Rainbow Electronics MAX15031 User Manual

General Description

The MAX15031 consists of a constant-frequency pulsewidth modulating (PWM) step-up DC-DC converter with an internal switch and a high-side current monitor with high-speed adjustable current limiting. This device can generate output voltages up to 76V and provides current monitoring up to 4mA (up to 300mW). The MAX15031 can be used for a wide variety of applications such as avalanche photodiode biasing, PIN biasing, or varactor biasing, and LCD displays. The MAX15031 operates from 2.7V to 11V.

The constant-frequency (400kHz), current-mode PWM architecture provides low-noise output voltage that is easy to filter. A high-voltage, internal power switch allows this device to boost output voltages up to 76V. Internal soft-start circuitry limits the input current when the boost converter starts. The MAX15031 features a shutdown mode to save power.

The MAX15031 includes a current monitor with more than three decades of dynamic range and monitors current ranging from 500nA to 2mA with high accuracy. Resistor-adjustable current limiting protects the APD from optical power transients. A clamp diode protects the monitor’s output from overvoltage conditions. Other protection features include cycle-by-cycle current limiting of the boost converter switch, undervoltage lockout, and thermal shutdown if the die temperature reaches +160°C.

The MAX15031 is available in a thermally enhanced 4mm x 4mm, 16-pin TQFN package and operates over the -40°C to +125°C automotive temperature range.

Applications

Avalanche Photodiode Biasing and Monitoring

PIN Diode Bias Supplies

Low-Noise Varactor Diode Bias Supplies

FBON Modules

GPON Modules

LCD Displays

Features

o Input Voltage Range

+2.7V to +5.5V (Using Internal Charge Pump) or +5.5V to +11V

o Wide Output-Voltage Range from (VIN+ 1V) to 76V

o Internal 1Ω (typ) 80V Switch

o 300mW Boost Converter Output Power

o Accurate ±10% (500nA to 1mA) and ±3.5% (1mA

to 4mA) High-Side Current Monitor

o Resistor-Adjustable Ultra-Fast APD Current Limit

(1µs Response Time)

o Open-Drain Current-Limit Indicator Flag

o 400kHz Fixed Switching Frequency

o Constant PWM Frequency Provides Easy Filtering

in Low-Noise Applications

o Internal Soft-Start

o 2µA (max) Shutdown Current

o -40°C to +125°C Temperature Range

o Small Thermally Enhanced, 4mm x 4mm, 16-Pin

TQFN Package

MAX15031

80V, 300mW Boost Converter and Current

Monitor for APD Bias Applications

________________________________________________________________

Maxim Integrated Products

1

Pin Configuration

Ordering Information

19-4299; Rev 1; 3/09

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

EVALUATION KIT

AVAILABLE

PART TEMP RANGE

PIN-PACKAGE

MAX15031ATE+

-40°C to +125°C 16 TQFN-EP*

+

Denotes a lead(Pb)-free/RoHS-compliant package.

*

EP = Exposed pad.

Typical Operating Circuits appear at end of data sheet.

TOP VIEW

BIAS

13

14

SHDN

PGND

15

16

LX

*EXPOSED PAD

APD

12 11 9

+

12

PWR

(4mm

CLAMP

MAX15031

CP

THIN QFN

× 4mm)

10

3

CN MOUT

*EP

4

RLIM

IN

ILIM

8

7

CNTRL

FB

6

SGND

5

MAX15031

80V, 300mW Boost Converter and Current Monitor for APD Bias Applications

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(VIN= V

PWR

= 3.3V. V

SHDN

= 3.3V. CIN= C

PWR

= 10µF. CCP= 10nF, V

CNTRL

= VIN. V

RLIM

= 0. V

PGND

= V

SGND

= 0. V

BIAS

= 40V.

APD = unconnected. CLAMP = unconnected. ILIM = unconnected, MOUT = unconnected. T

A

= TJ= -40°C to +125°C, unless other-

wise noted. Typical values are at T

A

= +25°C.) (Note 2)

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.

Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial

.

PWR, IN to SGND ...................................................-0.3V to +12V

LX to PGND ............................................................-0.3V to +80V

BIAS, APD to SGND ...............................................-0.3V to +80V

SHDN to SGND............................................-0.3V to (V

IN

+ 0.3V)

CLAMP to SGND......................................-0.3V to (V

BIAS

+ 0.3V)

FB, ILIM, RLIM, CP, CN, CNTRL to SGND .............-0.3V to +12V

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

MOUT to SGND ....................................-0.3V to (V

CLAMP

+ 0.3V)

Continuous Power Dissipation

16-Pin TQFN (derate 25mW/°C above +70°C) ............2000mW

Thermal Resistance (Note 1)

θ

JA

....................................................................................40°C/W

θ

JC

......................................................................................6°C/W

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

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

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

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

Supply Voltage Range VIN, V

Supply Current I

Undervoltage Lockout Threshold V

Undervoltage Lockout Hysteresis V

Shutdown Current I

Shutdown Input Bias Current I

BOOST CONVERTER

Output-Voltage Adjustment Range

Switching Frequency f

Maximum Duty Cycle D

FB Set-Point Voltage V

FB Input Bias Current I

Internal Switch On-Resistance R

Peak Switch Current Limit I

LX Leakage Current VLX = 36V 1 µA

Line Regulation

Load Regulation 0 ≤ I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

PWR

CP connected to IN, CCP = open 5.5 11

VFB = 1.4V, no switching 1 2

SUPPLY

UVLO

UVLO_HYS

IN_SHDN

BIAS_SHDNVBIAS

SW

CLK

FB

VIN = 11V, VFB = 1.4V (no switching), C

= open, CP = IN

CP

VIN rising 2.375 2.5 2.675 V

SHDN pulled low 2 µA

= 3.3V, V

VIN = V

PWR

2.9V ≤ V

PWR

ILX = 100mA

ON

ILX = 100mA,

= V

V

CP

IN V

LIM_LX

2.9V ≤ V I

LOAD

PWR

= 4.5mA

≤ 4.5mA 1 %

LOAD

2.7 5.5

1.2 3

100 mV

= 0 30 µA

SHDN

VIN +

1V

76 V

= 5V 360 400 440

≤ 11V, V ≤ 11V, VIN = V

= V

IN

PWR

352 400 448

86 90 94 %

1.2201 1.245 1.2699 V

100 nA

V

= VIN = 2.9V,

PWR

V

= 5.5V

CP

= VIN = 5.5V,

V

PWR

= 10V

V

CP

V

= VIN = VCP = 5.5V 1 2

PWR

= VIN = VCP = 11V 1 2

PWR

12

0.8 1.2 1.6 A

≤ 11V, V

PWR

= VIN,

0.2 %

V

mA

kHz

Ω

MAX15031

80V, 300mW Boost Converter and Current

Monitor for APD Bias Applications

_______________________________________________________________________________________ 3

Note 2: All minimum/maximum parameters are tested at TA= +125°C. Limits over temperature are guaranteed by design. Note 3: Guaranteed by design and not production tested.

ELECTRICAL CHARACTERISTICS (continued)

(VIN= V

PWR

= 3.3V. V

SHDN

= 3.3V. CIN= C

PWR

= 10µF. CCP= 10nF, V

CNTRL

= VIN. V

RLIM

= 0. V

PGND

= V

SGND

= 0. V

BIAS

= 40V.

APD = unconnected. CLAMP = unconnected. ILIM = unconnected, MOUT = unconnected. T

A

= TJ= -40°C to +125°C, unless other-

wise noted. Typical values are at T

A

= +25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Soft-Start Duration 8ms

Soft-Start Steps (0.25 x I

LIM_LX

) to I

LIM_LX

32 Steps

CONTROL INPUT (CNTRL)

Maximum Control Input Voltage Range

FB set point is regulated to V

CNTRL

1.25 V

CURRENT MONITOR

Bias Voltage Range V

Bias Quiescent Current I

Voltage Drop V

Dynamic Output Resistance at MOUT

BIAS

DROPIAPD

R

MOUT

I

= 500nA 100 µA

APD

I

= 2mA 3.2 mA

APD

= 2mA, V

I

= 500nA 1 GΩ

APD

I

= 2.5mA 890 MΩ

APD

DROP

= V

BIAS

- V

APD

10 76 V

1V

MOUT Output Leakage APD is unconnected 1 nA

V

-

Output Clamp Voltage

Output Clamp Leakage Current V

Output-Voltage Range V

Current Gain I

Power-Supply Rejection Ratio PSRR

APD Input Current Limit I Current-Limit Adjustment Range 12.45kΩ ≥ R

Power-Up Settling Time t

MOUT

V

CLAMP

MOUT

MOUT/IAPD

Forward diode current = 1mA 0.5 0.73 0.95 V

10V ≤ V is unconnected

I

APD

I

APD

(∆I V

LIM_APDVAPD

I

MOUT

0.1%, 10nF connected

S

from APD to ground

BIAS

= V

BIAS

= 76V 1 nA

CLAMP

≤ 76V, 0 ≤ I

≤ 1mA, CLAMP

APD

V

BIAS

-

1V

= 500nA 0.095 0.1 0.11

= 2mA 0.965 0.1 0.1035

I

= 500nA

MOUT/IMOUT

= 10V to 76V

BIAS

= 35V, R

settles to within

APD

BIAS

,

(Note 3)

= 5µA to

I

APD

)/∆V

1mA

= 3.3kΩ 3.15 3.75 4.35 mA

LIM

≥ 2.5kΩ 15mA

LIM

I

= 500nA 7.5 ms

APD

I

= 2.5mA 90 µs

APD

-1000 +300 +1500

-250 +24 +250

V

ppm/V

LOGIC INPUTS/OUTPUTS

SHDN Input-Voltage Low V SHDN Input-Voltage High V ILIM Output-Voltage Low V ILIM Output Leakage Current I

OL

OH

IL

IH

I

= 2mA 0.3 V

LIM

V

= 11V 1 µA

ILIM

2.4 V

0.8 V

THERMAL PROTECTION

Thermal Shutdown Temperature rising +160 °C

Thermal Shutdown Hysteresis 10 °C

MAX15031

80V, 300mW Boost Converter and Current Monitor for APD Bias Applications

4 _______________________________________________________________________________________

Typical Operating Characteristics

(V

PWR

= VIN= 3.3V, V

OUT

= 70V, circuit of Figure 3 (Figure 4 for VIN> 5.5V), unless otherwise noted.)

EFFICIENCY vs. LOAD CURRENT

MAX15031 toc01

LOAD CURRENT (mA)

EFFICIENCY (%)

321

10

20

30

40

50

60

70

0

04

V

OUT

= 30V

V

OUT

= 55V

V

OUT

= 70V

V

IN

= 3.3V

EFFICIENCY vs. LOAD CURRENT

MAX15031 toc02

LOAD CURRENT (mA)

EFFICIENCY (%)

321

10

20

30

40

50

60

70

0

04

V

OUT

= 30V

V

OUT

= 55V

V

OUT

= 70V

V

IN

= 5V

EFFICIENCY vs. LOAD CURRENT

MAX15031 toc03

LOAD CURRENT (mA)

EFFICIENCY (%)

321

10

20

30

40

50

60

70

0

04

VIN = 3.3V

VIN = 5V

VIN = 8V

V

OUT

= 70V

MINIMUM STARTUP VOLTAGE

vs. LOAD CURRENT

MAX15031 toc04

LOAD CURRENT (mA)

MINIMUM STARTUP VOLTAGE (V)

321

2.49

2.50

2.51

2.52

2.53

2.54

2.55

2.48 04

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX15031 toc05

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (mA)

1097 82 3 4 5 61

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

0

011

VFB = 1.4V

TA = +125°C

TA = +85°C

TA = -40°C

TA = +25°C

NO-LOAD SUPPLY CURRENT

vs. SUPPLY VOLTAGE

XMAX15031 toc06

SUPPLY VOLTAGE (V)

NO-LOAD SUPPLY CURRENT (mA)

10987654

10

20

30

40

50

60

0

311

TA = +85°C

TA = -40°C

TA = +25°C

EXITING SHUTDOWN

MAX15031 toc07

1ms/div

V

OUT

50V/div

I

L

500mA/div

V

SHDN

2V/div

3V

0V

0mA

I

OUT

= 1mA

ENTERING SHUTDOWN

MAX15031 toc08

4ms/div

OUTPUT VOLTAGE 50V/div

INDUCTOR CURRENT 500mA/div

SHUTDOWN VOLTAGE 2V/div

3V

70V

0V

0mA

I

LOAD

= 1mA

LIGHT-LOAD SWITCHING

WAVEFORM WITH RC FILTER

MAX15031 toc09

1µs/div

V

BIAS

AC-COUPLED

V

LX

50V/div

I

L

500mA/div

1mV/div

0mA

0V

I

OUT

= 0.1mA, V

BIAS

= 70V

MAX15031

80V, 300mW Boost Converter and Current

Monitor for APD Bias Applications

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(V

PWR

= VIN= 3.3V, V

OUT

= 70V, circuit of Figure 3 (Figure 4 for VIN> 5.5V), unless otherwise noted.)

MAXIMUM LOAD CURRENT

vs. INPUT VOLTAGE

MAX15031 toc15

INPUT VOLTAGE (V)

MAXIMUM LOAD CURRENT (mA)

1097 85 64

10

20

30

40

50

60

70

80

90

100

110

0

311

A

B

C

A: V

OUT

= 30V, B: V

OUT

= 35V, C: V

OUT

= 45V,

D: V

OUT

= 55V, E: V

OUT

= 60V, F: V

OUT

= 72V

D

E

F

LOAD REGULATION

MAX15031 toc14

LOAD CURRENT (mA)

OUTPUT VOLTAGE (V)

4321

68.2

68.4

68.6

68.8

69.0

69.2

69.4

69.6

69.8

70.0

68.0 05

BIAS CURRENT

vs. BIAS VOLTAGE

MAX15031 toc16

BIAS VOLTAGE (V)

BIAS CURRENT (mA)

70605040302010

0.1

1

10

0.01 080

I

APD

= 2mA

I

APD

= 500nA

LOAD-TRANSIENT RESPONSE

100ms/div

HEAVY-LOAD SWITCHING

WAVEFORM WITH RC FILTER

MAX15031 toc11

V

OUT

= 3.3V

V

IN

= 70V

V

OUT

AC-COUPLED 200mV/div

I

LOAD

5mA/div 0mA

LINE-TRANSIENT RESPONSE

100ms/div

MAX15031 toc12

V

OUT

I

OUT

t

RISE

= 70V

= 1mA

= 50µs

V

IN

2V/div

3.3V

V

OUT

AC-COUPLED 100mV/div

MAX15031 toc10

I

OUT

1µs/div

= 4mA, V

BIAS

= 70V

V

BIAS

AC-COUPLED 1mV/div

V

LX

50V/div

0V

I

L

500mA/div 0mA

LX LEAKAGE CURRENT

vs. TEMPERATURE

200

CURRENT INTO

180

LX PIN

160

140

120

100

80

60

LX LEAKAGE CURRENT (nA)

40

20

0

-40 125

TEMPERATURE (°C)

MAX15031 toc13

1109565 80-10 5 20 35 50-25

MAX15031

80V, 300mW Boost Converter and Current Monitor for APD Bias Applications

6 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

(V

PWR

= VIN= 3.3V, V

OUT

= 70V, circuit of Figure 3 (Figure 4 for VIN> 5.5V), unless otherwise noted.)

BIAS CURRENT

vs. APD CURRENT

MAX15031 toc17

APD CURRENT (mA)

BIAS CURRENT (mA)

10.10.010.001

0.1

1

10

0.01

0.0001 10

V

BIAS

= 70V

BIAS CURRENT

vs. TEMPERATURE

MAX15031 toc18

TEMPERATURE (°C)

BIAS CURRENT (mA)

1109580655035205-10-25

0.1

1

10

0.01

-40 125

I

APD

= 2mA

I

APD

= 500nA

GAIN ERROR

vs. APD CURRENT

MAX15031 toc19

I

APD

(µA)

GAIN ERROR (%)

1000100101

-4

-3

-2

-1

0

1

2

3

4

5

-5

0.1 10,000

V

BIAS

= 70V

GAIN ERROR

vs. TEMPERATURE

MAX15031 toc20

TEMPERATURE (°C)

GAIN ERROR (%)

11095-25 -10 5 35 50 6520 80

-2.5

-2.0

-1.5

-1.0

-0.5

0

0.5

1.0

-3.0

-40 125

V

BIAS

= 70V

I

APD

= 500nA

I

APD

= 50µA

I

APD

= 5µA

I

APD

= 2mA

I

APD

= 500µA

GAIN ERROR

vs. BIAS VOLTAGE

MAX15031 toc21

BIAS VOLTAGE (V)

GAIN ERROR (%)

706020 30 40 50

-0.60

-0.40

-0.20

0

0.20

0.40

0.60

0.80

-0.80 10 80

I

APD

= 500nA

I

APD

= 50µA

I

APD

= 5µA

I

APD

= 2mA

I

APD

= 500µA

APD TRANSIENT RESPONSE

MAX15031 toc22

20µs/div

V

APD

AC-COUPLED 70V 2V/div

I

APD

2.5mA/div

I

MOUT

0.25mA/div

0mA

STARTUP DELAY

MAX15031 toc23

200µs/div

V

BIAS

20V/div

I

MOUT

20nA/div

3V

0nA

I

APD

= 500nA