MicroCap, Low-Dropout, Linear Regulator MAX8869 low-dropout linea
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MicroCap, Low-Dropout, Linear Regulator
MAX8869 low-dropout linear regulator operates from +2.7V +5.5V input delivers guaranteed load current with 200mV dropout. highaccuracy (±1%) output voltage preset +5V, +3.3V, +2.5V, +1.8V, +1.0V adjustable from +0.8V with external resistor-divider. MAX8869 uses MicroCaptechnology requires only small output capacitor guaranteed stability. internal PMOS pass transistor allows 500µA supply current, making this regulator useful networking telecom hardware well battery-operated equipment. Other features include softstart, low-power shutdown, short-circuit protection, thermal shutdown protection. MAX8869 available 1.5W, 16-pin TSSOP package, which smaller than SOT223 only 1.1mm high. Guaranteed Output Current Stable with COUT 200mV Dropout Output Voltage Accuracy Preset +5V, +3.3V, +2.5V, +1.8V, +1.0V Adjustable from +0.8V +5.0V 54dB PSRR 100kHz Adjustable Soft-Start Reset Output Foldback Output Current Limit Thermal Overload Protection High-Power 16-Pin TSSOP Package (1.5W) Smaller than SOT223 (only 1.1mm high)
Features
MAX8869
_Applications
Telecom Hardware Network Equipment Mobile Phone Base Stations Personal Computers Notebook Computers
PART MAX8869EUE50 MAX8869EUE33 MAX8869EUE25 MAX8869EUE18 MAX8869EUE10
Ordering Information
TEMP. RANGE -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C -40°C +85°C PINPACKAGE TSSOP-EP** TSSOP-EP TSSOP-EP TSSOP-EP TSSOP-EP VOUT* +5.0 +3.3 +2.5 +1.8 +1.0
MicroCap trademark Maxim Integrated Products.
adjustable from +0.8V +5.0V. Contact factory other preset output voltages. **EP Exposed pad.
Configuration Typical Operating Circuit
VIEW
N.C. N.C.
MAX8869 +2.7V +5.5V SHDN RESET OUTPUT
SHDN
MAX8869
N.C.
TSSOP-EP
Maxim Integrated Products
free samples latest literature, visit www.maxim-ic.com phone 1-800-998-8800. small orders, phone 1-800-835-8769.
MicroCap, Low-Dropout, Linear Regulator MAX8869
ABSOLUTE MAXIMUM RATINGS
SHDN, RST, .-0.3V OUT, .-0.3V (VIN 0.3V) Output Short-Circuit Duration .Indefinite Continuous Power Dissipation +70°C) 16-Pin TSSOP-EP (derate 19mW/°C above +70°C).1.5W Operating Temperature Range .-40°C +85°C Junction Temperature .+150°C Storage Temperature Range .-65°C 150°C Lead Temperature (soldering, 10s) .+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 +2.7V VOUT(NOM) 0.5V (whichever greater), SHDN open, GND, COUT 1µF, +85°C, unless otherwise noted. Typical values +25°C.)
PARAMETER Input Voltage Range Input Undervoltage Lockout Output Voltage Accuracy Regulation Voltage (Adjustable Mode) Line Regulation Load Regulation Adjustable Output Voltage Range Maximum Output Current Short-Circuit Current Limit In-Regulation Current Limit Dual Mode Threshold Input Bias Current Ground Current Dropout Voltage (Note Output Voltage Noise Power-Supply Rejection Ratio Shutdown Supply Current SHDN Input Threshold SHDN Input Bias Current Soft-Start Charge Current Output Voltage Operating Voltage Range Valid Leakage Trip Level Referred Nominal VOUT Release Delay Thermal Shutdown Threshold TSHDN PSRR IOFF ISET IGND VSET +0.9V IOUT 100µA IOUT IOUT 1mA, +2.7V +5.5V IOUT VOUT +3.3V (Note 10Hz 1MHz, COUT 1µF, IOUT 150mA 100kHz, COUT SHDN GND, +5.5V, VOUT +2.7V +5.5V SHDN ISINK ISINK 10µA +5.5V Falling edge, typical hysteresis 10mV Rising edge Typical thermal hysteresis +20°C 0.01 VLNR VLDR IOUT ILIM ILIM SYMBOL Typical hysteresis 50mV IOUT 1mA, +85°C IOUT 150mA, +85°C VOUT 0.5V +5.5V, IOUT 10mA IOUT Continuous VOUT VSET 0.76V CONDITIONS 2.35 2.45 2.55 UNITS ARMS µVRMS
Dual Mode trademark Maxim Integrated Products.
MicroCap, Low-Dropout, Linear Regulator
ELECTRICAL CHARACTERISTICS
(VIN +2.7V VOUT(NOM) 0.5V (whichever greater), SHDN open, GND, COUT 1µF, -40°C +85°C, unless otherwise noted.) (Note
PARAMETER Input Voltage Range Input Undervoltage Lockout Output Voltage Accuracy Regulation Voltage (Adjustable Mode) Load Regulation Adjustable Output Voltage Range Maximum Output Current Short-Circuit Current Limit In-Regulation Current Limit Dual Mode Threshold Input Bias Current Ground Current Dropout Voltage (Note Shutdown Supply Current SHDN Input Threshold SHDN Input Bias Current Output Voltage Operating Voltage Range Valid Leakage Trip Level Referred Nominal VOUT Release Delay IOFF ISET IGND VSET +0.9V IOUT 100µA IOUT VOUT +3.3V (Note SHDN GND, +5.5V, VOUT +2.7V +5.5V SHDN ISINK ISINK 10µA +5.5V Falling edge, typical hysteresis 10mV Rising edge IOUT ILIM ILIM Continuous VOUT VSET +0.76V VLDR SYMBOL Typical hysteresis 50mV IOUT 1mA, +85°C IOUT 150mA, +85°C IOUT CONDITIONS UNITS ARMS
MAX8869
Note Dropout voltage (VIN VOUT) when VOUT falls 100mV below value VOUT measured when VOUT(NOM) +0.5V. Since minimum input voltage 2.7V, this specification only meaningful when VOUT 2.7V. Note output voltage externally using resistive voltage-divider from SET. Note Specifications -40°C guaranteed design, production tested.
MicroCap, Low-Dropout, Linear Regulator MAX8869
Typical Operating Characteristics
(VIN +5V, VOUT +2.5V, SHDN open, COUT 1µF, +25°C, unless otherwise noted.)
OUTPUT VOLTAGE DEVIATION OUTPUT CURRENT
MAX8869-01
OUTPUT VOLTAGE DEVIATION TEMPERATURE
MAX8869-02
GROUND CURRENT INPUT VOLTAGE
IOUT IOUT 0.5A
MAX8869-03
OUTPUT VOLTAGE DEVIATION -0.5 -1.0 -1.5 -2.0 -2.5 -3.0
IOUT 250mA OUTPUT VOLTAGE DEVIATION -0.5 -1.0 -1.5
GROUND CURRENT (mA) IOUT
OUTPUT CURRENT
TEMPERATURE (°C)
INPUT VOLTAGE
GROUND CURRENT OUTPUT CURRENT
MAX8869-04
GROUND CURRENT TEMPERATURE
MAX8869-05
DROPOUT VOLTAGE OUTPUT CURRENT
VOUT +3.3V DROPOUT VOLTAGE (mV)
MAX8869-06
GROUND CURRENT (mA)
GROUND CURRENT (mA)
IOUT 250mA
IOUT
1000 OUTPUT CURRENT (mA) TEMPERATURE (°C)
1000 1250 1500 OUTPUT CURRENT (mA)
DROPOUT VOLTAGE INPUT VOLTAGE
MAX8869-07
PSRR FREQUENCY
MAX8869-08
OUTPUT NOISE SPECTRAL DENSITY FREQUENCY
IOUT 250mA
MAX8869-09
DROPOUT VOLTAGE (mV)
IOUT 500mA DROPOUT, VOUT
PSRR (dB) IOUT 300mA 0.01
NOISE (µV/Hz) 1000
0.01 0.01 1000 FREQUENCY (kHz) FREQUENCY (kHz)
INPUT VOLTAGE
MicroCap, Low-Dropout, Linear Regulator MAX8869
Typical Operating Characteristics (continued)
(VIN +5V, VOUT +2.5V, SHDN open, COUT 1µF, +25°C, unless otherwise noted.)
OUTPUT NOISE OUTPUT CURRENT
OUTPUT NOISE (µVRMS) 0.001 0.01 VOUT
MAX8869-10
LINE-TRANSIENT RESPONSE
MAX8869-11
LOAD-TRANSIENT RESPONSE
MAX8869-12
3.6V IOUT
100mA
VOUT 10mV/div AC-COUPLED IOUT 250mA 200µs/div 20µs/div
50mV/div AC-COUPLED
OUTPUT CURRENT
LOAD-TRANSIENT RESPONSE
MAX8869-13
OUTPUT NOISE
MAX8869-14
SHUTDOWN RESPONSE
MAX8869-15
1MHz BANDWIDTH IOUT 10mA VSHDN 100µV/div VOUT 200mV/div AC-COUPLED VOUT
IOUT 100µA
5V/div
2V/div
20µs/div
4ms/div
40µs/div
SOFT-START RESPONSE
MAX8869-16
RESET OUTPUT RESPONSE
MAX8869-17
VSHDN
5V/div
5V/div
1A/div VOUT 2V/div OUTPUT DELAY 2V/div
VOUT 100nF 10ms/div
2V/div
1ms/div
MicroCap, Low-Dropout, Linear Regulator MAX8869
Description
NAME N.C. Connection. internally connected. Regulator Input. Connect power source (+2.7V +5.5V). Bypass with greater capacitor (see Capacitor Selection Regulator Stability). Connect pins together proper operation. Reset Output. Open-drain output when VOUT below nominal value. remains while output voltage (VOUT) below reset threshold least after VOUT rises within regulation. Connect 100k pullup resistor obtain output voltage. Active-Low Shutdown Input. logic reduces supply current 0.1µA. Connect SHDN normal operation. shutdown, soft-start capacitor discharges. Soft-Start Control Pin. Connect soft-start capacitor from (see Soft-Start Capacitor Selection). Leave open disable soft-start. Ground. This exposed also function heatsink. Solder both large circuit-board ground plane maximize power dissipation. Voltage-Setting Input. Connect factory-preset output voltage. Connect external resistor-divider adjustable output operation. Regulator Output. Bypass with greater low-ESR capacitor (see Capacitor Selection Regulator Stability). Connect pins together proper operation. FUNCTION
SHDN
Detailed Description
MAX8869 features Dual Mode operation, allowing fixed output +5V, +3.3V, +2.5V, +1.8V, +1.0V, adjustable output from +0.8V +5.0V. regulators guaranteed supply continuous output current with only output capacitance. shown functional diagram (Figure device 0.8V reference, error amplifier, MOSFET driver, P-channel pass transistor, internal feedback voltage-divider, soft-start function, reset timer, Dual Mode VOUT comparators. 0.8V reference connected error amplifier's inverting input. error amplifier compares this reference with selected feedback voltage amplifies difference. MOSFET driver reads error signal applies appropriate drive P-channel transistor. feedback voltage high, pass transistor's gate pulled allowing less current pass output. VOUT comparator senses when
feedback voltage dropped below expected level, causing low. output voltage back through either internal resistor-divider connected external resistor network connected SET. Dual Mode comparator examines VSET selects feedback path. VSET below 80mV, internal feedback path used output voltage regulated factory-preset voltage. Otherwise, output voltage with external resistor-divider.
Internal P-Channel Pass Transistor
MAX8869 features P-channel MOSFET pass transistor. Unlike similar designs using pass transistors, P-channel MOSFETs require base drive, which reduces quiescent current. PNP-based regulators also waste considerable current dropout when pass transistor saturates high base-drive currents under large loads. MAX8869 does suffer from these problems consumes only 500µA quiescent current even dropout.
MicroCap, Low-Dropout, Linear Regulator MAX8869
SHUTDOWN THERMAL SENSOR ERROR SHUTDOWN LOGIC MOSFET DRIVER WITH FOLDBACK CURRENT LIMIT VOUT DETECTOR 736mV 0.8V REFERENCE 80mV NMOS
MAX8869
PMOS
SHDN
DELAY TIMER
DUAL MODE COMPARATOR
Figure Functional Diagram
where VSET +0.8V. simplify resistor selection:
MAX8869 SHDN RESET OUTPUT COUT
(VOUT VSET Since input bias current nominally 50nA, large resistance values used minimize power consumption without losing efficiency. acceptable preset voltage mode, impedance between ground should less than 10k. Otherwise, spurious conditions could cause voltage exceed 80mV Dual Mode threshold.
Shutdown
Figure Typical Operating Circuit with Preset Output Voltage
Output Voltage Selection
MAX8869 features Dual Mode operation. Connect (Figure preset voltage mode (see Ordering Information). adjustable mode, output between +0.8V +5.0V through external resistors connected voltage-divider (Figure output voltage following equation: VOUT VSET
logic SHDN disables MAX8869. shutdown, pass transistor, control circuitry, reference, biases turned off, reducing supply current typically 0.1µA. Connect SHDN normal operation. shutdown, soft-start capacitor discharged.
Comparator
MAX8869 features indicator that asserts when output voltage falls regulation. open-drain goes when falls
MicroCap, Low-Dropout, Linear Regulator MAX8869
MAX8869 SHDN COUT SHDN RESET OUTPUT COUT MAX8869
RESET OUTPUT
Figure Typical Operating Circuit with Adjustable Output Voltage
Figure Typical Operating Circuit with Soft-Start CurrentLimit Reduction
below nominal output voltage. remains after returned nominal value. 100k pullup resistor from suitable logic supply voltage (typically OUT) provides logic control signal. used power-on-reset signal microcontroller (µC) drive external indicating power failure. during shutdown. remains valid input voltage
Soft-Start
shown Figure capacitor allows gradual buildup MAX8869 output, reducing initial in-rush current peaks startup. When SHDN driven low, soft-start capacitor discharged. When SHDN driven high power applied device, constant current charges soft-start capacitor. resulting linear ramp voltage increases current-limit comparator threshold, limiting P-channel gate drive (see Soft-Start Capacitor Selection). Leave floating disable soft-start feature.
tying resistor (RSS) between GND, that ILIM ILIM_NOM (ISS 1.25) where With place, soft-start still achieved placing capacitor (CSS) parallel with RSS. output current ramps asymptotically reduced current limit rather than nominal one, increasing softstart time. time required current limit reach steady-state value given RSSCSS.
Thermal Overload Protection
Thermal overload protection limits total power dissipation MAX8869. When junction temperature exceeds +170°C, thermal sensor turns pass transistor, allowing cool. thermal sensor turns pass transistor once IC's junction temperature drops approximately 20°C. Continuous short-circuit conditions will consequently result pulsed output. Thermal overload protection designed safeguard MAX8869 event fault conditions. continuous operation, exceed absolute maximum junction temperature rating +150°C.
Current Limiting
MAX8869 features current limit when output voltage regulation. When output voltage drops below nominal, current limit folds back 1.7A. output shorted ground indefinite period time without damaging device. Avoid continuous output current more than prevent damage. Both in-regulation short-circuit current limits reduced from their nominal values reducing voltage soft-start (SS) below 1.25V. current limits scale proportionately with voltage ILIM ILIM_NOM (VSS 1.25). Since sources nominal current, current limit
Operating Region Power Dissipation
Maximum power dissipation MAX8869 depends thermal resistance case circuit board, temperature difference between junction ambient air, rate flow. power dissipation across device IOUT (VIN VOUT). resulting maximum power dissipation PMAX [(TJ(MAX) CA)] where J(MAX) temperature difference between maximum allowed junction (150°C) surrounding air; (junction case)
MicroCap, Low-Dropout, Linear Regulator
MAXIMUM CONTINUOUS CURRENT MAXIMUM OUTPUT CURRENT TYPICAL DROPOUT VOLTAGE LIMIT +150°C INPUT-OUTPUT DIFFERENTIAL VOLTAGE TYPICAL SUPPLY VOLTAGE LIMIT +25°C
+50°C +70°C
less ensure stability optimum transient response. This particularly true applications with very output voltage (<2V) high output current (>0.5A). Since some capacitor dielectrics vary over bias voltage temperature, consult capacitor manufacturer specifications ensure that capacitors meet these requirements over voltage temperature conditions used.
MAX8869
Soft-Start Capacitor Selection
capacitor (CSS) connected from causes MAX8869 output current slowly rise during startup, reducing stress input supply. rise time full current limit (tSS) determined 2.08 10-4 where Typical capacitor values between 10nF 100nF, with rating, sufficient. Because this ramp applied current-limit comparator, actual time output voltage ramp depends load current output capacitor. Leave open disable soft-start.
Figure Power Operating Region: Maximum Output Current Input-Output Differential Voltage
thermal resistance package chosen, thermal resistance from case through board, copper traces, other materials surrounding air. Figure shows allowable power dissipation typical boards +25°C, +50°C, +70°C ambient temperatures. MAX8869 TSSOP-EP package features exposed thermal underside. This lowers package's thermal resistance providing direct thermal heat path from board. Additionally, ground (GND) also channels heat. Connect exposed thermal circuit ground using large (1in2 minimum recommended) multiple vias ground plane.
Input-Output (Dropout) Voltage
regulator's minimum input-to-output voltage differential (dropout voltage) determines lowest usable supply voltage. battery-powered systems, this determines useful end-of-life battery voltage. Since P-channel MOSFET used pass device, dropout voltage product RDS(ON) load current (see Electrical Characteristics Dropout Voltage Output Current Typical Operating Characteristics). MAX8869 operating current remains dropout.
Applications Information
Capacitor Selection Regulator Stability
Capacitors required MAX8869 input output. Connect greater capacitors between MAX8869's relatively high bandwidth, only surfacemount ceramic capacitors that have equivalent series resistance (ESR) high self-resonant frequency (SRF). Make input output traces least 2.5mm wide (the width four parallel pins), connect COUT within minimize impact board trace inductance. width ground trace should maximized underneath ensure good connection between (GND) ground side capacitors. output capacitor's affect stability output noise. capacitors with greater than 5MHz
Noise, PSRR, Transient Response
MAX8869 designed achieve dropout voltage quiescent current battery-powered systems while still maintaining good noise, transient response, rejection (see PSRR Frequency Typical Operating Characteristics). When operating from very noisy sources, supply noise rejection transient response improved increasing values input output capacitors employing passive postfiltering. MAX8869 output noise typically 150µV RMS. (see Output Noise plot Typical Operating Characteristics).
Chip Information
TRANSISTOR COUNT: 1088
MicroCap, Low-Dropout, Linear Regulator MAX8869
Package Information
TSSOP.EPS
Note: MAX8869EUE exposed thermal bottom side package.
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 2000 Maxim Integrated Products Printed registered trademark Maxim Integrated Products.
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