Maxim MAX1771EPA, MAX1771CPA, MAX1771C-D, MAX1771MJA, MAX1771ESA Datasheet

19-0263; Rev 1; 7/95

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

12V or Adjustable, High-Efficiency,

Low IQ, Step-Up DC-DC Controller

_______________General Description

The MAX1771 step-up switching controller provides
90% efficiency over a 30mA to 2A load. A unique cur­rent-limited pulse-frequency-modulation (PFM) control
scheme gives this device the benefits of pulse-width­modulation (PWM) converters (high efficiency at heavy
loads), while using less than 110µA of supply current (vs.
2mA to 10mA for PWM converters).

This controller uses miniature external components. Its
high switching frequency (up to 300kHz) allows sur­face-mount magnetics of 5mm height and 9mm diame­ter. It accepts input voltages from 2V to 16.5V. The
output voltage is preset at 12V, or can be adjusted
using two resistors.

The MAX1771 optimizes efficiency at low input voltages
and reduces noise by using a single 100mV current-limit
threshold under all load conditions. A family of similar
devices, the MAX770–MAX773, trades some full-load
efficiency for greater current-limit accuracy; they provide
a 200mV current limit at full load, and switch to 100mV
for light loads.

The MAX1771 drives an external N-channel MOSFET
switch, allowing it to power loads up to 24W. If less power
is required, use the MAX756/MAX757 or MAX761/MAX762
step-up switching regulators with on-board MOSFETs.

An evaluation kit is available. Order the MAX1771EVKIT-SO.

________________________Applications

Positive LCD-Bias Generators
Flash Memory Programmers
High-Power RF Power-Amplifier Supply
Palmtops/Hand-Held Terminals
Battery-Powered Applications
Portable Communicators

____________________________Features

♦ 90% Efficiency for 30mA to 2A Load Currents
♦ Up to 24W Output Power
♦ 110µA Max Supply Current
♦ 5µA Max Shutdown Current
♦ 2V to 16.5V Input Range
♦ Preset 12V or Adjustable Output Voltage
♦ Current-Limited PFM Control Scheme
♦ Up to 300kHz Switching Frequency
♦ Evaluation Kit Available

______________Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX1771CPA 0°C to +70°C 8 Plastic DIP
MAX1771CSA 0°C to +70°C 8 SO
MAX1771C/D 0°C to +70°C Dice*
MAX1771EPA -40°C to +85°C 8 Plastic DIP
MAX1771ESA -40°C to +85°C 8 SO
MAX1771MJA -55°C to +125°C 8 CERDIP**

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

__________________Pin Configuration

MAX1771

__________Typical Operating Circuit

TOP VIEW

INPUT 

2V TO V

OUT

ON/OFF

OUTPUT

SHDN

REF

FB AGND GND

________________________________________________________________

CS

V+

N

EXT

MAX1771

12V

EXT

SHDN

1
2

V+

MAX1771

3

FB

4

DIP/SO

Maxim Integrated Products

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

8

CS

7

GND

6

AGND

5

REF

1

12V or Adjustable, High-Efficiency,
Low IQ, Step-Up DC-DC Controller

ABSOLUTE MAXIMUM RATINGS

Supply Voltage

V+ to GND ...............................................................-0.3V, 17V

EXT, CS, REF, SHDN, FB to GND ...................-0.3V, (V+ + 0.3V)

GND to AGND.............................................................0.1V, -0.1V

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

= +70°C)

A

MAX1771

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+ = 5V, I

Input Voltage Range V

Minimum Start-Up Voltage 1.8 2.0 V
Supply Current 85 110

Standby Current

Output Voltage (Note 1) V

Output Voltage Line Regulation
(Note 2)

Output Voltage Load Regulation
(Note 2)

Maximum Switch On-Time tON(max) 12 16 20
Minimum Switch Off-Time t

Efficiency 92

Reference Voltage V

REF Load Regulation 0µA ≤ I

FB Trip Point Voltage V

= 0mA, TA= T

LOAD

PARAMETER

to T

MIN

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

MAX

SYMBOL CONDITIONS MIN TYP MAX UNITS

MAX1771 (internal feedback resistors) 2.0 12.5
MAX1771C/E (external resistors) 3.0 16.5
MAX1771MJA (external resistors) 3.1 16.5

V+ = 16.5V, SHDN = 0V (normal operation)
V+ = 10.0V, SHDN ≥ 1.6V (shutdown)
V+ = 16.5V, SHDN ≥ 1.6V (shutdown)

V+ = 2.0V to 12.0V, over full load range,
Circuit of Figure 2a

V+ = 5V to 7V, V
I

= 700mA, Circuit of Figure 2a

LOAD

V+ = 6V, V
500mA, Circuit of Figure 2a

(min) 1.8 2.3 2.8

OFF

V+ = 5V, V
Circuit of Figure 2a

I

0µA

REF

FB

REF =

REF

3V ≤ V+ ≤ 16.5V 40 100
MAX1771C 1.4700 1.5 1.5300
MAX1771E 1.4625 1.5 1.5375
MAX1771M 1.4550 1.5 1.5450

Operating Temperature Ranges

MAX1771C_A .....................................................0°C to +70°C

MAX1771E_A ..................................................-40°C to +85°C

MAX1771MJA................................................-55°C to +125°C

Junction Temperatures

MAX1771C_A/E_A.......................................................+150°C

MAX1771MJA ..............................................................+175°C

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

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

25
4

11.52 12.0 12.48

= 12V

= 12V, I

OUT

= 12V, I

OUT

≤ 100µA

OUT

= 0mA to

LOAD

= 500mA,

LOAD

MAX1771C 1.4700 1.5 1.5300
MAX1771E 1.4625 1.5 1.5375
MAX1771M 1.4550 1.5 1.5450
MAX1771C/E 410
MAX1771M 415

5 mV/V

20 mV/A

µA
µA

µs
µs

%

V

mV

µV/VREF Line Regulation

V

_______________________________________________________________________________________

2

12V or Adjustable, High-Efficiency,

Low IQ, Step-Up DC-DC Controller

ELECTRICAL CHARACTERISTICS (continued)

(V+ = 5V, I

FB Input Current I

SHDN Input High Voltage V
SHDN Input Low Voltage V
SHDN Input Current ±1

Current-Limit Trip Level V

CS Input Current 0.01 ±1
EXT Rise Time V+ = 5V, 1nF from EXT to ground 55 ns
EXT Fall Time V+ = 5V, 1nF from EXT to ground 55 ns

Note 1: Output voltage guaranteed using preset voltages. See Figures 4a–4d for output current capability versus input voltage.
Note 2: Output voltage line and load regulation depend on external circuit components.

= 0mA, TA= T

LOAD

PARAMETERS

to T

MIN

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

MAX

SYMBOL CONDITIONS

MAX1771C ±20

FB

MAX1771M ±60
V+ = 2.0V to 16.5V 1.6 V

IH

V+ = 2.0V to 16.5V 0.4 V

IL

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

V+ = 5V to 16V

CS

MAX1771C/E
MAX1771M

MIN TYP MAX

85 100 115
75 100 125

UNITS

nAMAX1771E ±40

µA

mV

µA

__________________________________________Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

EFFICIENCY vs. LOAD CURRENT

100

95
90

85
80

75

EFFICIENCY (%)

70
65

60

(BOOTSTRAPED MODE)

VIN = 10V

VIN = 5V

1



10

LOAD CURRENT (mA)

100



VIN = 3V

VIN = 8V

V

= 12V

OUT

CIRCUIT OF
FIGURE 2a

1000

10,000

MAX1771–01

EFFICIENCY vs. LOAD CURRENT

(NON-BOOTSTRAPED MODE)

100

95

VIN =10V

90

85
80

VIN = 5V

75

EFFICIENCY (%)

70
65

60

1



10



100

LOAD CURRENT (mA)

VIN = 8V

V

= 12V

OUT

CIRCUIT OF
FIGURE 2b

1000

10,000

700

600

MAX1771–02

500

400

300

LOAD CURRENT (mA)

200

100

0

LOAD CURRENT vs.

MINIMUM START-UP INPUT VOLTAGE

= 12V, CIRCUIT OF FIGURE 2a

V

OUT

EXTERNAL FET THRESHOLD
LIMITS FULL-LOAD START-UP
BELOW 3.5V

2.00

2.25 2.50 2.75 3.00 3.25 3.50

MINIMUM START-UP INPUT VOLTAGE (V)

MAX1771

MAX1771-TOC3

_______________________________________________________________________________________

3

12V or Adjustable, High-Efficiency,
Low IQ, Step-Up DC-DC Controller

____________________________Typical Operating Characteristics (continued)

(TA = +25°C, unless otherwise noted.)

SUPPLY CURRENT vs. TEMPERATURE

4

V

= 12V, VIN = 5V

OUT

CIRCUIT OF FIGURE 2a
BOOTSTRAPPED MODE

MAX1771

3

2

SUPPLY CURRENT (mA)

250

200

150

100

50

REFERENCE OUTPUT RESISTANCE (Ω)

SCHOTTKY DIODE

1

LEAKAGE EXCLUDED

0

-50 -25 0

-75

0

-60 -20 60 140

TEMPERATURE (°C)

REFERENCE OUTPUT RESISTANCE vs.

TEMPERATURE

-40 0 8040 120
TEMPERATURE (°C)



ENTIRE
CIRCUIT

25 50 75 100 125

10µA

50µA

20 100

100µA

0.8

MAX1771-04

0.6

0.4

SUPPLY CURRENT (mA)

0.2

0

1.506

1.504

MAX1771-07

1.502

1.500

1.498

REFERENCE (V)

1.496

1.494

1.492

SUPPLY CURRENT vs. SUPPLY VOLTAGE



V

= 12V

OUT

BOOTSTRAPPED
CIRCUIT OF
FIGURE 2a

NON-BOOTSTRAPPED



CIRCUIT OF FIGURE 2b

12

2

68

4

SUPPLY VOLTAGE (V)

REFERENCE vs. TEMPERATURE

-60 -20 60 140

20 100-40 0 8040 120

TEMPERATURE (°C)

10



EXT RISE/FALL TIME vs. SUPPLY VOLTAGE

250

MAX1771-05

200

150

100

EXT RISE/FALL TIME (ns)

50

MAX1771-08

0

2

MAXIMUM SWITCH ON-TIME vs.

16.5



16.0



ON(MAX) (µs)

t



15.5

-60

68

4

SUPPLY VOLTAGE (V)

TEMPERATURE

-30 0 30 60
TEMPERATURE (°C)

C

EXT

C

EXT

C

EXT

C

EXT



= 2200pF



= 1000pF



= 446pF



= 100pF



90

10

120 150

MAX1771-06

12

MAX1771-09

SHUTDOWN CURRENT vs. TEMPERATURE

4.0

3.5

3.0

2.5

2.0

1.5

1.0

SHUTDOWN CURRENT (µA)

0.5
0

-60 -20 60 140

_______________________________________________________________________________________

4

V+ = 8V

V+ = 4V

TEMPERATURE (°C)

V+ = 15V

20 100-40 0 8040 120

MAX1771-10

MINIMUM SWITCH OFF-TIME vs.

2.30



2.25

OFF(MIN) (µs)

t



2.20

-60

TEMPERATURE

-30 0 30 60
TEMPERATURE (°C)

MAX1771-11



t



t

120 150

90

MAXIMUM SWITCH ON-TIME/

MINIMUM SWITCH OFF-TIME RATIO

8.0





7.5

7.0

OFF(MIN) RATIO



6.5

ON(MAX)/

6.0

-30 0 30 60

-60

vs. TEMPERATURE



TEMPERATURE (°C)

90

MAX1771-12

120 150

12V or Adjustable, High-Efficiency,

Low IQ, Step-Up DC-DC Controller

____________________________Typical Operating Characteristics (continued)

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

HEAVY-LOAD SWITCHING WAVEFORMS

A



B

C

= 5V, I

= 900mA, V

V

IN

OUT

A: EXT VOLTAGE, 10V/div
B: INDUCTOR CURRENT, 1A/div

RIPPLE, 50mV/div, AC-COUPLED

C: V

OUT

OUT

2µs/div

= 12V

LINE-TRANSIENT RESPONSE

A



V

OUT

0V
I

LIM

0A

7V



5V

MEDIUM-LOAD SWITCHING WAVEFORMS

A



B

C

= 5V, I

= 500mA, V

V

IN

OUT

A: EXT VOLTAGE, 10V/div
B: INDUCTOR CURRENT, 1A/div

RIPPLE, 50mV/div, AC-COUPLED

C: V

OUT

OUT

10µs/div

= 12V

LOAD-TRANSIENT RESPONSE



A

V

OUT

0V
I

LIM

0A


500mA


0A

MAX1771

B

= 700mA, V

I

OUT

, 5V to 7V, 2V/div

A: V

IN

RIPPLE, 100mV/div, AC-COUPLED

B: V

OUT

_______________________________________________________________________________________

0V

B

5ms/div

= 12V

OUT

= 6V, V

V

IN

OUT

A: LOAD CURRENT, 0mA to 500mA, 500mA/div

RIPPLE, 100mV/div, AC-COUPLED

B: V

OUT

5ms/div

= 12V

5