Rainbow Electronics MAX8719 User Manual

General Description

The MAX8718/MAX8719 are micropower, 8-pin TDFN
linear regulators that supply always-on, keep-alive
power to CMOS RAM, real-time clocks (RTC), and
microcontrollers in systems with high-voltage batteries.
The circuits consist of a 100mA linear regulator and a
power-good comparator (PGOOD) with fixed-output
delay. Key features include wide input voltage range,
low-dropout voltage, and low-quiescent supply current.

Despite a miserly 25µA (max) no-load quiescent cur­rent, the MAX8718/MAX8719 have good line- and load­transient response and excellent AC power-supply
rejection. They provide a clean fixed 5V or 3.3V output
(MAX8718), or an adjustable 1.24V to 28V output
(MAX8719), even when subjected to fast supply-volt­age changes that occur during the switchover from bat­tery to AC-adapter input power. The space-saving
TDFN package has excellent thermal characteristics
and tolerates up to 1951mW of power dissipation.
Internal foldback current limiting and thermal shutdown
protect the regulator from overload and thermal faults.

In addition to the main notebook-computer application,
these devices are useful in other low-power, high-volt­age applications (4V < VIN< 28V) such as smart batter­ies, current control loops, telecom emergency power,
and housekeeping power for off-line supplies.

The MAX8718/MAX8719 are available in a thermally
enhanced 3mm x 3mm, 8-lead TDFN package.

Applications

CMOS/RTC Backup Power
Microcontroller Power
Notebook Computers
Smart-Battery Packs
PDAs and Handy-Terminals
Battery-Powered Systems

Features

♦ 4V to 28V Input Range
♦ 18µA Quiescent Supply Current
♦ <3µA Shutdown Supply Current
♦ 100mA Output Current
♦ 3.3V or 5V, Pin-Selectable Output (MAX8718)
♦ Adjustable 1.24V to 28V Output (MAX8719)
♦ ±2% Output Accuracy
♦ Thermal-Overload Protection
♦ Delayed Power-Good Output
♦ Thermally Enhanced 8-Pin TDFN Package

MAX8718/MAX8719

High-Voltage, Low-Power Linear Regulators for

Notebook Computers

________________________________________________________________ Maxim Integrated Products 1

TDFN

3mm × 3mm

TOP VIEW

1
2

8

7
3
4

6

5

SHDN
PGOOD

V

CC

OUT
I.C.

GND

5/3 (FB)

IN

MAX8718
MAX8719

() ARE FOR THE MAX8719.

Pin Configuration

Ordering Information

19-3495; Rev 0; 11/04

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

PART

TEMP RANGE

PIN-PACKAGE

OUTPUT

VOLTAGE

MAX8718ETA

8 TDFN 3mm x
3mm

3.3V/5V

MAX8719ETA

8 TDFN 3mm x
3mm

Adjustable

-40°C to +85°C

-40°C to +85°C

MAX8718/MAX8719

High-Voltage, Low-Power Linear Regulators for
Notebook Computers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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 to GND...............................................................-0.3V to +30V

SHDN to GND..............................................-0.3V to (V

IN

+ 0.3V)

5/3 (MAX8718) to GND.............................................-0.3V to +6V

FB (MAX8719) to GND.............................................-0.3V to +6V

OUT (MAX8718) to GND..........................................-0.3V to +6V

OUT (MAX8719) to GND........................................-0.3V to +30V

V

CC

to GND (MAX8718)...........................................-0.3V to +6V

V

CC

to GND (MAX8719)........................................-0.3V to +2.7V

PGOOD to GND .....................................................-0.3V to +30V

I.C. to GND...............................................................-0.3V to +6V

OUT Short Circuit to GND.......................................................30s

Continuous Power Dissipation (T

A

= +70°C)

8-Pin TDFN (derate 24.4mW/°C above +70°C) ..........1951mW

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

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1. VIN= 15V, I

OUT

= 5µA, TA= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

Input Voltage Range V

IN

428V

SHDN = IN, TA = +25°C1218µs

Supply Current (MAX8718) I

IN

SHDN = IN, VIN = 6V to 28V 25 µA
0V < VCC < 2.7V, TA = +25°C

VCC Input Current (MAX8719)

0V < V

CC

< 2.7V, TA = 0°C to +85°C

µA

0V < VCC < 5.5V, TA = +25°C 3.4

VCC Input Current (MAX8718)

0V < V

CC

< 5.5V, TA = 0°C to +85°C 2.3

µA

OUT Minimum Load Current 5µA
Shutdown Supply Current SHDN = 0V 1.2 3 µA
Dropout Supply Current V

OUT

set to 5V, VIN = 4.7V 85 µA

VIN = 6V to 28V, I

LOAD

= 1mA, 5/3 = GND,

T

A

= +25°C

VIN = 6V to 28V, I

LOAD

= 1mA, 5/3 = OUT,

T

A

= +25°C

VIN = 6V to 28V, I

LOAD

= 5µA to 100mA,

5/3 = GND

OUT Output Voltage (MAX8718)

V

IN

= 6V to 28V, I

LOAD

= 5µA to 100mA,

5/3 = OUT

V

FB = OUT, VIN = 6V to 28V, I

LOAD

= 1mA

FB Threshold (MAX8719) V

FB

FB = OUT, VIN = 6V to 28V,
I

LOAD

= 5µA to 100mA (Note 2)

V

VFB = 1.3V, TA = +25°C -30

FB Input Current (MAX8719) I

FB

VFB = 1.3V, TA = 0°C to +85°C15

nA

V

5/3

= 5V, TA = +25°C -30

5/3 Input Current (MAX8718) I

5/3

V

5/3

= 5V, TA = 0°C to +85°C2

nA

Dropout Voltage

I

LOAD

= 100mA (Note 3) 560 mV

-0.1 +0.1

0.04

V

DROPOUT

3.26 3.33 3.40

4.95 5.05 5.15

3.15 3.48

4.75 5.25

1.215 1.240 1.265

1.18 1.28
+30

+30

MAX8718/MAX8719

High-Voltage, Low-Power Linear Regulators for

Notebook Computers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1. VIN= 15V, I

OUT

= 5µA, TA= 0°C to +85°C. Typical values are at TA= +25°C, unless otherwise noted.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

V

IN

= 6V, TA = +25°C

Output Current Limit I

LIM

V

OUT

= 0, VIN = 6V

340

mA

Output Reverse Leakage Current

V

OUT

forced to 5.5V, IN = unconnected 70 µA

MAX8718

Capacitive Load Requirements

MAX8719

µF/mA

Startup Time Response

Rising edge of IN or SHDN to OUT within
spec limits, C

OUT

= 10µF, R

LOAD

= 500Ω,

V

OUT

= 5V

1ms

Startup Output Overshoot

C

OUT

= 10µF, R

LOAD

= 500Ω, OUT within

90% of the nominal output voltage

0.5 %

TA = +25°C, rising edge only

0.88 ×

0.9 ×

0.92 ×

VCC Threshold (MAX8718)

0°C < T

A

< +85°C, rising edge only

0.85 ×

0.9 ×

0.95 ×

V

TA = +25°C, rising edge only

0.88 ×

0.9 ×

0.92 ×
V

FB

VCC Threshold (MAX8719)

0°C < T

A

< +85°C, rising edge only

0.85 ×

0.9 ×

0.95 ×
V

FB

V

VCC to PGOOD Delay VTH to (VTH - 100mV) 4.5 µs
PGOOD Active-Timeout Period

300 ms

PGOOD Output Leakage Current

PGOOD = 5.5V, VCC = 5.5V 0.1 µA

PGOOD Output Low Voltage I

SINK

= 1.6mA, VCC = GND 0.3 V
VCC Input Hysteresis 2%
Thermal-Shutdown Threshold V

SHDN

= 0 or 15V, 20°C hysteresis

°C

SHDN Input Low Voltage

V

SHDN Input High Voltage 1.4 V
SHDN Input Bias Current V

SHDN

= 0 or 15V, TA = 0°C to +85°C-1

+1 µA

210

125

0.16

0.23

V

V

V

V

100 185

V

OUT

OUT

FB

FB

OUT

V

OUT

V

FB

V

FB

+165

+0.1

V

OUT

V

OUT

0.25