General Description
The MAX1963/MAX1976 low-dropout linear regulators operate from a +1.62V to +3.6V supply and deliver a guaranteed 300mA continuous load current with a low 100mV dropout. The high-accuracy (±0.5%) output voltage is preset to an internally trimmed voltage in the +0.75V to +3.0V range. An active-low, open-drain reset output remains asserted for at least 2.2ms (MAX1963)or 70ms (MAX1976) after the output voltage reaches regulation. These devices are offered in 6-pin thin SOT23 and 6-pin 3mm x 3mm thin DFN packages.
An internal PMOS pass transistor allows the low supply current to remain independent of load and dropout volt-age, making these devices ideal for portable battery-pow-ered equipment such as personal digital assistants (PDAs), cell phones, cordless phones, and notebook com-puters. Other features include logic-controlled shutdown,short-circuit protection, and thermal-overload protection.
Applications
Notebook Computers Cellular and PCS Telephones Personal Digital Assistants (PDAs)Hand-Held Computers Digital Cameras PCMCIA Cards CD and MP3 Players
Features
?Low 1.62V Minimum Input Voltage ?Guaranteed 300mA Output Current ?±2.5% Accuracy Over Load/Line/Temp ?Low 100mV Dropout at 300mA Load ?2.2ms (MAX1963) or 70ms (MAX1976) RESET Output Flag ?Supply Current Independent of Load and Dropout Voltage ?Logic-Controlled Shutdown
?Thermal-Overload and Short-Circuit Protection ?Preset Output Voltages (0.75V to 3.0V)?Tiny 6-Pin Thin SOT23 Package (<1.1mm High)?Thin 6-Pin TDFN Package (<0.8mm High)
MAX1963/MAX1976
Low-Input-Voltage, 300mA LDO Regulators
with RESET in SOT and TDFN
________________________________________________________________Maxim Integrated Products
1
Ordering Information
19-3040; Rev 2; 5/07
For pricing, delivery, and ordering information,please contact Maxim/Dallas Direct!at 1-888-629-4642, or visit Maxim’s website at https://www.wendangku.net/doc/0a10665536.html,.
Pin Configurations
*Insert the desired three-digit suffix (see the Selector Guide) into the blanks to complete the part number. Contact the factory for other output voltages.
Selector Guide appears at end of data sheet.
Typical Operating Circuit
M A X 1963/M A X 1976
Low-Input-Voltage, 300mA LDO Regulators with RESET in SOT and TDFN 2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
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.
IN, SHDN , RESET to GND.....................................-0.3V to +4.0V OUT to GND ................................................-0.3V to (V IN + 0.3V)Output Short-Circuit Duration.....................................Continuous Continuous Power Dissipation (T A = +70°C)
6-Pin SOT23 (derate 9.1mW/°C above +70°C)............727mW 6-Pin TDFN (derate 24.4mW/°C above +70°C).........1951mW
Operating Temperature Range ...........................-40°C to +85°C Junction Temperature.....................................................+150°C Storage Temperature Range.............................-65°C to +150°C Lead Temperature (soldering, 10s).................................+300°C
MAX1963/MAX1976
Low-Input-Voltage, 300mA LDO Regulators
with RESET in SOT and TDFN
_______________________________________________________________________________________3
Note 2:The dropout voltage is defined as V IN - V OUT , when V OUT is 4% lower than the value of V OUT when V IN = V OUT + 0.5V.
Typical Operating Characteristics
(V IN = (V OUT + 0.5V) or 1.8V, whichever is greater; SHDN = IN, C IN = 1μF, C OUT = 4.7μF, T A = +25°C, unless otherwise noted.)
OUTPUT VOLTAGE ACCURACY
vs. LOAD CURRENT
LOAD CURRENT (mA)
O U T P U T V O L T A G E A
C C U R A C Y (%)
250
200
150
100
50
-0.1
0.1
0.2-0.2
300
OUTPUT VOLTAGE ACCURACY
vs. INPUT VOLTAGE
INPUT VOLTAGE (V)
O U T P U T V O L T A G E A C C U R A C Y (%)
3.0
2.6
2.2
1.8
-0.25
0.25
0.50
-0.50
1.4
3.4
OUTPUT VOLTAGE ACCURACY
vs. TEMPERATURE
TEMPERATURE (°C)
O U T P U T V O L T A G E A C C U R A C Y (%)
603510-15-1.0-0.500.5
1.01.5-1.5
-4085
ELECTRICAL CHARACTERISTICS (continued)
(V IN = (V OUT + 0.5V) or 1.8V, whichever is greater; SHDN = IN, C IN = 1μF, C OUT = 4.7μF, T A = -40°C to +85°C, unless otherwise noted. Typical values are at T = +25°C.) (Note 1)
M A X 1963/M A X 1976
Low-Input-Voltage, 300mA LDO Regulators with RESET in SOT and TDFN 4_______________________________________________________________________________________
GROUND-PIN CURRENT vs. LOAD CURRENT
LOAD CURRENT (mA)
G R O U N D -P I N C U R R E N T (μA )
1001
10
0.1
708090
100
110120600.01
1000
GROUND-PIN CURRENT vs. INPUT VOLTAGE
INPUT VOLTAGE (V)
G R O U N D -P I N C U R
R E N T (μA )
3.2
2.8
2.4
2.0
1.6
20
4060801001200
1.2
3.6
GROUND-PIN CURRENT vs. TEMPERATURE
TEMPERATURE (°C)
G R O U N D -P I N C U R R E N T (μA )
60
40
20
-20
60
708090100110120
50
-40
80
DROPOUT VOLTAGE vs. LOAD CURRENT
LOAD CURRENT (mA)
V D R O P O U T (m V )
250
200
150
100
50
4020608010012000
300
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
FREQUENCY (kHz)
P S R R (d B )
100
101
1020
304050607080
0.1
1000
LINE-TRANSIENT RESPONSE
MAX1963/76 toc09
40μs/div
V IN 500mV/div
1.5V 10mV/div AC-COUPLED
V OUT
3.5V
Typical Operating Characteristics (continued)
(V IN = (V OUT + 0.5V) or 1.8V, whichever is greater; SHDN = IN, C IN = 1μF, C OUT = 4.7μF, T A = +25°C, unless otherwise noted.)
LINE-TRANSIENT RESPONSE
NEAR DROPOUT
MAX1963/76 toc10
40μs/div
V IN 500mV/div
1.5V 10mV/div AC-COUPLED
V OUT
1.8V
MAX1963/MAX1976
Low-Input-Voltage, 300mA LDO Regulators
with RESET in SOT and TDFN
_______________________________________________________________________________________5
LOAD-TRANSIENT RESPONSE
MAX1963/76 toc11
20μs/div
200mA/div
20mV/div AC-COUPLED
200mA V OUT
I OUT 20mA
V IN = 3.6V V OUT = 1.5V
LOAD-TRANSIENT RESPONSE
NEAR DROPOUT
MAX1963/76 toc12
20μs/div
200mA/div
20mV/div AC-COUPLED
200mA V OUT
V IN = 1.8V V OUT = 1.5V
I OUT 20mA
Typical Operating Characteristics (continued)
(V IN = (V OUT + 0.5V) or 1.8V, whichever is greater; SHDN = IN, C IN = 1μF, C OUT = 4.7μF, T A = +25°C, unless otherwise noted.)
SHUTDOWN RESPONSE
MAX1963/76 toc13
100μs/div 1V/div
500mV/div
V OUT
V SHDN
MAX1963/76 toc14
40ms/div
1V/div
1V/div
1V/div
V OUT
00
0V SHDN
V RESET
MAX1976A
SHUTDOWN/RESET RESPONSE
MAX1963/76 toc15
200ms/div
2V/div
1V/div
1V/div
V OUT
V IN
000
V MAX1976A
LINE/RESET RESPONSE
M A X 1963/M A X 1976
Detailed Description
The MAX1963/MAX1976 are low-dropout, high-accuracy,low-quiescent-current linear regulators designed primarily for battery-powered applications. These devices supply loads up to 300mA and are available with preset output voltages from +0.75V to +3.0V. As illustrated in Figure 1,the MAX1963/MAX1976 consist of a reference, an error amplifier, a P-channel pass transistor, an internal feed-back voltage-divider, and a power-good comparator.
The 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.
Low-Input-Voltage, 300mA LDO Regulators with RESET in SOT and TDFN 6
_______________________________________________________________________________________
Pin Description
Figure 1. Functional Diagram
Internal P-Channel Pass Transistor The MAX1963/MAX1976 feature a 0.33Ω(R DS(ON)) P-channel MOSF ET pass transistor. Unlike similar designs using PNP pass transistors, P-channel MOSFETs require no base drive, which reduces quies-cent current. PNP-based regulators also waste consid-erable current in dropout when the pass transistor saturates and use high base-drive currents under large loads. The MAX1963/MAX1976 do not suffer from these problems and consume only 90μA (typ) of quiescent current under heavy loads, as well as in dropout.
Shutdown Pull SHDN low to enter shutdown. During shutdown, the output is disconnected from the input, an internal 1.5kΩresistor pulls OUT to GND, RESET is actively pulled low, and the supply current drops below 1μA.
RESET Output The MAX1963/MAX1976 microprocessor (μP) supervisory circuitry asserts a guaranteed logic-low reset during power-up, power-down, and brownout conditions down to +1V. RESET asserts when V OUT is below the reset threshold and remains asserted for at least t RP after V OUT rises above the reset threshold of regulation.
Current Limit The MAX1963/MAX1976monitor and control the pass transistor’s gate voltage, limiting the output current to 450mA (min). If the output exceeds I LIM, the MAX1963/ MAX1976 output voltage drops.
Thermal-Overload Protection Thermal-overload protection limits total power dissipa-tion in the MAX1963/MAX1976. When the junction tem-perature exceeds T J= +165°C, a thermal sensor turns off the pass transistor, allowing the IC to cool. The ther-mal sensor turns the pass transistor on again after the junction temperature cools by 15°C, resulting in a pulsed output during continuous thermal-overload con-ditions. Thermal-overload protection safeguards the MAX1963/MAX1976 in the event of fault conditions. For continuous operation, do not exceed the absolute maxi-mum junction-temperature rating of T J= +150°C.
Operating Region and Power Dissipation The MAX1963/MAX1976 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 airflow. The power dissipated in the device is P = I OUT?(V IN-V OUT). The maximum allowed power dissipation is:
P MAX= (T J(MAX)- T A) / (θJC+ θCA)
between the MAX1963/MAX1976 die junction and the surrounding air, θJC is the thermal resistance of the junction to the case, and θCA is the thermal resistance
from the case through the PC board, copper traces,
and other materials to the surrounding air. F or best heatsinking, expand the copper connected to the exposed paddle or GND.
MAX1963/MAX1976
Low-Input-Voltage, 300mA LDO Regulators
with RESET in SOT and TDFN _______________________________________________________________________________________7
M A X 1963/M A X 1976
The MAX1963/MAX1976 deliver up to 300mA and oper-ate with an input voltage up to +3.6V. However, when using the 6-pin SOT23 version, high output currents can only be sustained when the input-output differential voltage is less than 2V, as shown in Figure 2.
The maximum allowed power dissipation for the 6-pin TDFN is 1.951W at T A = +70°C. Figure 3 shows that the maximum input-output differential voltage is not limited by the TDFN package power rating.
Applications Information
Capacitor Selection and
Regulator Stability
Capacitors are required at the MAX1963/MAX1976input and output for stable operation over the full tem-perature range and with load currents up to 300mA.Connect a 1μF ceramic capacitor between IN and GND and a 4.7μF low-ESR ceramic capacitor between OUT and GND. The input capacitor (C IN ) lowers the source impedance of the input supply. Use larger output capacitors to reduce noise and improve load-transient response, stability, and power-supply rejection.The output capacitor’s equivalent series resistance (ESR) affects stability and output noise. Use output capacitors with an ESR of 30m Ωor less to ensure sta-bility and optimize transient response. Surface-mount ceramic capacitors have very low ESR and are com-monly available in values up to 10μF. Connect C IN and C OUT as close to the MAX1963/MAX1976 as possible to minimize the impact of PC board trace inductance.
Noise, PSRR, and Transient Response
The MAX1963/MAX1976 are designed to operate with low dropout voltages and low quiescent currents in bat-tery-powered systems while still maintaining good noise, transient response, and AC rejection. See the T ypical Operating Characteristics for a plot of Power-Supply Rejection Ratio (PSRR) versus F requency.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.The MAX1963/MAX1976 load-transient response (see the Typical Operating Characteristics ) shows two com-ponents of the output response: a near-zero DC shift from the output impedance due to the load-current change, and the transient response. A typical transient
response for a step change in the load current from 20mA to 200mA is 20mV. Increasing the output capacitor’s value and decreasing the ESR attenuates the overshoot.
Input-Output (Dropout) Voltage
A regulator’s minimum input-output voltage difference (dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the MAX1963/MAX1976 use a P-channel MOSFET pass tran-sistor, the dropout voltage is a function of drain-to-source on-resistance (R DS(ON) = 0.33Ω) multiplied by the load current (see the Typical Operating Characteristics ).
V DROPOUT = V IN - V OUT = 0.33Ω?I OUT
The MAX1963/MAX1976 ground current reduces to 70μA in dropout.
Low-Input-Voltage, 300mA LDO Regulators with RESET in SOT and TDFN 8_______________________________________________________________________________________
Chip Information
TRANSISTOR COUNT: 2556PROCESS: BiCMOS
Selector Guide
(Note: Standard voltage options, shown in bold , are available.Contact the factory for other output voltages between 1.5V and 4.5V. Minimum order quantity is 15,000 units.)
MAX1963/MAX1976
Low-Input-Voltage, 300mA LDO Regulators
with RESET in SOT and TDFN
_______________________________________________________________________________________9
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 https://www.wendangku.net/doc/0a10665536.html,/packages .)
M A X 1963/M A X 1976
Low-Input-Voltage, 300mA LDO Regulators with RESET in SOT and TDFN 10______________________________________________________________________________________
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to https://www.wendangku.net/doc/0a10665536.html,/packages
.)
MAX1963/MAX1976
Low-Input-Voltage, 300mA LDO Regulators
with RESET in SOT and TDFN
______________________________________________________________________________________
11
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to https://www.wendangku.net/doc/0a10665536.html,/packages .)
M A X 1963/M A X 1976
Low-Input-Voltage, 300mA LDO Regulators with RESET in SOT and TDFN 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?2007 Maxim Integrated Products
is a registered trademark of Maxim Integrated Products, Inc.
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,go to https://www.wendangku.net/doc/0a10665536.html,/packages .)
Revision History
Pages changed at Rev 2: 1, 2, 9–12