Rainbow Electronics MAX8614B User Manual

General Description

The MAX8614A/MAX8614B dual-output step-up DC-DC
converters generate both a positive and negative sup­ply voltage that are each independently regulated. The
positive output delivers up to 50mA while the inverter
supplies up to 100mA with input voltages between 2.7V
and 5.5V. The MAX8614A/MAX8614B are ideal for pow­ering CCD imaging devices and displays in digital
cameras and other portable equipment.

The MAX8614A/MAX8614B generate an adjustable
positive output voltage up to +24V and a negative out­put down to 16V below the input voltage. The
MAX8614B has a higher current limit than the
MAX8614A. Both devices operate at a fixed 1MHz fre­quency to ease noise filtering in sensitive applications
and to reduce external component size.

Additional features include pin-selectable power-on
sequencing for use with a wide variety of CCDs, True
Shutdown™, overload protection, fault flag, and internal
soft-start with controlled inrush current.

The MAX8614A/MAX8614B are available in a space­saving 3mm x 3mm 14-pin TDFN package and
are specified over the -40°C to +85°C extended
temperature range.

Applications

CCD Bias Supplies and OLED Displays

Digital Cameras

Camcorders and Portable Multimedia

PDAs and Smartphones

Features

♦ Dual Output Voltages (+ and -)

♦ Adjustable Up to +24V and Down to -10V at 5.5V

IN

♦ Output Short/Overload Protection

♦ True Shutdown on Both Outputs

♦ Controlled Inrush Current During Soft-Start

♦ Selectable Power-On Sequencing

♦ Up to 90% Efficiency

♦ 1µA Shutdown Current

♦ 1MHz Fixed-Frequency PWM Operation

♦ Fault-Condition Flag

♦ Thermal Shutdown

♦ Small, 3mm x 3mm, 14-Pin TDFN Package

MAX8614A/MAX8614B

Dual-Output (+ and -) DC-DC

Converters for CCD

________________________________________________________________ Maxim Integrated Products 1

19-4014; Rev 0; 3/06

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.

14 13 12 11 10

9

8

1

+

23

4567

LXN

VCCPVP

PGNDREF

AV

CC

FBN

ONBST

TOP VIEW

MAX8614A
MAX8614B

LXP

ONINV

SEQFBP

FLT

GND

TDFN

Pin Configuration

Typical Operating Circuit

Ordering Information

True Shutdown is a trademark of Maxim Integrated Products, Inc.

+Denotes lead-free package.

PART

MAX8614AETD+

MAX8614BETD+

INPUT

(2.7V TO 5.5V)

TEMP

RANGE

-40°C to
+85°C

-40°C to
+85°C

PIN­PACKAGE

14 TDFN
3mm x 3mm
(T1433-2)

14 TDFN
3mm x 3mm
(T1433-2)

TOP

MARK

ABG 0.44/0.33

ABH 0.8/0.75

ILIM

BST/INV

V

CC

ONINV

ONBST

AV

CC

MAX8614A
MAX8614B

REF

AV

CC

SEQ

FLT

GND PGND

LXN

FBN
PVP

LXP

FBP

V

-7.5V

V
+15V

INV

REF

BST

MAX8614A/MAX8614B

Dual-Output (+ and -) DC-DC
Converters for CCD

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.

VCC, AVCCto GND...................................................-0.3V to +6V

LXN to V

CC

.............................................................

-18V to +0.3V

LXP to PGND ..........................................................-0.3V to +33V

REF, ONINV, ONBST, SEQ, FBN, FBP

FLT to GND..........................................-0.3V to (AV

CC

+ 0.3)V

PVP to GND................................................-0.3V to (V

CC

+ 0.3)V

AV

CC

to VCC..........................................................-0.3V to +0.3V

PGND to GND .......................................................-0.3V to +0.3V

Continuous Power Dissipation (T

A

= +70°C Multilayer Board)
14-Pin 3mm x 3mm TDFN (derate 18.2mW/°C above
T

A

= +70°C) ............................................................1454.4mW

Operating Temperature Range ...........................-40°C to +85°C

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

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

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

ELECTRICAL CHARACTERISTICS

(VCC= V

AVCC

= V

ONINV = VONBST

= 3.6V, PGND = SEQ = GND, C6 = 0.22µF, C1 = 2.2µF, C2 = 4.7µF, Figure 1, TA= 0°C to +85°C,

unless otherwise noted. Typical values are at T

A

= +25°C.)

AVCC and VCC Voltage Range (Note 1) 2.7 5.5 V

UVLO Threshold VCC rising 2.42 2.55 2.66 V

UVLO Hysteresis 25 mV

Step-Up Output Voltage Adjust Range V

PARAMETER CONDITIONS MIN TYP MAX UNITS

AVCC

24 V

Inverter Output Voltage Adjust Range V

LXP Current Limit

LXP Short-Circuit Current Limit

LXN Current Limit

LXN On-Resistance V

LXP On-Resistance V

PVP On-Resistance V

Maximum Duty Cycle Step-up and inverter 82 90 %

Quiescent Current (Switching, No Load)

Quiescent Current (No Switching, No Load)

Shutdown Supply Current

FBP Line Regulation V

FBN Line Regulation V

- VCC (Note 2) -16 0 V

INV

MAX8614B 0.7 0.8 0.9

MAX8614A 0.34 0.44 0.52

MAX8614B 0.90 1.05 1.20

MAX8614A 0.52 0.61 0.70

MAX8614B 0.65 0.75 0.85

MAX8614A 0.28 0.33 0.38

= 3.6V 0.6 1.1 Ω

CC

= 3.6V 0.625 Ω

CC

= 3.6V 0.15 0.3 Ω

CC

I

AVCC

I

VCC

I

AVCC

I

V

CC

T

= +25°C 0.1 5

A

T

= +85°C 0.1

A

= 2.7V to 5.5V -20 mV/D

CC

= 2.7V to 5.5V 20

CC

0.75 1.4

23

400 800

815

mA

µA

µA

mV/

(D - 0.5)

A

A

A

MAX8614A/MAX8614B

Dual-Output (+ and -) DC-DC

Converters for CCD

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(VCC= V

AVCC

= V

ONINV = VONBST

= 3.6V, PGND = SEQ = GND, C6 = 0.22µF, C1 = 2.2µF, C2 = 4.7µF, Figure 1, TA= 0°C to +85°C,

unless otherwise noted. Typical values are at T

A

= +25°C.)

FBP Load Regulation

FBN Load Regulation

Oscillator Frequency 0.93 1 1.07 MHz

Soft-Start Interval Step-up and inverter 10 ms

Overload-Protection Fault Delay 100 ms

FBP, FBN, REFERENCE

REF Output Voltage No load 1.24 1.25 1.26 V

REF Load Regulation 0µA < I

REF Line Regulation 3.3V < V

FBP Threshold Voltage No load 0.995 1.010 1.025 V

FBN Threshold Voltage No load -10 0 +10 mV

FBP Input Leakage Current V

FBN Input Leakage Current FBN = -10mV

LXN Input Leakage Current V

LXP Input Leakage Current V

PVP Input Leakage Current V

FLT Input Leakage Current V

FLT Input Resistance Fault mode, T

ONINV, ONBST, SEQ LOGIC INPUTS

Logic-Low Input 2.7V < V

Logic-High Input 2.7V < V

Bias Current T

PARAMETER CONDITIONS MIN TYP MAX UNITS

I

= I

LXP

I

= I

LXP

I

= I

LXN

I

= I

LXN

FBP =

= -12V

LXN

= 23V

LXP

= 0V

PVP

= 3.6V

FLT

= +25°C 0.1 1 µA

A

, MAX8614B -15

ILIMMIN

, MAX8614A -35

ILIMMIN

, MAX8614B 17.5

ILIMMIN

, MAX8614A 65

ILIMMIN

< 50µA 10 mV

REF

< 5.5V 2 5 mV

AVCC

T

= +25°C -50 +5 +50

1.025V

= +25°C 10 20 Ω

A

< 5.5V 0.5 V

AVCC

< 5.5V 1.6 V

AVCC

A

T

= +85°C +5

A

T

= +25°C -50 +5 +50

A

T

= +85°C +5

A

T

= +25°C -5 +0.1 +5

A

T

= +85°C +0.1

A

T

= +25°C -5 +0.1 +5

A

T

= +85°C +0.1

A

T

= +25°C -5 +0.1 +5

A

T

= +85°C +0.1

A

T

= +25°C -1 +0.1 +1

A

T

= +85°C +0.1

A

mV/A

mV/A

nA

nA

µA

µA

µA

µA

MAX8614A/MAX8614B

Dual-Output (+ and -) DC-DC
Converters for CCD

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS

(VCC= V

AVCC

= V

ONINV = VONBST

= VEN= 3.6V, PGND = SEQ = GND, C6 = 0.22µF, C1 = 2.2µF, C2 = 6.7µF, Figure 1, TA= -40°C

to +85°C, unless otherwise noted.) (Note 3)

Note 1: Output current and on-resistance are specified at 3.6V input voltage. The IC operates to 2.7V with reduced performance.
Note 2: The specified maximum negative output voltage is referred to V

CC

, and not to GND. With VCC= 3.3V, the maximum negative

output is then -12.7V.

Note 3: Specifications to -40°C are guaranteed by design, not production tested.

A

= VCC Voltage Range (Note 1) 3 5.5 V

VCC

UVLO Threshold VCC rising 2.42 2.82 V

Step-Up Output Voltage Adjust Range V

Inverter Output Voltage Adjust Range V

LXP Current Limit

LXP Short-Circuit Current Limit

LXN Current Limit

LXN On-Resistance V

PVP On-Resistance V

Maximum Duty Cycle Step-up and inverter 82 %

Quiescent Current (Switching, No Load)

Quiescent Current (No Switching, No Load)

Oscillator Frequency 0.93 1.07 MHz

FBP, FBN, REFERENCE

REF Output Voltage No load 1.235 1.260 V

FBP Threshold Voltage No load 0.995 1.025 V

FBN Threshold Voltage No load -10 +10 mV

ONINV, ONBST SEQ LOGIC INPUTS

Logic-Low Input 2.7V < V

Logic-High Input 2.7V < V

PARAMETER CONDITIONS MIN TYP MAX UNITS

AVCC

- VCC (Note 2) -16 0 V

INV

MAX8614B 0.7 0.9

MAX8614A 0.34 0.52

MAX8614B 0.9 1.2

MAX8614A 0.52 0.70

MAX8614B 0.65 0.85

MAX8614A 0.28 0.38

= 3.6V 1.1 Ω

CC

= 3.6V 0.3 Ω

CC

I

AVCC

I

VCC

I

AVCC

I

VCC

< 5.5V 0.5 V

AVCC

< 5.5V 1.6 V

AVCC

24 V

1.4

3

800

15

A

A

A

mA

µA

MAX8614A/MAX8614B

Dual-Output (+ and -) DC-DC

Converters for CCD

_______________________________________________________________________________________ 5

Typical Operating Characteristics

(TA= +25°C, VCC= V

AVCC

= 3.6V, SEQ = GND, Figure 1, unless otherwise noted.)

MAXIMUM OUTPUT CURRENT

vs. INPUT VOLTAGE

350

300

250

200

150

100

MAXIMUM OUTPUT CURRENT (mA)

50

0

2.5 3.0 3.5 4.0 4.5 5.0 5.5

V

V

= 15V

OUT

INPUT VOLTAGE (V)

= 10V

OUT

V

= 20V

OUT

POSITIVE OUTPUT EFFICIENCY

vs. OUTPUT CURRENT

100

90

80

70

60

50

40

EFFICIENCY (%)

30

20

10

0

0.1 1 10 100

VCC = 5V

VCC = 3V

OUTPUT CURRENT (mA)

MAXIMUM OUTPUT CURRENT

vs. INPUT VOLTAGE

V

= -5V

INV

V

= -7.5V

INV

V

INPUT VOLTAGE (V)

NEGATIVE OUTPUT EFFICIENCY

vs. OUTPUT CURRENT

VCC = 3.6V

VCC = 3V

VCC = 5V

L = 4.7µH, C = 4.7µF

OUTPUT CURRENT (mA)

VCC = 3.6V

VCC = 4.2V

L = 10µH, C = 10µF

300

250

MAX8614A/B toc01

200

150

100

50

MAXIMUM OUTPUT CURRENT (mA) .

0

2.5 3.0 3.5 4.0 4.5 5.0 5.5

100

90

80

MAX8614A/B toc04

70

60

50

40

EFFICIENCY (%)

30

20

10

0

0.1 1 10 100

= -10V

INV

VCC = 4.2V

MAX8614A/B toc02

EFFICIENCY (%)

MAX8614A/B toc05

EFFICIENCY (%)

POSITIVE OUTPUT EFFICIENCY

vs. OUTPUT CURRENT

100

90

80

70

60

50

40

30

20

10

0

0.1 1 10 100
OUTPUT CURRENT (mA)

VCC = 5V

VCC = 3V

VCC = 3.6V

L = 2.2µH, C = 2.2µF

VCC = 4.2V

NEGATIVE OUTPUT EFFICIENCY

vs. OUTPUT CURRENT

100

90

80

70

60

50

40

30

20

10

0

0.1 1 10 100

VCC = 3.6V

VCC = 3V

VCC = 4.2V

VCC = 5V

L = 10µH, C = 10µF

OUTPUT CURRENT (mA)

MAX8614A/B toc03

MAX8614A/B toc06

OUTPUT EFFICIENCY

vs. OUTPUT CURRENT

100

90

80

70

60

50

40

EFFICIENCY (%)

30

20

BOTH OUTPUTS LOADED EQUALLY

10

L1 = 2.2µH, C1 = 2.2µF, L2 = 4.7µH, C2 = 4.7µF

0

0.1 1 10 100
OUTPUT CURRENT (mA)

VCC = 5V

VCC = 3V

VCC = 3.6V

VCC = 4.2V

MAX8614A/B toc07

100

90

80

70

60

50

40

EFFICIENCY (%)

30

20

10

0

0.1 1 10 100 1000

OUTPUT EFFICIENCY

vs. OUTPUT CURRENT

VCC = 5V

VCC = 4.2V

VCC = 3V

VCC = 3.6V

BOTH OUTPUTS LOADED EQUALLY
L1 = 10µH, C1 = 10µF, L2 = 10µH, C2 = 10µF

OUTPUT CURRENT (mA)

MAX8614A/B toc08