Low-Dropout, 300mA Linear Regulator µMAX MAX8860 low-noise, low-d
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Low-Dropout, 300mA Linear Regulator µMAX
MAX8860 low-noise, low-dropout linear regulator operates from +2.5V +6.5V input guaranteed deliver 300mA. Typical output noise this device 60µVRMS, typical dropout 105mV 200mA. addition available preset output voltages (+1.8V, +2.5V, +2.77V, +2.82V, +3.0V, +3.3V), Dual Modefeature allows device configured adjustable output regulator from +1.25V +6.5V. Designed with internal P-channel MOSFET pass transistor, MAX8860 120µA supply current. output fault-detection circuit indicates loss regulation. Other features include 10nA, logic-controlled shutdown mode, short-circuit thermal-shutdown protection, reverse battery protection. MAX8860 available miniature 8-pin µMAX package. High Output Current (300mA) Output Voltage Noise: 60µVRMS 105mV Dropout 200mA Output 120µA No-Load Supply Current Thermal-Overload Short-Circuit Protection Reverse Battery Protection 10nA Logic-Controlled Shutdown FAULT Indicator Small, Space-Saving µMAX Package (1.1mm height) Small 2.2µF Output Capacitor Saves Space Cost
Features
MAX8860
Applications
Wireless Handsets Core Power PCMCIA Cards Hand-Held Instruments Palmtop Computers Electronic Planners
MAX8860EUA18 MAX8860EUA25 MAX8860EUA27 MAX8860EUA28 MAX8860EUA30 MAX8860EUA33 -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C PART
Ordering Information
TEMP. RANGE PINPACKAGE µMAX µMAX µMAX µMAX µMAX µMAX VOUT +1.80 +2.50 +2.77 +2.82 +3.00 +3.30
Typical Operating Circuit
INPUT +2.5V +6.5V OUTPUT 300mA 100k 2.2µF
Configuration
VIEW
FAULT SHDN
MAX8860
2.2µF SHDN FAULT
FAULTDETECT OUTPUT
33nF
MAX8860
µMAX Dual Mode trademark Maxim Integrated Products. Maxim Integrated Products
free samples latest literature: http://www.maxim-ic.com, phone 1-800-998-8800. small orders, phone 1-800-835-8769.
Low-Dropout, 300mA Linear Regulator µMAX MAX8860
ABSOLUTE MAXIMUM RATINGS
SHDN .-7V SHDN .-7V +0.3V SET, FAULT .-0.3V -0.3V (VIN 0.3V) FAULT Sink Current .20mA Continuous Output Current .330mA Output Short-Circuit Duration .Continuous Continuous Power Dissipation +70°C) 8-Pin µMAX (derate 4.1mW/°C above +70°C) .330mW Thermal Resistance (JA) 8-Pin µMAX .+244°C/W Operating Temperature Range MAX8860EUA_ .-40°C +85°C Junction Temperature .+150°C Storage Temperature Range .-65°C +150°C Lead Temperature (soldering, 10sec) .+300°C
Stresses beyond those listed under "Absolute Maximum Ratings" cause permanent damage device. These stress ratings only, functional operation device these other conditions beyond those indicated operational sections specifications implied. Exposure absolute maximum rating conditions extended periods affect device reliability.
ELECTRICAL CHARACTERISTICS
(VIN +3.6V, 33nF, -40°C +85°C, unless otherwise noted. Typical values +25°C.) (Note PARAMETER Input Voltage (Note MAX8860EUA33 MAX8860EUA30 +25°C -40°C +85°C +25°C -40°C +85°C CONDITIONS 3.24 3.21 2.95 2.92 2.78 2.75 2.73 2.70 2.46 2.43 1.77 1.755 1.230 1.220 1.25 average current rating IOUT IOUT 300mA +25°C +85°C VOUT SHDN IOUT Dropout Voltage (Note Line Regulation Load Regulation IOUT 200mA IOUT 300mA +2.5V +6.5V, OUT, IOUT IOUT 100µA 300mA -0.1 0.01 0.05 0.01 0.0001 0.0006 %/mA 1.248 1.80 2.50 2.77 2.82 3.00 3.35 3.38 3.05 3.08 2.87 2.90 2.81 2.84 2.54 2.57 1.83 1.845 1.267 1.275 UNITS
Output Voltage
+25°C 100µA IOUT MAX8860EUA28 -40°C +85°C 300mA, VOUT +1V, +25°C MAX8860EUA27 -40°C +85°C MAX8860EUA25 MAX8860EUA18 +25°C -40°C +85°C +25°C -40°C +85°C +25°C -40°C +85°C
Threshold Voltage Adjustable Output Voltage Range (Note Maximum Output Current Output Current Limit Supply Current Shutdown Supply Current
OUT, +2.5V +6.5V, IOUT
Low-Dropout, 300mA Linear Regulator µMAX
ELECTRICAL CHARACTERISTICS (continued)
(VIN +3.6V, 33nF, -40°C +85°C, unless otherwise noted. Typical values +25°C.) (Note PARAMETER Output Voltage Noise Output Voltage Noise Density SHDN Input Threshold SHDN Input Bias Current Input Leakage Current (Note FAULT Detection Voltage (Note FAULT Output Voltage FAULT Output Off-Leakage Current Thermal Shutdown Temperature Thermal Shutdown Hysteresis Start-Up Time Note Note Note Note COUT 10µF, VOUT final value IOUT 10mA, 10Hz 100kHz CONDITIONS COUT 2.2µF COUT 10µF COUT 100µF 10Hz 100kHz, COUT 10µF VIH, 2.5V 5.5V VIL, 2.5V 5.5V SHDN VSET +1.3V GND, IOUT 200mA +2.5V, ISINK FAULT +3.6V +25°C +85°C 0.01 +25°C +85°C +25°C +85°C 0.01 0.01 0.25 nVHz µVRMS UNITS
MAX8860
Specifications -40°C guaranteed design production tested. Guaranteed line-regulation test. Adjustable mode only. dropout voltage defined VOUT when VOUT 100mV below value VOUT VOUT +2V. Since minimum input voltage 2.5V, this applicable only voltages 2.5V higher. Note FAULT detection voltage difference from input output voltage. Maintain input above this level ensure good line load regulation.
Typical Operating Characteristics
(VIN VOUT 0.5V, COUT 2.2µF, 33nF, +25°C, unless otherwise noted.)
NORMALIZED OUTPUT VOLTAGE LOAD CURRENT
MAX8860 toc01
NORMALIZED OUTPUT VOLTAGE TEMPERATURE
MAX8860 toc02
SUPPLY CURRENT LOAD CURRENT
SUPPLY CURRENT (µA) +85°C +25°C -40°C
MAX8860 toc03
VOUT NORMALIZED IOUT OUTPUT VOLTAGE
VOUT NORMALIZED +25°C, IOUT OUTPUT VOLTAGE -0.1 -0.2 IOUT 200mA
IOUT IOUT 100mA
-0.2
-0.4 LOAD CURRENT (mA)
-0.3 TEMPERATURE (°C)
LOAD CURRENT (mA)
Low-Dropout, 300mA Linear Regulator µMAX MAX8860
Typical Operating Characteristics (continued)
(VIN VOUT 0.5V, COUT 2.2µF, 33nF, +25°C, unless otherwise noted.)
LOAD SUPPLY CURRENT INPUT VOLTAGE
MAX8860 toc04
DROPOUT VOLTAGE LOAD CURRENT
DROPOUT VOLTAGE (mV) +85°C -40°C +25°C
MAX8860 toc05
FAULT DETECT THRESHOLD LOAD CURRENT
MAX8860 toc06
SUPPLY CURRENT (µA) INPUT VOLTAGE -40°C +25°C +85°C
FAULT DETECT THRESHOLD (mV)
FAULT HIGH
FAULT
LOAD CURRENT (mA)
LOAD CURRENT (mA)
POWER-SUPPLY REJECTION RATIO FREQUENCY
MAX8860 toc07
OUTPUT NOISE SPECTRAL DENSITY
MAX8860 toc08
OUTPUT NOISE (10Hz 1MHz)
MAX8860 toc09
0.01
ILOAD 10mA
NOISE (µV/Hz)
COUT 2.2µF COUT 10µF VOUT 500µV/div ILOAD 200mA
PSRR (dB)
0.01 1000 FREQUENCY (kHz) 1000 1ms/div FREQUENCY (kHz)
LOAD-TRANSIENT RESPONSE
MAX8860 toc10
LINE-TRANSIENT RESPONSE
+4.3V +3.3V
MAX8860 toc12
200mA ILOAD
VOUT 20mV/div VOUT 200mV VOUT 2mV/div
ILOAD 200mA 400µs/div 500µs/div
Low-Dropout, 300mA Linear Regulator µMAX MAX8860
Typical Operating Characteristics (continued)
(VIN VOUT 0.5V, COUT 2.2µF, 33nF, +25°C, unless otherwise noted.)
POWER-UP RESPONSE
MAX8860 toc13
POWER-DOWN RESPONSE
FAULT
MAX8860 toc14
SHUTDOWN/POWER-UP
SHDN
MAX8860 toc15
5ms/div VOUT FAULT
VOUT
VOUT 2ms/div 400µs/div
Description
NAME SHDN FAULT FUNCTION Regulator Output. Bypass with 2.2µF, low-ESR capacitor stable operation. Supply Input. Connect power source (+2.5V +6.5V). Bypass with 2.2µF capacitor GND. Ground Output Voltage Set. Connect internally threshold. Connect resistor-divider adjustable output voltages. Output Voltage Selection section more information. Compensation Capacitor. Connect 0.033µF capacitor from GND. Shutdown Input. Connect normal operation. Drive SHDN turn regulator. Fault Output. high-impedance, open-drain output. When MAX8860 regulation, FAULT goes low. shutdown, FAULT high impedance. Connect unused.
Detailed Description
MAX8860 low-dropout, low-quiescent-current linear regulator designed primarily battery-powered applications. supplies adjustable +1.25V +6.5V output voltage fixed-voltage output +1.8V (MAX8860EUA18), +2.5V (MAX8860EUA25), +2.77V (MAX8860EUA27), +2.82V (MAX8860EUA28), +3.0V (MAX8860EUA30), +3.3V (MAX8860EUA33) load currents 300mA. devices with 2.77V 2.82V nominal outputs designed guarantee minimum output voltages 2.70V 2.75V, respectively. device consists +1.25V reference, error amplifier, MOSFET driver, P-channel pass transistor, Dual Mode comparator, fault detector, internal-feedback voltage divider (Figure 1.25V bandgap reference connected error amplifier's inverting input. error amplifier compares
this reference selected feedback voltage amplifies difference. MOSFET driver reads error signal applies appropriate drive Pchannel pass transistor. feedback voltage lower than reference voltage, pass-transistor gate pulled lower, allowing more current pass increasing output voltage. feedback voltage higher than reference voltage, pass-transistor gate driven higher, allowing less current pass output. output voltage back through either internal resistor voltage divider connected OUT, external resistor network connected SET. Dual Mode comparator examines VSET selects feedback path. below 60mV, internal feedback used output voltage regulated preset output voltage. Additional blocks include output current limiter, reverse battery protection, thermal sensor, fault detector, shutdown logic.
Low-Dropout, 300mA Linear Regulator µMAX MAX8860
SHDN REVERSE BATTERY PROTECTION
ERROR SHUTDOWN LOGIC
DRIVER WITH ILIMIT
FAULT DETECT
MAX8860
THERMAL SENSOR
1.25V DUAL-MODE COMPARATOR 60mV
FAULT
Figure Functional Diagram
Internal P-Channel Pass Transistor
MAX8860 features typical P-channel MOSFET pass transistor. This provides several advantages over similar designs using pass transistors, including longer battery life. PNP-based regulators waste considerable amounts current dropout when pass transistor saturates. They also high basedrive currents under large loads. P-channel MOSFET requires base-drive current, which reduces quiescent current considerably. MAX8860 consumes less than 165µA quiescent current whether dropout, light-load, heavy-load applications (see Typical Operating Characteristics).
OUTPUT VOLTAGE
2.2µF BATTERY
MAX8860
SHDN
COUT 2.2µF 100k
33nF
FAULT
Output Voltage Selection
MAX8860 features Dual Mode operation: operates either preset voltage mode adjustable mode. preset voltage mode, internal, trimmed feedback resistors output voltage adjustable +1.25V +6.5V output voltage fixed-voltage output +1.8V (MAX8860EUA18), +2.5V (MAX8860EUA25), +2.77V (MAX8860EUA27), +2.82V (MAX8860EUA28), +3.V (MAX8860EUA30), +3.3V (MAX8860EUA33). Select this mode connecting ground. adjustable mode, select output between 1.25V 6.5V using external resistors connected voltage divider (Figure Calculate output voltage with following equation:
Figure Adjustable Output Using External Feedback Resistors
VOUT VSET where VSET 1.25V. simplify resistor selection, following equation: VSET
Low-Dropout, 300mA Linear Regulator µMAX
Choose 100k optimize power consumption, accuracy, high-frequency power-supply rejection. Ensure that total current through external resistive feedback load resistors less than 10µA. Since VSET tolerance typically less than ±20mV, output using fixed resistors instead trim pots. preset voltage mode, connect GND. Keep impedances between ground less than 100k. Otherwise, spurious conditions cause VSET exceed 60mV Dual Mode threshold. maximum power dissipation PMAX (TJMAX where: TJMAX +150°C ambient temperature 244°C/W MAX8860's pins perform dual function providing electrical connection well channeling heat away from die. wide circuit-board traces large, solid copper polygons improve power dissipation. Using multiple vias buried ground planes further enhances thermal conductivity.
MAX8860
Shutdown
Drive SHDN place MAX8860 shutdown mode. shutdown mode, pass transistor, control circuit, reference, biases turned off, reducing supply current typically 10nA. Connect SHDN normal operation.
Reverse Battery Protection
MAX8860 unique protection scheme that limits reverse supply current less than when either falls below GND. circuitry monitors polarity these pins, disconnecting internal circuitry parasitic diodes when applied voltage reversed. This feature prevents device from overheating damaging improperly installed battery.
Current Limit
MAX8860 includes short-circuit protection. includes current limiter that controls pass transistor's gate voltage limit output current about 770mA. design purposes, minimum current limit 330mA.
Thermal-Overload Protection
Thermal-overload protection limits total power dissipation MAX8860. When junction temperature (TJ) exceeds +170°C, thermal sensor sends signal shutdown logic, turning pass transistor allowing cool. pass transistor turns again after IC's junction temperature typically cools 20°C, resulting pulsed output during continuous thermal-overload conditions. Thermal-overload protection designed protect MAX8860 against fault conditions. Stressing device with high-load currents high input-output differential voltages (which result temperatures above +125°C) cause momentary overshoot 200ms) when load completely removed. Remedy this raising minimum load current from (+125°C) 100µA (+150°C). This accomplished with external load resistor. continuous operation, exceed absolute maximum junction temperature rating +150°C.
Integrator Circuitry
MAX8860 uses external 33nF compensation capacitor minimizing load- line-regulation errors lowering output noise. When output voltage shifts varying load current input voltage, integrator capacitor voltage raised lowered compensate systematic offset error amplifier. Compensation limited minimize transient overshoot when device goes dropout, current limit, thermal shutdown.
Fault-Detection Circuitry
When output voltage goes regulation-such during dropout, current limit, thermal shutdown- FAULT goes low. addition, fault-detection circuitry detects when input-to-output voltage differential insufficient ensure good load line regulation output. When input-to-output voltage differential less than 130mV load current 200mA, FAULT also goes low. differential threshold designed always higher than track with dropout voltage, scale proportionally with load current (see Fault Detect Threshold Load Current graph Typical Operating Characteristics). FAULT open-drain N-channel MOSFET. create voltage level output, connect pull-up resistor from FAULT OUT. minimize current consumption, make this resistor large practical. 100k resistor works well most applications.
Operating Region Power Dissipation
Maximum power dissipation MAX8860 depends thermal resistance case circuit board, temperature difference between junction ambient air, rate flow. power dissipated device IOUT (VIN VOUT)
Low-Dropout, 300mA Linear Regulator µMAX MAX8860
+5.5V Minimum Load Current Requirements
When operating MAX8860 with input voltage above +5.5V, minimum load current 20µA required maintain regulation preset voltage mode. When setting output with external resistors, ensure that minimum current through external feedback resistors load least 30µA. This applies only when input voltage exceeds +5.5V. input voltages less than +5.5V, MAX8860 maintains regulation stability without external loading.
Power-Supply Rejection Operation from Sources Other than Batteries
MAX8860 designed deliver dropout voltage quiescent current battery-powered systems. Power-supply rejection 67dB frequencies rolls above 100kHz. high frequencies, output capacitor major contributor rejection power-supply noise (see Power-Supply Rejection Ratio Frequency graph Typical Operating Characteristics). When operating from sources other than batteries, improve supply-noise rejection transient response increasing values input output capacitors, using passive filtering techniques (see supply load-transient responses Typical Operating Characteristics).
Applications Information
Capacitor Selection Regulator Stability
Typically, 2.2µF capacitor input 2.2µF capacitor output MAX8860. Capacitor type critical, long less than 0.5. Larger capacitor values lower provide better supply-noise rejection transient response. higher-value capacitors (10µF) large, fast input load transients anticipated device located several inches from power source. stable operation over full temperature range, with load currents 300mA, minimum outputcapacitor value 2.2µF recommended. There upper limit capacitor size. circuit used generate typical operating characteristics data used 2.2µF, X7R, (1206) ceramic capacitors. These capacitors typically have 50m.
Load-Transient Considerations
MAX8860 load-transient response graph (see Typical Operating Characteristics) shows output response changing load current. Reduce overshoot increasing output capacitor's value decreasing ESR.
Input-Output (Dropout) Voltage
regulator's minimum input-output voltage differential dropout voltage) determines lowest usable supply voltage. battery-powered systems, this determines useful end-of-life battery voltage. Because MAX8860 uses P-channel MOSFET pass transistor, dropout voltage function RDS(ON) (typically 0.5) multiplied load current (see Electrical Characteristics).
Chip Information
TRANSISTOR COUNT:
Maxim cannot assume responsibility circuitry other than circuitry entirely embodied Maxim product. circuit patent licenses implied. Maxim reserves right change circuitry specifications without notice time.
_Maxim Integrated Products, Gabriel Drive, Sunnyvale, 94086 408-737-7600 1999 Maxim Integrated Products Printed registered trademark Maxim Integrated Products.
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