Maxim MAX742C-D, MAX742CPP, MAX742CWP, MAX742EPP, MAX742EWP Datasheet

_______________General Description

The MAX742 DC-DC converter is a controller for dual-out­put power supplies in the 3W to 60W range. Relying on
simple two-terminal inductors rather than transformers, the
MAX742 regulates both outputs independently to within
±4% over all conditions of line voltage, temperature, and
load current.

The MAX742 has high efficiency (up to 92%) over a wide
range of output loading. Two independent PWM current­mode feedback loops provide tight regulation and opera­tion free from subharmonic noise. The MAX742 can
operate at 100kHz or 200kHz, so it can be used with small
and lightweight external components. Also ripple and
noise are easy to filter. The MAX742 provides a regulated
output for inputs ranging from 4.2V to 10V (and higher with
additional components).

External power MOSFETs driven directly from the MAX742
are protected by cycle-by-cycle overcurrent sensing. The
MAX742 also features undervoltage lockout, thermal shut­down, and programmable soft-start.

If 3W of load power or less is needed, refer to the MAX743
data sheet for a device with internal power MOSFETs.

________________________Applications

DC-DC Converter Module Replacement
Distributed Power Systems
Computer Peripherals

____________________________Features

♦ Specs Guaranteed for In-Circuit Performance
♦ Load Currents to ±2A
♦ 4.2V to 10V Input-Voltage Range
♦ Switches From ±15V to ±12V Under Logic Control
♦ ±4% Output Tolerance Max Over Temp, Line,

and Load

♦ 90% Typ Efficiency
♦ Low-Noise, Current-Mode Feedback
♦ Cycle-by-Cycle Current Limiting
♦ Undervoltage Lockout and Soft-Start
♦ 100kHz or 200kHz Operation

MAX742

Switch-Mode Regulator with

+5V to ±12V or ±15V Dual Output

________________________________________________________________

Maxim Integrated Products

1

MAX742

P

R

+5V
INPUT

S

-SENSE

-DRIVE

PWM

N

R

S

+SENSE

+DRIVE

-VO

+VO

PWM

OSC

+2.0V
VREF

CC+

CC-

__________Simplified Block Diagram

20
19
18
17
16
15
14
13

1
2
3
4
5
6
7
8

CSH+
CSL+
GND
EXT+

AV

AGND

CC+

FB+

TOP VIEW

PUMP
PDRV
EXT­V+

SS

VREF

12/15

100/200

12
11

9

10

CSH­CSL-

FB-

CC-

DIP/SO

MAX742

__________________Pin Configuration

19-3105; Rev 2; 8/96

PART

MAX742CPP

MAX742CWP
MAX742C/D 0°C to +70°C

0°C to +70°C

0°C to +70°C

TEMP. RANGE PIN-PACKAGE

20 Plastic DIP
20 Wide SO
Dice*

EVALUATION KIT MANUAL

FOLLOWS DATA SHEET

MAX742EWP
MAX742MJP -55°C to +125°C

-40°C to +85°C 20 Wide SO
20 CERDIP

MAX742EPP -40°C to +85°C 20 Plastic DIP

______________Ordering Information

* Contact factory for dice specifications

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

MAX742

Switch-Mode Regulator with
+5V to ±12V or ±15V Dual Output

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 2, +4.5V < V+ < +5.5V.)

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.

V+, AV+ to AGND, GND.........................................-0.3V to +12V

PDRV to V+.............................................................+0.3V to -14V

FB+, FB- to GND..................................................................±25V

Input Voltage to GND

(CC+, CC-, CSH+, CSL+, CSH-, CSL-,
SS, 100/200

, 12/15)..................................-0.3V to (V+ + 0.3V)

Output Voltage to GND

(EXT+, PUMP) ..........................................-0.3V to (V+ + 0.3V)

EXT- to PDRV................................................-0.3V to (V+ + 0.3V)

Continuous Power Dissipation (any package)

up to +70°C.....................................................................500mW

derate above +70°C by ..........................................100mW/°C

Operating Temperature Ranges

MAX742C_ _ .......................................................0°C to +70°C

MAX742E_ _ ....................................................-40°C to +85°C

MAX742MJP ..................................................-55°C to +125°C

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

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

0mA < IL< 100mA,
12/15 = 0V

CONDITIONS

14.40 15.60

V

14.55 15.45

Output Voltage, ±15V Mode
(Notes 1, 2)

UNITSMIN TYP MAXSYMBOLPARAMETER

TA= +25°C
TA= T

MIN

to T

MAX

TA= +25°C
TA= T

MIN

to T

MAX

0mA < IL< 125mA,
12/15 = V+

11.52 12.48

V

11.64 12.36

Output Voltage, ±12V Mode
(Notes 1, 2)

No EXT- or PUMP load,
FB+ = FB- = open circuit

I

LOAD

= 0mA to 100mA

V+ = 4.5V to 5.5V, PDRV from PUMP

CSL+ = 0V, FB+ = open circuit

EXT+ or EXT-

100/200 = V+

100/200 = 0V

CSH- = V+, FB- = open circuit

CONDITIONS

mV150 225 300

Negative Current-Limit Threshold
(CSH- to CSL-)

mA

3

No-Load Supply Current

mV30 100

%/%0.01 0.05Line Regulation

Load Regulation (Note 2)

mV150 225 300

Positive Current-Limit Threshold
(CSH+ to CSL+)

%85 90Duty-Cycle Limit (Note 3)

kHzf

OSC

/2PUMP Frequency

kHz

75 100 125

V3.8 4.2UVLOUndervoltage Lockout
V0.2Undervoltage Lockout Hysteresis
V2.0Reference Output Voltage

170 200 230

f

OSC

Oscillator Frequency

UNITSMIN TYP MAXSYMBOLPARAMETER

V+ = 5V

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 2, V+ = 5V, 100/200 = 12/15 = 0V; TA= T

MIN

to T

MAX

, unless otherwise noted.)

10V+ = 10V

MAX742

Switch-Mode Regulator with

+5V to ±12V or ±15V Dual Output

_______________________________________________________________________________________ 3

Note 1: Devices are 100% tested to these limits under 0mA to 100mA and to 125mA conditions using automatic test equipment.

The ability to drive loads up to 1A is guaranteed by the current-limit threshold, output swing, and the output current
source/sink tests. See Figures 2 and 3.

Note 2: Actual load capability of the circuit of Figure 2 is ±200mA in ±15V mode and ±250mA in ±12V mode. Load regulation is

tested at lower limits due to test equipment limitations.

Note 3: Guaranteed by design.
Note 4: Measured at Point A, circuit of Figure 2, with PDRV disconnected.

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 2, V+ = 5V, 100/200 = 12/15 = 0V; TA= T

MIN

to T

MAX

, unless otherwise noted.)

EXT+, EXT-, IL= -1mA, V+ = 4.5V, PDRV= -3V

EXT+, EXT-, IL= 1mA, V+ = 4.5V, PDRV= -3V

V+ = 3.8V, SS = 2V

CC+, CC-

V+ = 4.5V, PDRV = -3V,
TA= +25°C

V+ = 4.5V, IL= -5mA, TA= +25°C

SS = 0V

CONDITIONS

mA-2 -0.5Soft-Start Sink Current

µA37Soft-Start Source Current

V-2.8V

OL

V4.3V

OH

Output Voltage High
Output Voltage Low

°C190Thermal-Shutdown Threshold

kΩ10Compensation Pin Impedance

mA

100 200

Output Sink Current

200 350

V-3PUMP Output Voltage (Note 4)

UNITSMIN TYP MAXSYMBOLPARAMETER

EXT+ = 4.5V
EXT- = 4.5V
EXT+ = 0V

V+ = 4.5V, PDRV = -3V,
TA= +25°C

EXT- = -3V

mA

-200 -100

Output Source Current

-350 -200

EXT+, C

LOAD

= 2nF

ns

70

Output Rise/Fall Time

100EXT-, C

LOAD

= 4nF, PDRV = -3V

MAX742

Switch-Mode Regulator with
+5V to ±12V or ±15V Dual Output

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(Circuit of Figure 2, V+ = 5V, TA = +25°C, unless otherwise noted.)

25



06



UNDERVOLTAGE LOCKOUT HYSTERESIS

5

10

20

MAX742 -1

SUPPLY VOLTAGE (V)

QUIESCENT SUPPLY CURRENT (mA)

15

4

23 51

±15V MODE,
200kHz MODE

LOCKOUT
ENABLED

-4.5



0



CHARGE-PUMP LOAD REGULATION

-2.5

-5.0

-3.0

-4.0

MAX742 -2

CHARGE-PUMP LOAD CURRENT (mA)

CHARGE-PUMP OUTPUT VOLTAGE (V)

-3.5

4

23 75 6 10 891

MEASURED AT POINT A

V+ = 5V

V+ = 4.5V

5



0



PDRV CURRENT vs. C

EXT-

1

6

2

4

MAX742 -3

CAPACITANCE AT EXT- (nF)

PDRV CURRENT (mA)

3

4

231

PDRV FORCED TO -4V
PUMP DISCONNECTED

200kHz

100kHz

50



0

EFFICIENCY vs. LOAD CURRENT,

22W CIRCUIT, ±15V MODE

60

70

90

MAX742 -4

LOAD CURRENT (mA)

EFFICIENCY (%)

80

±800

±400 ±600 ±1000±200

100kHz

200kHz

CIRCUIT OF FIGURE 3,
INDUCTORS = GOWANDA 121-AT2502
(MPP CORE),
Q2 = TWO IRF9Z30 IN PARALLEL
±15V MODE





0

PEAK INDUCTOR CURRENT vs.

LOAD CURRENT

100

200

400

MAX742 -7

LOAD CURRENT (mA)

PEAK INDUCTOR CURRENT (mA)

300

500

700
600

800

1000

900

1100



1200

200

100 15050

100kHz

200kHz

MEASURED AT LX-,
±15V MODE

50



0

EFFICIENCY vs. LOAD CURRENT,

6W CIRCUIT, ±15V MODE

60

70

90

MAX742 -5

LOAD CURRENT (mA)

EFFICIENCY (%)

80

±200

±100 ±150 ±250±50

100kHz

200kHz

INDUCTORS = GOWANDA 050-AT1003
(MPP CORE)

50



0

EFFICIENCY vs. LOAD CURRENT,

6W CIRCUIT, ±12V MODE

60

70

90

MAX742 -6

LOAD CURRENT (mA)

EFFICIENCY (%)

80

±300

±150 ±225±75

100kHz

200kHz

INDUCTORS = GOWANDA 050-AT1003
(MPP CORE)





0

CURRENT-LIMIT THRESHOLD vs.

SOFT-START VOLTAGE

50

100

200

MAX742 -8

SOFT-START VOLTAGE (V)

CURRENT-LIMIT THRESHOLD (mV)

150

3

12