Maxim MAX8860EUA27 Low-dropout, 300ma linear regulator in î¼max Datasheet

19-1422; Rev 1; 12/99
Low-Dropout, 300mA
Linear Regulator in µMAX
Features
The MAX8860 low-noise, low-dropout linear regulator
operates from a +2.5V to +6.5V input and is guaranteed to deliver 300mA. Typical output noise for this
device is 60µVRMS, and typical dropout is 105mV at
200mA. In addition to the six available preset output
voltages (+1.8V, +2.5V, +2.77V, +2.82V, +3.0V, and
+3.3V), the Dual Mode™ feature allows the device to
be configured as an adjustable output regulator from
+1.25V to +6.5V.
♦ High Output Current (300mA)
Designed with an internal P-channel MOSFET pass transistor, the MAX8860 has a low 120µA supply current. An
output fault-detection circuit indicates loss of regulation.
Other features include a 10nA, logic-controlled shutdown mode, short-circuit and thermal-shutdown protection, and reverse battery protection. The MAX8860 is
available in a miniature 8-pin µMAX package.
♦ 10nA Logic-Controlled Shutdown
♦ Low Output Voltage Noise: 60µVRMS
♦ Low 105mV Dropout at 200mA Output
♦ Low 120µA No-Load Supply Current
♦ Thermal-Overload and Short-Circuit Protection
♦ Reverse Battery Protection
♦ FAULT Indicator
♦ Small, Space-Saving µMAX Package
(1.1mm max height)
♦ Small 2.2µF Output Capacitor
Saves Space and Cost
Applications
Wireless Handsets
Ordering Information
DSP Core Power
PCMCIA Cards
PART
TEMP. RANGE
Hand-Held Instruments
Palmtop Computers
Electronic Planners
Typical Operating Circuit
INPUT
+2.5V TO
+6.5V
MAX8860
C1
2.2µF
SHDN
SET
GND
OUT
R1
100k
-40°C to +85°C
8 µMAX
+1.80
MAX8860EUA25
-40°C to +85°C
8 µMAX
+2.50
MAX8860EUA27
MAX8860EUA28
MAX8860EUA30
MAX8860EUA33
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
8 µMAX
8 µMAX
8 µMAX
8 µMAX
+2.77
+2.82
+3.00
+3.30
Pin Configuration
C2
2.2µF
FAULTDETECT
OUTPUT
FAULT
CC
C3
33nF
VOUT
(V)
MAX8860EUA18
OUTPUT
UP TO
300mA
OUT
IN
PINPACKAGE
TOP VIEW
OUT
1
8
IN
2
7
SHDN
GND
3
6
CC
OUT
4
5
SET
MAX8860
FAULT
µMAX
Dual Mode is a trademark of Maxim Integrated Products.
________________________________________________________________ Maxim Integrated Products
1
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
MAX8860
General Description
MAX8860
Low-Dropout, 300mA
Linear Regulator in µMAX
ABSOLUTE MAXIMUM RATINGS
IN, SHDN to GND .......................................................-7V to +7V
SHDN to IN ...............................................................-7V to +0.3V
SET, CC, FAULT to GND ..........................................-0.3V to +7V
OUT to GND .............................................. -0.3V to (VIN + 0.3V)
FAULT Sink Current ...........................................................20mA
Continuous Output Current ..............................................330mA
Output Short-Circuit Duration ....................................Continuous
Continuous Power Dissipation (TA = +70°C)
8-Pin µMAX (derate 4.1mW/°C above +70°C) ............330mW
Thermal Resistance (θJA)
8-Pin µMAX ............................................................+244°C/W
Operating Temperature Range
MAX8860EUA_ _ ...........................................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10sec) ............................+300°C
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 = +3.6V, CCC = 33nF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
CONDITIONS
MIN
Input Voltage (Note 2)
TA = +25°C
3.24
TA = -40°C to +85°C
3.21
TA = +25°C
2.95
TA = -40°C to +85°C
2.92
TA = +25°C
100µA < IOUT
MAX8860EUA28
TA = -40°C to +85°C
< 300mA,
VIN = VOUT +1V,
TA = +25°C
MAX8860EUA27
SET = GND
TA = -40°C to +85°C
2.78
MAX8860EUA33
MAX8860EUA30
Output Voltage
MAX8860EUA25
MAX8860EUA18
SET Threshold Voltage
SET = OUT, VIN = +2.5V to +6.5V,
IOUT = 1mA
2.43
VOUT = 0, SHDN = GND
V
3.35
3.05
3.08
2.82
2.87
2.90
2.77
2.81
2.54
2.57
1.77
1.755
TA = +25°C
1.230
TA = -40°C to +85°C
1.220
1.275
1.25
6.5
1.80
1.83
1.845
1.248
1.267
300
120
IOUT = 300mA
165
TA = +25°C
0.01
TA = +85°C
0.05
IOUT = 1mA
0.6
IOUT = 200mA
105
IOUT = 300mA
155
Load Regulation
IOUT = 100µA to 300mA
-0.1
V
V
mA
770
IOUT = 0
VIN = +2.5V to +6.5V, SET = OUT, IOUT = 1mA
V
2.84
2.50
TA = -40°C to +85°C
Line Regulation
2
UNITS
6.5
TA = +25°C
330
Shutdown Supply Current
MAX
3.38
3.00
2.70
TA = -40°C to +85°C
DC average current rating
SET = GND
Dropout Voltage (Note 4)
2.73
2.46
Output Current Limit
Supply Current
3.3
2.75
TA = +25°C
Adjustable Output Voltage
Range (Note 3)
Maximum Output Current
TYP
2.5
0.01
SET = OUT
0.0001
SET = GND
0.0006
_______________________________________________________________________________________
mA
270
1
µA
µA
220
mV
0.1
%/V
%/mA
Low-Dropout, 300mA
Linear Regulator in µMAX
MAX8860
ELECTRICAL CHARACTERISTICS (continued)
(VIN = +3.6V, CCC = 33nF, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
CONDITIONS
IOUT = 10mA,
10Hz < f < 100kHz
Output Voltage Noise
Output Voltage Noise Density
MIN
TYP
COUT = 2.2µF
65
COUT = 10µF
60
COUT = 100µF
55
10Hz < f < 100kHz, COUT = 10µF
µVRMS
nV√Hz
2.0
V
VIL, 2.5V ≤ VIN ≤ 5.5V
0.4
SHDN Input Bias Current
SHDN = GND or IN
SET Input Leakage Current (Note 3)
VSET = +1.3V
FAULT Detection Voltage (Note 5)
SET = GND, IOUT = 200mA
FAULT Output Low Voltage
VIN = +2.5V, ISINK = 2mA
FAULT Output Off-Leakage Current
UNITS
190
VIH, 2.5V ≤ VIN ≤ 5.5V
SHDN Input Threshold
MAX
V FAULT = +3.6V
TA = +25°C
0.01
TA = +85°C
0.5
TA = +25°C
0.01
TA = +85°C
0.5
0.01
TA = +85°C
0.5
nA
2.5
130
TA = +25°C
V
100
nA
280
mV
0.25
V
100
nA
Thermal Shutdown Temperature
170
°C
Thermal Shutdown Hysteresis
20
°C
120
µs
Start-Up Time
COUT = 10µF, VOUT to 90% of final value
Specifications to -40°C are guaranteed by design and not production tested.
Guaranteed by line-regulation test.
Adjustable mode only.
The dropout voltage is defined as VIN - VOUT when VOUT is 100mV below the value of VOUT for VIN = VOUT +2V. Since the
minimum input voltage is 2.5V, this is applicable only for voltages of 2.5V or higher.
Note 5: The FAULT detection voltage is the difference from input to output voltage. Maintain the input above this level to ensure
good line and load regulation.
Note 1:
Note 2:
Note 3:
Note 4:
Typical Operating Characteristics
(VIN = VOUT + 0.5V, CIN = COUT = 2.2µF, CCC = 33nF, TA = +25°C, unless otherwise noted.)
NORMALIZED OUTPUT VOLTAGE
vs. TEMPERATURE
0
0.1
IOUT = 0
IOUT = 100mA
0
-0.1
-0.2
TA = +85°C
160
TA = +25°C
140
MAX8860 toc03
180
TA = -40°C
120
100
80
60
40
IOUT = 200mA
-0.2
200
SUPPLY CURRENT (µA)
0.2
VOUT NORMALIZED AT +25°C, IOUT = 0
0.2
OUTPUT VOLTAGE (%)
OUTPUT VOLTAGE (%)
VOUT NORMALIZED AT IOUT = 0
SUPPLY CURRENT vs. LOAD CURRENT
0.3
MAX8860 toc01
0.4
MAX8860 toc02
NORMALIZED OUTPUT VOLTAGE
vs. LOAD CURRENT
20
-0.4
-0.3
0
50
100
150
200
LOAD CURRENT (mA)
250
300
0
-40
-20
0
20
40
TEMPERATURE (°C)
60
80
0
50
100
150
200
250
300
LOAD CURRENT (mA)
_______________________________________________________________________________________
3
Typical Operating Characteristics (continued)
(VIN = VOUT + 0.5V, CIN = COUT = 2.2µF, CCC = 33nF, TA = +25°C, unless otherwise noted.)
NO LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE
TA = -40°C
80
60
TA = +25°C
120
TA = +85°C
100
TA = -40°C
80
60
40
40
MAX8860 toc06
FAULT DETECT THRESHOLD (mV)
120
MAX8860 toc05
140
250
200
FAULT = HIGH
150
100
FAULT = LOW
50
20
20
0
0
0
1
2
3
4
5
0
6
50
100
150
200
250
0
300
50
100
150
200
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
OUTPUT NOISE SPECTRAL DENSITY
OUTPUT NOISE
(10Hz TO 1MHz)
10
MAX8860 toc07
0
-10
ILOAD = 10mA
250
NOISE (µV/√Hz)
-20
-30
-40
-50
1.0
COUT = 2.2µF
VOUT
500µV/div
COUT = 10µF
0.1
ILOAD = 200mA
-60
-70
0.01
0.1
1
10
100
1000
0.1
FREQUENCY (kHz)
1
10
100
1ms/div
1000
FREQUENCY (kHz)
LINE-TRANSIENT RESPONSE
LOAD-TRANSIENT RESPONSE
MAX8860 toc10
200mA
ILOAD
0
MAX8860 toc12
0.01
+4.3V
VIN
+3.3V
VOUT
20mV/div
VIN = VOUT + 200mV
VOUT
2mV/div
ILOAD = 200mA
400µs/div
4
300
MAX8860 toc09
0
MAX8860 toc08
SUPPLY CURRENT (µA)
TA = +85°C
100
160
DROPOUT VOLTAGE (mV)
TA = +25°C
140
180
MAX8860 toc04
180
160
FAULT DETECT THRESHOLD
vs. LOAD CURRENT
DROPOUT VOLTAGE vs. LOAD CURRENT
200
PSRR (dB)
MAX8860
Low-Dropout, 300mA
Linear Regulator in µMAX
500µs/div
_______________________________________________________________________________________
Low-Dropout, 300mA
Linear Regulator in µMAX
0
FAULT
2V
0
VIN
4V
3V
4V
4V
SHDN
2V
0
VIN
3V
3V
VOUT
VOUT
1V
1V
2V
VOUT
1V
0
0
0
2V
2V
MAX8860 toc15
MAX8860 toc13
FAULT
2V
SHUTDOWN/POWER-UP
POWER-DOWN RESPONSE
4V
MAX8860 toc14
POWER-UP RESPONSE
4V
5ms/div
400µs/div
2ms/div
Pin Description
PIN
NAME
1, 4
OUT
FUNCTION
Regulator Output. Bypass with 2.2µF, low-ESR capacitor to GND for stable operation.
2
IN
3
GND
Supply Input. Connect to power source (+2.5V to +6.5V). Bypass with 2.2µF capacitor to GND.
Ground
5
SET
Output Voltage Set. Connect to GND for internally set threshold. Connect to resistor-divider for adjustable
output voltages. See Output Voltage Selection section for more information.
6
CC
Compensation Capacitor. Connect a 0.033µF capacitor from CC to GND.
7
SHDN
Shutdown Input. Connect to IN for normal operation. Drive SHDN low to turn off the regulator.
8
FAULT
Fault Output. A high-impedance, open-drain output. When the MAX8860 is out of regulation, FAULT goes
low. In shutdown, the FAULT pin is high impedance. Connect to GND if unused.
Detailed Description
The MAX8860 is a low-dropout, low-quiescent-current
linear regulator designed primarily for battery-powered
applications. It supplies an adjustable +1.25V to
+6.5V output voltage or a fixed-voltage output of +1.8V
(MAX8860EUA18), +2.5V (MAX8860EUA25), +2.77V
(MAX8860EUA27), +2.82V (MAX8860EUA28), +3.0V
(MAX8860EUA30), or +3.3V (MAX8860EUA33) for load
currents up to 300mA. The devices with 2.77V and
2.82V nominal outputs are designed to guarantee minimum output voltages of 2.70V and 2.75V, respectively.
The device consists of a +1.25V reference, error amplifier, MOSFET driver, P-channel pass transistor, Dual
Mode comparator, fault detector, and internal-feedback
voltage divider (Figure 1).
The 1.25V bandgap reference is connected to the error
amplifier’s inverting input. The error amplifier compares
this reference to the selected feedback voltage and
amplifies the difference. The MOSFET driver reads the
error signal and applies the appropriate drive to the Pchannel pass transistor. If the feedback voltage is lower
than the reference voltage, the pass-transistor gate is
pulled lower, allowing more current to pass and
increasing the output voltage. If the feedback voltage
is higher than the reference voltage, the pass-transistor
gate is driven higher, allowing less current to pass to
the output. The output voltage is fed back through
either an internal resistor voltage divider connected to
OUT, or an external resistor network connected to SET.
The Dual Mode comparator examines VSET and selects
the feedback path. If V SET is below 60mV, internal
feedback is used and the output voltage is regulated to
the preset output voltage. Additional blocks include an
output current limiter, reverse battery protection, a thermal sensor, a fault detector, and shutdown logic.
_______________________________________________________________________________________
5
MAX8860
Typical Operating Characteristics (continued)
(VIN = VOUT + 0.5V, CIN = COUT = 2.2µF, CCC = 33nF, TA = +25°C, unless otherwise noted.)
MAX8860
Low-Dropout, 300mA
Linear Regulator in µMAX
IN
SHDN
REVERSE
BATTERY
PROTECTION
CC
ERROR
AMP
P
MOS DRIVER
WITH ILIMIT
SHUTDOWN
LOGIC
OUT
MAX8860
SET
FAULT
DETECT
THERMAL
SENSOR
FAULT
1.25V
REF
DUAL-MODE
COMPARATOR
60mV
GND
Figure 1. Functional Diagram
Internal P-Channel Pass Transistor
The MAX8860 features a 0.5Ω typical P-channel
MOSFET pass transistor. This provides several advantages over similar designs using PNP pass transistors,
including longer battery life. PNP-based regulators
waste considerable amounts of current in dropout when
the pass transistor saturates. They also use high basedrive currents under large loads. The P-channel
MOSFET requires no base-drive current, which reduces
quiescent current considerably. The MAX8860 consumes less than 165µA of quiescent current whether in
dropout, light-load, or heavy-load applications (see
Typical Operating Characteristics).
Output Voltage Selection
The MAX8860 features Dual Mode operation: it operates
in either a preset voltage mode or an adjustable mode.
In preset voltage mode, internal, trimmed feedback
resistors set the output voltage to an adjustable +1.25V
to +6.5V output voltage or a fixed-voltage output of
+1.8V (MAX8860EUA18), +2.5V (MAX8860EUA25),
+2.77V (MAX8860EUA27), +2.82V (MAX8860EUA28),
+3.V (MAX8860EUA30), or +3.3V (MAX8860EUA33).
Select this mode by connecting SET to ground. In
adjustable mode, select an output between 1.25V and
6.5V using two external resistors connected as a voltage
divider to SET (Figure 2). Calculate the output voltage
with the following equation:
6
OUTPUT
VOLTAGE
OUT
IN
CIN
2.2µF
MAX8860
SHDN
R1
COUT
2.2µF
SET
BATTERY
100k
R2
CC
33nF
FAULT
GND
Figure 2. Adjustable Output Using External Feedback
Resistors

R1 
VOUT = VSET 1 +

 R2 
where VSET = 1.25V. To simplify resistor selection, use
the following equation:
V

R1 = R2  OUT − 1
 VSET

_______________________________________________________________________________________
Low-Dropout, 300mA
Linear Regulator in µMAX
Shutdown
Drive SHDN low to place the MAX8860 in shutdown
mode. In shutdown mode, the pass transistor, control
circuit, reference, and all biases are turned off, reducing the supply current to typically 10nA. Connect SHDN
to IN for normal operation.
Current Limit
The MAX8860 includes short-circuit protection. It includes
a current limiter that controls the pass transistor’s gate
voltage to limit the output current to about 770mA. For
design purposes, the minimum current limit is 330mA.
Thermal-Overload Protection
Thermal-overload protection limits total power dissipation in the MAX8860. When the junction temperature
(TJ) exceeds +170°C, the thermal sensor sends a signal to the shutdown logic, turning off the pass transistor
and allowing the IC to cool. The pass transistor turns on
again after the IC’s junction temperature typically cools
by 20°C, resulting in a pulsed output during continuous
thermal-overload conditions.
Thermal-overload protection is designed to protect the
MAX8860 against fault conditions. Stressing the device
with high-load currents and high input-output differential voltages (which result in die temperatures above
+125°C) may cause a momentary overshoot (2% to 8%
for 200ms) when the load is completely removed.
Remedy this by raising the minimum load current from
0 (+125°C) to 100µA (+150°C). This is accomplished
with an external load resistor. For continuous operation,
do not exceed the absolute maximum junction temperature rating of +150°C.
Operating Region and
Power Dissipation
Maximum power dissipation of the MAX8860 depends
on the thermal resistance of the case and circuit board,
the temperature difference between the die junction
and ambient air, and the rate of air flow. The power dissipated by the device is:
P = IOUT (VIN - VOUT)
The maximum power dissipation is:
PMAX = (TJMAX - TA) / θJA
where: TJMAX = +150°C
TA is the ambient temperature
θJA = 244°C/W
The MAX8860’s pins perform the dual function of providing an electrical connection as well as channeling heat
away from the die. Use wide circuit-board traces and
large, solid copper polygons to improve power dissipation. Using multiple vias to buried ground planes further
enhances thermal conductivity.
Reverse Battery Protection
The MAX8860 has a unique protection scheme that limits the reverse supply current to less than 1mA when
either V IN or V S HDN falls below GND. The circuitry
monitors the polarity of these two pins, disconnecting
the internal circuitry and parasitic diodes when the
applied voltage is reversed. This feature prevents the
device from overheating and damaging an improperly
installed battery.
Integrator Circuitry
The MAX8860 uses an external 33nF compensation
capacitor for minimizing load- and line-regulation errors
and for lowering output noise. When the output voltage
shifts due to varying load current or input voltage, the
integrator capacitor voltage is raised or lowered to
compensate for the systematic offset at the error amplifier. Compensation is limited to ±5% to minimize transient overshoot when the device goes out of dropout,
current limit, or thermal shutdown.
Fault-Detection Circuitry
When the output voltage goes out of regulation—such
as during dropout, current limit, or thermal shutdown—
FAULT goes low. In addition, the fault-detection circuitry
detects when the input-to-output voltage differential is
insufficient to ensure good load and line regulation at
the output. When the input-to-output voltage differential
is less than 130mV for a load current of 200mA, FAULT
also goes low. The differential threshold is designed to
be always higher than and track with the dropout voltage, and to scale proportionally with load current (see
Fault Detect Threshold vs. Load Current graph in the
Typical Operating Characteristics).
The FAULT pin is an open-drain N-channel MOSFET. To
create a voltage level output, connect a pull-up resistor
from FAULT to OUT. To minimize current consumption,
make this resistor as large as practical. A 100kΩ resistor
works well for most applications.
_______________________________________________________________________________________
7
MAX8860
Choose R2 = 100kΩ to optimize power consumption,
accuracy, and high-frequency power-supply rejection.
Ensure that the total current through the external resistive feedback and load resistors is not less than 10µA.
Since the VSET tolerance is typically less than ±20mV,
set the output using fixed resistors instead of trim pots.
In preset voltage mode, connect SET to GND. Keep
impedances between SET and ground to less than
100kΩ. Otherwise, spurious conditions can cause VSET
to exceed the 60mV Dual Mode threshold.
MAX8860
Low-Dropout, 300mA
Linear Regulator in µMAX
VIN > +5.5V Minimum Load
Current Requirements
Power-Supply Rejection and Operation
from Sources Other than Batteries
When operating the MAX8860 with an input voltage
above +5.5V, a minimum load current of 20µA is
required to maintain regulation in preset voltage mode.
When setting the output with external resistors, ensure
that the minimum current through the external feedback
resistors and load is at least 30µA. This applies only
when the input voltage exceeds +5.5V. For input voltages less than +5.5V, the MAX8860 maintains regulation and stability without external loading.
The MAX8860 is designed to deliver low dropout voltage and low quiescent current in battery-powered systems. Power-supply rejection is 67dB at low frequencies
and rolls off above 100kHz. At high frequencies, the output capacitor is the major contributor to the rejection of
power-supply noise (see the Power-Supply Rejection
Ratio vs. Frequency graph in the Typical Operating
Characteristics).
When operating from sources other than batteries,
improve supply-noise rejection and transient response
by increasing the values of the input and output capacitors, and by using passive filtering techniques (see the
supply and load-transient responses in the Typical
Operating Characteristics).
Applications Information
Capacitor Selection and
Regulator Stability
Typically, use a 2.2µF capacitor on the input and a
2.2µF capacitor on the output of the MAX8860.
Capacitor type is not critical, as long as it has an ESR
less than 0.5Ω. Larger capacitor values and lower ESR
provide better supply-noise rejection and transient
response. Use higher-value capacitors (10µF) if large,
fast input or load transients are anticipated or if the
device is located several inches from the power source.
For stable operation over the full temperature range,
with load currents up to 300mA, a minimum outputcapacitor value of 2.2µF is recommended. There is no
upper limit to capacitor size. The circuit used to generate the typical operating characteristics data used
2.2µF, X7R, 16V (1206) ceramic capacitors. These
capacitors typically have an ESR of 50mΩ.
Load-Transient Considerations
The MAX8860 load-transient response graph (see
Typical Operating Characteristics) shows the output
response due to changing load current. Reduce overshoot by increasing the output capacitor’s value and
decreasing its ESR.
Input-Output (Dropout) Voltage
A regulator’s minimum input-output voltage differential
(or dropout voltage) determines the lowest usable supply
voltage. In battery-powered systems, this determines the
useful end-of-life battery voltage. Because the MAX8860
uses a P-channel MOSFET pass transistor, its dropout
voltage is a function of RDS(ON) (typically 0.5Ω) multiplied by the load current (see Electrical Characteristics).
Chip Information
TRANSISTOR COUNT: 148
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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 1999 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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