19-1422; Rev 1; 12/99 Low-Dropout, 300mA Linear Regulator in µMAX Features The MAX8860 low-noise, low-dropout linear regulator operates from a +2.5V to +6.5V input and is guaranteed to deliver 300mA. Typical output noise for this device is 60µVRMS, and typical dropout is 105mV at 200mA. In addition to the six available preset output voltages (+1.8V, +2.5V, +2.77V, +2.82V, +3.0V, and +3.3V), the Dual Mode™ feature allows the device to be configured as an adjustable output regulator from +1.25V to +6.5V. ♦ High Output Current (300mA) Designed with an internal P-channel MOSFET pass transistor, the MAX8860 has a low 120µA supply current. An output fault-detection circuit indicates loss of regulation. Other features include a 10nA, logic-controlled shutdown mode, short-circuit and thermal-shutdown protection, and reverse battery protection. The MAX8860 is available in a miniature 8-pin µMAX package. ♦ 10nA Logic-Controlled Shutdown ♦ Low Output Voltage Noise: 60µVRMS ♦ Low 105mV Dropout at 200mA Output ♦ Low 120µA No-Load Supply Current ♦ Thermal-Overload and Short-Circuit Protection ♦ Reverse Battery Protection ♦ FAULT Indicator ♦ Small, Space-Saving µMAX Package (1.1mm max height) ♦ Small 2.2µF Output Capacitor Saves Space and Cost Applications Wireless Handsets Ordering Information DSP Core Power PCMCIA Cards PART TEMP. RANGE Hand-Held Instruments Palmtop Computers Electronic Planners Typical Operating Circuit INPUT +2.5V TO +6.5V MAX8860 C1 2.2µF SHDN SET GND OUT R1 100k -40°C to +85°C 8 µMAX +1.80 MAX8860EUA25 -40°C to +85°C 8 µMAX +2.50 MAX8860EUA27 MAX8860EUA28 MAX8860EUA30 MAX8860EUA33 -40°C to +85°C -40°C to +85°C -40°C to +85°C -40°C to +85°C 8 µMAX 8 µMAX 8 µMAX 8 µMAX +2.77 +2.82 +3.00 +3.30 Pin Configuration C2 2.2µF FAULTDETECT OUTPUT FAULT CC C3 33nF VOUT (V) MAX8860EUA18 OUTPUT UP TO 300mA OUT IN PINPACKAGE TOP VIEW OUT 1 8 IN 2 7 SHDN GND 3 6 CC OUT 4 5 SET MAX8860 FAULT µMAX Dual Mode is a trademark of Maxim Integrated Products. ________________________________________________________________ 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 1-800-835-8769. MAX8860 General Description MAX8860 Low-Dropout, 300mA Linear Regulator in µMAX ABSOLUTE MAXIMUM RATINGS IN, SHDN to GND .......................................................-7V to +7V SHDN to IN ...............................................................-7V to +0.3V SET, CC, FAULT to GND ..........................................-0.3V to +7V OUT to GND .............................................. -0.3V to (VIN + 0.3V) FAULT Sink Current ...........................................................20mA Continuous Output Current ..............................................330mA Output Short-Circuit Duration ....................................Continuous Continuous Power Dissipation (TA = +70°C) 8-Pin µMAX (derate 4.1mW/°C above +70°C) ............330mW Thermal Resistance (θJA) 8-Pin µMAX ............................................................+244°C/W Operating Temperature Range MAX8860EUA_ _ ...........................................-40°C to +85°C Junction Temperature ......................................................+150°C Storage Temperature Range ............................-65°C to +150°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 = +3.6V, CCC = 33nF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS MIN Input Voltage (Note 2) TA = +25°C 3.24 TA = -40°C to +85°C 3.21 TA = +25°C 2.95 TA = -40°C to +85°C 2.92 TA = +25°C 100µA < IOUT MAX8860EUA28 TA = -40°C to +85°C < 300mA, VIN = VOUT +1V, TA = +25°C MAX8860EUA27 SET = GND TA = -40°C to +85°C 2.78 MAX8860EUA33 MAX8860EUA30 Output Voltage MAX8860EUA25 MAX8860EUA18 SET Threshold Voltage SET = OUT, VIN = +2.5V to +6.5V, IOUT = 1mA 2.43 VOUT = 0, SHDN = GND V 3.35 3.05 3.08 2.82 2.87 2.90 2.77 2.81 2.54 2.57 1.77 1.755 TA = +25°C 1.230 TA = -40°C to +85°C 1.220 1.275 1.25 6.5 1.80 1.83 1.845 1.248 1.267 300 120 IOUT = 300mA 165 TA = +25°C 0.01 TA = +85°C 0.05 IOUT = 1mA 0.6 IOUT = 200mA 105 IOUT = 300mA 155 Load Regulation IOUT = 100µA to 300mA -0.1 V V mA 770 IOUT = 0 VIN = +2.5V to +6.5V, SET = OUT, IOUT = 1mA V 2.84 2.50 TA = -40°C to +85°C Line Regulation 2 UNITS 6.5 TA = +25°C 330 Shutdown Supply Current MAX 3.38 3.00 2.70 TA = -40°C to +85°C DC average current rating SET = GND Dropout Voltage (Note 4) 2.73 2.46 Output Current Limit Supply Current 3.3 2.75 TA = +25°C Adjustable Output Voltage Range (Note 3) Maximum Output Current TYP 2.5 0.01 SET = OUT 0.0001 SET = GND 0.0006 _______________________________________________________________________________________ mA 270 1 µA µA 220 mV 0.1 %/V %/mA Low-Dropout, 300mA Linear Regulator in µMAX MAX8860 ELECTRICAL CHARACTERISTICS (continued) (VIN = +3.6V, CCC = 33nF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1) PARAMETER CONDITIONS IOUT = 10mA, 10Hz < f < 100kHz Output Voltage Noise Output Voltage Noise Density MIN TYP COUT = 2.2µF 65 COUT = 10µF 60 COUT = 100µF 55 10Hz < f < 100kHz, COUT = 10µF µVRMS nV√Hz 2.0 V VIL, 2.5V ≤ VIN ≤ 5.5V 0.4 SHDN Input Bias Current SHDN = GND or IN SET Input Leakage Current (Note 3) VSET = +1.3V FAULT Detection Voltage (Note 5) SET = GND, IOUT = 200mA FAULT Output Low Voltage VIN = +2.5V, ISINK = 2mA FAULT Output Off-Leakage Current UNITS 190 VIH, 2.5V ≤ VIN ≤ 5.5V SHDN Input Threshold MAX V FAULT = +3.6V TA = +25°C 0.01 TA = +85°C 0.5 TA = +25°C 0.01 TA = +85°C 0.5 0.01 TA = +85°C 0.5 nA 2.5 130 TA = +25°C V 100 nA 280 mV 0.25 V 100 nA Thermal Shutdown Temperature 170 °C Thermal Shutdown Hysteresis 20 °C 120 µs Start-Up Time COUT = 10µF, VOUT to 90% of final value Specifications to -40°C are guaranteed by design and not production tested. Guaranteed by line-regulation test. Adjustable mode only. The dropout voltage is defined as VIN - VOUT when VOUT is 100mV below the value of VOUT for VIN = VOUT +2V. Since the minimum input voltage is 2.5V, this is applicable only for voltages of 2.5V or higher. Note 5: The FAULT detection voltage is the difference from input to output voltage. Maintain the input above this level to ensure good line and load regulation. Note 1: Note 2: Note 3: Note 4: Typical Operating Characteristics (VIN = VOUT + 0.5V, CIN = COUT = 2.2µF, CCC = 33nF, TA = +25°C, unless otherwise noted.) NORMALIZED OUTPUT VOLTAGE vs. TEMPERATURE 0 0.1 IOUT = 0 IOUT = 100mA 0 -0.1 -0.2 TA = +85°C 160 TA = +25°C 140 MAX8860 toc03 180 TA = -40°C 120 100 80 60 40 IOUT = 200mA -0.2 200 SUPPLY CURRENT (µA) 0.2 VOUT NORMALIZED AT +25°C, IOUT = 0 0.2 OUTPUT VOLTAGE (%) OUTPUT VOLTAGE (%) VOUT NORMALIZED AT IOUT = 0 SUPPLY CURRENT vs. LOAD CURRENT 0.3 MAX8860 toc01 0.4 MAX8860 toc02 NORMALIZED OUTPUT VOLTAGE vs. LOAD CURRENT 20 -0.4 -0.3 0 50 100 150 200 LOAD CURRENT (mA) 250 300 0 -40 -20 0 20 40 TEMPERATURE (°C) 60 80 0 50 100 150 200 250 300 LOAD CURRENT (mA) _______________________________________________________________________________________ 3 Typical Operating Characteristics (continued) (VIN = VOUT + 0.5V, CIN = COUT = 2.2µF, CCC = 33nF, TA = +25°C, unless otherwise noted.) NO LOAD SUPPLY CURRENT vs. INPUT VOLTAGE TA = -40°C 80 60 TA = +25°C 120 TA = +85°C 100 TA = -40°C 80 60 40 40 MAX8860 toc06 FAULT DETECT THRESHOLD (mV) 120 MAX8860 toc05 140 250 200 FAULT = HIGH 150 100 FAULT = LOW 50 20 20 0 0 0 1 2 3 4 5 0 6 50 100 150 200 250 0 300 50 100 150 200 INPUT VOLTAGE (V) LOAD CURRENT (mA) LOAD CURRENT (mA) POWER-SUPPLY REJECTION RATIO vs. FREQUENCY OUTPUT NOISE SPECTRAL DENSITY OUTPUT NOISE (10Hz TO 1MHz) 10 MAX8860 toc07 0 -10 ILOAD = 10mA 250 NOISE (µV/√Hz) -20 -30 -40 -50 1.0 COUT = 2.2µF VOUT 500µV/div COUT = 10µF 0.1 ILOAD = 200mA -60 -70 0.01 0.1 1 10 100 1000 0.1 FREQUENCY (kHz) 1 10 100 1ms/div 1000 FREQUENCY (kHz) LINE-TRANSIENT RESPONSE LOAD-TRANSIENT RESPONSE MAX8860 toc10 200mA ILOAD 0 MAX8860 toc12 0.01 +4.3V VIN +3.3V VOUT 20mV/div VIN = VOUT + 200mV VOUT 2mV/div ILOAD = 200mA 400µs/div 4 300 MAX8860 toc09 0 MAX8860 toc08 SUPPLY CURRENT (µA) TA = +85°C 100 160 DROPOUT VOLTAGE (mV) TA = +25°C 140 180 MAX8860 toc04 180 160 FAULT DETECT THRESHOLD vs. LOAD CURRENT DROPOUT VOLTAGE vs. LOAD CURRENT 200 PSRR (dB) MAX8860 Low-Dropout, 300mA Linear Regulator in µMAX 500µs/div _______________________________________________________________________________________ Low-Dropout, 300mA Linear Regulator in µMAX 0 FAULT 2V 0 VIN 4V 3V 4V 4V SHDN 2V 0 VIN 3V 3V VOUT VOUT 1V 1V 2V VOUT 1V 0 0 0 2V 2V MAX8860 toc15 MAX8860 toc13 FAULT 2V SHUTDOWN/POWER-UP POWER-DOWN RESPONSE 4V MAX8860 toc14 POWER-UP RESPONSE 4V 5ms/div 400µs/div 2ms/div Pin Description PIN NAME 1, 4 OUT FUNCTION Regulator Output. Bypass with 2.2µF, low-ESR capacitor to GND for stable operation. 2 IN 3 GND Supply Input. Connect to power source (+2.5V to +6.5V). Bypass with 2.2µF capacitor to GND. Ground 5 SET Output Voltage Set. Connect to GND for internally set threshold. Connect to resistor-divider for adjustable output voltages. See Output Voltage Selection section for more information. 6 CC Compensation Capacitor. Connect a 0.033µF capacitor from CC to GND. 7 SHDN Shutdown Input. Connect to IN for normal operation. Drive SHDN low to turn off the regulator. 8 FAULT Fault Output. A high-impedance, open-drain output. When the MAX8860 is out of regulation, FAULT goes low. In shutdown, the FAULT pin is high impedance. Connect to GND if unused. Detailed Description The MAX8860 is a low-dropout, low-quiescent-current linear regulator designed primarily for battery-powered applications. It supplies an adjustable +1.25V to +6.5V output voltage or a fixed-voltage output of +1.8V (MAX8860EUA18), +2.5V (MAX8860EUA25), +2.77V (MAX8860EUA27), +2.82V (MAX8860EUA28), +3.0V (MAX8860EUA30), or +3.3V (MAX8860EUA33) for load currents up to 300mA. The devices with 2.77V and 2.82V nominal outputs are designed to guarantee minimum output voltages of 2.70V and 2.75V, respectively. The device consists of a +1.25V reference, error amplifier, MOSFET driver, P-channel pass transistor, Dual Mode comparator, fault detector, and internal-feedback voltage divider (Figure 1). The 1.25V bandgap reference is connected to the error amplifier’s inverting input. The error amplifier compares this reference to the selected feedback voltage and amplifies the difference. The MOSFET driver reads the error signal and applies the appropriate drive to the Pchannel pass transistor. If the feedback voltage is lower than the reference voltage, the pass-transistor gate is pulled lower, allowing more current to pass and increasing the output voltage. If the feedback voltage is higher than the reference voltage, the pass-transistor gate is driven higher, allowing less current to pass to the output. The output voltage is fed back through either an internal resistor voltage divider connected to OUT, or an external resistor network connected to SET. The Dual Mode comparator examines VSET and selects the feedback path. If V SET is below 60mV, internal feedback is used and the output voltage is regulated to the preset output voltage. Additional blocks include an output current limiter, reverse battery protection, a thermal sensor, a fault detector, and shutdown logic. _______________________________________________________________________________________ 5 MAX8860 Typical Operating Characteristics (continued) (VIN = VOUT + 0.5V, CIN = COUT = 2.2µF, CCC = 33nF, TA = +25°C, unless otherwise noted.) MAX8860 Low-Dropout, 300mA Linear Regulator in µMAX IN SHDN REVERSE BATTERY PROTECTION CC ERROR AMP P MOS DRIVER WITH ILIMIT SHUTDOWN LOGIC OUT MAX8860 SET FAULT DETECT THERMAL SENSOR FAULT 1.25V REF DUAL-MODE COMPARATOR 60mV GND Figure 1. Functional Diagram Internal P-Channel Pass Transistor The MAX8860 features a 0.5Ω typical P-channel MOSFET pass transistor. This provides several advantages over similar designs using PNP pass transistors, including longer battery life. PNP-based regulators waste considerable amounts of current in dropout when the pass transistor saturates. They also use high basedrive currents under large loads. The P-channel MOSFET requires no base-drive current, which reduces quiescent current considerably. The MAX8860 consumes less than 165µA of quiescent current whether in dropout, light-load, or heavy-load applications (see Typical Operating Characteristics). Output Voltage Selection The MAX8860 features Dual Mode operation: it operates in either a preset voltage mode or an adjustable mode. In preset voltage mode, internal, trimmed feedback resistors set the output voltage to an adjustable +1.25V to +6.5V output voltage or a fixed-voltage output of +1.8V (MAX8860EUA18), +2.5V (MAX8860EUA25), +2.77V (MAX8860EUA27), +2.82V (MAX8860EUA28), +3.V (MAX8860EUA30), or +3.3V (MAX8860EUA33). Select this mode by connecting SET to ground. In adjustable mode, select an output between 1.25V and 6.5V using two external resistors connected as a voltage divider to SET (Figure 2). Calculate the output voltage with the following equation: 6 OUTPUT VOLTAGE OUT IN CIN 2.2µF MAX8860 SHDN R1 COUT 2.2µF SET BATTERY 100k R2 CC 33nF FAULT GND Figure 2. Adjustable Output Using External Feedback Resistors R1 VOUT = VSET 1 + R2 where VSET = 1.25V. To simplify resistor selection, use the following equation: V R1 = R2 OUT − 1 VSET _______________________________________________________________________________________ Low-Dropout, 300mA Linear Regulator in µMAX Shutdown Drive SHDN low to place the MAX8860 in shutdown mode. In shutdown mode, the pass transistor, control circuit, reference, and all biases are turned off, reducing the supply current to typically 10nA. Connect SHDN to IN for normal operation. Current Limit The MAX8860 includes short-circuit protection. It includes a current limiter that controls the pass transistor’s gate voltage to limit the output current to about 770mA. For design purposes, the minimum current limit is 330mA. Thermal-Overload Protection Thermal-overload protection limits total power dissipation in the MAX8860. When the junction temperature (TJ) exceeds +170°C, the thermal sensor sends a signal to the shutdown logic, turning off the pass transistor and allowing the IC to cool. The pass transistor turns on again after the IC’s junction temperature typically cools by 20°C, resulting in a pulsed output during continuous thermal-overload conditions. Thermal-overload protection is designed to protect the MAX8860 against fault conditions. Stressing the device with high-load currents and high input-output differential voltages (which result in die temperatures above +125°C) may cause a momentary overshoot (2% to 8% for 200ms) when the load is completely removed. Remedy this by raising the minimum load current from 0 (+125°C) to 100µA (+150°C). This is accomplished with an external load resistor. For continuous operation, do not exceed the absolute maximum junction temperature rating of +150°C. Operating Region and Power Dissipation Maximum power dissipation of the MAX8860 depends on the thermal resistance of the case and circuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. The power dissipated by the device is: P = IOUT (VIN - VOUT) The maximum power dissipation is: PMAX = (TJMAX - TA) / θJA where: TJMAX = +150°C TA is the ambient temperature θJA = 244°C/W The MAX8860’s pins perform the dual function of providing an electrical connection as well as channeling heat away from the die. Use wide circuit-board traces and large, solid copper polygons to improve power dissipation. Using multiple vias to buried ground planes further enhances thermal conductivity. Reverse Battery Protection The MAX8860 has a unique protection scheme that limits the reverse supply current to less than 1mA when either V IN or V S HDN falls below GND. The circuitry monitors the polarity of these two pins, disconnecting the internal circuitry and parasitic diodes when the applied voltage is reversed. This feature prevents the device from overheating and damaging an improperly installed battery. Integrator Circuitry The MAX8860 uses an external 33nF compensation capacitor for minimizing load- and line-regulation errors and for lowering output noise. When the output voltage shifts due to varying load current or input voltage, the integrator capacitor voltage is raised or lowered to compensate for the systematic offset at the error amplifier. Compensation is limited to ±5% to minimize transient overshoot when the device goes out of dropout, current limit, or thermal shutdown. Fault-Detection Circuitry When the output voltage goes out of regulation—such as during dropout, current limit, or thermal shutdown— FAULT goes low. In addition, the fault-detection circuitry detects when the input-to-output voltage differential is insufficient to ensure good load and line regulation at the output. When the input-to-output voltage differential is less than 130mV for a load current of 200mA, FAULT also goes low. The differential threshold is designed to be always higher than and track with the dropout voltage, and to scale proportionally with load current (see Fault Detect Threshold vs. Load Current graph in the Typical Operating Characteristics). The FAULT pin is an open-drain N-channel MOSFET. To create a voltage level output, connect a pull-up resistor from FAULT to OUT. To minimize current consumption, make this resistor as large as practical. A 100kΩ resistor works well for most applications. _______________________________________________________________________________________ 7 MAX8860 Choose R2 = 100kΩ to optimize power consumption, accuracy, and high-frequency power-supply rejection. Ensure that the total current through the external resistive feedback and load resistors is not less than 10µA. Since the VSET tolerance is typically less than ±20mV, set the output using fixed resistors instead of trim pots. In preset voltage mode, connect SET to GND. Keep impedances between SET and ground to less than 100kΩ. Otherwise, spurious conditions can cause VSET to exceed the 60mV Dual Mode threshold. MAX8860 Low-Dropout, 300mA Linear Regulator in µMAX VIN > +5.5V Minimum Load Current Requirements Power-Supply Rejection and Operation from Sources Other than Batteries When operating the MAX8860 with an input voltage above +5.5V, a minimum load current of 20µA is required to maintain regulation in preset voltage mode. When setting the output with external resistors, ensure that the minimum current through the external feedback resistors and load is at least 30µA. This applies only when the input voltage exceeds +5.5V. For input voltages less than +5.5V, the MAX8860 maintains regulation and stability without external loading. The MAX8860 is designed to deliver low dropout voltage and low quiescent current in battery-powered systems. Power-supply rejection is 67dB at low frequencies and rolls off above 100kHz. At high frequencies, the output capacitor is the major contributor to the rejection of power-supply noise (see the Power-Supply Rejection Ratio vs. Frequency graph in the Typical Operating Characteristics). When operating from sources other than batteries, improve supply-noise rejection and transient response by increasing the values of the input and output capacitors, and by using passive filtering techniques (see the supply and load-transient responses in the Typical Operating Characteristics). Applications Information Capacitor Selection and Regulator Stability Typically, use a 2.2µF capacitor on the input and a 2.2µF capacitor on the output of the MAX8860. Capacitor type is not critical, as long as it has an ESR less than 0.5Ω. Larger capacitor values and lower ESR provide better supply-noise rejection and transient response. Use higher-value capacitors (10µF) if large, fast input or load transients are anticipated or if the device is located several inches from the power source. For stable operation over the full temperature range, with load currents up to 300mA, a minimum outputcapacitor value of 2.2µF is recommended. There is no upper limit to capacitor size. The circuit used to generate the typical operating characteristics data used 2.2µF, X7R, 16V (1206) ceramic capacitors. These capacitors typically have an ESR of 50mΩ. Load-Transient Considerations The MAX8860 load-transient response graph (see Typical Operating Characteristics) shows the output response due to changing load current. Reduce overshoot by increasing the output capacitor’s value and decreasing its ESR. Input-Output (Dropout) Voltage A regulator’s minimum input-output voltage differential (or dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the MAX8860 uses a P-channel MOSFET pass transistor, its dropout voltage is a function of RDS(ON) (typically 0.5Ω) multiplied by the load current (see Electrical Characteristics). Chip Information TRANSISTOR COUNT: 148 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. 8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.