Datasheet MAX8862LESE, MAX8862RESE, MAX8862TESE Datasheet (Maxim)

19-1117; Rev 0; 8/96

Low-Cost, Low-Dropout, Dual Linear Regulator

_______________General Description

The MAX8862 low-cost, low-dropout, dual linear voltage
regulator is ideal for battery-powered and portable
applications. The regulators have independent supply
inputs and provide 250mA and 100mA, respectively,
with a full-load dropout voltage of 160mV. Both regula­tors use P-channel MOSFET pass transistors and main­tain low quiescent current independent of load current.
In dropout, the MOSFET does not suffer from excessive
base currents, as do saturated PNP transistors.

The MAX8862 output voltage is preset to 4.95V (L),

3.175V (T), or 2.85V (R). This device employs Dual
Mode™ operation, allowing user-adjustable outputs
from +2V to +11V with external resistors. The input
supply-voltage range is 2.5V to 11.5V. Other features
include independent shutdown, power-good indicator,
short-circuit and reverse-battery protection, and ther­mal shutdown.

The MAX8862’s regulators are ideal power supplies for
the radio and the microcontroller (µC) used in digital,
cordless, and PCS phones. The main regulator is opti­mized for superior transient and dynamic response,
while the secondary regulator exhibits low-output, wide­band noise.

The MAX8862 comes in a 16-pin SO package with a
lead frame that uses multiple GND pins as a heat sink
for additional thermal dissipation.

________________________Applications

Cellular Phones Cordless Phones
PCS Phones PCMCIA Cards
Modems Hand-Held Instruments
Electronic Planners

__________Typical Operating Circuit

INPUT 1

2.5V TO 11.5V
1µF

OUTPUT 1
AT 250mA

3.3µF

IN1
SHDN1 SHDN2

MAX8862

OUT1 OUT2

100k

PWROK1
GND SET1 SET2 GND

IN2

REF2

INPUT 2

2.5V TO 11.5V

1µF

OUTPUT 2
AT 100mA

2.2µF

0.1µF

____________________________Features

♦ Low Cost
♦ Guaranteed 250mA and 100mA Output Currents,

with Current Limiting

♦ Dual Mode Operation:

Fixed or Adjustable Output from +2V to +11V

♦ +2.5V to +11.5V Input Range
♦ 160mV Dropout Voltage at 200mA Output Current
♦ Low Supply Current—Even in Dropout

200µA Operating
<1µA Shutdown

♦ Power-Good Indicator
♦ Reverse-Battery Protection
♦ Thermal Overload Protection

______________Ordering Information

PART*

MAX8862_ESE -40°C to +85°C

*Insert the desired suffix letter (from the table below) into the
blank to complete the part number.

SUFFIX

L
T
R 2.85

TEMP. RANGE PIN-PACKAGE

16 Narrow SO

FIXED OUTPUT VOLTAGE (V)

4.95

3.175

__________________Pin Configuration

TOP VIEW

N.C.

16

SET1

15
14

OUT1

13

GND
GND

12
11

REF2

10

SHDN2
IN2

9

SHDN1

PWROK1

GND
GND

OUT2

SET2

N.C.

IN1

1
2
3
4

MAX8862

5
6
7
8

MAX8862

Narrow SO

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 [phone]

Low-Cost, Low-Dropout, Dual Linear Regulator

ABSOLUTE MAXIMUM RATINGS

IN1, IN2 to GND (Note 1).....................................................±12V

SET1, SHDN1, PWROK1 to GND.............. -0.3V to (V

SET2, SHDN2, REF2 to GND....................... -0.3V, (V

Output Short-Circuit Duration ............................................Infinite

Continuous Power Dissipation (T

16-Pin Narrow SO (derate 20mW/°C above +70°C)............... 1W

= +70°C)

A

IN1
IN2

+ 0.3V)
+ 0.3V)

Note 1: Connect SHDN1 to IN1 and SHDN2 to IN2 through 20kΩ resistors to limit current flow in case a battery is reversed.

MAX8862

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 (Notes 2, 3)

(V

= V

IN_

OUT_(TYP)

Output Voltage

Maximum Output Current

Current Limit

Dropout Voltage (Note 4)

Line Regulation

Load Regulation

OUT2 Voltage Noise

REFERENCE

REF2 Output Voltage C
REF2 Line Regulation V
REF2 Load Regulation I

+ 1V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

CONDITIONS

0mA < I
0mA < I

V

IN1

V

IN2

I

OUT1

I

OUT2

V

IN1

I

OUT1

I

OUT1

I

OUT2

I

OUT1

I

OUT2

I

OUT1

I

OUT1

I

OUT2

C

OUT2

Z

OUT2

C

OUT2

Z

OUT2

REF2

IN2

REF2

≤ 250mA,

OUT1

≤ 100mA

OUT2

= 2.5V min, V
= 2.5V min, V

= V

= 11.5V

IN2

= I

OUT2

OUT1
OUT2

= 1mA

= 2V
= 2V

= 200mA, MAX8862L/T
= 100mA, MAX8862L/T
= 200mA, MAX8862R
= 100mA, MAX8862R

= I

= 15mA

OUT2

= 0mA to 250mA, C
= 0mA to 100mA, C

= 2.2µF

= 10mA

= 100µF

= 10mA

= 0.1µF 1.230 1.250 1.270 V

= 2.5V to 11.5V 1 mV

= 0µA to 10µA 6 mV

Operating Temperature Range ...........................-40°C to +85°C

Junction Temperature .....................................................+150°C

Storage Temperature Range.............................-65°C to +150°C

Lead Temperature (soldering, 10sec)............................ +300°C

MAX8862L
MAX8862T
MAX8862R

4.80 4.95 5.15

3.050 3.175 3.300

2.75 2.85 2.95

250
100

580
250

1.5
160 330
160 350
165 350
180 400

V

= (V

IN1

OUT1 (TYP)

to 11.5V
V

= (V

IN2

OUT2 (TYP)

to 11.5V

= 3.3µF

OUT1

= 2.2µF

OUT2

10Hz < f < 100kHz

+ 1V)

+ 1V)

0.03 0.1

0.02 0.08

0.015

0.02
277

10Hz < f < 1MHz 875
10Hz < f < 100kHz
10Hz < f < 1MHz

211
667

UNITSMIN TYP MAXPARAMETER

%/mA

µVRMS
mV

V2.5 11.5Input Voltage Range

V

V211Output Voltage Range

mA

mA

µA200 330Quiescent Current
µA0.01 1Shutdown Supply Current

mV

%/V

RMS

2 _______________________________________________________________________________________

Low-Cost, Low-Dropout, Dual Linear Regulator

SHDN

ELECTRICAL CHARACTERISTICS (Notes 2, 3)

(V

IN_

= V

OUT_(TYP)

+ 1V, TA= 0°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

CONDITIONS

PWROK1 OUTPUT

Falling edge at SET1 V1.175 1.200 1.225PWROK1 Trip Voltage
Rising edge at SET1

PWROK1

SINK

SHDN_

= 11.5V

= 0.5mA

= 11.5V

IN_

= V

IN_

= 11.5V

OUT_(TYP)

SHDN_ Logic Low
SHDN_ Logic High
SHDN_ Leakage Current

V
I

Shutdown mode, V
Active mode, V
V

SET_ INPUT

SET_ Threshold

SET_ = OUT_, I
V

= 1.30V

SET_

Internal feedback
External feedback

OUT1

= I

OUT2

THERMAL PROTECTION

ELECTRICAL CHARACTERISTICS (Notes 2, 3)

(V

= V

IN_

OUT_(TYP)

Output Voltage

Maximum Output Current

Current Limit

Dropout Voltage (Note 4)

+ 1V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

CONDITIONS

0mA < I
0mA < I

V

IN1

V

IN2

I

OUT1

I

OUT2

V

IN1

I

OUT1

I

OUT1

I

OUT2

I

OUT1

I

OUT2

≤ 250mA,

OUT1

≤ 100mA

OUT2

= 2.5V min, V
= 2.5V min, V

= V

= 11.5V

IN2

= I

OUT2

OUT1
OUT2

= 1mA

= 2V
= 2V

= 200mA, MAX8862L/T
= 100mA, MAX8862L/T
= 200mA, MAX8862R
= 100mA, MAX8862R

= 15mA

+ 1V to 11.5V

MAX8862L
MAX8862T
MAX8862R

40

250

160Thermal Shutdown Temperature

20Thermal Shutdown Hysteresis

4.80 4.95 5.15

3.050 3.175 3.300

2.740 2.85 2.960

250
100

580
250

1.5
160 330
160 350
165 350
180 400

MAX8862

UNITSMIN TYP MAXPARAMETER

mV15PWROK1 Hysteresis

µA0.01 1PWROK1 Leakage Current

mV25 200PWROK1 Low Voltage

V0.45
V1.8

µA0.01 1

V1.23 1.25 1.28SET_ Reference Voltage

µA0.01 0.1SET_ Input Bias Current

mV

°C

UNITSMIN TYP MAXPARAMETER

V2.5 11.5Input Voltage Range

V

V211Output Voltage Range

mA

mA

µA200 330Quiescent Current
µA0.01 1Shutdown Supply Current

mV

_______________________________________________________________________________________ 3

Low-Cost, Low-Dropout, Dual Linear Regulator

SHDN

ELECTRICAL CHARACTERISTICS (Notes 2, 3) (continued)

(V

= V

IN_

OUT_(TYP)

Line Regulation

MAX8862

Load Regulation

OUT2 Voltage Noise

REFERENCE

REF2 Output Voltage C
REF2 Line Regulation V
REF2 Load Regulation

PWROK1 OUTPUT

PWROK1 Trip Voltage Falling edge at SET1 1.165 1.200 1.235 V
PWROK1 Hysteresis Rising edge at SET1 15 mV
PWROK1 Leakage Current V
PWROK1 Low Voltage I

+ 1V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

CONDITIONS

V

= (V

IN1

I

= I

OUT1

I

OUT1

C

OUT2

C = 2.2µF, Z

C = 100µF, Z

REF2

= 2.5V to 11.5V 1 mV

IN2

I

REF2

PWROK1

SINK

= 15mA

OUT2

= 0 to 250mA, C

OUT1

= 3.3µF

= 2.2µF, 10Hz < f < 1MHz, I

= 10mA

OUT2

= 10mA

OUT2

= 0.1µF 1.217 1.250 1.277 V

= 0µA to 10µA 6 mV

= 11.5V 0.01 1 µA

= 0.5mA 25 200 mV

OUT1 (TYP)

to 11.5V
V

= (V

IN2

OUT2 (TYP)

to 11.5V

OUT2

10Hz < f < 100kHz
10Hz < f < 1MHz
10Hz < f < 100kHz
10Hz < f < 1MHz

+ 1V)

+ 1V)

= 10mA

- 277 -

- 875 -

- 211 -

- 667 -

0.03 0.12

0.02 0.10

0.015

0.02

UNITSMIN TYP MAXPARAMETER

%/V

%/mA

µV

RMS

SHDN_ Logic Low
SHDN_ Logic High
SHDN_ Leakage Current

= V

IN_

OUT_(TYP)

Active mode, V
V

= 11.5V 0.02 1 µA

SHDN_

= 11.5V 2.0 V

IN_

+ 1V to 11.5V

SET_ INPUT

SET_ Reference Voltage SET_ = OUT_, I
SET_ Input Bias Current V

SET_ Threshold

= 1.30V 0.01 0.1 µA

SET_

Internal feedback 30
External feedback 250

OUT1

= I

= 15mA 1.220 1.250 1.290 V

OUT2

THERMAL PROTECTION

Thermal Shutdown Temperature 160
Thermal Shutdown Hysteresis 10

Note 2: Guaranteed by design for TA= -40°C.
Note 3: Guaranteed for a junction temperature (T

design to operate up to T

Note 4: Dropout voltage is (VIN_ - V

the MAX8862 is tested by measuring the V
V

= 3.85V for the MAX8862R) then V

IN_

= +125°C. For TJabove +125°C, specifications exceed the operating limits.

J

_) when V

OUT

) equal to the operating temperature range. E-grade parts are guaranteed by

J

_ falls to 100mV below its nominal value at VIN_ = (V

OUT

_ at (V

OUT

is lowered until V

IN_

= 5.95V for the MAX8862L, V

IN_

falls 100mV below the measured value.

OUT_

= 4.175V for the MAX8862T, and

IN_

4 _______________________________________________________________________________________

0.45 VShutdown mode, V

_ + 1V). For example,

OUT

mV

°C

Low-Cost, Low-Dropout, Dual Linear Regulator

__________________________________________Typical Operating Characteristics

(V

= V



-40

-40

IN2

-20

-20 20

= 5.3V, C

QUIESCENT CURRENT 

vs. TEMPERATURE

V

IN1

04080

TEMPERATURE (°C)

OUTPUT VOLTAGE

vs. TEMPERATURE

TEMPERATURE (°C)

IN1

otherwise noted.)

260
240
220
200



180
160
140

QUIESCENT CURRENT (µA)

120
100

3.27

3.26

3.25

3.24

3.23

3.22

OUTPUT VOLTAGE (V)

3.21

3.20

= C

IN2

= 1µF, C

IN1



V

= V

= 12V

IN1

IN2

= V

= 7V

IN2

60

20

OUT1

OUT2

0

600
525

450
375

300
225

150

DROPOUT VOLTAGE (mV)

80 100

40

60

DROPOUT VOLTAGE
vs. LOAD CURRENT

75

0

0 80 200 320

40

LOAD CURRENT (mA)

_______________________________________________________________________________________

= 3.3µF, C

OUT1

120

MAX8862 TOC02

110

100

90

QUIESCENT CURRENT (µA)

80

0.001

100

MAX8862TOC06



OUT2

OUT1

120 280

160

0.01 0.1

101

100

99

98

97

96

NORMALIZED OUTPUT VOLTAGE (%)

95

0.001

0.01 0.1

240

= 2.2µF, SHDN1 = IN1, SHDN2 = IN2. TA= +25°C, unless

OUT2

QUIESCENT CURRENT

vs. LOAD CURRENT

I

I

10

1

LOAD CURRENT (mA)

OUTPUT VOLTAGE

vs. LOAD CURRENT

V

OUT1

V

OUT2

10

1

LOAD CURRENT (mA)

120

100

MAX8862 TOC03

Q2

Q1

100

100

80



60

40

SHUTDOWN CURRENT (nA)

20

1000

4

MAX8862TOC04

3

2

OUTPUT VOLTAGE (V)

1

0

1000

SHUTDOWN CURRENT 

vs. TEMPERATURE

0

-20 0 20 40 60 80

-40

OUTPUT VOLTAGE & QUIESCENT CURRENT

2

TEMPERATURE (°C)

MAX8862T

vs. SUPPLY VOLTAGE

V



(IQ1 + IQ2)

35

4

6

SUPPLY VOLTAGE (V)

OUT1/VOUT2

OVERSHOOT AND TIME

EXITING SHUTDOWN MODE

MAX8862TOC07



A



0V





B



0V

= 5.3V, I

V

IN1

A = SHDN1, 0.8V TO 2.4V, 1V/div
B = OUT1, 1V/div

OUT1

20µs/div

= 5mA



V

= V

= 12V

IN1

IN2

V

= V

IN1

IN2

89101112

7

MAX8862TOC14



= 7V

1V/div



1V/div

MAX8862 TOC01

100

260
240

MAX8862TOC05

220
200
180
160
140
120

100

MAX8862

QUIESCENT CURRENT (µA)

5

Low-Cost, Low-Dropout, Dual Linear Regulator

____________________________Typical Operating Characteristics (continued)

(V

= V

IN2

= 5.3V, C

IN1

otherwise noted.)

= C

IN2

= 1µF, C

IN1

OUT1 NOISE AND RIPPLE

OUT1

MAX8862TOC08

= 3.3µF, C

= 2.2µF, SHDN1 = IN1, SHDN2 = IN2. TA= +25°C, unless

OUT2

OUT2 NOISE AND RIPPLE

MAX8862TOC09

MAX8862

I

= 250mA, AC COUPLED

OUT1

OUT1 LOAD-TRANSIENT RESPONSE

A

B

= 7V, V

V

IN1

A = LOAD CURRENT, 0mA TO 300mA, 0.2A/div
B = V

= 3.2V

OUT1

RIPPLE, 50mV/div, AC COUPLED

OUT1

OUT2 LINE-TRANSIENT RESPONSE

5µs/div

2ms/div





V



OUT

500µV/div

V

OUT

1mV/div



5µs/div

= 100mA, AC COUPLED

I



MAX8862TOC10

300mA

0mA

OUT2

OUT2 LOAD-TRANSIENT RESPONSE

A

MAX8862TOC11

200mA
0mA



B



50mV/div



50mV/div



2ms/div

V

= 7V, V

= 3.2V

OUT2

RIPPLE, 50mV/div, AC COUPLED

OUT2

OUT1 LINE-TRANSIENT RESPONSE

MAX8862TOC13

MAX8862TOC12

IN2

A = LOAD CURRENT, 0mA TO 200mA, 0.2A/div
B = V

6.5V

A

B

5.5V

50mV/div



A

B





I

= 200mA, V

OUT2

A = V
B = V

OUT2

, 5.5V TO 6.5V, 1V/div

IN2

RIPPLE, 50mV/div, AC COUPLED

OUT2

1ms/div

= 3.2V

= 300mA, V

I

OUT1

= 5.5V TO 6.5V, 1V/div

A = V

IN1

RIPPLE, 50mV/div, AC COUPLED

B = V

OUT1

OUT1

1ms/div

= 3.2V

6 _______________________________________________________________________________________

6.5V

5.5V

50mV/div



Low-Cost, Low-Dropout, Dual Linear Regulator

______________________________________________________________Pin Description

PIN

Main Regulator Supply Input (2.5V to 11.5V). Bypass with a 1µF, low-ESR capacitor to GND.IN11

2

10

11 REF2 Secondary Reference Output. Bypass with a 0.1µF capacitor to GND.

14 OUT1

15 SET1

SHDN1

PWROK13

OUT26

SET27

SHDN2

Main Regulator Shutdown Input. A logic low turns off the main regulator and power-good comparator.
Power-Good Output. This open-drain output is low when V

lower than its nominal value).
Ground. Connect to a ground plane to maximize thermal dissipation.GND4, 5, 12, 13
Secondary Regulator Output. Bypass with a 2.2µF low-ESR (< 0.5Ω) capacitor to GND. To improve

load-transient response and noise performance, use a higher-value, lower-ESR capacitor.
OUT2 Voltage-Set Input. Connect to GND for the factory-preset output voltage. Connect to a resistive

divider from OUT2 to GND for adjustable output voltage.
No connect. There is no internal connection to this pin.N.C. 8, 16

Secondary Regulator Supply Input (2.5V to 11.5V). Bypass with a 1µF, low-ESR capacitor to GND.IN29
Secondary Regulator Shutdown Input. A logic-low input turns off the secondary regulator and the

reference.

Main Regulator Output. Bypass with a 3.3µF, low-ESR (< 0.5Ω) capacitor to GND. To improve load­transient response and noise performance, use a higher-value, lower-ESR capacitor.

OUT1 Voltage Set Input. Connect to GND for the factory-preset output voltage. Connect to a
resistive divider from OUT1 to GND for adjustable output voltage.

_______________Detailed Description

The MAX8862 features Dual Mode™ operation, allow­ing a fixed output of 4.95V (L), 3.175V (T), or 2.85V (R),
or an adjustable output from 2V to 11V. The regulator’s
outputs, OUT1 and OUT2, supply 250mA and 100mA,
respectively.

The block diagram (Figure 1) shows the contents of
each regulator. Note that the main regulator provides a
power-good indicator, and the secondary regulator’s
reference output voltage is available at REF2.

The 1.25V bandgap reference is connected to the error
amplifier’s inverting input. The error amplifier compares
this reference with the selected feedback voltage and
amplifies the difference. The MOSFET driver reads the
error signal and applies the appropriate drive to the
P-channel transistor. If the feedback voltage is lower
than the reference, the pass transistor’s gate is pulled
lower, allowing more current to pass and increase the
output voltage. If the feedback voltage is too high, the
pass transistor’s gate is pulled up, allowing less current
to pass to the output.

FUNCTIONNAME

is out of regulation (V

OUT1

OUT1

is 4%

The output voltage is fed back through either an
internal resistor voltage divider connected to OUT1/
OUT2, or an external resistor network connected to
SET1/SET2. The Dual Mode comparator examines
V

SET1/VSET2

and selects the feedback path. If this volt­age is below 40mV, internal feedback is used and the
output voltage is regulated to the factory-preset volt­age.

Internal P-Channel Pass Transistor

The MAX8862’s P-channel pass transistor provides
several advantages over similar designs using PNP
pass transistors, including longer battery life.

The P-channel MOSFET requires no continuous base
current, thereby reducing quiescent current consider­ably. PNP regulators normally waste a considerable
amount of current in dropout when the pass transistor
saturates; they also use high base-drive currents under
large loads. The MAX8862 does not suffer from these
problems: it consumes only 200µA of quiescent current
for both regulators under light and heavy loads, as well
as in dropout.

MAX8862

_______________________________________________________________________________________ 7

Low-Cost, Low-Dropout, Dual Linear Regulator

1N1

SHDN1

MAX8862

IN2

SHDN2

REF2

BIAS

BIAS

1.25V

1.25V

OUT1

R1

50mV

G1

R2

R3

G1

R4

80mV

MAX8862

80mV

PWROK1

SET1

GND

GND
OUT

SET2

GND

GND

Figure 1. Functional Diagram

The MAX8862’s Dual Mode operation allows a fixed or
adjustable output voltage. In preset/internal-feedback
mode (SET1/SET2 = GND), output voltages are factory
preset to 4.95V (L), 3.175V (T), or 2.85V (R).

In adjustable/external feedback mode, output voltage is
adjusted between 2V and 11V with two external resis­tors connected as a voltage divider to SET1/SET2
(Figure 2). Since the input bias current at SET1/SET2 is
<0.1µA, large resistance values can be used for R1
and R2 to minimize power consumption without losing
accuracy. Select R2 in the 10kΩ to 400kΩ range. R1 is
given by:

R1 = R2 (V

where V

8 _______________________________________________________________________________________

SET

= 1.25V.

OUT

/ V

SET

- 1)

The MAX8862’s main regulator features a power-good
indicator that asserts when the output voltage falls out
of regulation. In internal-feedback mode, the open­drain PWROK1 output goes low when OUT1 falls 4%
below its nominal value. When used in external feed­back mode, PWROK1 goes low when V

1.2V. A 100kΩ pull-up resistor from PWROK1 to V
provides a logic-control signal. This resistor also mini­mizes current flow to the input in case the battery is
reversed. PWROK1 can be used to reset a microcon­troller or to drive an external LED for indicating a power
failure.

Output Voltage Selection

Power-Good Comparator

SET1

falls below

IN1

Low-Cost, Low-Dropout, Dual Linear Regulator

MAX8862

GND

Figure 2. Adjustable Output Voltage



OUT_

SET_

OUTPUT

R1

R2

Reference

The MAX8862 provides a precision 1.25V reference at
REF2. Bypass REF2 with a 0.1µF capacitor to ground.
Larger bypassing capacitors will further reduce the
secondary regulator’s wideband noise.

Shutdown

The MAX8862’s regulators have individual shutdown
controls. A logic low on either SHDN1 or SHDN2 turns
off the corresponding internal reference, error com­parator, and pass transistors’ control logic, reducing
quiescent current to less than 1µA.

Current Limiting

The MAX8862 features a current limit for each regula­tor. It monitors and controls the pass transistor’s gate
voltage, limiting the output current to 580mA for the
main regulator and 250mA for the secondary regulator.
The current limits apply to all input and output voltage
conditions. The outputs can be shorted to ground for
an indefinite period of time if the package can dissipate
(V

x I

+ V

x I

IN1

LIM1

+150°C (see the

Region

section).

IN2

Power Dissipation and Operating

) without exceeding TJ=

LIM2

Thermal overload protection limits the MAX8862’s total

Thermal Overload Protection

power dissipation. When the junction temperature
exceeds TJ= +160°C, the thermal sensor sends a sig­nal to the shutdown logic, turning off the pass transis­tors and allowing the device to cool down. The thermal
sensor turns the pass transistors on again after the IC’s
junction temperature decreases by 20°C. If the thermal
overload condition persists, OUT1 and OUT2 pulse on
and off.

Thermal overload protection is designed to protect the
MAX8862 during fault conditions. For continuous oper­ation, the absolute maximum junction temperature rat­ing of TJ= +150°C should not be exceeded.

Reverse-Battery Protection

This feature protects the MAX8862 against polarity
reversal at the supply inputs. The inputs can handle
negative voltages up to -12V without suffering any ill
effects. When the input polarity is reversed, the output
will be at the same potential as ground, and no current
will flow from the output back to the input. This feature
protects both the device and the supply-voltage
source. The reverse currents that flow back to the input
are due to R

PWROK1

currents are approximately: I
R

PWROK1

) and I
ing the MAX8862 in continuous mode (V
and V

SHDN2

= V

, R

= |V

REV2

) place a resistor (>20kΩ) between

IN2

SHDN1

REV1

IN2

|

, and R

= |V

/ R

SHDN2

SHDN2

/ (R

IN1

|

. When operat-

SHDN1

. These

SHDN1

= V

IN1

shutdown and supply inputs to limit the current flow in
case the battery is reversed.

MAX8862

+

_______________________________________________________________________________________ 9

Low-Cost, Low-Dropout, Dual Linear Regulator

pins to ground using a large pad or ground plane.

100

80

60



(°C/W)

BA

40

MAX8862

R0

20

0

0

510152025

PC-BOARD COPPER FOIL AREA (Cm

MAX8862 FIG03

35

30

2

)

Figure 3. Typical Copper Thermal Resistance vs. Copper
Ground Pad Area

400
350
300

)

250

OUT2

200

+ I

150

OUT1

(I

100

50

MAXIMUM OUTPUT CURRENT (mA)

0

2

(R)

345

(T)



MAXIMUM CURRENT

(R)



(L)

MAXIMUM
SUPPLY
VOLTAGE

OPERATING REGION AT

= +25°C, TJ = +125°C

T

A

6

7

SUPPLY VOLTAGE (V)

8 9 10 11

MAX8862FGIG04

(L)

(T)

12

Figure 4. Safe Operating Regions: Main and Secondary
Regulators Maximum Output Current vs. Supply Voltage

__________Applications Information

Power Dissipation and Operating Region

The MAX8862’s maximum power dissipation 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 GND pins of the MAX8862 SO package perform
the dual function of providing an electrical connection
to ground and channeling heat away. Connect all GND

Where this is impossible, place a copper plane on an
adjacent layer. For a given power dissipation, the pad
should exceed the associated dimensions in Figure 3.
This figure shows a typical thermal resistance for a
35µm-thick copper foil as a function of its area

The power dissipation across the device is given by:

P = I

OUT1(VIN1

- V

OUT1

) + I

OUT2(VIN2

- V

The resulting power dissipation is as follows:

P = (TJ- TA) / (θJB+ θBA)

where (TJ- TA) is the temperature difference between
the MAX8862 die junction and the surrounding air, θ
(or θJC) is the thermal resistance of the package, and

θBAis the thermal resistance through the printed circuit

board, copper traces, and other materials to the sur­rounding air. The MAX8862’s narrow SO package has a
thermal resistance of θJB= +50°C/W.

The MAX8862 regulators deliver the rated output cur­rents and operate with input voltages up to 11.5V, but
not simultaneously. High output currents can only be
sustained when input-output differential voltages are
small, as shown in Figure 4.

Capacitor Selection and

Regulator Stability

Filter capacitors are required at the MAX8862’s inputs
and outputs. 1µF ceramic capacitors are required at
the inputs. The minimum output capacitance required
for stability is 3.3µF for OUT1 and 2.2µF for OUT2. The
capacitor values depend primarily on the desired
power-up time and load-transient response. Load­transient response is improved by using larger capaci­tor values. Input and output filter capacitors should be
soldered directly to pins to minimize lead inductance of
PC board traces.

The output capacitor’s equivalent series resistance
(ESR) affects stability and output noise. Surface-mount
ceramic capacitors have a very low ESR and are avail­able up to 10µF. Otherwise, other low-ESR (<0.5Ω)
capacitors should be used. If the selected capacitor’s
ESR is higher than the recommended value, the capac­itor value should be increased proportionally to main­tain minimum output noise under all input voltage and
output load conditions. Paralleling two or more capaci­tors also results in lower ESR.

1

.

OUT2

).

JB

1

This graph was generated by Mr. Kieran O’Malley of Cherry Semiconductor Corp. and was published in the October 26, 1995, issue

of EDN magazine.

10 ______________________________________________________________________________________

Low-Cost, Low-Dropout, Dual Linear Regulator

70

60

50

PSRR (dB)

40

30

20

0.01 1 100

A: I

OUT1

:

I

B

OUT1

C: I

OUT1

A
B
C

= 1mA
= 10mA

= 100mA

0.1
FREQUENCY (kHz)

OUT1
∆V
C

IN1

C

OUT1



IN1

= 1µF

10

= 1V
= 3.3µF



p-p

MAX8862FIG05A

70
65
60
55

50
45

PSRR (dB)

40
35
30
25
20

0.1

A: C

= 100µF

OUT1

B: C

= 10µF

OUT1



1 100

FREQUENCY (kHz)

OUT1



= 1V

IN1

OUT1

IN1

= 1µF

= 100mA



p-p

MAX8862FIG05B

1000

∆V
C
I

A

B





10

MAX8862

Figure 5a. Power-Supply Rejection Ratio vs. Ripple Frequency
for Light and Heavy Loads

Noise

The MAX8862’s OUT1 exhibits about 2.5mVp-p, and
OUT2 exhibits 1mVp-p of noise under full-load condi­tions. When using the MAX8862 for applications that
include analog-to-digital converters (ADCs) with resolu­tions greater than 12 bits, consider the ADC’s power­supply-rejection specifications.

PSRR and Operation

from Sources Other than Batteries

The MAX8862 is designed to achieve low dropout volt­ages and low quiescent currents in battery-powered
systems. However, to gain these benefits; the device
must trade away power-supply noise rejection, as well
as swift response to supply variations and load tran­sients. For a 1mA load current, power-supply rejection
typically changes from 58dB to 43dB when the input
frequency is changed from 1Hz to 10kHz. At higher fre­quencies, the circuit depends primarily on the output
capacitor’s characteristics, and the PSRR increases
(Figure 5).

When operating from sources other than batteries, sup­ply-noise rejection and transient response can be
improved by increasing the value of the input and out­put capacitors and employing passive filtering tech­niques. Do not use power supplies with ripple voltages
exceeding 200mV at 100kHz.

Figure 5b. Power-Supply Rejection Ratio vs. Ripple Frequency
for Various Output Capacitors

Overshoot and Transient Considerations

The

Typical Operating Characteristics

section shows
power-up, line, and load-transient response graphs.
Typical transients for step changes in the load current
from 0mA to 300mA are 100mVp-p. During recovery
from shutdown, overshoot is minimized by the 1µF
input, and output capacitors (3.3µF for OUT1, and

2.2µF for OUT2).

Input-Output (Dropout) Voltage

A regulator’s minimum input-to-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. Since
P-channel MOSFETs are used as pass transistors, the
dropout voltage is the product of the R
load current (see the

Electrical Characteristics

DS(ON)

and the

).

___________________Chip Information

TRANSISTOR COUNT: 457

______________________________________________________________________________________ 11

Low-Cost, Low-Dropout, Dual Linear Regulator

________________________________________________________Package Information

INCHES MILLIMETERS

DIM

D

MAX8862

e



A

A1

DIM

D
D
D

B
C
E
e
H
L

PINS



A

0.101mm

0.004in.

A1

B

C

0°-8°

L

Narrow SO

HE

SMALL-OUTLINE

PACKAGE

(0.150 in.)

MAX

MIN

0.069

0.053

0.010

0.004

0.019

0.014

0.010

0.007

0.157

0.150

0.228

0.016

8
14
16





0.244

0.050

INCHES MILLIMETERS

MIN

MAX

0.189

0.197

0.337

0.344

0.386

0.394

MIN

1.35

0.10

0.35

0.19

3.80


5.80

0.40

MIN

4.80

8.55

9.80

1.270.050

MAX

1.75

0.25

0.49

0.25

4.00


6.20

1.27

MAX

5.00

8.75

10.00

21-0041A

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are

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.

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

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 [phone]

12

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

12

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

12

__________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 [phone]

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

© 1996 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.