Rainbow Electronics MAX652 User Manual

_______________General Description

The MAX649/MAX651/MAX652 BiCMOS, step-down DC­DC switching controllers provide high efficiency over
three decades of load current. A unique, current-limited
pulse-frequency-modulated (PFM) control scheme gives
these devices the benefits of pulse-width-modulation
(PWM) converters (high efficiency at heavy loads), while
using only 100µA of supply current (vs. 2mA to 10mA for
PWM converters). The result is high efficiency over loads
ranging from 10mA to more than 2.5A.

These devices use miniature external components.
Their high switching frequency (up to 300kHz) allows
for less than 9mm diameter surface-mount inductors.

The MAX649/MAX651/MAX652 have dropout voltages
less than 1V and accept input voltages up to 16.5V.
Output voltages are preset at 5V (MAX649), 3.3V
(MAX651), and 3V (MAX652). These controllers can
also be adjusted to any voltage from 1.5V to the input
voltage by using two resistors.

These step-down controllers drive external P-channel
MOSFETs at loads greater than 10W. If less power is
required, use the MAX639/MAX640/MAX653 step-down
converters with on-chip FETs, which allow up to a
225mA load current.

________________________Applications

5V-to-3.3V Green PC Applications
High-Efficiency Step-Down Regulation
Minimum-Component DC-DC Converters
Battery-Powered Applications

____________________________Features

♦ More than 90% Efficiency (10mA to 1.5A Loads)
♦ More than 12.5W Output Power
♦ 100µA Max Quiescent Supply Current
♦ 5µA Max Shutdown Supply Current
♦ Less than 1.0V Dropout Voltage
♦ 16.5V Max Input Voltage
♦ 5V (MAX649), 3.3V (MAX651), 3V (MAX652),

or Adjustable Output Voltage

♦ Current-Limited Control Scheme
♦ Up to 300kHz Switching Frequency

______________Ordering Information

Ordering Information continued at end of data sheet.

* Dice are tested at T

A

= +25°C.

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

MAX649/MAX651/MAX652

5V/3.3V/3V or Adjustable, High-Efficiency,

Low IQ, Step-Down DC-DC Controllers

________________________________________________________________

Maxim Integrated Products

1

1
2
3
4

8
7
6
5

GND
EXT
CS
V+

REF

SHDN

FB

OUT

DIP/SO

TOP VIEW

MAX649
MAX651
MAX652

__________________Pin Configuration

__________Typical Operating Circuit

19-0225; Rev 3; 9/97

PART TEMP. RANGE PIN-PACKAGE

MAX649CPA

0°C to +70°C 8 Plastic DIP
MAX649CSA 0°C to +70°C 8 SO
MAX649C/D 0°C to +70°C Dice*
MAX649EPA -40°C to +85°C 8 Plastic DIP
MAX649ESA -40°C to +85°C 8 SO
MAX649MJA -55°C to +125°C 8 CERDIP**

MAX651

V+

CSSHDN

FB GND

ON/OFF

P

EXT

REF

OUT

OUTPUT

3.3V

INPUT

4V TO 16.5V

EVALUATION KIT

AVAILABLE

For free samples & the latest literature: http://www.maxim-ic.com, or phone [phone].
For small orders, phone [phone].

MAX649/MAX651/MAX652

5V/3.3V/3V or Adjustable, High-Efficiency,
Low IQ, Step-Down DC-DC Controllers

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V+ = 5V, TA= T

MIN

to T

MAX

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

PARAMETER SYMBOL MIN TYP MAX UNITS

1.455 1.5 1.545

1.4625 1.5 1.5375FB Trip Point

1.470 1.5 1.530
V

I

Q

25

FB Input Current I

FB

±50

nA

±70
±90

Output Voltage V

OUT

4.80 5.0 5.20
V

Supply Current

V+ Input Voltage Range V+ 4.0 16.5 V

80 100

µA

4

3.17 3.3 3.43

2.88 3.0 3.12

Reference Voltage V

REF

1.470 1.5 1.530
V

1.4625 1.5 1.5375

1.455 1.5 1.545

REF Load Regulation

410

mV

415

CONDITIONS

MAX649M, MAX65_M

Circuit of
Figure 1

MAX649E, MAX65_E

MAX649C, MAX65_C

V+ = 10V, SHDN ≥ 1.6V (shutdown)

MAX649C, MAX65_C
MAX649E, MAX65_E

MAX649C, MAX65_C, I

REF

= 0

MAX649E, MAX65_E, I

REF

= 0

MAX649M, MAX65_M

MAX649M, MAX65_M, I

REF

= 0

V+ = 16.5V, SHDN ≤ 0.4V (operating, switch off)
V+ = 16.5V, SHDN ≥ 1.6V (shutdown)

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

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

Continuous Power Dissipation (T

A

= +70°C)

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

Operating Temperature Ranges

MAX649C_A, MAX65_C_A ..................................0°C to +70°C

MAX649E_A, MAX65_E_A................................-40°C to +85°C

MAX649MJA, MAX65_MJA ............................-55°C to +125°C

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

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

MAX649, V+ = 6V to 16.5V
MAX651, V+ = 4V to 16.5V
MAX652, V+ = 4V to 16.5V

MAX649C/E, MAX65_C/E
MAX649M, MAX65_M

0 ≤ I

REF

≤ 100µA,

sourcing only
4V ≤ V+ ≤ 16.5VREF Line Regulation 40 100 µV/V

2.6

mV/V

1.7

1.9

Output Voltage
Line Regulation

Circuit of
Figure 1

MAX649, 6V ≤ V+ ≤ 16V,
I

LOAD

= 1A

MAX651, 4.5V ≤ V+ ≤ 16V,
I

LOAD

= 1A

MAX652, 4V ≤ V+ ≤ 16V,
I

LOAD

= 1A

MAX649/MAX651/MAX652

5V/3.3V/3V or Adjustable, High-Efficiency,

Low IQ, Step-Down DC-DC Controllers

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(V+ = 5V, TA= T

MIN

to T

MAX

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

PARAMETER

SYMBOL MIN TYP MAX

-45

UNITS

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

-45

SHDN Input Current 1 µA

Output Voltage
Load Regulation

-47

mV/A

CONDITIONS

Circuit of
Figure 1

MAX649, 0 ≤ I

LOAD

≤ 1.5A,

VIN= 10V
MAX651, 0 ≤ I

LOAD

≤ 1.5A,

VIN= 5V
MAX652, 0 ≤ I

LOAD

≤ 1.5A,

VIN= 5V
MAX649, V+ = 10V,

I

LOAD

= 1A

MAX651, V+ = 5V,
I

LOAD

= 1A

89

MAX652, V+ = 5V,
I

LOAD

= 1A

88

Efficiency

92

%

Circuit of
Figure 1

4V ≤ V+ ≤ 16.5VSHDN Input Voltage High 1.6 VV

IH

4V ≤ V+ ≤ 16.5V 0.4 VV

IL

SHDN Input Voltage Low

4V ≤ V+ ≤ 16.5VCS Input Current ±1 µA
V+ = 12V 12 16 20 µs

t

ON

(max)

Switch Maximum
On-Time

C

EXT

= 0.001µF, V+ = 12VEXT Rise Time 50 ns

C

EXT

= 0.001µF, V+ = 12VEXT Fall Time 50 ns

V+ = 12V

Switch Minimum
Off-Time

1.8 2.3 2.8 µs

t

OFF

(min)

MAX649C/E, MAX65_C/E

Current-Limit Trip
Level (V+ to CS)

180 210 240

mVV

CS

MAX649M, MAX65_M 160 210 260

4V ≤ V+ ≤ 16.5V

MAX649/MAX651/MAX652

5V/3.3V/3V or Adjustable, High-Efficiency,
Low IQ, Step-Down DC-DC Controllers

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

80

66

SUPPLY CURRENT vs. TEMPERATURE

68

78

I+ (mA)

76

74

-60 -20 60 140

MAX649-A01

TEMPERATURE (°C)

20 100-40 0 8040 120

72

70

V+ = 10V

V+ = 16.5V

V+ = 4V

4.0

0

SHUTDOWN CURRENT

vs. TEMPERATURE

0.5

3.5

I+ (mA)

3.0

2.5

-60 -20 60 140

MAX649-A02

TEMPERATURE (°C)

20 100-40 0 8040 120

2.0

1.5
V+ = 8V

V+ = 16.5V

V+ = 4V

1.0

2500

0

0 1 2 3 4 5 6 7 8 9 10 1112131415

MAX649 MAXIMUM LOAD CURRENT

vs. SUPPLY VOLTAGE

500

2000

MAX649-A03

INPUT VOLTAGE (V)

MAXIMUM LOAD CURRENT (mA)

1500

1000

V

OUT

= 5V

CIRCUIT OF FIGURE 1

100

90

0

100µ 1m 10m 100m 1

MAX649

EFFICIENCY vs. LOAD CURRENT

20

MAX649-A04

LOAD CURRENT (A)

EFFICIENCY (%)

40

60

80
70

50

30

10

VIN = 6V
V

IN

= 8V

V

IN

= 10V

V

IN

= 12V

V

IN

= 15V

V

OUT

= 5V

TOP TO BOTTOM:

17

15

SWITCH ON-TIME

vs. TEMPERATURE

t

ON

(ms)

-60 -40 -20 60

MAX649-A07

TEMPERATURE (°C)

0 20 40 80 100 120

16

V+ = 5V

100

90

0

100µ 1m 10m 100m 1

MAX651

EFFICIENCY vs. LOAD CURRENT

20

MAX649-A05

LOAD CURRENT (A)

EFFICIENCY (%)

40

60

80
70

50

30

10

VIN = 4.3V
V

IN

= 5V

V

IN

= 8V

V

IN

= 10V

V

IN

= 12V

V

IN

= 15V

V

OUT

= 3.3V

TOP TO BOTTOM:

100

90

0

100µ 1m 10m 100m 1

MAX652

EFFICIENCY vs. LOAD CURRENT

20

MAX649-A06

LOAD CURRENT (A)

EFFICIENCY (%)

40

60

80
70

50

30

10

VIN = 4.3V
V

IN

= 5V

V

IN

= 8V

V

IN

= 10V

V

IN

= 12V

V

IN

= 15V

V

OUT

= 3V

TOP TO BOTTOM:

2.5

1.5

SWITCH OFF-TIME
vs. TEMPERATURE

t

OFF

(ms)

MAX649-A08

TEMPERATURE (°C)

2.0

V+ = 5V

-60 -40 -20 600 20 40 80 100 120

8.0

6.0

SWITCH ON-TIME/OFF-TIME RATIO

vs. TEMPERATURE

6.4

7.6

t

ON

/tOFF RATIO

7.2

6.8

6.2

6.6

7.8

7.4

7.0

V+ = 5V

-60 -20 60 140

MAX649-A9

TEMPERATURE (°C)

20 100-40 0 8040 120

MAX649/MAX651/MAX652

5V/3.3V/3V or Adjustable, High-Efficiency,

Low IQ, Step-Down DC-DC Controllers

_______________________________________________________________________________________

5

130

20

EXT RISE AND FALL TIMES

vs. TEMPERATURE (1nF)

120

t

RISE

&

t

FALL

(ns)

110

90

-60 -20 60 140

MAX649-A10

TEMPERATURE (°C)

20 100-40 0 8040 120

V+ = 5V, t

RISE

100

80
70
60

40

50

30

V+ = 5V, t

FALL

V+ = 12V, t

RISE

V+ = 12V, t

FALL

C

EXT

= 1nF

500

50

EXT RISE AND FALL TIMES

vs. TEMPERATURE (5nF)

450

t

RISE

&

t

FALL

(ns)

400
350

-60 -20 60 140

MAX649-A11

TEMPERATURE (°C)

20 100-40 0 8040 120

V+ = 5V, t

RISE

300
250

150

200

100

V+ = 5V, t

FALL

V+ = 12V, t

RISE

C

EXT

= 5nF

V+ = 12V, t

FALL

1000

0

0 0.2 0.4 0.6 0.8 1.0

1.2

1.4 1.6

DROPOUT VOLTAGE
vs. LOAD CURRENT

200

300

100

800

900

MAX649-A12

LOAD CURRENT (A)

DROPOUT VOLTAGE (mV)

600
500

700

400

MAX649, V

OUT

= 5V

MAX652, V

OUT

= 3V

MAX651, V

OUT

= 3.3V

1100

600

DROPOUT VOLTAGE
vs. TEMPERATURE

700

1000

DROPOUT VOLTAGE (mV)

900

800

MAX651

-60 -20 60 140

MAX649-A13

TEMPERATURE (°C)

20 100-40 0 8040 120

I

LOAD

= 1A

CIRCUIT OF FIGURE 1

MAX649

MAX652

250

0

REFERENCE OUTPUT RESISTANCE

vs. TEMPERATURE

50

200

REFRENCE OUTPUT RESISTANCE (Ω)

150

100

-60 -20 60 140

MAX649-A16

TEMPERATURE (°C)

20 100-40 0 8040 120

I

REF

= 10µA

I

REF

= 50µA

I

REF

= 100µA

235

185

CS TRIP LEVEL

vs. TEMPERATURE

195

225

CS TRIP LEVEL (mV)

215

205

-60 -20 60 140

MAX649-A14

TEMPERATURE (°C)

20 100-40 0 8040 120

190

200

230

220

210

1.506

1.492

REFERENCE OUTPUT VOLTAGE

vs. TEMPERATURE

1.494

1.504

REFRENCE OUTPUT (V)

1.502

1.500

-60 -20 60 140

MAX649-A15

TEMPERATURE (°C)

20 100-40 0 8040 120

1.498

1.496

____________________________Typical Operating Characteristics (continued)

(TA = +25°C, unless otherwise noted.)