19-2107; Rev 3; 10/11 Regulated 3.3V/5.0V Step-Up/Step-Down Charge Pump The MAX1595 charge-pump regulator generates either 3.3V or 5V from a 1.8V to 5.5V input. The unique control architecture allows the regulator to step up or step down the input voltage to maintain output regulation. The 1MHz switching frequency, combined with a unique control scheme, allows the use of a ceramic capacitor as small as 1µF for 125mA of output current. The complete regulator requires three external capacitors—no inductor is needed. The MAX1595 is specifically designed to serve as a high-power, high- efficiency auxiliary supply in applications that demand a compact design. The MAX1595 is offered in space-saving 8-pin µMAX® and high-power 12-pin TQFN packages. Applications Features o Ultra-Small: Requires Only Three Ceramic Capacitors o No Inductors Required o Up to 125mA Output Current o Regulated ±3% Output Voltage o 1MHz Switching Frequency o 1.8V to 5.5V Input Voltage o 220µA Quiescent Current o 0.1µA Shutdown Current o Load Disconnect in Shutdown White LED Power Ordering Information Flash Memory Supplies Battery-Powered Applications Miniature Equipment PCMCIA Cards 3.3V to 5V Local Conversion Applications Backup-Battery Boost Converters 3V to 5V GSM SIMM Cards PART TEMP RANGE PIN-PACKAGE MAX1595EUA33+ MAX1595ETC33+ -40°C to +85°C 8 µMAX -40°C to +85°C 12 TQFN-EP* MAX1595EUA50+ -40°C to +85°C 8 µMAX MAX1595ETC50+ 12 TQFN-EP* -40°C to +85°C +Denotes a lead(Pb)-free/RoHS-compliant package. *EP = Exposed pad. Selector Guide µMAX is a registered trademark of Maxim Integrated Products, Inc. Typical Operating Circuit PART VOUT (V)** TOP MARK MAX1595EUA33+ MAX1595ETC33+ 3.3 — 3.3 AAEH MAX1595EUA50+ 5.0 — MAX1595ETC50+ AAEI 5.0 **Contact factory for other fixed-output voltages from 2.7V to 5.0V. Pin Configurations CXN INPUT CXP MAX1595 IN OUT OUTPUT TOP VIEW AOUT SHDN PGND GND AOUT 1 8 SHDN 2 7 CXP IN 3 6 CXN GND 4 5 PGND MAX1595 OUT µMAX Pin Configurations continued at end of data sheet. Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX1595 General Description MAX1595 Regulated 3.3V/5.0V Step-Up/ Step-Down Charge Pump ABSOLUTE MAXIMUM RATINGS IN, OUT, AOUT to GND............................................-0.3V to +6V SHDN to PGND ........................................................-0.3V to +6V PGND to GND .......................................................-0.3V to +0.3V CXN to PGND.....................-0.3V to (Lower of IN + 0.8V or 6.3V) CXP to GND ................................-0.8V to (Higher of OUT + 0.8V or IN + 0.8V but not greater than 6V) Continuous Output Current ...............................................150mA Continuous Power Dissipation (TA = +70°C) µMAX (derate 4.8mW/°C above +70°C) ..................387.8mW TQFN-EP (derate 24.4mW/°C above +70°C) .........1951.2mW Operating Temperature Range ...........................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Soldering Temperature (reflow) .......................................+260°C 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. PACKAGE THERMAL CHARACTERISTICS (Note 1) µMAX Junction-to-Ambient Thermal Resistance (θJA).....206.3°C/W Junction-to-Case Thermal Resistance (θJC)...............42°C/W TQFN Junction-to-Ambient Thermal Resistance (θJA)..........41°C/W Junction-to-Case Thermal Resistance (θJC).................6°C/W Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a fourlayer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial. ELECTRICAL CHARACTERISTICS (VIN = 2V for MAX1595_ _ _33, VIN = 3V for MAX1595_ _ _50, CIN = 1µF, CX = 0.22µF, COUT = 1µF, TA = -40° to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 2) PARAMETER Input Voltage Range SYMBOL CONDITIONS VIN MIN Input Undervoltage Lockout Threshold 1.40 Input Undervoltage Lockout Hysteresis TA = 0°C to +85°C 4.85 TA = -40°C to +85°C 4.80 VOUT 0 < ILOAD < 75mA, VIN TA = 0°C to +85°C = +2.0V TA = -40°C to +85°C 3.16 0 < ILOAD < 30mA, VIN TA = 0°C to +85°C = +1.8V TA = -40°C to +85°C No-Load Input Current 1.60 UNITS 5.5 V 1.72 V IQ 3.20 3.20 5.05 mV 5.15 5.20 3.33 3.40 3.44 3.33 3.16 V 3.40 3.44 VIN = +2.0V, MAX1595_ _ _33 220 320 VIN = +3.0V, MAX1595_ _ _50 240 350 1.0 1.15 MHz 5 µA 0.6 V 0.1 µA Switching Frequency fOSC ILOAD > 20mA, VOUT > VIN Shutdown Supply Current ISHDN VSHDN = 0V, VIN = +5.5V, VOUT = 0V SHDN Input Voltage Low VINL VIN = 2.0V to 5.5V SHDN Input Voltage High VINH VIN = 2.0V to 5.5V 0.85 1.6 SHDN Input Leakage Current Note 2: Specifications to -40°C are guaranteed by design, not production tested. 2 MAX 40 0 < ILOAD < 125mA, VIN = +3.0V Output Voltage TYP 1.8 _______________________________________________________________________________________ µA V Regulated 3.3V/5.0V Step-Up/Step-Down Charge Pump MAX1595 toc02 5.06 MAX1595 toc01 10000 5.04 50mV/div 100 10 OUTPUT VOLTAGE (V) 1000 SUPPLY CURRENT (µA) OUTPUT VOLTAGE vs. LOAD CURRENT OUTPUT WAVEFORM MAX1595 toc03 NO LOAD SUPPLY CURRENT vs. SUPPLY VOLTAGE VIN = 3.6V 5.02 VIN = 3.3V 5.00 4.98 VIN = 3V 4.96 4.94 1 4.92 VOUT = 5V VOUT = 5V 0 1 2 3 4 6 5 200ns/div OUTPUT WAVEFORM. AC-COUPLED. VIN = 3.6V, ILOAD = 100mA, COUT = 1µF SUPPLY VOLTAGE (V) VIN = 1.8V 80 70 VIN = 2.4V 50 40 1000 100 SHUTDOWN TIMING MAX1595 toc06 90 VIN = 3V 80 EFFICEINCY (%) 5V A 70 VIN = 3.3V 60 VIN = 3.6V 50 40 30 30 20 20 10 10 B 0 0 1 10 100 0.1 1 10 100 1000 100µs/div A: OUTPUT VOLTAGE: RL = 100Ω, 2V/div B: SHDN VOLTAGE: 2V/div LOAD CURRENT (mA) LOAD CURRENT (mA) OUTPUT VOLTAGE vs. SUPPLY VOLTAGE LOAD-TRANSIENT RESPONSE LINE-TRANSIENT RESPONSE MAX1595 toc08 MAX1595 toc07 A MAX1595 toc09 6 VOUT = 5V, ILOAD = 125mA 5 A B B OUTPUT VOLTAGE (V) EFFICIENCY (%) 10 LOAD CURRENT (mA) 100 MAX1595 toc04 100 60 1 5V EFFICIENCY vs. LOAD CURRENT 3V EFFICIENCY vs. LOAD CURRENT 90 VOUT = 5V 4.90 MAX1595 toc05 0.1 4 VOUT = 3.3V, ILOAD = 75mA 3 2 1 COUT = 1µF 0 2ms/div A: INPUT VOLTAGE: VIN = 3.1V TO 3.6V, 500mV/div B: OUTPUT VOLTAGE: ILOAD = 50mA, 100mV/div 200µs/div A: LOAD CURRENT: ILOAD = 5mA to 95mA, 100mA/div B: OUTPUT VOLTAGE: AC-COUPLED 100mV/div 0 1 2 3 4 5 6 SUPPLY VOLTAGE (V) _______________________________________________________________________________________ 3 MAX1595 __________________________________________Typical Operating Characteristics (Circuit of Figure 4, VIN = 2V for MAX1595_ _ _33, VIN = 3V for MAX1595_ _ _50, TA = +25°C, unless otherwise noted.) MAX1595 Regulated 3.3V/5.0V Step-Up/ Step-Down Charge Pump Pin Description PIN NAME FUNCTION µMAX TQFN-EP 1 12 AOUT Analog Power and Sense Input for Error Amplifier/Comparator. Connect to OUT at output filter capacitor. 2 1 SHDN Shutdown Input. When SHDN = low, the device turns off; when SHDN = high, the device activates. In shutdown, OUT is disconnected from IN. 3 2, 3 IN 4 4 GND 5 5, 6 PGND 6 7, 8 CXN Negative Terminal of the Charge-Pump Transfer Capacitor 7 9 CXP Positive Terminal of the Charge-Pump Transfer Capacitor 8 10, 11 OUT Output. Bypass to GND with output capacitor filter. — — EP Input Supply. Can range from 1.8V to 5.5V. Bypass to GND with a 1μF capacitor. Ground Power Ground Exposed Pad. Internally connected to GND. Connect to a large ground plane to maximize thermal performance. Not intended as an electrical connection point (TQFN package only). Detailed Description The MAX1595 charge pump provides either a 3.3V or 5V regulated output. It delivers a maximum 125mA load current. In addition to boost regulating from a lower supply, it is also capable of buck regulating from supplies that exceed the regulated output by a diode drop or more. Designed specifically for compact applications, a complete regulator circuit requires only three small external capacitors. An innovative control scheme provides constant frequency operation from medium to heavy loads, while smoothly transitioning to low-power mode at light loads to maintain optimum efficiency. In buck mode, switch S1 (Figure 1) is switched continuously to IN, while switch S2 alternates between IN and OUT. An amount of charge proportional to the difference between the output voltage and the supply voltage is stored on CX, which gets transferred to the output when the regulation point is reached. Maximum output ripple is proportional to the difference between the supply voltage and the output voltage, as well as to the ratio of the transfer capacitor (CX) to the output capacitor (COUT). The MAX1595 consists of an error amplifier, a 1.23V bandgap reference, internal resistive feedback network, oscillator, high-current MOSFET switches, and shutdown and control logic. Figure 1 shows an idealized unregulated charge-pump voltage doubler. The oscillator runs at a 50% duty cycle. During one half of the period, the transfer capacitor (CX) charges to the input voltage. During the other half, the doubler transfers the sum of CX and input voltage to the output filter capacitor (COUT). Rather 4 S2 IN S1 OUT CX CIN COUT OSC Figure 1. Unregulated Voltage Doubler than doubling the input voltage, the MAX1595 provides a regulated output voltage of either 3.3V or 5.0V. Shutdown Driving SHDN low places the device in shutdown mode. The device draws 0.1μA of supply current in this mode. When driven high, the MAX1595 enters a soft-start mode. Soft-start mode terminates when the output voltage regulates, or after 2ms, whichever comes first. In shutdown, the output disconnects from the input. Undervoltage Lockout The MAX1595 has an undervoltage-lockout that deactivates the devices when the input voltage falls below 1.6V. Below UVLO, hysteresis holds the device in shutdown until the input voltage rises 40mV above the lockout threshold. _______________________________________________________________________________________ Regulated 3.3V/5.0V Step-Up/Step-Down Charge Pump MAX1595 Applications Information Using white LEDs to backlight LCDs is an increasingly popular approach for portable information devices (Figure 2). Because the forward voltage of white LEDs exceeds the available battery voltage, the use of a charge pump such as the MAX1595 provides high efficiency, small size, and constant light output with changing battery voltages. If the output is used only to light LEDs, the output capacitor can be greatly reduced. The frequency modulation of the LED intensity is not discernible to the human eye, and the smaller capacitor saves both size and cost. Adding two Schottky diodes and two capacitors implements a tripler and allows the MAX1595_ _ _50 to regulate a current of 75mA with a supply voltage as low as 2.3V (Figure 3). CX = 0.1µF CXP CXN MAX1595_ _ _50 VIN IN OUT AOUT SHDN CIN = 1µF COUT = 0.47µF 100Ω 100Ω 100Ω PGND GND Figure 2. White LED Bias Supply Capacitor Selection The MAX1595 requires only three external capacitors (Figure 4). Their values are closely linked to the output current capacity, oscillator frequency, output noise content, and mode of operation. Generally, the transfer capacitor (CX) will be the smallest, and the input capacitor (CIN) is twice as large as CX. Higher switching frequencies allow the use of the smaller CX and CIN. The output capacitor (COUT) can be anywhere from 5-times to 50-times larger than CX. Table 1 shows recommended capacitor values. In addition, the following equation approximates output ripple: INPUT 2.3V IN AOUT SHDN OUTPUT REGULATED 5V 1µF 75mA OUT 1µF 1µF 0.22µF MAX1595_ _ _50 CXP 0.22µF CXN PGND GND VRIPPLE ≅ IOUT / (2 x fOSC x COUT) Table 2 lists the manufacturers of recommended capacitors. Ceramic capacitors will provide the lowest ripple due to their typically lower ESR. Figure 3. Regulated Voltage Tripler Power Dissipation The power dissipated in the MAX1595 depends on output current and is accurately described by: PDISS = IOUT (2VIN - VOUT) CXP ON PDISS must be less than that allowed by the package rating. Layout Considerations All capacitors should be soldered in close proximity to the IC. Connect ground and power ground through a short, low-impedance trace. The input supply trace should be as short as possible. Otherwise, an additional input supply filter capacitor (tantalum or electrolytic) may be required. 2 OFF 3 IN CIN 1µF SHDN CXN MAX1595 IN OUT PGND 5 GND 4 AOUT 7 6 8 CX 0.22µF OUT 1 COUT 1µF Figure 4. Standard Operating Circuit _______________________________________________________________________________________ 5 MAX1595 Regulated 3.3V/5.0V Step-Up/ Step-Down Charge Pump Table 1. Recommended Capacitor Values OUTPUT RIPPLE (mV) CIN (µF) CX (µF) COUT (µF) 70 1 0.22 1 35 2.2 0.47 2.2 Table 2. Recommended Capacitor Manufacturers VALUE (µF) VOLTAGE (V) TYPE SIZE MANUFACTURER PART 1 10 X7R 0805 Taiyo Yuden LMK212BJ105MG 0.22 10 X7R 0603 Taiyo Yuden LMK107BJ224MA 0.47 10 X7R 0603 Taiyo Yuden LMK107BJ474MA 0.1 10 X7R 0603 Taiyo Yuden LMK107BJ104MA Chip Information Pin Configurations (continued) PROCESS: CMOS TOP VIEW SHDN 1 IN 2 IN 3 AOUT OUT OUT 12 11 10 MAX1595 4 5 6 GND PGND PGND Package Information 9 CXP 8 CXN 7 CXN For the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status. PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND PATTERN NO. 8 μMAX U8+1 21-0036 90-0092 12 TQFN 1244+4 21-0139 90-0068 TQFN 6 _______________________________________________________________________________________ Regulated 3.3V/5.0V Step-Up/Down Charge Pump REVISION NUMBER REVISION DATE 2 6/09 Added EP (exposed pad) and top mark information 10/11 Updated Absolute Maximum Ratings section and added Package Thermal Characteristics section 3 DESCRIPTION PAGES CHANGED 1, 2, 4, 6 2 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. The parametric values (min and max limits) shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________ 7 © 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc. MAX1595 Revision History