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19-1301; Rev 1; 3/98
Low-Noise, Low-Dropout, 150mA Linear
Regulators with ‘2982 Pinout
__________________General Description
The MAX8877/MAX8878 low-noise, low-dropout linear
regulators operate from a 2.5V to 6.5V input and deliver
up to 150mA. These devices are pin-compatible with
the industry-standard ‘2982 and offer an improved
dropout voltage. Typical output noise is 30µVRMS, and
typical dropout is only 165mV at 150mA. The output
voltage is preset to voltages in the range of 2.5V to
5.0V, in 100mV increments.
Designed with an internal P-channel MOSFET pass
transistor, the MAX8877/MAX8878 maintain a low
100µA supply current, independent of the load current
and dropout voltage. Other features include a 10nA
logic-controlled shutdown mode, short-circuit and ther-
mal-shutdown protection, and reverse battery protec-
tion. The MAX8878 also includes an auto-discharge
function, which actively discharges the output voltage
to ground when the device is placed in shutdown. Both
devices come in a miniature 5-pin SOT23 package.
____________________________Features
o Pin-Compatible with the Industry-Standard ‘2982
o Low Output Noise: 30µVRMS
o Low 55mV Dropout at 50mA Output
(165mV at 150mA output)
o Low 85µA No-Load Supply Current
o Low 100µA Operating Supply Current
(even in dropout)
o Thermal-Overload and Short-Circuit Protection
o Reverse Battery Protection
o Output Current Limit
o Preset Output Voltages (±1.4% Accuracy)
o 10nA Logic-Controlled Shutdown
________________________Applications
Cellular Telephones
Cordless Telephones
PCS Telephones
PCMCIA Cards
Modems
Hand-Held Instruments
Palmtop Computers
Electronic Planners
_________________Ordering Information
PART**
MAX8877C/Dxy
MAX8877EUKxy-T
MAX8878C/Dxy
MAX8878EUKxy-T
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
Dice*
5 SOT23-5
Dice*
5 SOT23-5
*Dice are tested at TA = +25°C only.
**xy is the output voltage code (see Expanded Ordering
Information table at end of data sheet).
____________Typical Operating Circuit _____________________Pin Configuration
INPUT
2.5V TO 6.5V
IN OUT
CIN
1µF
ON
OFF
MAX8877
MAX8878
SHDN
COUT
1µF
BP
CBP
0.01µF
GND
OUTPUT
PRESET
2.5V TO 5.0V
150mA
TOP VIEW
IN 1
5 OUT
MAX8877
GND 2 MAX8878
SHDN 3
4 BP
SOT23-5
________________________________________________________________ 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 408-737-7600 ext. 3468.

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Low-Noise, Low-Dropout, 150mA Linear
Regulators with ‘2982 Pinout
ABSOLUTE MAXIMUM RATINGS
IN to GND ....................................................................-7V to +7V
Output Short-Circuit Duration ............................................Infinite
SHDN to GND..............................................................-7V to +7V
SHDN to IN ...............................................................-7V to +0.3V
OUT, BP to GND ..........................................-0.3V to (VIN + 0.3V)
Continuous Power Dissipation (TA = +70°C)
SOT23-5 (derate 7.1mW/°C above +70°C)..................571mW
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
θJB ..................................................................................140°C/W
Storage Temperature.........................................-65°C to +160°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 = VOUT(NOMINAL) + 0.5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
Input Voltage
Output Voltage Accuracy
Maximum Output Current
Current Limit
Ground Pin Current
VIN
ILIM
IQ
Dropout Voltage (Note 2)
Line Regulation
Load Regulation
Output Voltage Noise
SHUTDOWN
SHDN Input Threshold
SHDN Input Bias Current
VLNR
VLDR
en
VIH
VIL
ISHDN
Shutdown Supply Current
IQ(SHDN)
Shutdown Exit Delay
(Note 3)
Resistance Shutdown Discharge
THERMAL PROTECTION
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
TSHDN
TSHDN
IOUT = 0mA, TA = +25°C
IOUT = 0mA to 120mA, TA = -40°C to +85°C
No load
IOUT = 150mA
IOUT = 1mA
IOUT = 50mA
IOUT = 150mA
VIN = (VOUT + 0.1V) to 6.5V, IOUT = 1mA
IOUT = 0mA to 120mA, COUT = 1µF
f = 10Hz to 100kHz,
CBP = 0.01µF
COUT = 10µF
COUT = 100µF
VIN = 2.5V to 5.5V
VIN = 2.5V to 5.5V
VSHDN = VIN
VOUT = 0V
CBP = 0.1µF
COUT = 1µF, no load
MAX8878 only
TA = +25°C
TA = +85°C
TA = +25°C
TA = +85°C
TA = +25°C
TA = -40°C to +85°C
2.5
-1.4
-3
150
160
-0.15
390
85
100
1.1
55
165
0
0.01
30
20
2.0
0.01
0.5
0.01
0.2
30
300
155
15
6.5
1.4
2
180
120
0.15
0.04
0.4
100
1
150
300
UNITS
V
%
mA
mA
µA
mV
%/V
%/mA
µVRMS
V
nA
µA
µs
°C
°C
Note 1: Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range are guaranteed through
correlation using Statistical Quality Control (SQC) Methods.
Note 2: The dropout voltage is defined as VIN - VOUT, when VOUT is 100mV below the value of VOUT for VIN = VOUT + 0.5V.
Note 3: Time needed for VOUT to reach 95% of final value.
2 _______________________________________________________________________________________

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Low-Noise, Low-Dropout, 150mA Linear
Regulators with ‘2982 Pinout
__________________________________________Typical Operating Characteristics
(VIN = VOUT(NOMINAL) + 0.5V, CIN = 1µF, COUT = 1µF, CBP = 0.01µF, TA = +25°C, unless otherwise noted.)
OUTPUT VOLTAGE vs. LOAD CURRENT
(MAX887_EUK25)
2.60
2.55
2.50
2.45
2.40
0
50 100
LOAD CURRENT (mA)
150
GROUND PIN CURRENT vs. INPUT VOLTAGE
(MAX887_EUK25)
120
ILOAD = 50mA
100
80
NO LOAD
60
OUTPUT VOLTAGE vs. LOAD CURRENT
(MAX887_EUK50)
5.2
5.1
5.0
4.9
4.8
0
50 100
LOAD CURRENT (mA)
150
GROUND PIN CURRENT vs. INPUT VOLTAGE
(MAX887_EUK50)
120
ILOAD = 50mA
100
80
NO LOAD
60
110
105
100
95
90
85
80
75
70
65
60
0
GROUND PIN CURRENT
vs. LOAD CURRENT
MAX887_EUK50
MAX887_EUK25
50 100
LOAD CURRENT (mA)
150
OUTPUT VOLTAGE vs. INPUT VOLTAGE
6
NO LOAD
5
MAX887_EUK50
4
3
40 40
20 20
2 MAX887_EUK25
1
0
0
12345
INPUT VOLTAGE (V)
6
OUTPUT VOLTAGE vs. TEMPERATURE
(MAX887_EUK25)
2.60
ILOAD = 50mA
2.55
2.50
2.45
2.40
-40 -20
0 20 40 60
TEMPERATURE (°C)
80 100
0
0
12345
INPUT VOLTAGE (V)
6
OUTPUT VOLTAGE vs. TEMPERATURE
(MAX887_EUK50)
5.2
ILOAD = 50mA
5.1
5.0
4.9
4.8
-40 -20
0 20 40 60
TEMPERATURE (°C)
80 100
0
0
12345
INPUT VOLTAGE (V)
6
200
180
160
140
120
100
80
60
40
20
0
-40
GROUND PIN CURRENT
vs. TEMPERATURE
ILOAD = 50mA
MAX887_EUK50
MAX887_EUK25
-20 0 20 40 60 80 100
TEMPERATURE (°C)
_______________________________________________________________________________________ 3

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Low-Noise, Low-Dropout, 150mA Linear
Regulators with ‘2982 Pinout
____________________________Typical Operating Characteristics (continued)
(VIN = VOUT(NOMINAL) + 0.5V, CIN = 1µF, COUT = 1µF, CBP = 0.01µF, TA = +25°C, unless otherwise noted.)
DROPOUT VOLTAGE vs. LOAD CURRENT
(MAX887_EUK25)
250
DROPOUT VOLTAGE vs. LOAD CURRENT
(MAX887_EUK50)
200
POWER-SUPPLY REJECTION RATIO
vs. FREQUENCY
70
200 TA = +85°C
TA = +25°C
150
TA = -40°C
100
50
150 TA = +85°C
TA = +25°C
100
TA = -40°C
50
0
0
20 40 60 80 100 120 140 160
LOAD CURRENT (mA)
OUTPUT NOISE SPECTRAL DENSITY
vs. FREQUENCY
10
CBP = 0.01µF
ILOAD = 10mA
1
0.1
0.01
0
COUT = 1µF
COUT = 10µF
1 10 100
FREQUENCY (kHz)
1000
0
0
20 40 60 80 100 120 140 160
LOAD CURRENT (mA)
OUTPUT NOISE vs. BP CAPACITANCE
80
COUT = 10µF
70 ILOAD = 10mA
f = 10Hz to 100kHz
60
50
MAX887_EUK50
40
30 MAX887_EUK30
20
MAX887_EUK25
10
0
0.001
0.01
BP CAPACITANCE (µF)
0.1
60
COUT = 10µF
50
40
30
COUT = 1µF
20
10 ILOAD = 50mA
CBP = 0.1µF
0
0.01 0.1
1
10
FREQUENCY (kHz)
100
1000
OUTPUT NOISE vs. LOAD CURRENT
60
50 MAX887_EUK50
40
MAX887_EUK30
30
20 MAX887_EUK25
10 COUT = 10µF
CBP = 0.01µF
f = 10Hz to 100kHz
0
1 10
100
LOAD CURRENT (mA)
1000
OUTPUT NOISE 10Hz TO 100kHz
REGION OF STABLE COUT ESR
vs. LOAD CURRENT
100
VOUT
50µV/div
10 COUT = 10µF
1
STABLE REGION
0.1
COUT = 1µF
1ms/div
MAX887_EUK25, COUT = 10µF, ILOAD = 10mA, CBP = 0.1µF
0.01
0
100
LOAD CURRENT (mA)
150
4 _______________________________________________________________________________________

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Low-Noise, Low-Dropout, 150mA Linear
Regulators with ‘2982 Pinout
____________________________Typical Operating Characteristics (continued)
(VIN = VOUT(NOMINAL) + 0.5V, CIN = 1µF, COUT = 1µF, CBP = 0.01µF, TA = +25°C, unless otherwise noted.)
LINE-TRANSIENT RESPONSE
MAX8877-18
LOAD-TRANSIENT RESPONSE
MAX8877-19
LOAD-TRANSIENT RESPONSE
NEAR DROPOUT
MAX8877-20
4V
3V
3.01V
VIN 3.00V
3.01V
VOUT
3.00V
VOUT
2.99V
2.99V
3.001V
3.000V
2.999V
VOUT 50mA
ILOAD
50mA
ILOAD
100µs/div
MAX887_EUK30, ILOAD = 50mA
10µs/div
MAX887_EUK30, VIN = VOUT + 0.5V,
CIN = 10µF, ILOAD = 0mA TO 50mA
10µs/div
MAX887_EUK30, VIN = VOUT + 0.1V,
CIN = 10µF, ILOAD = 0mA TO 50mA
MAX887_EUK25
SHUTDOWN EXIT DELAY
MAX8877-21
MAX887_EUK50
SHUTDOWN EXIT DELAY
MAX8877-22
2V
VSHDN
2V
VSHDN
0V CBP = 0.01µF
0V CBP = 0.01µF
2V
1V CBP = 0.1µF
0V
5µs/div
MAX887_EUK25, ILOAD = 50mA
VOUT
4V
2V
CBP = 0.1µF
0V
5µs/div
MAX887_EUK50, ILOAD = 50mA
VOUT
ENTERING SHUTDOWN
MAX8877-23
VSHDN
2V
0V
5V
0V
500µs/div
MAX8878, NO LOAD
VOUT
______________________________________________________________Pin Description
PIN NAME
FUNCTION
1
IN
Regulator Input. Supply voltage can range from 2.5V to 6.5V. Bypass with a 1µF capacitor to GND (see
Capacitor Selection and Regulator Stability section).
2
GND
Ground. This pin also functions as a heatsink. Solder to a large pad or the circuit-board ground plane to
maximize power dissipation.
3
SHDN
Active-Low Shutdown Input. A logic low reduces the supply current to 10nA. On the MAX8878, a logic low
also causes the output voltage to discharge to GND. Connect to IN for normal operation.
4
BP
Reference-Noise Bypass. Bypass with a low-leakage, 0.01µF ceramic capacitor for reduced noise at the
output.
5
OUT
Regulator Output. Sources up to 150mA. Bypass with a 1µF (<0.2typical ESR) capacitor to GND.
_______________________________________________________________________________________ 5