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19-2072; Rev 0; 1/02
500mA Low-Dropout Linear Regulator in UCSP
General Description
The MAX1819 low-dropout linear regulator operates from a 2.5V to 5.5V supply and delivers a guaranteed 500mA load current with low 120mV dropout. The high-accuracy (1%) output voltage is preset at an internally trimmed voltage (see the Selector Guide) or can be adjusted from 1.25V to 5V with an external resistive-divider. An internal PMOS pass transistor allows the low 125A supply current to remain independent of load, making this device ideal for portable battery-operated equipment such as personal digital assistants (PDAs), cellular phones, cordless phones, base stations, and notebook computers. Other features include an active-low, open-drain reset output that indicates when the output is out of regulation, a 0.1A shutdown, short-circuit protection, and thermal shutdown protection. The device is available in a miniature 6-pin UCSPTM package. o Guaranteed 500mA Output Current o Low 90mV Dropout at 500mA o 1% Initial Output Accuracy o Preset Output at 1.5V, 1.8V, 2V, 2.5V, 3.3V, 5V o Adjustable Output from 1.25V to 5V o Power-OK Output o Low 125A Ground Current o 0.1A Shutdown Current o Thermal Overload Protection o Output Current Limit o Tiny 840mW 6-Pin UCSP Package
Features
MAX1819
Ordering Information
PART MAX1819EBL_ _ -T* TEMP RANGE -40C to +85C PIN-PACKAGE 6 UCSP
Applications
Notebook Computers Cellular and Cordless Telephones Personal Digital Assistants (PDAs) Palmtop Computers Base Stations USB Hubs Docking Stations
*Insert the desired two-digit suffix (see Selector Guide) into the blanks to complete the part number.
Selector Guide
PART AND SUFFIX MAX1819EBL 15 MAX1819EBL 18 MAX1819EBL 20 VOUT 1.5V or Adj 1.8V or Adj 2V or Adj 2.5V or Adj 3.3V or Adj 5V or Adj UCSP MARK AAH AAG AAC AAD AAE AAF
UCSP is a trademark of Maxim Integrated Products, Inc.
MAX1819EBL 25 MAX1819EBL 33 MAX1819EBL 50
Pin Configuration
TOP VIEW
(TOP OF PC BOARD/ BALLS SOLDERED DOWN) A 1 IN A1 2 POK A2 3 SHDN A3
Typical Operating Circuit
VIN = 2.5V TO 5.5V IN NC CIN 1F OUT VOUT COUT 3.3F
MAX1819
B
MAX1819
OUT SET C2 GND C3
RPOK 100k POK TO C
ON SHDN OFF
C
C1
SET
UCSP
GND
________________________________________________________________ Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at 1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
500mA Low-Dropout Linear Regulator in UCSP Linear Regulator in MAX1819
ABSOLUTE MAXIMUM RATINGS
IN, SHDN, POK, SET to GND ...................................-0.3V to +6V OUT to GND ................................................-0.3V to (VIN + 0.3V) Output Short-Circuit Duration ...............................................1min Continuous Power Dissipation (TA = +70C) (Note 1) 6-Pin UCSP (derate 10.5mW/C above +70C) ............840mW Operating Temperature Range ...........................-40C to +85C Junction Temperature ......................................................+150C Storage Temperature Range .............................-65C to +150C Soldering Temperature (10s) ...........................................+300C
Note 1: Thermal properties are specified with product mounted on PC board with one square-inch of copper area and still air.
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 = (VOUT + 500mV) or VIN = 2.5V, whichever is greater; SHDN = IN, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER Input Voltage Input Undervoltage Lockout SYMBOL VIN VUVLO Rising, 75mV hysteresis IOUT = 100mA, TA = +25C, VOUT 2V Output Voltage Accuracy (Preset Mode) IOUT = 100mA, TA = +25C, VOUT < 2V VOUT IOUT = 100mA, TA = -40C to +85C IOUT = 1mA to 500mA, VIN > VOUT + 0.5V, TA = -40C to +85C Adjustable Output Voltage Range SET Voltage Threshold (Adjustable Mode) Guaranteed Output Current (RMS) Short-Circuit Current Limit In-Regulation Current Limit SET Dual ModeTM Threshold SET Input Bias Current Ground-Pin Current ISET IQ VSET = 1.25V IOUT = 100A IOUT = 500mA VOUT = 5V Dropout Voltage (Note 3) VIN - VOUT IOUT = 500mA VOUT = 3.3V VOUT = 2.5V Line Regulation VLNR VIN from (VOUT + 100mV) to 5.5V, ILOAD = 5mA -0.15 VSET VIN = 2.7V, IOUT = 100mA, VOUT set to 2V VIN 2.7V VOUT = 0, VIN 2.7V VOUT > 96% of nominal value, VIN 2.7V 50 -100 125 150 125 133 165 0 220 232 280 +0.15 %/V mV TA = 0C to +85C TA = -40C to +85C CONDITIONS MIN 2.5 2.0 -1 -1.5 -2.5 -3 1.25 1.225 1.213 500 0.55 1.39 2 100 150 +100 250 2.50 1.250 2.15 TYP MAX 5.5 2.3 +1 +1.5 +2.5 +3 5.00 1.275 V 1.288 mA A A mV nA A V % UNITS V V
IOUT ILIM
Dual Mode is a trademark of Maxim Integrated Products, Inc.
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500mA Low-Dropout Linear Regulator in UCSP
ELECTRICAL CHARACTERISTICS (continued)
(VIN = (VOUT + 500mV) or VIN = 2.5V, whichever is greater; SHDN = IN, TA = -40C to +85C, unless otherwise noted. Typical values are at TA = +25C.) (Note 2)
PARAMETER Load Regulation Output Voltage Noise SHUTDOWN Shutdown Supply Current SHDN Input Threshold SHDN Input Bias Current POK OUTPUT POK Output Low Voltage Operating Voltage Range for Valid POK POK Output High Leakage Current POK Threshold THERMAL PROTECTION Thermal Shutdown Temperature Thermal Shutdown Hysteresis TSHDN TSHDN 170 20 C C VOL POK sinking 1mA POK sinking 100A POK = 5.5V, TA = +25C TA = +85C Rising edge, referred to VOUT(NOMINAL) 90 1.0 1 5 93 96 0.01 0.1 5.5 30 V V nA % IOFF VIH VIL I SHDN SHDN = GND, VIN = 5.5V 2.5V < VIN < 5.5V 2.5V < VIN < 5.5V SHDN = IN or GND, TA = +25C TA = +85C 1 5 1.6 0.6 70 0.1 15 A V nA SYMBOL VLDR CONDITIONS IOUT = 1mA to 500mA 10Hz to 1MHz, COUT = 3.3F (ESR < 0.1) MIN TYP 0.4 115 MAX 1.0 UNITS % VRMS
MAX1819
Note 2: All devices are 100% production tested at TA = +25C and up to 100mA. Limits over the operating temperature range and above 100mA are guaranteed by design. Note 3: The dropout voltage is defined as VIN - VOUT, when VOUT is 100mV below the value of VOUT measured for VIN = VOUT(NOM) + 500mV. Since the minimum input voltage is 2.5V, this specification is only meaningful when VOUT(NOM) > 2.5V. For VOUT(NOM) between 2.5V and 3.5V, use the following equations: Typical Dropout = -40mV/V VOUT(NOM) + 265mV; Guaranteed Maximum Dropout = -60mV/V VOUT(NOM) + 430mV. For VOUT(NOM) > 3.5V, Typical Dropout = 125mV; Maximum Dropout = 220mV.
Typical Operating Characteristics
(VIN = (VOUT + 500mV) or 2.5V, whichever is greater; SHDN = IN, CIN = 3.3F, COUT = 3.3F, TA = +25C, unless otherwise noted.)
GROUND-PIN CURRENT vs. INPUT VOLTAGE
MAX1819 toc01
GROUND-PIN CURRENT vs. LOAD CURRENT
MAX1819 toc02
GROUND-PIN CURRENT vs. TEMPERATURE
ILOAD = 150mA GROUND-PIN CURRENT (A) 170 5V OUTPUT 160
MAX1819 toc03
250 225 GROUND-PIN CURRENT (A) 200 175 150 125 100 75 50 25 0
IOUT = 150mA 3.3V OUTPUT
180
175 GROUND-PIN CURRENT (A) 165 155 145 135 125 115 0
3.3V OUTPUT 2.5V OUTPUT
2.5V OUTPUT 1.8V OUTPUT
150 1.5V OUTPUT
1.8V OUTPUT
140
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 INPUT VOLTAGE (V)
130 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A) -40 -15 10 35 60 85 TEMPERATURE (C)
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500mA Low-Dropout Linear Regulator in UCSP MAX1819
Typical Operating Characteristics (continued)
(VIN = (VOUT + 500mV) or 2.5V, whichever is greater; SHDN = IN, CIN = 3.3F, COUT = 3.3F, TA = +25C, unless otherwise noted)
DROPOUT VOLTAGE vs. LOAD CURRENT
260 240 220 200 180 160 140 120 100 80 60 40 20 0 0 100 200 300 400 500 600 700 800 LOAD CURRENT (A)
MAX1819 toc04
OUTPUT VOLTAGE ACCURACY vs. LOAD CURRENT
MAX1819 toc05
OUTPUT VOLTAGE ACCURACY vs. TEMPERATURE
0.4 OUTPUT VOLTAGE ACCURACY (%) 0.3 0.2 0.1 0 -0.1 -0.2 -0.3 -0.4 -0.5 -40 -15 10 35 60 85 ILOAD = 150mA
MAX1819 toc06
MAX1819 toc09
1.0 OUTPUT VOLTAGE ACCURACY (%) 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1.0 0 VOUT = 3.3V VOUT = 0.5V VOUT = 1.8V
0.5
VOUT = 3.3V TA = +85C
DROPOUT VOLTAGE (mV)
TA = +25C
TA = -40C
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 LOAD CURRENT (A)
TEMPERATURE (C)
POWER-SUPPLY REJECTION RATIO vs. FREQUENCY
MAX1819 toc07
LINE TRANSIENT
MAX1819 toc08
LOAD TRANSIENT RESPONSE
VIN = 3.8V VOUT = 3.3V 10mV/div IOUT 380mA 50mA
80 70 60 PSRR (dB) 50 40 30 20 10 0 0.01 0.1 1 10 100 COUT = 3.3F VOUT = 3.3V RLOAD = 100
VOUT = 2.5V IOUT = 5mA VOUT
3.5V VIN 3V VOUT
20mV/div
1000
100s/div
40s/div
FREQUENCY (kHz)
LOAD TRANSIENT RESPONSE NEAR DROPOUT
MAX1819 toc10
POWER-ON RESET
MAX1819 toc11
VIN = 3.35V VOUT = 3.5V VOUT
VPOK
50mV/div
0 VOUT 2V/div
IOUT
200mA 20mA
VIN
0
0 40s/div
10ms/div
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500mA Low-Dropout Linear Regulator in UCSP
Typical Operating Characteristics (continued)
(VIN = (VOUT + 500mV) or 2.5V, whichever is greater; SHDN = IN, CIN = 3.3F, COUT = 3.3F, TA = +25C, unless otherwise noted)
SHUTDOWN WAVEFORM
MAX1819 toc12
MAX1819
SHORT-CIRCUIT CURRENT LIMIT vs. SUPPLY VOLTAGE
VOUT(NOM) = 2V SHORT-CIRCUIT CURRENT LIMIT (A)
MAX1819 toc13
1.40
SHUTDOWN VOLTAGE
0
1.39
1.38
VOUT 0
2V/div
1.37
1.36
POK 200s/div
0 1.35 2.5 3.0 3.5 4.0 4.5 5.0 5.5 SUPPLY VOLTAGE (V)
Pin Description
PIN A1 A2 A3 C1 C2 C3 NAME IN POK SHDN OUT SET GND FUNCTION Regulator Input. Supply voltage can range from 2.5V to 5.5V. Bypass with a 1F capacitor to GND (see the Capacitor Selection and Regulator Stability section). Open-Drain POK Output. POK remains low while the output voltage (VOUT) is below the POK threshold. Connect a 100k pullup resistor from POK to OUT to obtain an output voltage. Active-Low Shutdown Input. A logic low reduces supply current below 15A. In shutdown, the POK and OUT are low. Connect to IN for normal operation. Regulator Output. Sources up to 500mA. Bypass with a 3.3F low-ESR capacitor to GND. Use a 4.7F capacitor for output voltages below 2V. Voltage-Setting Input. Connect to GND for preset output. Connect to a resistive voltage-divider between OUT and GND to set the output voltage between 1.25V and 5V. Ground
Detailed Description
The MAX1819 is a low-dropout, low-quiescent-current linear regulator designed primarily for battery-powered applications. The device supplies loads up to 500mA and is available with preset output voltages. As illustrated in Figure 1, the MAX1819 consists of a 1.25V reference, error amplifier, P-channel pass transistor, and internal feedback voltage-divider. The 1.25V reference is connected to the error amplifier, which compares this reference with the feedback voltage and amplifies the difference. If the feedback voltage is lower than the reference voltage, the pass-transistor
gate is pulled lower, which allows more current to pass to the output and increases the output voltage. If the feedback voltage is too high, the pass-transistor gate is pulled up, allowing less current to pass to the output. The output voltage is fed back through either an internal resistive-divider connected to OUT or an external resistor network connected to SET. The Dual Mode comparator examines VSET and selects the feedback path. If VSET is below 50mV, the internal feedback path is used and the output is regulated to the factory-preset voltage.
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500mA Low-Dropout Linear Regulator in UCSP MAX1819
VIN = 2.5V TO 5.5V CIN 1F
IN
THERMAL SENSOR MOSFET DRIVER WITH I LIM OUT VOUT = 1.25V TO 5V COUT 3.3F SHUTDOWN LOGIC ERROR AMPLIFIER VREF 1.25V 5k
ON OFF
SHDN
LOGIC SUPPLY VOLTAGE (VOUT) RPOK 100k TO C POK
R1
MAX1819
SET
R2 93% VREF 100mV GND
Figure 1. Functional Diagram
Additional blocks include an output current limiter, thermal sensor, and shutdown logic.
Internal P-Channel Pass Transistor
The MAX1819 features a 0.25 P-channel MOSFET pass transistor. Unlike similar designs using PNP pass transistors, P-channel MOSFETs require no base drive, which reduces quiescent current. PNP-based regulators also waste considerable current in dropout when the pass transistor saturates and use high base-drive currents under large loads. The MAX1819 does not suffer from these problems and consumes only 125A of quiescent current under heavy loads as well as in dropout.
(see the Selector Guide). For example, the MAX1819EBL33 has a preset 3.3V output voltage. The output voltage may also be adjusted by connecting a voltage-divider from OUT to SET to GND (Figure 2). Select R2 in the 25k to 100k range. Calculate R1 with the following equation: R1 = R2 [(VOUT / VSET) - 1] where VSET = 1.25V, and VOUT may range from 1.25V to 5V.
Shutdown
Pull SHDN low to enter shutdown. During shutdown, the output is disconnected from the input and supply current drops to 0.1A. When in shutdown, POK and OUT pull low. SHDN can be pulled as high as 6V, regardless of the input and output voltage.
Output Voltage Selection
The MAX1819's Dual Mode allows operation in either a preset voltage mode or an adjustable mode. Connect SET to GND to select the preset output voltage. The two-digit part number suffix identifies the output voltage
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500mA Low-Dropout Linear Regulator in UCSP MAX1819
VOUT -1 1.25V VOUT
MAXIMUM OUTPUT CURRENT (mA)
R1 = R2 V IN = 2.5V TO 5.5V IN OUT
MAXIMUM OUTPUT CURRENT vs. INPUT VOLTAGE (POWER DISSIPATION LIMIT)
MAXIMUM RECOMMENDED OUTPUT CURRENT TA = +85C TA = +70C
MAX1819 fig03
600
CIN 1F ON SHDN OFF
MAX1819
COUT 3.3F
R1
400 MAXIMUM INPUT VOLTAGE 5.5 6.0
SET
200
VOUT = 1.8V VOUT = 2.5V VOUT = 3.3V
R2 POK GND
0 2.5 3.0 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V)
Figure 2. Adjustable Output Using External Feedback Resistors
Figure 3. Power Operating Regions--Maximum Output vs. Supply Voltage
POK Output
The power-OK (POK) output pulls low when OUT is less than 93% of the nominal regulation voltage. Once OUT exceeds 93% of the nominal voltage, POK goes high impedance. POK is an open-drain N-channel output. To obtain a voltage signal, connect a pullup resistor from POK to OUT. A 100k resistor works well for most applications. POK can be used as a power-OK signal to a microcontroller (C), or drive an external LED to indicate power failure. When the MAX1819 is shut down, POK is held low independent of the output voltage. If unused, leave POK grounded or unconnected.
Operating Region and Power Dissipation
The MAX1819's maximum power dissipation depends on the thermal resistance of the IC package and circuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. The power dissipated in the device is P = IOUT x (VIN V OUT ). The maximum allowed power dissipation is 840mW at TA = +70C or: PMAX = (TJ(MAX) - TA) / ( JB + BA) where TJ - TA is the temperature difference between the MAX1819 die junction and the surrounding air, JB is the thermal resistance of the junction to the base, and BA is the thermal resistance through the PC board, copper traces, and other materials to the surrounding air. For best heatsinking, the copper area should be equally shared between the IN, OUT, and GND pins. The MAX1819 delivers up to 0.5A RMS and operates with input voltages up to 5.5V, but not simultaneously. High output currents can only be sustained when inputoutput differential voltages are low, as shown in Figure 3.
Current Limit
The MAX1819 monitors and controls the pass transistor's gate voltage, limiting the output current to 1.0A (typ). This current limit doubles when the output voltage is within 4% of the nominal value to improve performance with large load transients.
Thermal Overload Protection
Thermal overload protection limits total power dissipation in the MAX1819. When the junction temperature exceeds TJ = +170C, a thermal sensor turns off the pass transistor, allowing the IC to cool. The thermal sensor turns the pass transistor on again after the junction temperature cools by 20C, resulting in a pulsed output during continuous thermal overload conditions. Thermal overload protection protects the MAX1819 in the event of fault conditions. For continuous operation, do not exceed the absolute maximum junction-temperature rating of TJ = +150C.
_______________________________________________________________________________________
7
500mA Low-Dropout Linear Regulator in UCSP MAX1819
Applications Information
Capacitor Selection and Regulator Stability
Capacitors are required at the MAX1819's input and output for stable operation over the full temperature range and with load currents up to 500mA. Connect a 1F capacitor between IN and ground and a 3.3F lowESR capacitor between OUT and ground. For output voltages less than 2V, use a 4.7F low-ESR output capacitor. The input capacitor (CIN) lowers the source impedance of the input supply. Reduce noise and improve load-transient response, stability, and powersupply rejection by using larger output capacitors, such as 10F. The output capacitor's (COUT) equivalent series resistance (ESR) affects stability and output noise. Use output capacitors with an ESR of 0.1 or less to ensure stability and optimum transient response. Surfacemount ceramic capacitors have very low ESR and are commonly available in values up to 10F. C IN and COUT use short traces to connect to the MAX1819. The MAX1819 load-transient response (see the Typical Operating Characteristics) shows two components of the output response: a DC shift from the output impedance due to the load current change, and the transient response. Increasing the output capacitor's value and decreasing the ESR attenuates the overshoot.
Input-Output (Dropout) Voltage
A regulator's minimum input-to-output voltage differential (dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the MAX1819 uses a P-channel MOSFET pass transistor, its dropout voltage is a function of drain-to-source on-resistance (RDS(ON)) multiplied by the load current (see the Typical Operating Characteristics). VDROPOUT = VIN - VOUT = RDS(ON) x IOUT The MAX1819 ground current remains at approximately 150A in dropout.
Chip Information
TRANSISTOR COUNT: 845
Noise, PSRR, and Transient Response
The MAX1819 is designed to operate with low dropout voltages and low quiescent currents in battery-powered systems while still maintaining good noise, transient response, and AC rejection. See the Typical Operating Characteristics for a plot of Power-Supply Rejection Ratio (PSRR) vs. Frequency. When operating from noisy sources, improved supply-noise rejection and transient response can be achieved by increasing the values of the input and output bypass capacitors and through passive filtering techniques.
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_______________________________________________________________________________________
500mA Low-Dropout Linear Regulator in UCSP MAX1819
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to www.maxim-ic.com/packages.)
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ______________________9 (c) 2002 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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