19-1859; Rev 4; 7/09
Low-Dropout, 300mA Linear Regulators in SOT23
General Description
The MAX8887/MAX8888 low-dropout linear regulators
operate from a 2.5V to 5.5V input and deliver up to
300mA continuous (500mA pulsed) current. The
MAX8887 is optimized for low-noise operation, while the
MAX8888 includes an open-drain power-OK (POK) ouput
flag. Both regulators feature exceptionally low 100mV
dropout at 200mA. These devices are available in a vari-
ety of preset output voltages in the 1.5V to 3.3V range.
An internal PMOS pass transistor allows the low 55µA
supply current to remain independent of load, making
these devices ideal for portable battery-powered equip-
ment such as personal digital assistants (PDAs), cellu-
lar phones, cordless phones, and notebook computers.
Other features include a micropower shutdown mode,
short-circuit protection, thermal shutdown protection,
and an active-low open-drain POK output that indicates
when the output is out of regulation. The
MAX8887/MAX8888 are available in a thin 5-pin SOT23
package that is only 1mm high.
Features
♦
Guaranteed 300mA Output Current (500mA for
Pulsed Loads)
♦
Low 100mV Dropout at 200mA Load
♦
POK Output (MAX8888)
♦
42µV
RMS
Output Noise (MAX8887)
♦
Preset Output Voltages (1.5V, 1.8V, 2.85V, and
3.3V)
♦
55µA No-Load Supply Current
♦
Thermal-Overload and Short-Circuit Protection
♦
Foldback Output Current-Limit Protection
♦
60dB PSRR at 1kHz
♦
0.1µA Shutdown Current
♦
Thin 5-Pin SOT23 Package, 1mm High
MAX8887/MAX8888
Ordering Information
PART
MAX8887
EZK15+T
MAX8887EZK18+T
TEMP
RANGE
PIN-
PACKAGE
TOP
MARK
ADQD
ADPX
ADPY
ADPZ
—
ADQE
ADQA
—
ADQB
ADQC
—
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
-40°C to +85°C 5 SOT23
________________________Applications
Notebook Computers
Wireless Handsets
PDAs and Palmtop Computers
Digital Cameras
PCMCIA Cards
Hand-Held Instruments
MAX8887EZK29+T
MAX8887EZK33+T
MAX8887EZKxy+T*
MAX8888
EZK15+T
MAX8888EZK18+T
MAX8888EZK18/V+T
MAX8888EZK29+T
MAX8888EZK33+T
MAX8888EZKxy+T*
Typical Operating Circuit
INPUT
2.5V TO 5.5V
IN
C
IN
2.2µF
OUT
V
OUT
300mA
C
OUT
2.2µF
POK
ON
SHDN
OFF
GND
(BP)
C
BP
0.01µF
*Other
versions (xy) between +1.5 and +3.3V are available in
100mV increments. Contact factory for other versions. Minimum
order quantity is 25,000 units.
+Denotes
a lead(Pb)-free RoHS-compliant package.
/V denotes an automotive qualified
part.
Pin Configurations
TOP VIEW
IN
1
5
OUT
IN
1
5
OUT
MAX8887
MAX8888
GND
2
MAX8887
GND
2
MAX8888
SHDN
3
( ) ARE FOR MAX8887 ONLY.
4
BP
SHDN
3
4
POK
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Low-Dropout, 300mA Linear Regulators in SOT23
MAX8887/MAX8888
ABSOLUTE MAXIMUM RATINGS
IN,
SHDN,
POK, to GND...........................................-0.3V to +7V
OUT, BP to GND ............................................-0.3 to (V
IN
+ 0.3V)
Output Short-Circuit Duration.....................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
5-Pin SOT23 (derate 9.1mW/°C above +70°C)............727mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+500°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
(V
IN
= V
OUT
+ 1V,
SHDN
= IN, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
Input Voltage
Input Undervoltage Lockout
SYMBOL
V
IN
V
IN
rising
(2% typical hysteresis)
T
A
= +25°C, I
OUT
= 100mA
Output Voltage Accuracy
I
OUT
= 100µA to 300mA,
T
A
= 0°C to +85°C
I
OUT
= 100µA to 300mA
Maximum Output Current
Current Limit
Ground-Pin Current
Continuous
10ms pulse
V
OUT
= 0
V
OUT
> 93% of nominal value
No load
I
OUT
= 300mA
I
OUT
= 1mA
Dropout Voltage (Note 2)
V
OUT
= +3.3V
I
OUT
= 200mA
I
OUT
= 300mA
Line Regulation
V
IN
= 2.5V or (V
OUT
+ 0.4V) to 5.5V,
I
OUT
= 5mA
MAX8887
Output Noise
MAX8888
MAX8887
PSRR
MAX8888
10Hz to 100kHz, C
BP
= 0.01µF,
C
OUT
= 2.2µF, ESR
COUT
< 0.1Ω
10Hz to 100kHz, C
OUT
= 2.2µF,
ESR
COUT
< 0.1Ω
f < 1kHz, C
BP
= 0.01µF,
C
OUT
= 4.7µF, ESR
COUT
< 0.1Ω
f < 1kHz, C
OUT
= 2.2µF,
ESR
COUT
< 0.1Ω
-0.15
300
420
55
65
0.5
100
150
0
42
µV
RMS
360
60
dB
40
0.15
%/V
200
100
CONDITIONS
MIN
2.5
2.15
-1.2
-2
-3
300
500
TYP
MAX
5.5
2.4
+1.2
+2
+3
mA
mA
µA
%
UNITS
V
V
mV
2
_______________________________________________________________________________________
Low-Dropout, 300mA Linear Regulators in SOT23
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
OUT
+ 1V,
SHDN
= IN, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 1)
PARAMETER
SHUTDOWN
Shutdown Supply Current
SHDN
Input Threshold
SHDN
Input Bias Current
OUT Discharge Resistance in
Shutdown
POK (MAX8888 ONLY)
POK Trip Level, Referred to OUT
Set Point
Operating IN Voltage Range for
Valid POK
POK Output Voltage Low
POK Output Leakage Current
THERMAL PROTECTION
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
170
20
°C
°C
V
OL
I
SINK
= 1mA
V
POK
= 5.5V,
SHDN
= IN
V
OUT
falling
(1% typical hysteresis)
90
1.0
92.5
95
5.5
0.1
100
%
V
V
nA
V
IH
V
IL
SHDN
= GND, V
IN
= 5.5V
2.5V
≤
V
IN
≤
5.5V
2.5V
≤
V
IN
≤
5.5V
SHDN
= IN or GND
SHDN
= GND
10
650
1.6
0.6
100
1100
0.1
2
µA
V
nA
Ω
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX8887/MAX8888
Note 1:
All parts are 100% tested at T
A
= +25°C. Limits over the operating temperature range are guaranteed by design.
Note 2:
Typical and maximum dropout voltage for different output voltages are shown in the
Typical Operating Characteristics
curves.
Typical Operating Characteristics
(Typical
Operating Circuit,
T
A
= +25°C, unless otherwise noted.)
OUTPUT VOLTAGE vs. INPUT VOLTAGE
MAX8887/8 toc01
OUTPUT VOLTAGE ACCURACY
vs. LOAD CURRENT
MAX8887/8 toc02
OUTPUT VOLTAGE ACCURACY
vs. TEMPERATURE
0.04
0.03
0.02
% DEVIATION
0.01
0.0
-0.01
-0.02
-0.03
-0.04
-0.05
I
OUT
= 0
V
IN
= V
OUT
+ 500mV
MAX8887/8 toc03
3.5
3.0
OUTPUT VOLTAGE (V)
2.5
2.0
1.5
1.0
0.5
0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
I
OUT
= 0
I
OUT
= 300mA
1.0
0.8
0.6
% DEVIATION (%)
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
-1.0
0.05
5.5
0
50
100
150
200
250
300
-40
-15
10
35
60
85
INPUT VOLTAGE (V)
LOAD CURRENT (mA)
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Low-Dropout, 300mA Linear Regulators in SOT23
MAX8887/MAX8888
Typical Operating Characteristics (continued)
(Typical
Operating Circuit,
T
A
= +25°C, unless otherwise noted.)
DROPOUT VOLTAGE vs. LOAD CURRENT
MAX8887/8 toc04
DROPOUT VOLTAGE vs. OUTPUT VOLTAGE
MAX8887/8 toc05
GROUND-PIN CURRENT vs. INPUT VOLTAGE
MAX8887/8 toc06
160
140
120
V
DROPOUT
(mV)
300
I
OUT
= 200mA
250
MAXIMUM
V
DROPOUT
(mV)
200
150
TYPICAL
100
150
125
100
I
LOAD
= 300mA
75
50
25
0
I
LOAD
= 0
T
A
= +85°C
100
80
60
40
20
0
0
50
100
150
200
250
300
LOAD CURRENT (mA)
T
A
= -40°C
50
0
2.5
2.7
2.9
V
OUT
(V)
3.1
3.3
GROUND-PIN CURRENT (µA)
T
A
= +25°C
0
1.0
2.0
3.0
4.0
5.0
INPUT VOLTAGE (V)
GROUND-PIN CURRENT vs. LOAD CURRENT
MAX8887/8 toc07
GROUND-PIN CURRENT vs. TEMPERATURE
MAX8887/8 toc08
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
MAX8887/8 toc09
100
V
IN
= 5.5V
GROUND-PIN CURRENT (µA)
70
68
GROUND-PIN CURRENT (µA)
66
64
I
OUT
= 0
V
IN
= V
OUT
+ 500mV
70
60
50
PSRR (dB)
40
30
20
10
0
V
OUT
= 3.30V
I
LOAD
= 30mA
0.01
0.1
1
10
C
OUT
= 2.2µF
C
BP
= 0.01µF
80
V
IN
= 3.8V
60
62
60
58
56
54
52
40
20
0
0
50
100
150
200
250
300
LOAD CURRENT (mA)
50
-40
-15
10
35
60
85
TEMPERATURE (°C)
MAX8887 ONLY
100
1000
FREQUENCY (kHz)
MAX8887
OUTPUT NOISE DC TO 1MHz
MAX8887/8 toc10
LOAD-TRANSIENT RESPONSE
MAX8887/8 toc11
300mA
I
OUT
V
OUT
50µV/div
V
OUT
50mV/div
AC-COUPLED
10mA
V
OUT
= 1.8V, V
IN
= 3.8V, I
LOAD
= 15mA
40ms/div
10µs/div
V
OUT
= 3.3V
V
IN
= 3.8V
4
_______________________________________________________________________________________
Low-Dropout, 300mA Linear Regulators in SOT23
Typical Operating Characteristics (continued)
(Typical
Operating Circuit,
T
A
= +25°C, unless otherwise noted.)
LOAD-TRANSIENT RESPONSE
NEAR DROPOUT
MAX8887/8 toc12
MAX8887/MAX8888
LINE-TRANSIENT RESPONSE
MAX8887/8 toc13
300mA
4.5V
I
OUT
10mA
V
IN
V
OUT
50mV/div
AC-COUPLED
V
OUT
20mV/div
AC-COUPLED
V
OUT
= 3.3V
I
LOAD
= 100mA
100µs/div
4V
V
OUT
= 3.3V
V
IN
= 3.4V
10µs/div
SHUTDOWN WAVEFORM
MAX8887/8 toc14
POK WAVEFORM
MAX8887/8 toc15
V
SHDN
2V/div
V
IN
V
OUT
= 3.3V, R
LOAD
= 100Ω
2V/div
V
OUT
1V/div
DC-COUPLED
V
OUT
2V/div
V
POK
2V/div
V
OUT
= 3.3V, R
LOAD
= 10Ω
20µs/div
20ms/div
Pin Description
MAX8887
1
2
3
MAX8888
1
2
3
NAME
IN
GND
SHDN
FUNCTION
Regulator Input. Supply voltage can range from 2.5V to 5.5V. Bypass with 2.2µF
capacitor to GND (see the
Capacitor Selection and Regulator Stability
section).
Ground
Active-Low Shutdown Input. A logic low reduces the supply current to below 0.1µA.
In shutdown, POK and OUT are driven low. Connect to IN for normal operation.
Open-Drain Active-Low POK Output. POK remains low while the output voltage (V
OUT
) is
below the reset threshold. Connect a 100kΩ pullup resistor to OUT to obtain a logic level
output. POK is driven low in shutdown. If not used, leave this pin unconnected.
Reference Bypass. Bypass with a low-leakage 0.01µF ceramic capacitor.
Regulator Output. Sources up to 300mA guaranteed. Bypass with 2.2µF (<0.2Ω typical
ESR) ceramic capacitor to GND.
—
4
5
4
—
5
POK
BP
OUT
_______________________________________________________________________________________
5
模拟电子
