Rainbow Electronics MAX5097 User Manual

General Description

The MAX5096/MAX5097 easy-to-use, Dual Mode™,
DC-DC converters operate as LDO (low dropout) or
switch-mode buck converters. At a high output load,
the converters operate as high-efficiency pulse-width­modulated (PWM) switch-mode converters and reduce
the power dissipation. The devices switch to a low-qui­escent-current (IQ) LDO mode of operation at light load.
During the key-off condition, the system’s microcon­troller drives the LDO/BUCK input on the fly and forces
the MAX5096/MAX5097 into LDO Mode, thereby reduc­ing the quiescent current significantly.

In Buck Mode, the MAX5096/MAX5097 operate from a 5V
to 40V input voltage range and deliver up to 600mA of
load current with excellent load and line regulation. The
fixed-switching frequency versions of 135kHz and
330kHz are available. The MAX5096/MAX5097 DC-DC
internal oscillator can be synchronized to an external
clock. External compensation and a current-mode control
scheme make it easy to design with.

In LDO Mode, the MAX5096/MAX5097 operate from a
4V to 40V input voltage. The LDO Mode operation is
intended for a lower output load current of up to
100mA. The quiescent current at 100µA load in LDO
Mode is only 41µA (typ).

The MAX5096/MAX5097 feature an enable input that
shuts down the device, reducing the current consump­tion to 6µA (typ). Additional features include a power-on
reset output with a capacitor-adjustable timeout period,
programmable soft-start, output tracking, output over­load, short-circuit and thermal shutdown protections.

The MAX5096/MAX5097 operate over the -40°C to
+125°C automotive temperature range and are avail­able in thermally enhanced 20-pin TSSOP or 16-pin
TQFN packages.

Applications

Automotive

Industrial

Features

♦ High-Efficiency Switcher Mode (Buck Mode) or

Low-Quiescent-Current Linear Regulator
(LDO Mode) Operation

♦ Wide Operating Input Voltage Range

+5V to +40V Buck Mode
+4V to +40V LDO Mode

♦ Fixed 3.3V or 5V and Adjustable (1.24V to 11V)

Output Voltage Versions

♦ 6µA (typ) Shutdown Current
♦ Fixed 135kHz or 330kHz Switching Frequency
♦ External Frequency Synchronization
♦ Programmable Soft-Start
♦ Integrated Microprocessor Reset (RESET) Circuit

with Programmable Timeout Period

♦ Thermal and Short-Circuit Protection
♦ -40°C to +125°C Automotive Temperature Range
♦ Thermally-Enhanced Package Dissipates

2.6W at TA= +70°C (16-Pin TQFN)

1.7W at TA= +70°C (20-Pin TSSOP)

MAX5096/MAX5097

40V, 600mA Buck Converters with Low-

Quiescent-Current Linear Regulator Mode

________________________________________________________________ Maxim Integrated Products 1

19-0603; Rev 0; 7/06

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.

Ordering Information

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX5096AATE+*

T1655-2

MAX5096BATE+

T1655-2

MAX5096AAUP+*

U20E-4

MAX5096BAUP+*

U20E-4

MAX5097AATE+

T1655-2

MAX5097BATE+*

T1655-2

MAX5097AAUP+*

U20E-4

MAX5097BAUP+*

U20E-4

TQFN

+

LX

16

1

2

3

4

12

11

10

9

15 14 13

5678

IN

IN

LX

EN

OUT

ADJ

LDO/BUCK

SGND

RESET

BP

SYNC

SS

CT

COMP

PGND

MAX5096
MAX5097

TOP VIEW

20

19

18

17

16

15

14

1

2

3

4

5

6

7

LX

LX

N.C.

ENPGND

IN

IN

IN

TOP VIEW

MAX5096
MAX5097

OUT

ADJ

N.C.BP

138N.C.

129 COMPSYNC

1110 CTSS

SGND

TSSOP

LDO/BUCK

RESET

+

Pin Configurations

*Future product—contact factory for availability.
+Denotes lead-free package.
**EP = Exposed pad.

Dual Mode is a trademark of Maxim Integrated Products, Inc.

-40°C to +125°C 16 TQFN-EP**

-40°C to +125°C 16 TQFN-EP**

-40°C to +125°C 20 TSSOP-EP**

-40°C to +125°C 20 TSSOP-EP**

-40°C to +125°C 16 TQFN-EP**

-40°C to +125°C 16 TQFN-EP**

-40°C to +125°C 20 TSSOP-EP**

-40°C to +125°C 20 TSSOP-EP**

MAX5096/MAX5097

40V, 600mA Buck Converters with Low­Quiescent-Current Linear Regulator Mode

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.

(All voltages referenced to PGND, unless otherwise noted.)

IN (transient, 1ms) ..................................................-0.3V to +45V

SGND ....................................................................-0.3V to +0.3V

LX....................................................................-1V to (V

IN

+ 0.3V)

LX Current ................................................................................2A

EN ................................................................-0.3V to (V

IN

+ 0.3V)

BP, SYNC, LDO/BUCK, RESET to SGND...............-0.3V to +12V

BP, RESET Output Current..................................................25mA

CT, SS, ADJ, COMP to SGND ....................-0.3V to (V

BP

+ 0.3V)

OUT ........................................................................-0.3V to +11V

OUT Short-Circuit Duration ........................................Continuous

Continuous Power Dissipation (T

A

= +70°C)*

16-Pin TQFN (derate 33.3mW/°C above +70°C) ........2666mW

20-Pin TSSOP (derate 21.7mW/°C above +70°C) ......1739mW

Thermal Resistance:

(

θJA, 16-Pin TQFN)* ...................................................30.0°C/W

(θ

JC

, 16-Pin TQFN).......................................................1.7°C/W

(θ

JA

, 20-Pin TSSOP)* .................................................46.0°C/W

(θ

JC

, 20-Pin TSSOP)........................................................2°C/W

Operating Temperature Range .........................-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-60°C to +150°C

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

ELECTRICAL CHARACTERISTICS

(VIN= +14V, I

OUT

= 1mA, CIN= 100µF, C

OUT

= 22µF, L = 22µH, CBP= 1µF, VEN= +2.4V (Figure 2), SGND = PGND = 0V, TA= TJ=

-40°C to +125°C, unless otherwise noted. Typical values are at T

A

= TJ= +25°C.) (Note 1)

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

SYSTEM INPUT

Input Voltage Range (LDO Mode)

LDO/BUCK = high 4 40 V

Input Voltage Range (Buck
Mode)

LDO/BUCK = low 5 40 V

Internal Input Undervoltage
Lockout

V

UVLO

VBP rising 3.5

3.9 V

Internal Input Undervoltage
Lockout Hysteresis

VBP falling

V

BP (Internal Regulator) Output
Voltage

V

BP

VIN = +4.5V, IBP = 100µA

4

V

I

Q

LDO/BUCK = high,
measured at input supply
return, V

OUT

= 5V,

I

OUT

= 100µA

T

A

= -40°C to

+125°C

41 70

Quiescent Supply Current
(LDO Mode)

I

Q

LDO/BUCK = high,
measured at input supply
return, V

OUT

= 5V,

I

OUT

= 100mA

T

A

= -40°C to

+125°C

44 100

µA

Buck Converter No-Load Supply
Current

VIN = 14V, V

OUT

= 5V, I

OUT

= 0

µA

TA = -40°C to
+125°C

619

Shutdown Supply Current I

SHDN

VEN = 0V, measured
from EN

T

A

= -40°C to

+85°C

612

µA

*As per JEDEC 51 Standard—Multilayer Board.

V

IN_LDO

V

IN_BUCK

3.65

V

UVLO_HYS

I

Q_BUCK

3.75

0.185

680

4.20

MAX5096/MAX5097

40V, 600mA Buck Converters with Low-

Quiescent-Current Linear Regulator Mode

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VIN= +14V, I

OUT

= 1mA, CIN= 100µF, C

OUT

= 22µF, L = 22µH, CBP= 1µF, VEN= +2.4V (Figure 2), SGND = PGND = 0V, TA= TJ=

-40°C to +125°C, unless otherwise noted. Typical values are at T

A

= TJ= +25°C.) (Note 1)

PARAMETER

CONDITIONS

UNITS

BUCK MODE

Supply Current
(Buck Converter On)

I

S

LDO/BUCK = low,
V

ADJ

= 1.4V, MAX5096,

no switching

135kHz
version

980 µA

Supply Current
(Buck Converter On)

I

S

LDO/BUCK = low,
V

ADJ

= 1.4V, MAX5097,

no switching

330kHz
Version

µA

5V version, 5.5V ≤ VIN ≤ 40V, no load

5

Fixed Output Voltage V

OUT

3.3V version, 5.5V ≤ VIN ≤ 40V, no load

3.3

V

ADJ Set Point V

FB

50% duty cycle, no load

V

ADJ Input Bias Current I

FB

V

ADJ

= 1.5V 5 100 nA

ADJ rising

Dual Mode ADJ Threshold

ADJ falling 62

mV

Maximum Duty Cycle D

MAX

V

ADJ

= 0.5V

%

Error Amplifier Transconductance

Gm

EA

V

COMP

= V

ADJ

, I

COMP

= ±10µA 55

210 µS

Adjustable Output Voltage Range

V

ADJ

V

Minimum Output Current I

OUT

VIN = 6.5V to 40V

mA

Switch Current Limit

VIN = 6V to 40V

1.5

A

Internal Switch On-Resistance

)

VIN = 14V, I

DRAIN

= 100mA 0.9 2.1 Ω

Switch Leakage Current I

SW_L

V

IN

= 40V, V

ADJ

= 1.5V

3µA

VIN = 14V, V

OUT

= 5V, I

OUT

= 400mA 85

Efficiency η

V

IN

= 14V, V

OUT

= 3.3V, I

OUT

= 400mA 81

%

MAX5096

148 kHz

Switching Frequency f

SW

MAX5097

350 kHz

MAX5096

500 kHz

Synchronization SYNC Input f

SYNC

MAX5097

500 kHz

SYNC Input High Threshold

VBP = 4V 2.0 V

SYNC Input Low Threshold

VBP = 4V 0.8 V

SYNC Input Minimum High Pulse
Width

ns

SYNC Input Leakage V

SYNC

=11V 1 µA

LDO MODE

Guaranteed Output Current I

OUT

(Note 2)

mA

SYMBOL

MIN TYP MAX

693

720 1000

4.85

3.196

1.189 1.237 1.280

V

ADJTH_R

V

ADJTH_F

I

SW_LIM

R

DS(ON

1.237 11.000

1.15

125

100

136

600

0.05

V

SYNCH

V

SYNCL

120 135

300 330

120

300

100

250

5.12

3.391

1.90

MAX5096/MAX5097

40V, 600mA Buck Converters with Low­Quiescent-Current Linear Regulator Mode

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(VIN= +14V, I

OUT

= 1mA, CIN= 100µF, C

OUT

= 22µF, L = 22µH, CBP= 1µF, VEN= +2.4V (Figure 2), SGND = PGND = 0V, TA= TJ=

-40°C to +125°C, unless otherwise noted. Typical values are at T

A

= TJ= +25°C.) (Note 1)

PARAMETER

CONDITIONS

UNITS

5V version, MAX5096B/MAX5097B,

5.5V ≤ V

IN

≤ 40V, I

OUT

= 10mA

5

V

Output Voltage V

OUT

3.3V version, MAX5096A/MAX5097A,
4V ≤ V

IN

≤ 40V, I

OUT

= 10mA

3.3

V

ADJ Set Point V

ADJ

I

OUT

= 10mA

V

ADJ Input Bias Current I

FB

V

ADJ

= 4V 0.5

nA

Adjustable Output Voltage Range

V

ADJ

I

OUT

= 10mA

V

Dropout Voltage ∆V

DO

I

OUT

= 100mA,

V

OUT

= 0.98 x V

OUT(NOMINAL)

(5V version

only), MAX5096B/MAX5097B

V

Startup Response Time

Rising edge of EN to
V

OUT

= 10% V

OUT(NOMINAL)

,

R

L

= 500Ω, V

ADJ

= SGND,

LDO/BUCK = 4V, C

SS

= 2nF

300 µs

5V version,
+5.5V ≤ V

IN

≤ +40V, I

OUT

= 100mA

Line Regulation

∆V

OUT

/

∆V

IN

3.3V version,
+4V ≤ V

IN

≤ +40V, I

OUT

= 100mA

mV/V

TJ = +25°C

5V version,
I

OUT

= 100µA to

1

TJ = +25°C

Load Regulation

∆V

OUT

/

∆I

OUT

3.3V version,
I

OUT

= 100µA to

1

mV/mA

Power-Supply Rejection Ratio PSRR

I

OUT

= 10mA, f = 100Hz, 500mV

P-P

,

V

OUT

= +5V, VIN = +14V

60 dB

Short-Circuit Current I

SC

VIN = 6V 150 330

mA

BUCK MODE (LDO MODE TRANSITION)

LDO/BUCK High Threshold 2.0 V
LDO/BUCK Low Threshold 0.8 V
LDO/BUCK Input Leakage LDO/BUCK = 11V 1 µA

Transition Timing from LDO Mode
to Buck Mode

Falling edge of LDO/BUCK to buck
converter on

32

Clock

Periods

Transition Timing from Buck
Mode to LDO Mode

Rising edge of LDO/BUCK to LDO
operation

100 µs

SOFT-START, ENABLE (EN) AND RESET

Soft-Start Charge Current I

SS

VSS = 0.1V 3 5 7 µA

Soft-Start Reference Voltage

V

OUT

= V

OUT(NOMINAL)

- 20% 0.9

1.1 V

EN High-Voltage Threshold V

ENH

EN = high, regulator on 1.4 V

SYMBOL

MIN TYP MAX

100mA, VIN = +14V

= -40°C to +125°C 0.242

T

J

100mA, VIN = +14V

= -40°C to +125°C 0.164

T

J

4.89

3.219

1.21 1.2375 1.26

1.237 11.000

0.125

0.093

0.242 0.374

0.164 0.237

5.09

3.378

100

0.37

500

V

SS-REF

0.99

MAX5096/MAX5097

40V, 600mA Buck Converters with Low-

Quiescent-Current Linear Regulator Mode

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(VIN= +14V, I

OUT

= 1mA, CIN= 100µF, C

OUT

= 22µF, L = 22µH, CBP= 1µF, VEN= +2.4V (Figure 2), SGND = PGND = 0V, TA= TJ=

-40°C to +125°C, unless otherwise noted. Typical values are at T

A

= TJ= +25°C.) (Note 1)

PARAMETER

CONDITIONS

UNITS

EN Low-Voltage Threshold V

ENL

Regulator off 0.4 V

EN Input Pulldown VEN = 2V, LDO/BUCK = 4V 0.5 µA
RESET Voltage Threshold High

V

OUT

rising 90 92 94

% V

OUT

RESET Voltage Threshold Low

V

OUT

falling 87 90 92

% V

OUT

RESET Output-Low Voltage V

RL

I

SINK

= 1mA 0.2 V

RESET Output-High Leakage
Current

I

RH

V

RESET

= 5V, V

ADJ

= 1.5V 1 µA

RESET Output Minimum Timeout
Period

C

CT

= 0 25 µs

V

OUT

to RESET Delay V

OUT

falling 10mV/µs, CCT = 0 6 µs

Delay Comparator Threshold V

CT_TH

VCT rising

V

Delay Comparator Threshold
Hysteresis

mV

CT Charge Current I

CH

1

µA

CT Discharge Current I

DISCH

VCT = 1V

mA

THERMAL SHUTDOWN

Thermal Shutdown Temperature

)

Temperature rising

°C

Thermal Shutdown Hysteresis

)

20 °C

Note 1: Limits to -40°C are guaranteed by design.
Note 2: The continuous maximum output current from LDO is limited by package power dissipation.

SYMBOL

V

RESET_H

V

RESET_L

T

J(SHDN

∆T

J(SHDN

MIN TYP MAX

1.18 1.2374 1.29

100

0.74

13.8

+165

1.20

MAX5096/MAX5097

40V, 600mA Buck Converters with Low­Quiescent-Current Linear Regulator Mode

6 _______________________________________________________________________________________

Typical Operating Characteristics

(VIN= +14V, VEN= +2.4V, MAX5097AATE+, Figures 2 and 4, TA= +25°C, unless otherwise specified.)

OUTPUT VOLTAGE vs. INPUT VOLTAGE

(LDO MODE)

MAX5096 toc01

INPUT VOLTAGE (V)

OUTPUT VOLTAGE (V)

10

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0

1 100

I

OUT

= 50mA

OUTPUT VOLTAGE vs. INPUT VOLTAGE

(BUCK MODE)

MAX5096 toc02

INPUT VOLTAGE (V)

OUTPUT VOLTAGE (V)

10

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0

1100

I

OUT

= 600mA

0

10

70

30

20

40

50

60

80

-40 -10 5 20-25 35 50 9580 11065 125

QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE (LDO MODE)

MAX5096 toc03

TEMPERATURE (°C)

QUIESCENT SUPPLY CURRENT (µA)

VIN = 14V
V

OUT

= 3.3V

I

OUT

= 100mA

I

OUT

= 100µA

I

OUT

= 0

640

660

650

680

670

700

690

710

NO-LOAD SUPPLY CURRENT

vs. TEMPERATURE (BUCK MODE)

MAX5096 toc04

VIN = 14V
V

OUT

= 3.3V

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

NO-LOAD SUPPLY CURRENT (µA)

0

4

2

8

6

12

10

14

SHUTDOWN CURRENT

vs. TEMPERATURE

MAX5096 toc05

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

SHUTDOWN CURRENT (µA)

VEN = 0V
V

IN

= 14V

3.0

3.1

3.2

3.3

3.4

3.5

OUTPUT VOLTAGE vs. TEMPERATURE

(LDO MODE)

MAX5096 toc06

OUTPUT VOLTAGE (V)

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

V

OUT

= 3.3V

I

OUT

= 10mA

I

OUT

= 100µA

I

OUT

= 10mA

3.24

3.28

3.26

3.32

3.30

3.36

3.34

3.38

OUTPUT VOLTAGE

vs. TEMPERATURE (BUCK MODE)

MAX5096 toc07

-40 -10 5 20-25 35 50 9580 11065 125

TEMPERATURE (°C)

OUTPUT VOLTAGE (V)

V

OUT

= 3.3V

I

OUT

= 100µA

I

OUT

= 100mA

I

OUT

= 600mA

0

0.04

0.02

0.10

0.08

0.06

0.16

0.14

0.12

0.18

04020 60 80 100

DROPOUT VOLTAGE

vs. OUTPUT CURRENT (LDO MODE)

MAX5096 toc08

OUTPUT CURRENT (mA)

DROPOUT VOLTAGE (V)

V

OUT

= 5V

0

30

20

10

40

50

60

70

80

90

100

0.01 0.1 1

EFFICIENCY vs. LOAD CURRENT

(V

OUT

= 3.3V)

MAX5096 toc09

LOAD CURRENT (A)

EFFICIENCY (%)

VIN = 5V

VIN = 14V

VIN = 24V

VIN = 40V

fSW = 330kHz