19-0177; Rev 1; 8/98 3.3V-Input to Regulated 5V-Output Charge Pumps These complete 5V regulators require only one resistor and three external capacitors—no inductors are needed. High switching frequencies (externally adjustable up to 2MHz) and a unique regulation scheme allow the use of capacitors as small as 1µF per 100mA of output current. The MAX683/MAX684 are offered in a spacesaving 8-pin µMAX package that is only 1.1mm high, while the MAX682 is available in an 8-pin SO. Features ♦ Ultra-Small: 1µF Capacitors per 100mA of Output Current ♦ No Inductors Required ♦ 1.1mm Height in µMAX Package (MAX683/MAX684) ♦ Up to 250mA Output Current (MAX682) ♦ Regulated ±4% Output Voltage ♦ 50kHz to 2MHz Adjustable Switching Frequency ♦ 2.7V to 5.5V Input Voltage ♦ 100µA Quiescent Current in Pulse-Skipping Mode ♦ 0.1µA Shutdown Current Applications Ordering Information Flash Memory Supplies Battery-Powered Applications PART TEMP. RANGE PIN-PACKAGE -40°C to +85°C 8 SO MAX683EUA -40°C to +85°C 8 µMAX MAX684EUA -40°C to +85°C 8 µMAX Miniature Equipment MAX682ESA PCMCIA Cards 3.3V to 5V Local Conversion Applications Backup-Battery Boost Converters 3V to 5V GSM SIMM Cards Typical Operating Circuit Pin Configurations TOP VIEW CXN CXP SKIP 1 MAX682 INPUT 2.7V TO 5.5V IN REXT OUT SHDN SHDN PGND 2 OUT 7 CXP SKIP 1 SHDN 2 MAX682 3 6 CXN IN GND 4 5 PGND GND 4 IN SKIP GND OUTPUT 5V/250mA 8 SO 3 MAX683 MAX684 8 OUT 7 CXP 6 CXN 5 PGND µMAX ________________________________________________________________ Maxim Integrated Products 1 For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800. For small orders, phone 408-737-7600 ext. 3468. MAX682/MAX683/MAX684 General Description The MAX682/MAX683/MAX684 charge-pump regulators generate 5V from a 2.7V to 5.5V input. They are specifically designed to serve as high-efficiency auxiliary supplies in applications that demand a compact design. The MAX682, MAX683, and MAX684 deliver 250mA, 100mA, and 50mA output current, respectively. MAX682/MAX683/MAX684 3.3V-Input to Regulated 5V-Output Charge Pumps ABSOLUTE MAXIMUM RATINGS IN, OUT, SHDN, SKIP to GND.................................-0.3V to +6V PGND to GND.....................................................................±0.3V CXN to GND ................................................-0.3V to (VIN + 0.3V) CXP to GND..............................................-0.3V to (VOUT + 0.3V) Continuous Output Current MAX682........................................................................300mA MAX683........................................................................150mA MAX684..........................................................................75mA Output Short-Circuit Duration ...............................................5sec Continuous Power Dissipation (TA = +70°C) 8-Pin SO (derate 5.9mW/°C above +70°C).................471mW 8-Pin µMAX (derate 4.1mW/°C above +70°C) ............330mW Operating Temperature Range MAX68_E_A ....................................................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range .............................-65°C to +160°C Lead Temperature (soldering, 10sec) .............................+300°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. ELECTRICAL CHARACTERISTICS (VIN = 3V, V SKIP = 0V, CIN = 1µF, CX = 0.47µF, COUT = 2µF, I SHDN = 22µA; IMAX = 250mA for MAX682, IMAX = 100mA for MAX683, IMAX = 50mA for MAX684; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER Input Voltage Range SYMBOL VIN CONDITIONS Regulation with VIN > 3.6V requires SKIP = high Input Undervoltage Lockout Threshold MIN 2.7 2.0 Input Undervoltage Lockout Hysteresis VOUT Maximum Output Current IMAX 0 < ILOAD ≤ IMAX; 3.0V ≤ IN ≤ 3.6V for SKIP = 0, 3.0V ≤ IN ≤ 3.6V for SKIP = 0, 3.0V ≤ IN ≤ 5.5V for SKIP = IN 4.80 MAX682 250 MAX683 100 MAX684 50 SKIP = 0, VIN = 3.6V Load Regulation IQ ∆VLDR SKIP = VIN = 3.6V SHDN Logic Low Input SHDN On Bias Voltage VON, SHDN TA = +25°C ISHDN ISHDN = 22µA ISHDN =4.4µA Shutdown Supply Current Shutdown Exit Time 2 UNITS 5.5 V 2.6 V IQ, SHDN tSTART mV 5.20 7.5 MAX683 2.5 MAX684 1.7 0.18 mA -3 630 690 1 % 0.35 V 750 mV 50 µA 0°C < TA < +85°C 850 1000 1200 -40°C < TA < +85°C 750 1000 1300 0°C < TA < +85°C 160 200 250 -40°C < TA < +85°C 150 200 270 0.1 5 SHDN = 0, VIN = 5.5V, VOUT = 0 RL = 5V/IMAX V mA 0.1 (Note 2) Switching Frequency (Note 2) 5.05 MAX682 SKIP = high, 0 ≤ ILOAD ≤ IMAX VINL, SHDN SHDN Input Current Range 2.35 MAX 100 Output Voltage No-Load Input Current TYP 50 _______________________________________________________________________________________ kHz µA µs 3.3V-Input to Regulated 5V-Output Charge Pumps (VIN = 3V, V SKIP = 0V, CIN = 1µF, CX = 0.47µF, COUT = 2µF, ISHDN = 22µA; IMAX = 250mA for MAX682, IMAX = 100mA for MAX683, IMAX = 50mA for MAX684; TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER SYMBOL SKIP Input Voltage Low VINL, SKIP SKIP Input Voltage High VINH, SKIP SKIP Input Leakage Current ISKIP CONDITIONS MIN TYP MAX UNITS 0.8 VIN = 5.5V 2.4 VIN = 5.5V, V SKIP = 0V or 5.5V -1 V 1 µA Note 1: Specifications to -40°C are guaranteed by design and not production tested. Note 2: Current into SHDN determines oscillator frequency: REXT (kΩ) = 45000 (VIN - 0.69V) / fOSC (kHz) __________________________________________Typical Operating Characteristics (Circuit of Figure 5, VIN = 3.3V, component values from Tables 2 and 3, TA = +25°C, unless otherwise noted.) OUTPUT VOLTAGE vs. LOAD CURRENT (SKIP = LOW) MAX682 6 4 MAX683 2 5.00 MAX684 MAX682 4.75 MAX683 4.50 SKIP = HIGH ISHDN = 22µA 5.25 OUTPUT VOLTAGE (V) 5.25 OUTPUT VOLTAGE (V) 8 5.50 MAX682 TOC03 SKIP = HIGH ISHDN = 22µA SUPPLY CURRENT (mA) 5.50 MAX682 TOC01 10 OUTPUT VOLTAGE vs. LOAD CURRENT (SKIP = HIGH) 4.25 MAX682 TOC04 NO-LOAD SUPPLY CURRENT vs. SUPPLY VOLTAGE 5.00 MAX684 4.75 MAX683 4.50 MAX682 4.25 MAX684 4.00 3 4 5 4.00 1 6 SUPPLY VOLTAGE (V) 1000 1 10 5.00 4.75 SKIP = HIGH 4.25 4.00 1000 NO-LOAD SUPPLY CURRENT vs. SHUTDOWN PIN INPUT CURRENT MAX682 TOC08 5.25 10M OSCILLATOR FREQUENCY (Hz) MAX682 TOC06 SKIP = LOW 100 LOAD CURRENT (mA) OSCILLATOR FREQUENCY vs. SHUTDOWN PIN INPUT CURRENT 5.50 OUTPUT VOLTAGE (V) 100 LOAD CURRENT (mA) OUTPUT VOLTAGE vs. SUPPLY VOLTAGE 4.50 10 1M 100k 100 SKIP = HIGH NO-LOAD SUPPLY CURRENT (mA) 2 MAX682 TOC09 0 MAX682 10 MAX683 1 3.75 MAX684 0.1 10k 3.50 2 3 4 SUPPLY VOLTAGE (V) 5 6 0.1 1 10 SHDN INPUT CURRENT (µA) 100 0.1 1 10 100 SHDN INPUT CURRENT (µA) _______________________________________________________________________________________ 3 MAX682/MAX683/MAX684 ELECTRICAL CHARACTERISTICS (continued) Typical Operating Characteristics (continued) (Circuit of Figure 5, VIN = 3.3V, component values from Tables 2 and 3, TA = +25°C, unless otherwise noted.) 80 70 70 VIN = 3.3V VIN = 3.6V 50 40 60 VIN = 3.3V EFFICIENCY (%) 80 70 VIN = 3.6V 50 40 60 30 30 20 20 20 10 10 10 0 0 1 10 100 1000 0 0.1 1 10 100 0.1 1000 1 10 LOAD CURRENT (mA) LOAD CURRENT (mA) MAX682 EFFICIENCY vs. LOAD CURRENT (SKIP = HIGH) MAX683 EFFICIENCY vs. LOAD CURRENT (SKIP = HIGH) MAX684 EFFICIENCY vs. LOAD CURRENT (SKIP = HIGH) 90 70 60 VIN = 3.3V 50 40 VIN = 5.0V 30 ISHDN = 22µA 0 60 VIN = 3.3V 50 40 VIN = 5.0V 100 60 VIN = 3.3V 50 40 20 20 10 10 1000 VIN = 3.0V VIN = 5.0V 30 ISHDN = 22µA ISHDN = 22µA 0 0 10 80 70 30 20 10 VIN = 3.0V EFFICIENCY (%) 80 70 EFFICIENCY (%) 80 90 MAX682 TOC14 100 MAX682 TOC13 VIN = 3.0V 90 1 10 LOAD CURRENT (mA) 100 1000 1 10 100 LOAD CURRENT (mA) LOAD CURRENT (mA) OUTPUT WAVEFORM (SKIP = HIGH) OUTPUT WAVEFORM (SKIP = LOW) MAX682 TOC16 MAX682 TOC17 50mV/div 200ns/div SKIP = HIGH, ISHDN = 22µA, ILOAD = 250mA, MAX682 4 100 LOAD CURRENT (mA) 100 1 VIN = 3.6V 40 30 0.1 VIN = 3.3V 50 MAX682 TOC15 60 VIN = 3.0V 90 80 EFFICIENCY (%) EFFICIENCY (%) VIN = 3.0V 90 100 MAX682 TOC11 VIN = 3.0V 90 100 MAX682 TOC10 100 MAX684 EFFICIENCY vs. LOAD CURRENT (SKIP = LOW) MAX683 EFFICIENCY vs. LOAD CURRENT (SKIP = LOW) MAX682 TOC12 MAX682 EFFICIENCY vs. LOAD CURRENT (SKIP = LOW) EFFICIENCY (%) MAX682/MAX683/MAX684 3.3V-Input to Regulated 5V-Output Charge Pumps 50mV/div 200ns/div SKIP = LOW, ILOAD = 250mA, MAX682 _______________________________________________________________________________________ 3.3V-Input to Regulated 5V-Output Charge Pumps LINE-TRANSIENT RESPONSE SHUTDOWN TIMING LOAD-TRANSIENT RESPONSE MAX682 TOC20 MAX682 TOC18 A MAX682 TOC19 A A B B B 100µs/div A: OUTPUT VOLTAGE: SKIP = HIGH, RL = 5V / IMAX, 2V/div B: SHDN VOLTAGE: 1V/div 2ms/div 2ms/div A: INPUT VOLTAGE: VIN = 3.1V TO 3.6V, 500mV/div B: OUTPUT VOLTAGE: SKIP = HIGH, ISHDN = 22µA, ILOAD = 250mA, 50mV/div, MAX682 A: LOAD CURRENT: ILOAD = 5mA TO 250mA, 500mA/div B: OUTPUT VOLTAGE: SKIP = HIGH, ISHDN = 22µA, 100mV/div, MAX682 Pin Description PIN NAME FUNCTION 1 SKIP 2 SHDN Shutdown Input. Drive SHDN through an external resistor. When SHDN = low, the device turns off. When current is sourced into SHDN through REXT, the device activates, and the SHDN pin input current sets the oscillator’s switching frequency. REXT (kΩ) = 45000 (V IN - 0.69V) / fOSC (kHz). 3 IN Input Supply Pin. Can range from 2.7V to 5.5V for SKIP = high, and 2.7V to 3.6V for SKIP = low. Bypass to PGND with a suitable value capacitor (see Capacitor Selection section). 4 GND 5 PGND 6 CXN Negative Terminal of the Charge-Pump Transfer Capacitor 7 CXP Positive Terminal of the Charge-Pump Transfer Capacitor 8 OUT Fixed 5V Power Output. Bypass to PGND with output filter capacitor. When SKIP = low, the regulator operates in low-quiescent-current skip mode. When SKIP = high, the regulator operates in constant-frequency mode, minimizing output ripple and noise. SKIP must be tied high for input voltages above 3.6V. Ground Pin. Connect to PGND through a short trace. Power Ground Pin _______________________________________________________________________________________ 5 MAX682/MAX683/MAX684 Typical Operating Characteristics (continued) (Circuit of Figure 5, VIN = 3.3V, component values from Tables 2 and 3, TA = +25°C, unless otherwise noted.) MAX682/MAX683/MAX684 3.3V-Input to Regulated 5V-Output Charge Pumps Detailed Description The MAX682/MAX683/MAX684 charge pumps provide a regulated 5V output from a 2.7V to 5.5V input. They deliver a maximum of 250mA, 100mA, or 50mA load current, respectively. Designed specifically for compact applications, a complete regulator circuit requires only three small external capacitors and one resistor. An externally adjustable switching frequency and innovative control scheme allow the circuit to be optimized for efficiency, size, or output noise. The devices also contain a shutdown feature. The MAX682/MAX683/MAX684 consist of an error amplifier, a 1.23V bandgap reference, an internal resistive feedback network, an oscillator, high-current MOSFET switches, and shutdown and control logic (Figure 1). Figure 2 shows an idealized unregulated chargepump 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 stacks the voltage across CX and the input voltage, and transfers the sum of the two voltages to the output filter capacitor (COUT). Rather than simply doubling the input voltage, the MAX682/MAX683/MAX684 provide a regulated fixed output voltage (5V) using either skip mode or constantfrequency mode. Skip mode and constant-frequency mode are externally selected via the SKIP input pin. S2 IN OUT CX S1 CIN COUT OSC Figure 2. Unregulated Voltage Doubler S2 IN S1 OUT CX CIN EN OSCILLATOR OUT IN Figure 3. Skip-Mode Regulation Skip Mode 1.23V SKIP CONTROL LOGIC CXP SHDN SHDN EN SWITCHES CXN OSC In skip mode (SKIP = low), the error amplifier disables switching when it detects an output higher than 5V. The device then skips switching cycles until the output voltage drops. Then the error amplifier reactivates the oscillator. Figure 3 illustrates the regulation scheme. This regulation method minimizes operating current because the device does not switch continuously. SKIP is a logic input and should not remain floating. Constant-Frequency Mode PGND Figure 1. Functional Block Diagram 6 When SKIP is high, the charge pump runs continuously at the selected frequency. Figure 4 shows a block diagram of the device in constant-frequency mode. The error amplifier controls the charge on CX by driving the gate of the N-channel FET. When the output voltage falls, the gate drive increases, resulting in a larger voltage across CX. This regulation scheme minimizes output ripple. Since the device switches continuously, the _______________________________________________________________________________________ 3.3V-Input to Regulated 5V-Output Charge Pumps OUT S2 CX S1 CIN OSC COUT N-CHANNEL Figure 4. Constant-Frequency-Mode Regulation Table 1. Tradeoffs Between Operating Modes FEATURE Best Light-Load Efficiency SKIP MODE (SKIP = LOW) ✔ Smallest External Component Size Output Ripple Amplitude and Frequency Load Regulation CONSTANTFREQUENCY MODE (SKIP = HIGH) ✔ Relatively large amplitude, variable frequency Relatively small amplitude, constant frequency Very Good Good output noise contains well-defined frequency components, and the circuit requires much smaller external capacitors for a given output ripple. However, constantfrequency mode, due to higher operating current, is less efficient at light loads than skip mode. Note: For input voltages above 3.6V, the devices must operate in constant-frequency mode. Table 1 summarizes the tradeoffs between the two operating modes. Frequency Selection and Shutdown The SHDN pin on the MAX682/MAX683/MAX684 performs a dual function: it shuts down the device and determines the oscillator frequency. The SHDN input looks like a diode to ground and should be driven through a resistor. Driving SHDN low places the device in shutdown mode. This disables all switches, the oscillator, and control logic. The device typically draws 0.1µA (5µA max) of supply current in this mode and the output presents a 50kΩ impedance to ground. The device exits shutdown once SHDN is forward biased (minimum of 1µA of current). The typical no-load shutdown exit time is 50µs. When SHDN is pulled high through an external resistor to V IN , the bias current into SHDN determines the charge-pump frequency. To select the frequency, calculate the external resistor value, REXT, using the following formula: REXT = 45000 (VIN - 0.69V) / fOSC where REXT is in kΩ and fOSC is in kHz. Program the frequency in the 50kHz to 2MHz range. This frequency range corresponds to SHDN input currents between 1µA and 50µA. Proper operation of the oscillator is not guaranteed beyond these limits. Currents lower than 1µA may shut down the device. The forward-biased diode voltage from the SHDN input to GND has a temperature coefficient of -2mV/°C. Undervoltage Lockout The MAX682/MAX683/MAX684 have an undervoltagelockout feature that deactivates the devices when the input voltage falls below 2.25V. Regulation at low input voltages cannot be maintained. This safety feature ensures that the device shuts down before the output voltage falls out of regulation by a considerable amount (typically 10% with no load). Once deactivated, hysteresis holds the device in shutdown until the input voltage rises 100mV above the lockout threshold. Applications Information Capacitor Selection The MAX682/MAX683/MAX684 require only three external capacitors (Figure 5). 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 C X . Higher switching frequencies allow the use of smaller CX and CIN. The output capacitor (COUT) can be anywhere from 5-times to 50-times larger than CX, depending on the mode of operation and ripple tolerance. In continuous switching mode, smaller output ripple allows smaller COUT. In skip mode, a larger COUT is required to maintain low output ripple. Tables 2 and 3 show capacitor values recommended for lowest supply-current operation (skip mode) and smallest size operation (constant-frequency mode), respectively. _______________________________________________________________________________________ 7 MAX682/MAX683/MAX684 IN MAX682/MAX683/MAX684 3.3V-Input to Regulated 5V-Output Charge Pumps Table 2. Recommended Capacitor Values for Quiescent Current (Skip Mode) OFF VOUT COUT (µF) OUTPUT CIN CX PART RIPPLE (mA) (µF) (µF) TANTALUM CERAMIC (mV) MAX682 250 MAX683 100 MAX684 50 2.2 1 1 47 10 ON VON REXT 22 4.7 100 0.47 0.22 10 2.2 100 3 IN 1 100 0.47 CXP 2 SHDN MAX682 MAX683 MAX684 IN CXN OUT SKIP CIN GND PGND 4 5 7 CX 6 8 OUT COUT Figure 5. Standard Operating Circuit 5V/500mA Table 3. Recommended Capacitor Values for Smallest Size (Constant-Frequency Mode, ISHDN = 22µA, 1MHz) PART OUTPUT (mA) CIN (µF) CX (µF) CERAMIC COUT (µF) 3.3VIN IN VOUT RIPPLE (mV) 100k 1µF MAX682 250 1 0.47 2.2 80 MAX683 100 0.47 0.22 1 80 SHDN 50 0.22 0.1 0.47 100k 1µF CXP 0.47µF OUT SKIP MAX682 MAX682 4.7µF SHDN CXP 0.47µF CXN GND MAX684 IN OUT SKIP PGND CXN GND PGND 80 Figure 6. Paralleling Two MAX682s Table 4. Recommended Capacitor Manufacturers PHONE NUMBER VALUE DESCRIPTION MANUFACTURER 47µF to 10µF 595D-series tantalum surface mount Sprague (603) 224-1961 47µF to 10µF TPS-series surface mount AVX (803) 946-0690 0.1µF to 2.2µF Ceramic surface mount TDK (847) 390-4373 In addition, the following two equations approximate output ripple for each mode. In skip mode, output ripple is dominated by ESR, and is approximately: VRIPPLE(SKIP) ≅ (2VIN - VOUT)ESRCOUT / RTX 8 where ESRCOUT is the ESR of the output filter capacitance, and RTX is the open-loop output transfer resistance of the IC. RTX is typically 0.8Ω for the MAX682, 1.6Ω for the MAX683, and 3Ω for the MAX684. In constant-frequency mode, output ripple is dominated by COUT and is approximately: VRIPPLE(const-freq) ≅ IOUT / (2 x fOSC x COUT) All capacitors must maintain a low (<100mΩ) equivalent series resistance (ESR). Table 4 lists the manufacturers of recommended capacitors. Surface-mount tantalum capacitors will work well for most applications. Ceramic capacitors will provide the lowest ripple due to their typically lower ESR. If the source impedance or inductance of the input supply is large, additional input bypassing (2.2µF to 22µF) may be needed. This additional capacitance need not be a low-ESR type. _______________________________________________________________________________________ 3.3V-Input to Regulated 5V-Output Charge Pumps Paralleling Devices The MAX682/MAX683/MAX684 can be paralleled to yield higher load currents. The circuit of Figure 6 can deliver 500mA at 5V. It uses two MAX682s in parallel. The devices can share the output capacitors, but each one requires its own transfer capacitor (CX) and input capacitor. For best performance, the paralleled devices should operate in the same mode (skip or constant frequency). Layout Considerations All capacitors should be soldered in close proximity to the IC. Connect ground and power ground through a short, low-impedance trace. If a high-value resistor is driving the shutdown input and is picking up noise (i.e., frequency jitter at CXP and CXN), bypass SHDN to GND with a small capacitor (0.01µF). Chip Information TRANSISTOR COUNT: 659 SUBSTRATE CONNECTED TO GND 8LUMAXD.EPS Package Information _______________________________________________________________________________________ 9 MAX682/MAX683/MAX684 Power Dissipation The power dissipated in the MAX682/MAX683/MAX684 depends on output current and is accurately described by: PDISS = IOUT (2VIN - VOUT) PDISS must be less than that allowed by the package rating. See the Absolute Maximum Ratings for 8-pin µMAX (MAX683/MAX684) and SO (MAX682) powerdissipation limits and deratings. 3.3V-Input to Regulated 5V-Output Charge Pumps SOICN.EPS MAX682/MAX683/MAX684 Package Information 10 ______________________________________________________________________________________ 3.3V-Input to Regulated 5V-Output Charge Pumps MAX682/MAX683/MAX684 NOTES ______________________________________________________________________________________ 11 MAX682/MAX683/MAX684 3.3V-Input to Regulated 5V-Output Charge Pumps NOTES 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. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1998 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.