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MAX8882EUTJJ中文资料

General Description

The MAX8882/MAX8883 dual, low-noise, low-dropout linear regulators operate from a +2.5V to +6.5V input and deliver up to 160mA each of continuous current.Both versions offer low output noise and low dropout of only 72mV at 80mA. Designed with an internal P-channel MOSFET pass transistor, the MAX8882/MAX8883 maintain a low 165μA supply current (both LDOs on), independent of the load current and dropout voltage. Other features include short-circuit protection and thermal-shutdown protection. The MAX8882 has a single shutdown input and provides an external refer-ence bypass pin to improve noise performance. The MAX8883 includes two independent logic-controlled shutdown inputs. The MAX8882/MAX8883 are both available in a miniature 6-pin SOT23 package.

________________________Applications

μP/DSP Core/IO Power Cellular and PCS Telephones PDAs and Palmtop Computers Notebook Computers Digital Cameras Hand-Held Instruments

Features

o Two LDOs in Tiny SOT23

o Up to 160mA Output Current (each LDO)o 40μV RMS Output Noise (MAX8882)o 72mV Dropout at 80mA Load

o Low 165μA Operating Supply Current

o 62dB PSRR (greater than 56dB to 100kHz)o

Independent Low-Power Shutdown Controls (MAX8883)

o Thermal-Overload and Short-Circuit Protection o Output Current Limit

MAX8882/MAX8883

Dual, Low-Noise, Low-Dropout, 160mA Linear

Regulators in SOT23

________________________________________________________________Maxim Integrated Products 1

Pin Configurations

19-1818; Rev 1; 10/01

Ordering Information

Typical Operating Circuit

Selector Guide

Pin Configurations continued at end of data sheet.

Minimum order quantity is 50,000 units.

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/ae13872336.html,.

*See Selector Guide

M A X 8882/M A X 8883

Dual, Low-Noise, Low-Dropout, 160mA Linear Regulators in SOT232_______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V IN = +3.6V, SHDN = SHDNA = SHDNB = IN, T A = -40°C to +85°C, unless otherwise noted. Typical values are at T A = +25°C.) (Note 1)

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 , SHDNA , SHDNB , BP to GND...............-0.3V to +7.0V OUTA, OUTB 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 8.7mW/°C above +70°C)............695mW

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

MAX8882/MAX8883

Dual, Low-Noise, Low-Dropout, 160mA Linear

Regulators in SOT23

_______________________________________________________________________________________3

050

150

100

200250

SUPPLY CURRENT vs. SUPPLY VOLTAGE

SUPPLY VOLTAGE (V)

S U P P L Y C U R R E N T (μA )

04020

80601201001401801602000

SUPPLY CURRENT vs. LOAD CURRENT

LOAD CURRENT (mA)

S U P P L Y C U R R E N T (μA )

60402080100120140

160180200

-4010-15356085

SUPPLY CURRENT vs. TEMPERATURE

TEMPERATURE (°C)

S U P P L Y C U R R E N T (μA )

01530456075900

7080

DROPOUT VOLTAGE vs. LOAD CURRENT

LOAD CURRENT (mA)D R O P O U T V O L T A G E (m V )

604020801001201401601802002.5 2.7 2.9 3.1 3.3DROPOUT vs. V OUT

V OUT (V)

D R O P O U T (m V )

-1.0

-0.6-0.8-0.2-0.40.200.40.80.61.0

-40-105-252035506580

OUTPUT VOLTAGE ACCURACY

vs. TEMPERATURE

M A X 8882/83 t o c 06

TEMPERATURE (°C)

O U T P U T V O L T A G E (%)

Typical Operating Characteristics

(V OUT _ = 2.85V, I OUT _ = 80mA, V IN = +3.6V, C OUT _ = 2.2μF, C BP = 0.01μF, and C IN = 2.2μF, unless otherwise noted.)

Note 3:See the Typical Operating Characteristics for guaranteed specifications at voltages other than 3.3V.

M A X 8882/M A X 8883

Dual, Low-Noise, Low-Dropout, 160mA Linear Regulators in SOT234_______________________________________________________________________________________

Typical Operating Characteristics (continued)

(V OUT _ = 2.85V, I OUT _ = 80mA, V IN = +3.6V, C OUT _ = 2.2μF, C BP = 0.01μF, and C IN = 2.2μF, unless otherwise noted.)

MAX8882 OUTPUT NOISE

(10Hz to 100kHz)

M A X 8882/3 t o c 10

1ms/div

500μV/div (AC-COUPLED)

V OUT _

LINE TRANSIENT

MAX8882/3 toc11

50μs/div V IN

V OUT _

4.5V 3.5V 1V/div

20mV/div

(AC-COUPLED)

LOAD TRANSIENT

(V IN = 3.35V, I LOAD = 0 TO 80mA)

MAX8882/3 toc12

10μs/div

V OUT _

I LOAD

20mV/div

(AC-COUPLED)

50mA/div

0201040306050700.01

0.1

100

1000

PSRR vs. FREQUENCY

FREQUENCY (kHz)

P S R R (d B )

0.01

0.1

1000

CHANNEL-TO-CHANNEL ISOLATION

vs. FREQUENCY

FREQUENCY (kHz)

C H A N N E L -T O -C H A N N E L I S O L A T I O N (d B )

120

02040608010010

100

10000

100.01

101000OUTPUT NOISE SPECTRAL DENSITY

vs. FREQUENCY

100

1000

M A X 8882/3 t o c 09

N O I S E D E N S I T Y (n V /H z )

0.11100

MAX8882/MAX8883

Dual, Low-Noise, Low-Dropout, 160mA Linear

Regulators in SOT23

LOAD TRANSIENT NEAR DROPOUT

10μs/div

20mV/div

50μA/div V OUT

I LOAD

V IN = V OUT + 0.1V

SHUTDOWN RESPONSE

1ms/div

20V/div

OUTPUT VOLTAGE

SHUTDOWN VOLTAGE

1V/div MAX8883

NAME

OUTB

2GND —

Typical Operating Characteristics (continued)

(V OUT _ = 2.85V, I OUT _ = 80mA, V IN = +3.6V, C OUT _ = 2.2μF, C BP = 0.01μF, and C IN = 2.2μF, unless otherwise noted.)

M A X 8882/M A X 8883

Detailed Description

The MAX8882/MAX8883 are low-noise, low-dropout,low-quiescent-current linear regulators designed primar-ily for battery-powered applications. These parts are available with preset output voltages ranging from 1.8V to 3.3V, and the parts can supply loads up to 160mA.

Shutdown

MAX8882

The MAX8882 has a single shutdown control input (SHDN ). Drive SHDN low to shut down both outputs,reducing supply current to 10nA. Connect SHDN to a logic-high, or IN, for normal operation.

MAX8883

The MAX8883 has independent shutdown control inputs (SHDNA and SHDNB ). Drive SHDNA low to shut down OUTA. Drive SHDNB low to shut down OUTB.Drive both SHDNA and SHDNB low to shut down the entire chip, reducing supply current to 10nA. Connect both SHDNA and SHDNB to a logic-high, or IN, for nor-mal operation.

Internal P-Channel Pass Transistor

The MAX8882/MAX8883 feature two 1?P-channel MOSFET pass transistors. A P-channel MOSFET pro-vides several advantages over similar designs using PNP pass transistors, including longer battery life. It requires no base drive, which reduces quiescent cur-rent significantly. PNP-based regulators waste consid-erable current in dropout when the pass transistor saturates, and they also use high base-drive currents under large loads. The MAX8882/MAX8883 do not suf-fer from these problems and only consume 165μA of quiescent current whether in dropout, light-load, or heavy-load applications (see the Typical Operating Characteristics ). While a PNP-based regulator has dropout voltage that is independent of the load, a P-channel MOSFET ’s dropout voltage is proportional to load current, providing for low dropout voltage at heavy loads and extremely low dropout voltage at lighter loads.

Current Limit

The MAX8882/MAX8883 contain two independent cur-rent limiters, one for each regulator, which monitor and control the pass transistor ’s gate voltage, limiting the guaranteed maximum output current to 160mA mini-mum. The output can be shorted to ground for an indef-inite time without damaging the part.

Thermal-Overload Protection

Thermal-overload protection limits total power dissipa-tion in the MAX8882/MAX8883. When the junction tem-perature exceeds T J = +160°C, the thermal sensor sig-nals the shutdown logic, turning off the pass transistor and allowing the IC to cool. The thermal sensor will turn the pass transistor on again after the IC ’s junction tem-perature cools by 10°C, resulting in a pulsed output during continuous thermal-overload conditions.Thermal-overload protection is designed to protect the MAX8882/MAX8883 in the event of fault conditions. For continual operation, do not exceed the absolute maxi-mum junction-temperature rating of T J = +150°C.

Operating Region and Power Dissipation

The MAX8882/MAX8883’s maximum power dissipation depends on the thermal resistance of the case and cir-cuit board, the temperature difference between the die junction and ambient air, and the rate of air flow. The power dissipation across the device is P = I OUT (V IN -V OUT ) (Figure 1). The maximum power dissipation is:

P MAX = (T J - T A ) / (T JB + T BA )where T J - T A is the temperature difference between the MAX8882/MAX8883 die junction and the surround-ing air, T JB (or T JC ) is the thermal resistance of the package, and T BA is the thermal resistance through the printed circuit board, copper traces, and other materi-als to the surrounding air.

The GND pin of the MAX8882/MAX8883 performs the dual functions of providing an electrical connection to the ground and channeling heat away. Connect the GND pin to ground using a large pad or ground plane.

Dual, Low-Noise, Low-Dropout, 160mA Linear Regulators in SOT236

_______________________________________________________________________________________

Figure 1. MAX8882/MAX8883 Safe Operating Region

Low-Noise Operation (MAX8882)

An external 0.01μF bypass capacitor at BP, in conjunc-tion with an internal resistor, creates a lowpass filter.The MAX8882 exhibits 40μV RMS of output voltage noise with C BP = 0.01μF and C OUT _ = 4.7μF. (See the Output Noise Spectral Density graph in the Typical Operating Characteristics .)

Applications Information

Capacitor Selection and

Regulator Stability

Use a 2.2μF capacitor on the MAX8882/MAX8883 input and a 2.2μF capacitor on the outputs. Larger input capacitor values and lower ESRs provide better supply-noise rejection and line-transient response. To reduce noise, improve load transients, and for loads up to 160mA, use larger output capacitors (up to 10μF). For stable operation over the full temperature range and with load currents up to 80mA, use 2.2μF.

Note that some ceramic dielectrics exhibit large capac-itance and ESR variation with temperature. With dielectrics such as Z5U and Y5V, it may be necessary to use 4.7μF or more to ensure stability at temperatures below -10°C. With X7R or X5R dielectrics, 2.2μF is suffi-cient at all operating temperatures. These regulators are optimized for ceramic capacitors, and tantalum capacitors are not recommended.

Use a 0.01μF bypass capacitor at BP (MAX8882) for low output voltage noise. Increasing the capacitance will slightly decrease the output noise, but increase the startup time. (See the Shutdown Response graph in the Typical Operating Characteristics .)

PSRR and Operation from Sources

Other than Batteries

The MAX8882/MAX8883 are designed to deliver low dropout voltages and low quiescent currents in battery-powered systems. Power-supply rejection is 62dB at low frequencies and rolls off above 100kH z. (See the PSRR vs. Frequency graph in the Typical Operating Characteristics.)

When operating from sources other than batteries,improved supply-noise rejection and transient response can be achieved by increasing the values of the input and output bypass capacitors and through passive fil-tering techniques.

Dropout Voltage

A regulator ’s minimum input-output voltage differential (or dropout voltage) determines the lowest usable sup-ply voltage. In battery-powered systems, this deter-mines the useful end-of-life battery voltage. Because the MAX8882/MAX8883 use a P-channel MOSFET pass transistor, their dropout voltage is a function of drain-to-source on-resistance (R DS(ON)) multiplied by the load current (see the Typical Operating Characteristics ).

Chip Information

TRANSISTOR COUNT: 493PROCESS: BiCMOS

MAX8882/MAX8883

Dual, Low-Noise, Low-Dropout, 160mA Linear

Regulators in SOT23

_______________________________________________________________________________________7

Pin Configurations (continued)

M A X 8882/M A X 8883

Dual, Low-Noise, Low-Dropout, 160mA Linear Regulators in SOT23Maxim cannot assume responsibility f or 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?2001 Maxim Integrated Products

Printed USA

is a registered trademark of Maxim Integrated Products.

Package Information