Maxim MAX761EPA, MAX761ESA, MAX761MJA, MAX762C-D, MAX761C-D Datasheet

...

19-0201; Rev 0; 11/93

Evaluation Kit

Available

12V/15V or Adjustable, High-Efficiency,

Low IQ, Step-Up DC-DC Converters

_______________General Description

The MAX761/MAX762 step-up switching regulators provide high efficiency over a wide range of load currents, delivering up to 150mA. A unique, current-limited pulse-frequency-modulated (PFM) control scheme gives the devices the benefits of pulse-width-modulated (PWM) converters (high efficiency with heavy loads), while using less than 110µA of supply current (vs. 2mA to 10mA for PWM converters). The result is high efficiency over a wide range of loads.

The MAX761/MAX762 input voltage range is 2V to 16.5V. Output voltages are preset to 12V (MAX761) and 15V (MAX762), or they can be set with two external resistors. With a 5V input, the MAX761 guarantees a 12V, 150mA output. Its high efficiency, low supply current, fast start-up time, SHDN controlling capability, and small size make the MAX761 ideal for powering flash memory.

The MAX761/MAX762 have an internal 1A power MOSFET, making them ideal for minimum-component, low- and medium-power applications. These devices use tiny external components, and their high switching frequencies (up to 300kHz) allow for small surface-mount magnetics.

For increased output drive capability or higher output voltages, use the MAX770–MAX773, which are similar in design to the MAX761/MAX762, but drive external power MOSFETs. For stepping up to 5V, see the MAX756/ MAX757 and MAX856-MAX859 data sheets.

_________________________Applications

Flash Memory Programming PCMCIA Cards Battery-Powered Applications High-Efficiency DC-DC Converters

____________________________Features

♦ High Efficiency for a Wide Range of Load Currents ♦ 12V/150mA Flash Memory Programming Supply ♦ 110µA Max Supply Current ♦ 5µA Max Shutdown Supply Current ♦ 2V to 16.5V Input Voltage Range ♦ 12V (MAX761), 15V (MAX762) or Adjustable Output ♦ Current-Limited PFM Control Scheme ♦ 300kHz Switching Frequency ♦ Internal, 1A, N-Channel Power FET ♦ LBI/LBO Low-Battery Comparator

______________Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX761CPA

MAX761CSA 0°C to +70°C 8 SO MAX761C/D 0°C to +70°C Dice* MAX761EPA -40°C to +85°C 8 Plastic DIP MAX761ESA -40°C to +85°C 8 SO MAX761MJA -55°C to +125°C 8 CERDIP** MAX762CPA MAX762CSA 0°C to +70°C 8 SO MAX762C/D 0°C to +70°C Dice* MAX762EPA -40°C to +85°C 8 Plastic DIP MAX762ESA -40°C to +85°C 8 SO MAX762MJA -55°C to +125°C 8 CERDIP**

* Contact factory for dice specifications. ** Contact factory for availability and processing to MIL-STD-883.

0°C to +70°C 8 Plastic DIP

MAX761/MAX762

__________Typical Operating Circuit

INPUT

4.75V

TO 12V

DETECTOR INPUT

ON/OFF

LOW-BATTERY

33µF

MAX761

SHDN

LBI

REF

GND

________________________________________________________________

LBO

18µH

OUTPUT

12V

V+

150mA

33µF

LOW-BATTERY DETECTOR OUTPUT

__________________Pin Configuration

TOP VIEW

LBO

1 2

LBI

MAX761 MAX762

SHDN

DIP/SO

Maxim Integrated Products

Call toll free 1-800-998-8800 for free samples or literature.

V+

GND

REF

12V/15V or Adjustable, High-Efficiency, Low IQ, Step-Up DC-DC Converters

ABSOLUTE MAXIMUM RATINGS

Supply Voltage V+ to GND.......................................-0.3V to 17V

REF, LBO, LBI, SHDN, FB............................-0.3V to (V+ + 0.3V)

LX..............................................................................-0.3V to 17V

LX Peak Current....................................................................1.5A

LBO Current..........................................................................5mA

Continuous Power Dissipation (T

Plastic DIP (derate 9.09mW/°C above +70°C) ............727mW

SO (derate 5.88mW/°C above +70°C).........................471mW

CERDIP (derate 8.00mW/°C above +70°C).................640mW

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

MAX761/MAX762

(V+ = 5V, I

Minimum Operating Voltage 1.7 V Minimum Start-Up Voltage 1.7 2.0 V

Supply Current

Shutdown Current 15µA

Output Voltage (Note 1)

Peak Current at LX I Maximum Switch-On Time t Minimum Switch-Off Time t Load Regulation 0.0042 %/mA Line Regulation 0.08 %/V

Efficiency 86 %

Reference Voltage V

= 0mA, C

LOAD

PARAMETER SYMBOL MIN TYP MAX

= +70°C)

= 0.1µF, TA= T

REF

OUT

PEAK

OFF

REF

to T

MIN

Figure 2, bootstrapped Figure 3 or 5 with

external resistors. Figure 2, bootstrapped

Figure 2, bootstrapped V+ = 16.5V, normal operation, SHDN = 0V,

non-bootstrapped Figure 2, MAX761, VIN= 5V, SHDN = 0V,

normal operation V+ = 10.0V, shutdown mode, SHDN = V+

Figure 2, MAX761, bootstrapped

Figure 2, MAX762, bootstrapped

See Figure 4b

Figure 2, 0mA ≤ I Figure 2, 4V ≤ VIN≤ 6V, bootstrapped

Figure 2, bootstrapped, V 60mA ≤ I

MAX76_C MAX76_E MAX76_M

typical values are at TA= +25°C, unless otherwise noted.)

MAX,

LOAD

Operating Temperature Ranges:

MAX76_C_A........................................................0°C to +70°C

MAX76_E_A.....................................................-40°C to +85°C

MAX76_MJA ..................................................-55°C to +125°C

Junction Temperatures:

MAX76_C_A/E_A..........................................................+150°C

MAX76_MJA.................................................................+175°C

Storage Temperature Range.............................-65°C to +160°C

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

CONDITIONS

2 16.5 MAX76_C/E MAX76_M

0mA ≤ I 3V ≤ V+ ≤ 12V

0mA ≤ I

4.75V ≤ V+ ≤ 12V 0mA ≤ I

3V ≤ V+ ≤ 15V 0mA ≤ I

4.75V ≤ V+ ≤ 15V

≤ 200mA, bootstrapped

LOAD

≤ 120mA

OUT

LOAD

= 12V,

≤ 75mA,

≤ 150mA,

≤ 50mA,

≤ 100mA,

3 16.5Supply Voltage V+

3.1 16.5

88 110

300

11.52 12.0 12.48

14.4 15.0 15.6

0.75 1.0 1.25 A 6810µs

1.0 1.3 1.6 µs

1.4700 1.50 1.5300

1.4625 1.50 1.5375

1.4550 1.50 1.5450

UNITS

µA

2 _______________________________________________________________________________________

12V/15V or Adjustable, High-Efficiency,

Low IQ, Step-Up DC-DC Converters

ELECTRICAL CHARACTERISTICS (continued)

(V+ = 5V, I

Reference Load Regulation Reference Line Regulation

LX Leakage Current

Voltage Trip Point

LX On Resistance SHDN Input High Voltage SHDN Input Low Voltage V SHDN Leakage Current -1 1 µA

LBI Threshold Voltage

LBI Hysteresis 20 mV LBI Leakage Current LBO Leakage Current -1 1 µA LBO Voltage V LBI to LBO Delay 2.5 µs

= 0mA, C

LOAD

PARAMETER

= 0.1µF, TA= T

REF

SYMBOL MIN TYP MAX

IH IL

to T

MIN

0µA ≤ I

3.0V ≤ V+ ≤ 16.5V

V+ = 16.5V, LX = 17V

MAX76_C MAX76_E MAX76_M MAX76_C MAX76_E MAX76_M V+ > 5.0V

2.0V ≤ V+ ≤ 16.5V

2.0V ≤ V+ ≤ 16.5V V+ = 16.5V, SHDN = 0V or V+

LBI falling

V+ = 16.5V, V V+ = 16.5V, V V+ = 5.0V, I Overdrive = 5mV

, typical values are at TA= +25°C, unless otherwise noted.)

MAX

CONDITIONS

≤ 100µA

LOAD

= 1.5V

LBI

= 16.5V

LBO

= 1mA

SINK

MAX76_C/E MAX76_M

MAX76_C MAX76_E MAX76_M

-5 5

-10 10

-30 30

-20 20

-40 40FB Leakage Current I

-60 60

1.4700 1.50 1.5300

1.4625 1.50 1.5375

1.4550 1.50 1.5450

1.6 V

1.4700 1.50 1.5300

1.4625 1.50 1.5375

1.4550 1.50 1.5450

-20 20 nA

10 15

30 100 µV/V

1.0 2.2

0.4 V

MAX761/MAX762

UNITS

µA

Ω

Note 1: See

to switching on and off times, on-resistance, and peak-current ratings.

Typical Operating Characteristics

_______________________________________________________________________________________ 3

for output current capability versus input voltage. Guarantees based on correlation

12V/15V or Adjustable, High-Efficiency, Low IQ, Step-Up DC-DC Converters

__________________________________________Typical Operating Characteristics

(Circuit of Figure 2, TA= +25°C, unless otherwise noted.)

EFFICIENCY vs. OUTPUT CURRENT

100

90 80 70 60 50 40

EFFICIENCY (%)

30 20

MAX761/MAX762

0.1 10 1000

400 350 300 250 200 150 100

MAXIMUM OUTPUT CURRENT (mA)

3.0 6.0

BOOTSTRAPPED

VIN = 10V

VIN = 5V

VIN = 2V

= 12V

OUT

1 100 OUTPUT CURRENT (mA)

MAXIMUM OUTPUT CURRENT vs. 

INPUT VOLTAGE

BOOTSTRAPPED

NON-BOOTSTRAPPED

= 12V

OUT

4.0

3.5 4.5 5.5 SUPPLY VOLTAGE (V)

5.0

NO-LOAD START-UP VOLTAGE

3.5

3.0

2.5

NON-BOOTSTRAPPED

(EXTERNAL RESISTORS)

2.0

1.5

BOOTSTRAPPED

1.0

(INTERNAL RESISTORS)

NO-LOAD START-UP VOLTAGE (V)

0.5

-60 -20 60 140

-40 0 8040 120

20 100

TEMPERATURE (°C)

= 12V

OUT

BOOTSTRAPPED

(EXTERNAL RESISTORS)

EFFICIENCY vs. OUTPUT CURRENT

100

MAX761-01

80 70 60 50 40

EFFICIENCY (%)

30 20 10

250

MAX761-04

200

150

100

REFERENCE OUTPUT RESISTANCE (Ω)

2.2

MAX761-07

2.1

2.0

1.9

1.8

1.7

1.6

START-UP VOLTAGE (V)

1.5

1.4

1.3

NON-BOOTSTRAPPED

VIN = 10V

0.1 10 1000

1 100 OUTPUT CURRENT (mA)

REFERENCE OUTPUT RESISTANCE vs.

TEMPERATURE

-60 -20 60 140

-40 0 8040 120

0.1 10 1000

20 100

TEMPERATURE (°C)

MAX761

START-UP VOLTAGE vs. R

1 100

LOAD

VIN = 5V

= 12V

OUT

10µA

50µA

LOAD

= 12V

OUT

BOOTSTRAPPED INTERNAL RESISTORS

(kΩ)

100µA

2.00

MAX761-02

1.75

1.50

1.25

1.00

0.75

0.50

QUIESCENT CURRENT (mA)

0.25 0

01 3 6

1.506

MAX761-05

1.504

1.502

1.500

1.498

1.496

REFERENCE OUTPUT (V)

1.494

1.492

-60 -20 60 140

1.6

MAX761-08

1.4

1.2

1.0

0.8

LX ON-RESISTANCE (Ω)

0.6

0.4

-60 -20 60 140

QUIESCENT CURRENT vs. 

INPUT VOLTAGE

= 12V

BOOTSTRAPPED

(INTERNAL RESISTORS)

0.5 1.5 3.52.5 4.5 5.5 INPUT VOLTAGE (V)

REFERENCE vs.TEMPERATURE

COEFFICIENT

20 100-40 0 8040 120

TEMPERATURE (°C)

LX ON-RESISTANCE vs.

TEMPERATURE

V+ = 5V

V+ = 12V

-40 0 8040 120

20 100

TEMPERATURE (°C)

OUT

BOOTSTRAPPED

(EXTERNAL RESISTORS)

NON-BOOTSTRAPPED

MAX761-03

MAX761-06

MAX761-09

4 _______________________________________________________________________________________

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