19-1802; Rev 0; 10/00 ILABLE N KIT AVA EVALUATIO High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 Features ♦ Reverse Battery Protection for DC-DC Converter and Load ♦ Up to 90% Efficiency ♦ No External Diode or FETs Needed ♦ Internal Synchronous Rectifier ♦ 4µA Quiescent Current ♦ <1µA Shutdown Supply Current ♦ +1.5V to +5.5V Input Voltage Range ♦ Accurate SHDN Threshold for Low-Battery Cutoff ♦ BATT Connected to OUT in Shutdown for Backup Power (MAX1832/MAX1833) ♦ RST Output (MAX1833/MAX1835) ♦ Fixed +3.3V Output Voltage (MAX1833/MAX1835) ♦ Adjustable Output Voltage (MAX1832/MAX1834) ♦ Up to 150mA Output Current ________________________Applications Medical Diagnostic Equipment Pagers Hand-Held Instruments Remote Wireless Transmitters Digital Cameras Cordless Phones Battery Backup PC Cards Local 3.3V or 5V Supply ♦ Tiny 6-Pin SOT23 Package Ordering Information PART TEMP. RANGE PINPACKAGE MAX1832EUT-T -40°C to +85°C 6 SOT23-6 AAOT MAX1833EUT-T -40°C to +85°C 6 SOT23-6 AAOU MAX1834EUT-T -40°C to +85°C 6 SOT23-6 AAOV MAX1835EUT-T -40°C to +85°C 6 SOT23-6 AAOW Note: Requires special solder temperature profile described in the Absolute Maximum Ratings. Selector Guide Pin Configurations TOP VIEW SHDN 1 BATT 2 6 MAX1832 MAX1834 GND 3 SOT23-6 FB SHDN 1 5 OUT BATT 2 4 LX GND 3 TOP MARK 6 MAX1833 MAX1835 RST 5 OUT 4 LX PART OUTPUT VOLTAGE OUTPUT VOLTAGE IN SHUTDOWN MAX1832EUT-T Adjustable VBATT MAX1833EUT-T Fixed 3.3V VBATT MAX1834EUT-T Adjustable VBATT - 0.7V MAX1835EUT-T Fixed 3.3V VBATT - 0.7V SOT23-6 ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX1832–MAX1835 General Description The MAX1832–MAX1835 are high-efficiency step-up converters with complete reverse battery protection that protects the device and the load when the battery is reversed. They feature a built-in synchronous rectifier, which allows for over 90% efficiency and reduces size and cost by eliminating the need for an external Schottky diode. These step-up converters operate from a +1.5V to +5.5V input voltage range and deliver up to 150mA of load current. The MAX1833/MAX1835 have a fixed +3.3V output, and the MAX1832/MAX1834 have adjustable outputs from +2V to +5.5V. In shutdown, the MAX1832/MAX1833 connect the battery input to the voltage output, allowing the input battery to be used as a backup or real-time clock supply when the converter is off (see Selector Guide). The MAX1832–MAX1835 are available in a miniature 6pin SOT23 package. The MAX1832EVKIT is available to shorten the design cycle. MAX1832–MAX1835 High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 ABSOLUTE MAXIMUM RATINGS BATT, LX to GND.........................................................-6V to +6V LX to OUT ....................................................................-6V to +1V SHDN to GND..............................................-6V to (VOUT + 0.3V) OUT, FB, RST TO GND ............................................-0.3V to +6V LX Current ................................................................................1A Continuous Power Dissipation (TA = +70°C) SOT23-6 (derate 9.1mW/°C above +70°C) (Note 1)....727mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) (Note 2) ...................+300°C Note 1: Thermal properties are specified with product mounted on PC board with one square-inch of copper area and still air. Note 2: This device is constructed using a unique set of packaging techniques that impose a limit on the thermal profile the device can be exposed to during solder attach and rework. This limit permits only the use of the solder profiles recommended in the industry-standard specification, IPC/JEDEC J-STD-020A, paragraph 7.6, Table 3 for the IR/VPR and Convection reflow. Preheating is required. Hand or wave soldering is not allowed. Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (V SHDN = +1.5V, VOUT = +3.3V, VBATT = +2V, GND = 0, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER SYMBOL Output Range VOUT Battery Input Range VBATT Startup Battery Input Voltage VSU MIN TYP 2.0 1.5 RLOAD = 2.6kΩ TA = +25°C 1.22 TA = -40°C to +85°C 1.24 Output Voltage VOUT MAX1833/ MAX1835 TA = +25°C 3.225 TA = -40°C to +85°C 3.208 FB Trip Voltage VFB MAX1832/ MAX1834 TA = +25°C 1.208 TA = -40°C to +85°C 1.204 3.5 IFB MAX1832/ MAX1834, VFB = +1.3V TA = +25°C FB Input Bias Current TA = -40°C to +85°C 4.0 0.4 N-Channel On-Resistance RNCH VOUT = +3.3V ILX = 100mA TA = +25°C P-Channel On-Resistance RPCH VOUT = +3.3V ILX = 100mA TA = +25°C N-Channel Switch Current Limit IMAX Switch Maximum On-Time tON VOUT = +3.3V 3.290 MAX UNITS 5.5 V 5.5 V 1.5 3.355 3.372 1.228 1.248 1.252 TA = -40°C to +85°C 0.5 TA = -40°C to +85°C 1.2 1.3 0.73 435 TA = -40°C to +85°C 400 525 615 650 3.5 5 6.5 2 17 34 TA = -40°C to +85°C 0 VOUT = +3.3V Quiescent Current into OUT (Note 4) VOUT = +3.5V, VFB = +1.3V Shutdown Current into OUT VOUT = +3.5V, V SHDN = VFB = 0V TA = +25°C 39 2.5 TA = -40°C to +85°C 7.0 8.0 0.05 _______________________________________________________________________________________ V Ω Ω V TA = +25°C Synchronous Rectifier ZeroCrossing Current V nA 1.6 TA = +25°C V 20 1.5 ILX = 100mA, PCH off, VOUT = +3.5V, VFB = +1.3V P-Channel Catch-Diode Voltage 2 CONDITIONS MAX1832/MAX1834 1 mA µs mA µA µA High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 (V SHDN = +1.5V, VOUT = +3.3V, VBATT = +2V, GND = 0, TA = -40°C to +85°C. Typical values are at TA = +25°C, unless otherwise noted.) (Note 3) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0 10 µA 1.8 5.0 Reverse Battery Current into OUT VOUT = 0, VBATT = V SHDN = VLX = -3V Quiescent Current into BATT VOUT = +3.5V, VFB = +1.3V Shutdown Current into BATT VOUT = +3.5V, VBATT = +2V, V SHDN = 0 0.001 1 µA Reverse Battery Current into BATT VOUT = 0, VBATT = V SHDN = VLX = -3V 0.002 10 µA SHDN Logic Low VBATT = +1.5V to +5.5V 0.3 V 1.228 1.271 SHDN Threshold Rising edge TA = +25°C TA = -40°C to +85°C 6.0 TA = +25°C 1.185 TA = -40°C to +85°C 1.170 SHDN Threshold Hysteresis 1.286 0.02 µA V V SHDN Input Bias Current VOUT = +5.5V, V SHDN = +5.5V, TA = +25°C 13 100 nA SHDN Reverse Battery Current VOUT = 0, VBATT = V SHDN = VLX = -3V 52 150 µA MAX1833/ MAX1835, falling edge 2.980 3.110 RST Threshold RST Voltage Low TA = +25°C 2.830 TA = -40°C to +85°C 2.800 V I RST = 1mA, VOUT = +2.5V TA = +25°C RST Leakage Current V RST = +5.5V LX Leakage Current VLX = +5.5V LX Reverse Battery Current VOUT = 0, VBATT = V SHDN = VLX = -3V Maximum Load Current Efficiency 3.140 ILOAD TA = -40°C to +85°C TA = +25°C TA = -40°C to +85°C 0.2 0.1 100 1 1 100 100 0.001 10 V nA nA µA VBATT = +2V, VOUT = +3.3V 150 mA VBATT = +2V, VOUT = +3.3V, ILOAD = 40mA 90 % Note 3: All units are 100% production tested at TA=+25°C. Limits over the operating temperature range are guaranteed by design and not production tested. Note 4: Supply current into OUT. This current correlates directly to the actual battery-supply current, but is reduced in value according to the step-up ratio and efficiency. _______________________________________________________________________________________ 3 MAX1832–MAX1835 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (VOUT = +3.3V, VBATT = +2V, unless otherwise noted.) (Figure 1) EFFICIENCY vs. LOAD CURRENT (VOUT = 3.3V) VBATT = +2.7V 75 VSHDN = VBATT R1 = 309Ω R2 = 100kΩ MAX1834 VBATT = +1.5V 85 1 10 100 VBATT = +1.5V VSHDN = VBATT R1 = 100kΩ R2 = 100kΩ CIN = 20µF COUT = 20µF MAX1834 75 VSHDN = VBATT MAX1835 75 0.1 80 80 65 1000 70 0.1 1 10 100 1000 0.1 1 10 10 100 ILOAD (mA) ILOAD (mA) ILOAD (mA) MAXIMUM OUTPUT CURRENT vs. BATTERY VOLTAGE STARTUP BATTERY VOLTAGE vs. LOAD RESISTANCE INPUT CURRENT AND OUTPUT VOLTAGE vs. BATTERY VOLTAGE (SHUTDOWN, NO LOAD) VSHDN = VBATT 1.6 IBATT (µA) VBATT (V) VOUT = +5.0V 1.5 VOUT = +5.0V 1.4 4 VOUT 3 0.6 2 0.4 IBATT VOUT = +3.3V 0.2 1 0 0 1.3 0 VOUT = +2.5V 1.2 1 2 3 4 5 6 10 -1 -0.2 100 1k -6 -5 -4 -3 -2 -1 0 10k 1 2 3 4 5 6 VBATT (V) RLOAD (Ω) VBATT (V) INPUT CURRENT AND OUTPUT VOLTAGE vs. BATTERY VOLTAGE (SHUTDOWN, LOADED) INPUT CURRENT AND OUTPUT VOLTAGE vs. BATTERY VOLTAGE (ON, NO LOAD) INPUT CURRENT AND OUTPUT VOLTAGE vs. BATTERY VOLTAGE (ON, LOADED) 120 4 200 VOUT 3 150 100 2 IBATT 1 50 0 0 -1 -50 -6 -5 -4 -3 -2 -1 0 1 VBATT (V) 2 3 4 5 6 IBATT (µA) 100 80 3.5 3.0 2.5 IBATT 2.0 VOUT 60 1.5 40 1.0 20 0.5 IBATT 0 -20 -6 -5 -4 -3 -2 -1 0 1 VBATT (V) 2 3 4 5 6 MAX1832/35 toc09 300 4.0 IBATT (mA) 140 5 MAX1832/35 toc08 VSHDN = VBATT RLOAD = ∞ R3 = 1MΩ R4 = 220kΩ C1 = 10nF VOUT (V) 160 6 VOUT (V) 250 MAX1832/35 toc07 VSHDN = 0 RLOAD = 22Ω MAX1833 VSHDN = VBATT V = 3.3V 250 OUT RLOAD = 22Ω R3 = 1MΩ 200 R4 = 220kΩ C1 = 10nF 150 6 5 IBATT 4 3 VOUT 100 2 50 1 0 0 0 -0.5 -50 -1 -6 -5 -4 -3 -2 -1 0 1 VBATT (V) _______________________________________________________________________________________ 2 3 4 5 6 VOUT (V) 50 300 6 5 0.8 150 100 1.0 MAX1832/35 toc06 VSHDN = 0 RLOAD = ∞ MAX1833 VOUT (V) VOUT = +3.3V 1.2 MAX1832/35 toc05 VOUT = +2.5V 200 1.7 MAX1832/35 toc04 250 ILOAD (mA) VBATT = +2.0V VBATT = +1.5V 70 4 VBATT = +2.0V EFFICIENCY (%) EFFICIENCY (%) EFFICIENCY (%) 85 80 VBATT = +2.7V 90 85 MAX1832/35 toc02 VBATT = +3.3V 90 95 MAX1832/35 toc01 95 EFFICIENCY vs. LOAD CURRENT (VOUT = 2.5V) MAX1832/35 toc03 EFFICIENCY vs. LOAD CURRENT (VOUT = 5.0V) IBATT (mA) MAX1832–MAX1835 High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 High-Efficiency Step-Up Converters with Reverse Battery Protection in a SOT23-6 ON/OFF RESPONSE LOAD TRANSIENT MAX1832/35 toc10 MAX1832/35 toc11 VBATT 1V/div VOUT 100mV/div VOUT 1V/div ILOAD 100mA/div 0 2ms/div VSHDN = VBATT = 2.0V, RLOAD = 22Ω, VOUT = 3.3V 40µs/div RLOAD = 22Ω TO 200Ω, VOUT = +3.3V, VBATT = +2.0V SHUTDOWN RESPONSE LINE TRANSIENT MAX1832/35 toc13 MAX1832/35 toc12 VSHDN 1V/div VBATT 500mV/div 0 VOUT 1V/div VOUT 50mV/div 0 MAX1833 40µs/div RLOAD = 22Ω, VBATT = 3.3V, VBATT = 2.0V 40µs/div IOUT = 100mA, VOUT = +3.3V, VBATT = +2.0V TO +2.5V SWITCHING WAVEFORMS MAX1832/35 toc14 VLX 500mA/div VOUT 100mV/div VLX 2V/div 10µs/div IOUT = 40mA, VOUT = +3.3V, VBATT = +2.0V _______________________________________________________________________________________ 5 MAX1832–MAX1835 Typical Operating Characteristics (continued) (VOUT = +3.3V, VBATT= +2V, unless otherwise noted.) (Figure 1) High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 MAX1832–MAX1835 Pin Description PIN MAX1832 MAX1834 NAME MAX1833 MAX1835 FUNCTION 1 1 SHDN Shutdown. A high logic level turns on the device. When SHDN is low the part is off, and the current into BATT is typically 0.1µA. For the MAX1832/MAX1833, the battery is connected to OUT through an internal PFET and the external inductor when SHDN is low. SHDN can be used for low-battery cutoff (1.228V threshold). See Low-Battery Cutoff. SHDN has reverse battery protection. 2 2 BATT Battery Voltage Connection. BATT has reverse battery protection. 3 3 GND Ground 4 4 LX 5 5 OUT 6 — FB — 6 RST Inductor Connection. N-channel MOSFET switch drain and synchronous rectifier P-channel switch drain. LX has reverse battery protection. Output Voltage. Bootstrapped supply for the device. Output sense point for MAX1833/MAX1835. MAX1832/MAX1834 Feedback Input. Set the output voltage through a resistor-divider network. See Setting the Output Voltage. MAX1833/MAX1835 Power-On Reset Open-Drain Output. RST pulls low when the output is 10% below the regulation point. If not used, connect to GND. +1.5V TO +3.3V BATTERY 10µF +1.5V TO +5.0V BATTERY 10µF 10µH LX R4 220kΩ R3 1MΩ BATT 100kΩ MAX1833 MAX1835 C1 10nF RST SHDN OUTPUT +3.3V 10µF OUT LX R4 220kΩ POWER-ON RESET Figure 1a. MAX1833/MAX1835 Typical Operating Circuit BATT OUTPUT +5.0V OUT R2 309kΩ MAX1832 MAX1834 FB SHDN R3 1MΩ GND 6 10µH C1 10nF GND R1 100kΩ Figure 1b. MAX1832/MAX1834 Typical Operating Circuit _______________________________________________________________________________________ High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 The MAX1832–MAX1835 compact, high-efficiency step-up converters feature 4µA quiescent supply current to ensure the highest possible efficiency over a wide load range. With a minimum +1.5V input voltage, these devices are well suited for applications with two alkaline cells, two nickel-metal-hydride (NiMH) cells, or one lithium ion (Li+) cell. For the MAX1832 and MAX1833, the battery is connected to OUT through the inductor and an internal PFET when SHDN is low. This allows the input battery to be used as a backup or realtime clock supply when the converter is off by eliminating the voltage drop across the PFET body diode. The MAX1832–MAX1835 are ideal for low-power applications where ultra-small size is critical. These devices feature built-in synchronous rectification that significantly improves efficiency and reduces size and cost by eliminating the need for an external Schottky diode. Furthermore, these devices are the industry’s first boost regulators to offer complete reverse battery protection. This proprietary design protects the battery, IC, and the circuitry powered by the IC in the event the input batteries are connected backwards. Control Scheme A current-limited control scheme is a key feature of the MAX1832–MAX1835. This scheme provides ultra-low quiescent current and high efficiency over a wide output current range. There is no oscillator. The inductor current is limited by the 0.5A N-channel current limit or by the 5µs switch maximum on-time. Following each on-cycle, the inductor current must ramp to zero before another cycle may start. When the error comparator senses that the output has fallen below the regulation threshold, another cycle begins. An internal synchronous rectifier eliminates the need for an external Schottky diode reducing cost and board space. While the inductor discharges, the P-channel MOSFET turns on and shunts the MOSFET body diode. As a result, the rectifier voltage drop is significantly reduced, improving efficiency without adding external components. reverse battery protection N-channel MOSFET opens, protecting the device and load (Figures 2 and 3). Previously, this level of protection required additional circuitry and reduced efficiency due to added components in the battery current path. Applications Information Shutdown When SHDN is low, the device is off and no current is drawn from the battery. When SHDN is high, the device is on. If SHDN is driven from a logic-level output, the logic high (on) level should be referenced to VOUT to avoid intermittent turn on. If SHDN is not used at all, connect it to OUT. With SHDN connected to OUT, the MAX1834/MAX1835 startup voltage (1.65V) is slightly higher, due to the voltage across the PFET body diode. The SHDN pin has reverse battery protection. In shutdown, the MAX1832/MAX1833 connect the battery input to the output through the inductor and the internal synchronous rectifier PFET. This allows the input battery (rather than a separate backup battery) to provide backup power for devices such as an idled microcontroller, SRAM, or real-time clock, without the usual diode forward drop. If the output has a residual voltage during shutdown, a small amount of energy will be transfered from the output back to the input immediately after shutdown. This energy transfer may cause a slight momemntary “bump” in the input voltage. The magnitude and duration of the input bump are related to the ratio of CIN and COUT and the ability of the input to sink current. With battery input sources, the bump will be negligible, but with power-supply inputs (that typically cannot sink current), the bump may be 100s of mV. In shutdown, the MAX1834/MAX1835 do not turn on the internal PFET and thus do not have an output-to-input current path in shutdown. This allows a separate backup battery, such as a Li+ cell, to be diode-connected at the output, without leakage current flowing to the input. The MAX1834/MAX1835 still have the typical input-tooutput current path from the battery to the output, through the PFET body diode, in shutdown. Reverse Battery Protection The MAX1832–MAX1835 have a unique proprietary design that protects the battery, IC, and circuitry powered by the IC in the event that the input batteries are connected backwards. When the batteries are connected correctly, the reverse battery protection N-channel MOSFET is on and the device operates normally. When the batteries are connected backwards, the Low-Battery Cutoff The SHDN trip threshold of the MAX1832–MAX1835 can be used as a voltage detector, with a resistordivider, to power down the IC when the battery voltage falls to a set level (Figure 1). The SHDN trip threshold is 1.228V. To use a resistor-divider to set the shutdown voltage, select a value for R3 in the 100kΩ to 1MΩ _______________________________________________________________________________________ 7 MAX1832–MAX1835 Detailed Description MAX1832–MAX1835 High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 OUT STARTUP CIRCUITRY ZEROCROSSING DETECTOR MAX1832 MAX1834 P SHDN CONTROL LOGIC LX DRIVER FB N ERROR COMPARATOR BATT REVERSE BATTERY N PROTECTION MOSFET CURRENT LIMIT 1.228V GND Figure 2. MAX1832/MAX1834 Simplified Functional Diagram OUT MAX1833 MAX1835 STARTUP CIRCUITRY ZEROCROSSING DETECTOR P CONTROL LOGIC N 1.228V REVERSE BATTERY N PROTECTION MOSFET RST N LX DRIVER ERROR COMPARATOR BATT CURRENT LIMIT RESET GND 1.1V SHDN Figure 3. MAX1833/MAX1835 Simplified Functional Diagram 8 _______________________________________________________________________________________ High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 Table 1. Suggested Inductors and Suppliers MANUFACTURER INDUCTOR PHONE Coilcraft DS1608C-103 DO1606T-103 847-639-6400 Sumida CDRH4D18-100 CR43-100 847-956-0666 Murata LQH4N100K 814-237-1431 Power-On Reset The MAX1833/MAX1835 provide a power-on reset output (RST). A 100kΩ to 1MΩ pullup resistor from RST to OUT provides a logic control signal. This open-drain output pulls low when the output is 10% below its regulation point. If not used, connect it to GND. Setting the Output Voltage The output voltage of the MAX1832/MAX1834 is adjustable from +2V to +5.5V, using external resistors R1 and R2 (Figure 1b). Since FB leakage is 20nA (max), select feedback resistor R1 to be 100kΩ to 1MΩ. Calculate R2 as follows: V R2 = R1 OUT − 1 V FB where VFB = 1.228V. Inductor Selection The control scheme of the MAX1832–MAX1835 permits flexibility in choosing an inductor. A 10µH inductor performs well for most applications, but values from 4.7µH to 100µH may also be used. Small inductance values typically offer smaller physical size. Large inductance values minimize output ripple but reduce output power. Output power is reduced when the inductance is large enough to prevent the maximum current limit (525mA) from being reached before the maximum on-time (5µs) expires. For maximum output current, choose L such that: VBATT(MAX) (1µs) 0.525A IOUT(MAX) = 0.525A × 2 <L < VBATT(MIN) (5µs) VBATT(MIN) − 0.525A 0.525A (RNCH + RIND ) 2 VOUT where RIND is the inductor series resistance, and RNCH is the RDS(ON) of the N-channel MOSFET (0.4Ω typ). MAX1832–MAX1835 range to minimize battery drain. Calcuate R4 as follows: R4 = R3 ✕ (VOFF / VSHDN - 1) VOFF is the battery voltage at which the part will shut down and VSHDN = 1.228V. Note that input ripple can sometimes cause false shutdowns. To minimize the effect of ripple, connect a low-value capacitor (C1) from SHDN to GND to filter out input noise. Select a C1 value such that the R4 ✕ C1 time constant is above 2ms. Table 2. Suggested Surface-Mount Capacitors and Manufacturers VALUE (µF) DESCRIPTION MANUFACTURER PHONE 594/595 Dseries tantalum Sprague 603-224-1961 TAJ, TPSseries tantalum AVX 803-946-0690 4.7 to 10 X7R ceramic TDK 847-390-4373 4.7 to 22 X7R ceramic Taiyo Yuden 408-573-4150 4.7 to 47 Capacitor Selection Choose an output capacitor to achieve the desired output ripple percentage. COUT > 0.5 × L × 0.525A 2 r% × VOUT 2 where r is the desired output ripple in %. A 10µF ceramic capacitor is a good starting value. The input capacitor reduces the peak current drawn from the battery and can be the same value as the input capacitor. A larger input capacitor can be used to further reduce ripple and improve efficiency. PC Board Layout and Grounding Careful printed circuit layout is important for minimizing ground bounce and noise. Keep the IC’s GND pin and the ground leads of the input and output filter capacitors less than 0.2in (5mm) apart. In addition, keep all connections to the FB and LX pins as short as possible. In particular, when using external feedback resistors, _______________________________________________________________________________________ 9 MAX1832–MAX1835 High-Efficiency Step-Up Converters with Reverse Battery Protection in SOT23-6 6LSOT.EPS Package Information Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 10 © 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.