME DESCRIPTION IN Unregulated IC Supply Voltage Input – Input range from +1.6V to 6.0V. Bypass with a 1µF or greater capacitor. FB Feedback Input – Connect to a resistive divider network between the output and GND to set the output voltage between VCC (IN) and 25V. The feedback threshold is 1.20V. SHDN Active-Low Shutdown Input – A logic low shuts down the device and reduces the supply current to 0.1µA. When shutdown, the LX1742 isolates the output from the input by turning off the internal MOSFET between LX and OUT. Connect SHDN to VCC for normal operation. SW Inductor Switching Connection – Internally connected to the drain of a 28V N-channel MOSFET. LX is high impedance in shutdown. CS Current-Sense Amplifier Input – Connecting a resistor between CS and GND sets the peak inductor current limit. Common terminal for ground reference. ADJ PWM Signal Input – Connects to the internal reference, via an internal filter and gain resistor, allowing a dynamic output voltage adjustment ±15% in corresponding to a varying duty cycle. 50% duty cycle yields a nominal output set via the FB pin (See Note) or ADJ input voltage range from 0.9V to 1.5V DC OUT Output voltage is adjustable up to 25V (maximum). Copyright 2000 Rev. 1.0, 2002-08-23 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 2 PACKAGE DATA GND LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION Unless otherwise specified, the following specifications apply over the operating ambient temperature 0°C ≤ TA ≤ 70°C except where otherwise noted and the following test conditions: VIN = 3.0V, VADJ = 0V, SHDN = VIN, VFB = 1.0V, Pin 8 = (not connected), Pin 1 = (+5V through 39.2Ω). Parameter Symbol Test Conditions Min LX1742 Typ Units Max ` Operating Voltage Minimum Start-up Voltage Start-up Voltage Temperature Coefficient TA = +25°C 1.6 kVST Guaranteed: not tested V SHDN < 0.4V VADJ = GND VFB IFB FB Threshold Voltage FB Input Bias Current ADJ Input Voltage Range 1.175 0 Switching mode VADJ 1 Shutdown High Input Voltage Shutdown Low Input Voltage Current Sense Bias Current Internal NFET On-resistance Switch Pin Leakage Current Switch Off-Time Diode Forward Voltage Diode Reverse Current 80 0.5 1.200 0 IADJ I SHDN V SHDN V SHDN ICS RDS(ON) ILEAK tOFF VF IR ADJ Input Bias Current Shutdown Input Bias Current 6.0 1.6 V V -2 Not Switching IQ Quiescent Current Notes: 1. 2. VIN VSU VADJ = VFB = 1.20V SHDN = GND VIN = 2V VIN = 2V 0 -50 1.6 2.0 TA = +25°C; ISW = 10mA; VFB = 1V VSW = 25V VFB = 1V TA = +25°C; IF = 150mA TA = +25°C; VR = 25V mV/°C 100 1.0 1.225 200 µA µA V nA VIN – 100mV V 200 50 4.0 1.1 0.23 300 1.0 1.5 0.4 6.0 WWW . Microsemi .C OM ELECTRICAL CHARACTERISTICS nA nA V V µA Ω µA ns V µA When using a DC source to adjust VOUT, the recommended VADJ (range) is 0.9V to 1.50V: see figure 9. Guaranteed typical value (not tested) @ TA=25°C (see section “Inductor Selection & Current Limit Programming”). SIMPLIFIED BLOCK DIAGRAM FB A ADJ O ff-time Controller SW OUT Reference Logic B GND 4µ A Current Limiter CS Shutdown Logic IN Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 SHDN Page 3 ELECTRICALS 1.2V Reference Copyright 2000 Rev. 1.0, 2002-08-23 Driver LX1742 I N T E G R A T E D High Efficiency High Voltage Boost Controller P R O D U C T S P RODUCTION WWW . Microsemi .C OM APPLICATION CIRCUITS Typical LCD Bias Applications L1 VBAT = (1.6V to 6.0V) CR1 UPS5819 47µH R VOUT = VREF 1 + 1 R2 SW IN SHDN OUT R1 LX1742 LX1742 C2* 1nF FB ADJ CS RCS 4kΩ GND C1 10µF R2 * Optional Component used to reduce output voltage ripple. Figure 1 – Circuit Showing Fixed Output Voltage Operation Using an External Schottky Diode Switch (CR1). L1 VBAT = (1.6V to 6.0V) CR1 UPS5819 47µH R VOUT = VADJ 1 + 1 R2 SW IN OUT SHDN LX1742 LX1742 RPWM 100kHz VPWM = 3.0V FB GND C 2* 1nF C1 10µF CS ADJ 625kΩ R1 RCS 4kΩ R2 * Optional Component used to reduce output voltage ripple. Figure 2 – Circuit Showing Dynamic Output Voltage Operation Via PWM Input Using an External Schottky Diode Switch (CR1). Copyright 2000 Rev. 1.0, 2002-08-23 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 APPLICATIONS Note: An in-series RPWM will attenuate the PWM amplitude to the proper signal level at the ADJ pin. With the RPWM value shown, a PWM signal having a duty of 30% to 50% will generate 0.9V to 1.5V at the ADJ pin. Page 4 LX1742 I N T E G R A T E D High Efficiency High Voltage Boost Controller P R O D U C T S P RODUCTION APPLICATION CIRCUITS (CONTINUED) WWW . Microsemi .C OM Typical LCD Bias Applications (Cont) L1 VBAT = (1.6V to 6.0V) 47µH SW IN OUT SHDN LX1742 LX1742 + - FB GND C2* 1nF C1 10µF CS ADJ VADJ = 0.9V to 1.5V R1 R VOUT = VADJ 1+ 1 R2 RCS 4kΩ R2 * Optional Component used to reduce output voltage ripple. Figure 3 – Circuit Showing Dynamic Output Voltage Operation Via Analog Voltage Input and Using the Internal Diode Switch (Optional). APPLICATIONS Copyright 2000 Rev. 1.0, 2002-08-23 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 5 LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION APPLICATION INFORMATION OUTPUT VOLTAGE PROGRAMMING Selecting the appropriate values for R1 and R2 in the voltage divider connected to the feedback pin programs the output voltage. Using a value between 40KΩ and 75KΩ for R2 works well in most applications. R1 can be determined by the following equation (where VREF = 1.29V nominal): The load is powered from energy stored in the output capacitor during the inductor charging cycle. Once the peak inductor current value is achieved, the driver output is turned off (off-time is typically 300ns) allowing a portion of the energy stored in the inductor to be delivered to the load. This causes the output voltage to continue to rise at the input to the feedback circuit (i.e., comparator A). If the voltage at the FB input is still less than 1.20V at the end of the off-time period, the output switches the internal FET “on” and the inductor charging cycle repeats until VFB is greater than the internal reference. Typical converter switching behavior is shown in Figure 11. INDUCTOR SELECTION AND CURRENT LIMIT PROGRAMMING Setting the level of peak inductor current to approximately 2X the expected maximum DC input current will minimize the inductor size, the input ripple current, and the output ripple voltage. The designer is encouraged to use inductors that will not saturate at the peak inductor current level. An inductor value of 47µH is recommended. Choosing a lower value emphasizes peak current overshoot while choosing a higher value emphasizes output ripple voltage. The peak switch current is defined using a resistor placed between the CS terminal and ground and the IPEAK equation is: The application of an external voltage source at the ADJ pin allows for output voltage adjustment over a typical range of approximately ±15%. The designer can select one of two possible methods. One option is to vary the reference voltage directly at the ADJ pin by applying a DC voltage from 0.9 to 1.5V. The second option is to connect a PWM logic signal to the ADJ pin (e.g., see Figure 2). The LX1742 includes an internal 50pF capacitor to ground that works with an external resistor to create a low-pass filter (i.e., filter out the AC component of a pulse width modulated input of fPWM ≥ 100KHz). Copyright 2000 Rev. 1.0, 2002-08-23 (VOUT - VREF ) VREF DESIGN EXAMPLE: Let R2 equals 72K and the required VOUT equal to 18V. R1 = 72KΩ × I PEAK = I MIN (18V - 1.20V ) = 1.MΩ 1.20V + V IN L t D + I SCALE R CS The maximum IPEAK value is limited by the ISRC value (max. = 0.8ARMS). The minimum IPEAK value is defined when RCS is zero. A typical value for the minimum peak current (IMIN) at 25oC is 104mA. The parameter tD is related to internal operation of the device. A typical value at 25oC is 800ns. A typical value of ISCALE at 25oC is 22mA per KΩ. All of these parameters have an effect on the final IPEAK value. DESIGN EXAMPLE: Determine IPEAK where VIN equals 3.0V and RCS equals 4.02KΩ using nominal values for all other parameters. IPEAK =104mA+ 3.0V 47µH ×800ns+ 22mA ×4.02KΩ kΩ The result of this example yields a nominal IPEAK equal to 243.5mA. Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 6 APPLICATIONS The adjustment voltage level is selectable (with limited accuracy) by implementing the voltage divider created between the external series resistor and the internal 2.5MΩ resistor. If the DC voltage at the ADJ pin drops below 0.6V, the device will revert to the internal reference voltage level of 1.20V. A typical adjustment curve is shown in Figure 9 (see section titled: Characteristic Curves). Disabling the LX1742 is achieved by driving the SHDN pin with a low-level logic signal thus reducing the device power consumption to less than 1µA. R1 = R2 × WWW . Microsemi .C OM FUNCTIONAL DESCRIPTION The LX1742 is a Pulse Frequency Modulated (PFM) boost converter that is optimized for large step up voltage applications like LCD biasing. It operates in a pseudohysteretic mode with a fixed switch “off time” of 300ns. Converter switching is enabled when the feedback voltage, VFB, falls below the 1.20V reference or VADJ (see Block Diagram). When this occurs, comparator A activates the off-time controller. The off-time controller and the current limiting circuits activate comparator B and toggles the output driver circuit. The output is switched “on”, and remains “on”, until the inductor current ramps up to the peak current level. This current level is set via the external RCS resistor and monitored through the CS and SRC inputs. LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION APPLICATION INFORMATION (CONTINUED) VRIPPLE = ∆VDROOP + ∆VOVERSHOOT + 10mV The initial droop can be estimated as follows where the 1.2 value in the denominator is an estimate of the typical voltage drop across the inductor and the internal FET’s RDS_ON: ∆VDROOP L × (IPK × IOUT ) C = OUT (VIN − 1.2) The output overshoot can be estimated as follows where the 0.5 value in the denominator is an estimate of the voltage drop across the diode: 1 ∆VOVERSHOOT = L × (I PK − IOUT )2 COUT (VOUT + 0.5 − VIN ) 2× DESIGN EXAMPLE: Determine the VRIPPLE where IPK equals 200mA, IOUT equals 35mA, L equals 47µH, COUT equals 4.7µF, VIN equals 3.0V, and VOUT equals 18.0V: 1 ∆VOVERSHOOT = Copyright 2000 Rev. 1.0, 2002-08-23 47µH 2 × (200mA − 35mA ) 4.7µF = 9.4mV (18.0 + 0.5 − 3.0) 2 × Therefore, for COUT equals 4.7µF: VRIPPLE = 38mV + 9.4mV + 10mV = 57.4mV Increasing the output capacitor value results in the reduction of the output voltage ripple voltage. Low ESR capacitors are recommended to reduce ripple caused by the switching current. Multi-layer ceramic capacitors with X5R or X7R dielectric are a superior choice featuring small size, very low ESR, and a temperature stable dielectric. Low ESR electrolytic capacitors such as solid tantalum or OS-CON types are also acceptable. Moreover, adding a capacitor from the output to the feedback pin (C2) allows the internal feedback circuitry to respond faster which further minimizes output voltage ripple and reduces noise coupling into the high impedance feedback input. DIODE SELECTION A Schottky diode is recommended for most applications (e.g. Microsemi UPS5819). The low forward voltage drop and fast recovery time associated with this type of device supports the switching demands associated with this circuit topology. The designer is encouraged to consider the diode’s average and peak current ratings with respect to the application’s output and peak inductor current requirements. Further, the diode’s reverse breakdown voltage characteristic must be capable of withstanding a negative voltage transition that is greater than VOUT. The LX1742 has a built in diode that may be used instead of an external device. Using this internal diode reduces system cost however, overall efficiency decreases. The electrical connections corresponding to use of the internal diode are shown in Figure 3. In this configuration, the inductor is connected between the input source and the SW pin (1). The output is taken directly from OUT pin (8). PCB LAYOUT The LX1742 produces high slew-rate voltage and current waveforms hence; the designer should take this into consideration when laying out the circuit. Minimizing trace lengths from the IC to the inductor, diode, input and output capacitors, and feedback connection (i.e., pin 3) are typical considerations. Moreover, the designer should maximize the DC input and output trace widths to accommodate peak current levels associated with this circuit. Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 APPLICATIONS ∆VDROOP 47 µH × (200mA × 35mA ) 4.7 µF = 38mV = (3.0 − 1.2) WWW . Microsemi .C OM OUTPUT RIPPLE CAPACITOR SELECTION Output voltage ripple is a function of the inductor value (L), the output capacitor value (COUT), the peak switch current setting (IPEAK), the load current (IOUT), the input voltage (VIN) and the output voltage (VOUT) for a this boost converter regulation scheme. When the switch is first turned on, the peak-to-peak voltage ripple is a function of the output droop (as the inductor current charges to IPEAK), the feedback transition error (i.e., typically 10mV), and the output overshoot (when the stored energy in the inductor is delivered to the load at the end of the charging cycle). Therefore the total ripple voltage is Page 7 LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION OVERVIEW The LXE1742 evaluation board is available from Microsemi for assessing overall circuit performance. The evaluation board, shown in Figure 5, is 3 by 3 inches (i.e., 7.6 X 7.6cm) square and factory calibrated to provide a nominal 18V output from a 1.6V to 6.0V input. Circuit designers can easily modify the output voltage and peak current to suit their particular application by adjusting the R2, R3, and R4 values accordingly. Further, other components are easily swapped out to promote design verification of any particular circuit application. Table 1 describes the evaluation board’s electrical interface. ELECTRICAL CONNECTIONS The system level DC input voltage is applied to VIN. Connect the test load to VOUT. The Vin & GND terminal at J4 provides easy test point access. A similar connection is available for monitoring the output voltage via J5. The output voltage is adjusted by selecting appropriate values for R3 and R24. Further adjustment of the output voltage is achieved by applying either a DC voltage or a PWM-type signal to the ADJ input (J4). The evaluation board accommodates both low frequency (f < 100KHz) and high frequency (f > 100KHz) PWM signals by connecting either JU1 or JU4 jumper position respectively. The ADJ pin is easily grounded for fixed voltage applications by inserting a jumper into the JU5 position. Table 2 provides a complete list of all jumper positions. Removing the jumper from the /SHDN position disables the LX1742 by disconnecting pin 4 from VIN. The load is still capable of drawing current through the inductor & diode circuit path when the IC is in shutdown mode. Hence, VOUT during shutdown will be approximately VIN minus the inductor and diode forward voltage drop. The LX1742 can achieve output voltages up to 25V. In certain applications, it is necessary to protect the load from excessive voltage excursions. The evaluation board provides a zener clamp diode (D1) for this purpose. The LXE1742 evaluation board offers a cost effective solution for evaluation of the LX1742. Table 3 provides the factory installed component list for the evaluation board and the board schematic is shown in Figure 4. WWW . Microsemi .C OM EVALUATION BOARD Table 1: Input and Output Pin Assignments Name Application Range VIN 0 to 6V Main power supply input for evaluation board Vin (J4) 0 to 6V Connected to VIN (Alternate position or test point) SHDN (J4) 0 to VIN Pulled up to VCC on board (10KΩ), Ground to inhibit the LX1742. Apply a DC input or PWM input to adjust the output voltage (note: see figure 9). GND (J4) 0 to VIN100mV 0V GND 0V ADJ (J4) 0 to VIN 0V VOUT VIN to 25V SWITCH N/A /SHDN 0 to VIN Circuit ground Additional circuit ground connection point. Apply a DC input or PWM input to adjust the output voltage. Additional circuit ground connection point. Output voltage test point. Programmed for 18V output, adjustable up to 25V. EVALUATION BOARD FDBK GND2 Description Test point for lX1742 pin 1. A DC voltage above (below) 1.6V (0.4V) enables (disables) the LX172 Note: All pins are referenced to ground. Copyright 2000 Rev. 1.0, 2002-08-23 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 8 LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION WWW . Microsemi .C OM EVALUATION BOARD (CONTINUED) Table 2: Jumper Pin Position Assignments Jumper / Position Function VIN n/a Attach the primary input power form to this contact. Input power may also be applied to the pin marked Vin on J4. VOUT n/a Use this contact to measure the circuit’s output voltage at pin 8. SWITCH n/a Use this contact to observe the switching waveform at the Schottky anode (i.e., LX1742 pin 1). FDBK n/a Use this contact to measure the circuit’s feedback voltage at pin 3. GND / GND2 n/a Use these contact to connect to circuit ground. /SHDN 1/0 JU3 1 JU1 1/0/0 JU4 0/1/0 JU5 0/0/1 Inserting a jumper (1) enables the LX1742 by connecting pin 4 directly to VIN. Removing this jumper (0) disables the LX1742 Remove the factory installed jumper and insert a 4 ~6cm wire loop (optional) to observe the inductor current waveform using a current probe. Use this position when adjusting the output with an external PWM that has a repetition rate less than 100KHz. Or when using a DC adjustment voltage. Use this position when adjusting the output with an external PWM that has a repetition rate in excess of 100KHz. Use this position to ground the ADJ (pin 5) when using the LX1742 in a fixed output voltage mode Note: (1) = jumper installed; (0) = jumper not installed. Table 3: Factory Installed Component List for the LX1742 Evaluation Board Ref Part Description C1 CAPACITOR, 4.7µF, 1210, 35V C2 CAPACITOR, 4.7µF, 1210, 35V C3 CAPACITOR, 1000pF, 0805, 35V C4 CAPACITOR, 2.2µF, 0603, 35V CAPACITOR, (SPARE); see note 1. CR1 Microsemi UPS5819, SCHOTTKY, 1A, 40V, POWERMITE L1 INDUCTOR, 47µH, 480mA, SMT Q1 MMBT3904 TRANSISTOR, NPN, 40V, SOT-23 D1 BZX84C24, ZENER DIODE, TBD R1 RESISTOR, 625K, 1/16W, 0805 R2, R5, R6 RESISTOR, 1.0K, 1/16W, 0805 R3 RESISTOR, 1.0M, 1/16W, 0805 R4 RESISTOR, 72K, 1/16W, 0805 R7 RESISTOR, 100K, 1/16W, 0805 U1 Microsemi LX1742CDU BOOST CONTROLLER; see note 2. Notes 1. 2. Copyright 2000 Rev. 1.0, 2002-08-23 EVALUATION BOARD C5 & C6 Use these locations to insert additional input (C6) and/or output (C5) capacitance. The minimum part set for a working power supply consists of: C1, C2, CR1, L1, R2, R3, R4, U1. Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 9 LX1742 I N T E G R A T E D High Efficiency High Voltage Boost Controller P R O D U C T S P RODUCTION EVALUATION BOARD (CONTINUED) J5 Testpoint CR1 UPS5819 J4 1 1 Vin 2 /SHDN 3 2 4 1 C1 4.7µF 35V + L1 47.0µH J3 Jumper + U1 J2 Jumper FB IN ADJ J1 R1 Jumper 625K 1 2 J4 Jumper R6 100K C4 2.2µF 35V J5 Jumper Testpoint TP3 R4 72K R2 1K Q1 MMBT3904/SOT D4 BZX84C24/SOT R5 1K 1 C2 4.7µF 35V Testpoint GND LX1742CDU 2 R3 1M CS /SHDN 2 C3 1000pF OUT SW 1 ADJ TP2 2 WWW . Microsemi .C OM TP1 R6 1K TP4 GND Testpoint Figure 4 – LXE1742 Boost Evaluation Board Schematic Note: Factory installed jumper positions shown Copyright 2000 Rev. 1.0, 2002-08-23 EVALUATION BOARD Figure 5 – LXE1742 - LX1742 Circuit Evaluation Board Figure 6 – LXE1742 - Evaluation Board Trace Layout Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 10 LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION X4 WWW . Microsemi .C OM EVALUATION BOARD (CONTINUED) X3 VIN L1 SWITCH Vin /SHDN ADJ CR1 GND U1 JU1 JU4 R1 GND R7 R2 VOUT FDBK Q1 GND2 JU5 Microsemi LX1742 X1 Figure 7 – LXE1742 - Bottom Trace Layer EVALUATION BOARD SGE#3503 REV X2 X2 Figure 8 – LXE1742 - Board Layout EVALUATION BOARD Copyright 2000 Rev. 1.0, 2002-08-23 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 11 LX1742 I N T E G R A T E D P R O D U C T S High Efficiency High Voltage Boost Controller P RODUCTION CHARACTERISTIC CURVES WWW . Microsemi .C OM 30 100% 25 Efficiency (%) Output Voltage 90% 20 15 10 80% 70% 5 60% 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Adj ustment Voltage 50% 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Output Current Figure 10 – Efficiency vs. Output Current (mA) Figure 9 – Typical VOUT versus VADJ 0 ~ 0.4V : LX1742 uses internal 1.2V reference. 0.5V ~ 0.7V : transition from internal to external reference. 0.8 to 1.5V : LX1742 defaults to external voltage reference. Top: VIN = 3.6V, VOUT = 5.2V, L1 = 47.0µH Bottom: VIN = 5.5V, VOUT = 18.0V, L1 = 47.0µH RDS_on (Ohms) 1.40 1.30 1.20 1.10 1.00 0 25 Temperature 75 C Ch1 – Switch voltage; Ch2 – Output voltage; Ch4 – Inductor current. (VIN = 3.6V, VOUT = 18V, RLOAD = 2KΩ) CHARTS Figure 12 – Typical RDS(on) vs. Temperature Figure 11 – Typical switching waveforms: Copyright 2000 Rev. 1.0, 2002-08-23 50 o Condition: VIN = 3.0V; ISW = 10mA Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 12 LX1742 I N T E G R A T E D High Efficiency High Voltage Boost Controller P R O D U C T S P RODUCTION DU WWW . Microsemi .C OM PACKAGE DIMENSIONS 8-Pin Miniature Shrink Outline Package (MSOP) A Dim B H G P M C N D L K A B C D G H J K L M N P MILLIMETERS MIN MAX 2.85 3.05 2.90 3.10 – 1.10 0.25 0.40 0.65 BSC 0.38 0.64 0.13 0.18 0.95 BSC 0.40 0.70 3° 0.05 0.15 4.75 5.05 INCHES MIN MAX .112 .120 .114 .122 – 0.043 0.009 0.160 0.025 BSC 0.015 0.025 0.005 0.007 0.037 BSC 0.016 0.027 3° 0.002 0.006 0.187 0.198 NOTES MECHANICALS PRODUCTION DATA – Information contained in this document is proprietary to Microsemi and is current as of publication date. This document may not be modified in any way without the express written consent of Microsemi. Product processing does not necessarily include testing of all parameters. Microsemi reserves the right to change the configuration and performance of the product and to discontinue product at any time. Copyright 2000 Rev. 1.0, 2002-08-23 Microsemi Integrated Products Division 11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570 Page 13