MAX16990ATCC/V+T - Maxim Integrated

General Description

The MAX16990/MAX16992 are high-performance,

current-mode PWM controllers with 4μA (typ) shut-

down current for wide input voltage range boost/SEPIC

converters. The 4.5V to 36V input operating volt-

age range makes these devices ideal in automotive

applications, such as front-end “preboost” or “SEPIC”

power supplies and for the first boost stage in high-

power LED lighting applications. An internal low-dropout

regulator (PVL regulator) with a 5V output voltage

enables the MAX16990/MAX16992 to operate directly

from an automotive battery input. The input operating

range can be extended to as low as 2.5V when the

converter output is applied to the SUP input.

There are multiple versions of the devices offering one

or more of the following functions: a synchronization

output (SYNCO) for two-phase operation, an overvoltage

protection function using a separate input pin (OVP), and

a reference input pin (REFIN) to allow on-the-fly output

voltage adjustment.

The MAX16990 and MAX16992 operate in different

frequency ranges. All versions can be synchronized to an

external master clock using the FSET/SYNC input.

In addition, the MAX16990/MAX16992 have a factory-

programmable spread-spectrum option. Both devices are

available in compact 12-pin TQFN and 10-pin µMAX®

packages.

Applications

●Automotive LED Lighting

● Automotive Audio/Navigation Systems

●Dashboards

Benets and Features

● Minimized Radio Interference with 2.5MHz Switching

Frequency Above the AM Radio Band

● Space-Efficient Solution Design with Minimized

External Components

• 100kHz to 1MHz (MAX16990) and 1MHz to

2.5MHz (MAX16992) Switching-Frequency Ranges

• 12-Pin TQFN (3mm x 3mm) and 10-Pin μMAX

Packages

●Spread Spectrum Simplifies EMI Management Design

● Flexibility with Available Configurations for Boost,

SEPIC, and Multiphase Applications

• Adjustable Slope Compensation

• Current-Mode Control

• Internal Soft-Start (9ms)

● Protection Features Support Robust Automotive

Applications

• Operating Voltage Range Down to 4.5V (2.5V or

Lower in Bootstrapped Mode), Immune to

Load-Dump Transient Voltages Up to 42V

• PGOOD Output and Hiccup Mode for Enhanced

System Protection

• Overtemperature Shutdown

• -40°C to +125°C Operation

Ordering Information appears at end of data sheet.

µMAX is a registered trademark of Maxim Integrated Products, Inc.

19-6632; Rev 12; 10/18

MAX16992AUBA /B

DRV

SUP

GND

1µF

SW_OUT

8V/2A

BATTERY INPUT

2.5V to 40V

PGOOD

PVL

PGOOD

PVL

FSET/SYNC

ENABLE

COMP

ISNS

1kΩ

22mΩ

12kΩ

13kΩ

10kΩ

17kΩ

91kΩ

22µF

0.47µH

47µF

CERAMIC

2.2µF

BOOTSTRAPPED 2.2MHz APPLICATION WITH LOW OPERATING VOLTAGE

Typical Application Circuit

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

EVALUATION KIT AVAILABLE

Click here for production status of specific part numbers.

EN, SUP, OVP, FB to GND ...................................-0.3V to +42V

DRV, SYNCO, FSET/SYNC, COMP,

PGOOD, ISNS, REFIN to GND ........... -0.3V to (VPVL + 0.3V)

PVL to GND ...............................................................-0.3V to 6V

Continuous Power Dissipation (TA = +70°C)

µMAX on SLB (derate 10.3mW/°C above +70°C) ......825mW

µMAX on MLB (derate 12.9mW/°C above +70°C) ....1031mW

TQFN on SLB (derate 13.2mW/°C above +70°C).....1053mW

TQFN on MLB (derate 14.7mW/°C above +70°C) .... 1176mW

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

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

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

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

Soldering Temperature (reflow) ....................................... +260°C

(Note 1)

µMAX (Single-Layer Board)

Junction-to-Ambient Thermal Resistance (θJA) ..........97°C/W

Junction-to-Case Thermal Resistance (θJC) .................5°C/W

µMAX (Four-Layer Board)

Junction-to-Ambient Thermal Resistance (θJA) ..........78°C/W

Junction-to-Case Thermal Resistance (θJC) ..................... 5°C/W

TQFN (Single-Layer Board)

Junction-to-Ambient Thermal Resistance (θJA) ..........76°C/W

Junction-to-Case Thermal Resistance (θJC) ............... 11°C/W

TQFN (Four-Layer Board)

Junction-to-Ambient Thermal Resistance (θJA) ..........68°C/W

Junction-to-Case Thermal Resistance (θJC) ............... 11°C/W

(VSUP = 14V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA =+25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

POWER SUPPLY

SUP Operating Supply Range VSUP 4.5 36 V

SUP Supply Current in Operation ICC

VFB = 1.1V, no

switching

MAX16990 0.75 1.3 mA

MAX16992 1.25 2

SUP Supply Current in Shutdown ISHDN VEN = 0V 4 7 µA

OVP Threshold Voltage VOVP OVP rising 105 110 115 % of

VFB

OVP Threshold Voltage

Hysteresis VOVPH 2.5 % of

VFB

OVP Input Current IOVP -1 +1 µA

PVL REGULATOR

PVL Output Voltage VPVL 4.7 5 5.3 V

PVL Undervoltage Lockout VUV SUP rising 3.8 4 4.3 V

PVL Undervoltage-Lockout

Hysteresis VUVH 0.4 V

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.

Package Thermal Characteristics

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.maximintegrated.com/thermal-tutorial.

Electrical Characteristics

www.maximintegrated.com Maxim Integrated

│

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

(VSUP = 14V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA =+25°C.) (Note 2)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

OSCILLATOR

Switching Frequency fSW

RFSET = 69kΩ360 400 440 kHz

RFSET = 12kΩ2000 2200 2400

Spread-Spectrum Spreading

Factor SS B, D, and F versions Q6 % of

fSW

Switching Frequency Range fSWR When set with

resistor on pin

MAX16990 100 1000 kHz

MAX16992 1000 2500

FSET/SYNC Frequency Range fSYNC Using external

SYNC signal

MAX16990 220 1000 kHz

MAX16992 1000 2500

FSET Regulation Voltage VFSET 12kΩ < RFSET < 69kΩ0.9 V

Soft-Start Time tSS Internally set 6 9 12 ms

Hiccup Period tHICCUP 55 ms

Maximum Duty Cycle DCMAX

MAX16990, RFSET = 69kΩ93 %

MAX16992, RFSET = 12kΩ85

Minimum On-Time tON 50 80 110 ns

THERMAL SHUTDOWN

Thermal-Shutdown Temperature TSTemperature rising 165 °C

Thermal-Shutdown Hysteresis TH10 °C

GATE DRIVERS

DRV Pullup Resistance RDRVH IDRV = 100mA 3 5.5 Ω

DRV Pulldown Resistance RDRVL IDRV = -100mA 1.4 2.5 Ω

DRV Output Peak Current IDRV

Sourcing, CDRV = 10nF 0.75 A

Sinking, CDRV = 10nF 1

REGULATION/CURRENT SENSE

FB Regulation Voltage VFB

VREFIN = VPVL Across full line, load,

and temperature

range

0.99 1 1.01

VREFIN = 2V 1.98 2 2.02

VREFIN = 0.5V 0.495 0.5 0.505

FB Input Current IFB -0.5 +0.5 μA

ISNS Threshold 212 250 288 mV

ISNS Leading-Edge Blanking

Time tBLANK

MAX16990 60 ns

MAX16992 40

Current-Sense Gain AVI 8 V/V

Peak Slope Compensation

Current-Ramp Magnitude Added to ISNS input 40 50 60 μA

PGOOD Threshold VPG

Percentage of final

value

Rising 85 90 95 %

Falling 80 85 90

Electrical Characteristics (continued)

www.maximintegrated.com Maxim Integrated

│

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

(VSUP = 14V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA =+25°C.) (Note 2)

Note 2: All devices 100% production tested at TA = +25°C. Limits over temperature are guaranteed by design.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

ERROR AMPLIFIER

REFIN Input Voltage Range 0.5 2 V

REFIN Threshold for 1V FB

Regulation

VPVL -

0.8

VPVL -

0.4

VPVL -

0.1 V

Error-Amplifier gmAVEA 700 μS

Error-Amplifier Output Impedance ROEA 50 MΩ

COMP Output Current ICOMP 140 μA

COMP Clamp Voltage 2.7 3 3.3 V

LOGIC-LEVEL INPUTS/OUTPUTS

PGOOD/SYNCO Output Leakage

Current VPGOOD/VSYNCO = 5V 0.5 µA

PGOOD/SYNCO Output Low

Level Sinking 1mA 0.4 V

EN High Input Threshold EN rising 1.7 V

EN Low Input Threshold 1.2 V

FSET/SYNC High Input

Threshold 2.5 V

FSET/SYNC Low Input Threshold 1 V

EN and REFIN Input Current -1 +1 µA

Electrical Characteristics (continued)

www.maximintegrated.com Maxim Integrated

│

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

(VSUP = 14V, TA = +25°C, unless otherwise noted.)

PVL VOLTAGE vs. SUPPLY VOLTAGE

MAX16990 toc04

SUPPLY VOLTAGE (V)

PVL VOLTAGE (V)

282012

4.2

4.1

4.3

4.5

4.4

4.6

4.7

4.8

4.9

5.0

5.1

5.2

4.0

4 36

IPVL = 10mA

IPVL = 1mA

MAX16990 INTERNAL OSCILLATOR

FREQUENCY vs. TEMPERATURE

MAX16990 toc07

TEMPERATURE (°C)

INTERNAL OSCILLATOR FREQUENCY (kHz)

20 40 60 80 1000-20

385

390

395

400

405

410

415

420

380

-40 120

RSET = 68.1kI

PVL VOLTAGE vs. SUPPLY VOLTAGE

MAX16990 toc05

SUPPLY VOLTAGE (V)

PVL VOLTAGE (V)

654

3.2

3.4

3.8

3.6

4.0

4.2

4.4

4.6

4.8

5.0

5.2

3.0

3 7

IPVL = 10mA

IPVL = 1mA

MAX16992 INTERNAL OSCILLATOR

FREQUENCY vs. SUPPLY VOLTAGE

MAX16990 toc08

SUPPLY VOLTAGE (V)

INTERNAL OSCILLATOR FREQUENCY (kHz)

282012

2100

2050

2150

2200

2250

2300

2350

2400

2000

4 36

RSET = 12.1kI

MAX16990 INTERNAL OSCILLATOR

FREQUENCY vs. SUPPLY VOLTAGE

MAX16990 toc06

SUPPLY VOLTAGE (V)

INTERNAL OSCILLATOR FREQUENCY (kHz)

282012

392

396

394

398

400

402

404

406

408

410

390

4 36

RSET = 68.1kI

MAX16992 INTERNAL OSCILLATOR

FREQUENCY vs. TEMPERATURE

MAX16990 toc09

TEMPERATURE (°C)

INTERNAL OSCILLATOR FREQUENCY (kHz)

20 40 60 80 1000-20

2130

2120

2110

2140

2150

2160

2170

2180

2190

2200

2100

-40 120

RSET = 12.1kI

SUPPLY CURRENT vs. SUPPLY VOLTAGE

MAX16990 toc01

SUPPLY VOLTAGE (V)

2.2MHz

SUPPLY CURRENT (mA)

400kHz

282012

0.2

0.4

0.6

0.8

1.0

1.2

1.4

4 36

VEN = VSUP

VFB = 1.1V

SHUTDOWN SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX16990 toc02

SUPPLY VOLTAGE (V)

VEN = 0V

SHUTDOWN SUPPLY CURRENT (µA)

282012

4 36

SHUTDOWN SUPPLY CURRENT

vs. TEMPERATURE

MAX16990 toc03

TEMPERATURE (°C)

SHUTDOWN SUPPLY CURRENT (µA)

20 40 60 80 1000-20

3.8

4.0

4.2

4.4

4.6

4.8

5.0

5.2

3.6

-40 120

VEN = 0V

Typical Operating Characteristics

Maxim Integrated

│

www.maximintegrated.com

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

(VSUP = 14V, TA = +25°C, unless otherwise noted.)

STARTUP RESPONSE

MAX16990 toc12

5V/div

VEN

VPVL

VOUT

VSUP

2ms/div

STARTUP RESPONSE

(WITH SWITCHED OUTPUT)

MAX16990 toc14

5V/div

VEN

VSW_OUT

VOUT

VPGOOD

2ms/div

STARTUP RESPONSE

MAX16990 toc13

5V/div

VEN

VDRV

VOUT

VPGOOD

2ms/div

OUTPUT LOAD TRANSIENT

MAX16990 toc15

5V/div

500mV/div

(AC-COUPLED)

1A/div

ILOAD

VOUT

VSUP

50ms/div

POWER-UP RESPONSE

MAX16990 toc10

5V/div

VPGOOD

VPVL

VOUT

VSUP

2ms/div

POWER-UP RESPONSE

MAX16990 toc11

5V/div

VPGOOD

VDRV

VOUT

VSUP

2ms/div

Typical Operating Characteristics (continued)

Maxim Integrated

│

www.maximintegrated.com

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

(VSUP = 14V, TA = +25°C, unless otherwise noted.)

0.5 1.0 1.5 2.0

OUTPUT VOLTAGE (V)

REFIN VOLTAGE (V)

OUT PUT VOLTAGE vs. REFIN VOLTAGE

toc18

OU T

= 0

OVP SHUTDOWN

MAX16990 toc20

5V/div

1V/div

5V/div

VPGOOD

VDRV

VOVP

VOUT

1s/div

SWITCHING WAVEFORM

MAX16990 toc19

5V/div

1A/div

ILOAD

VLX

VIN

VOUT

500ns/div

HICCUP MODE

MAX16990 toc21

5V/div

VPGOOD

VDRV

VOUT

20ms/div

LINE TRANSIENT

MAX16990 toc16

5V/div

500mV/div

(AC-COUPLED)

1A/div

ILOAD

VOUT

VSUP

20ms/div

MAX16992 VSYNC vs. VSYNCO

MAX16990 toc17

2V/div

VSYNCO

VSYNC

200ns/div

Typical Operating Characteristics (continued)

Maxim Integrated

│

www.maximintegrated.com

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

(VSUP = 14V, TA = +25°C, unless otherwise noted.)

100

200

300

400

500

600

700

800

900

1000

1100

0100 200 300

INTERNAL OSCILLATOR FREQUQNCY (kHz)

RSET(kΩ)

MAX16990 INTERNAL OSCILLATOR

FREQUENCY vs. RSET

MAX16990/2 toc25

MAX16990 MAXIMUM DUTY

CYCLE vs. TEMPERATURE

MAX16990 toc28

TEMPERATURE (°C)

MAXIMUM DUTY CYCLE (%)

12010060 800 20 40-20

94.7

94.9

95.1

95.3

95.5

95.7

95.9

94.5

-40

RSET = 68.1kI

CURRENT-LIMIT THRESHOLD

vs. TEMPERATURE

MAX16990 toc26

TEMPERATURE (°C)

CURRENT-LIMIT THRESHOLD (mV)

12010060 800 20 40-20

242

244

246

248

250

252

254

256

258

260

240

-40

COLD-CRANK INPUT VOLTAGE TRANSIENT

MAX16990 toc29

5V/div

1A/div

5V/div

VPGOOD

ILOAD

VOUT

VIN

20ms/div

MAX16992 MAXIMUM DUTY

CYCLE vs. TEMPERATURE

MAX16990 toc27

TEMPERATURE (°C)

MAXIMUM DUTY CYCLE (%)

12010060 800 20 40-20

87.5

88.0

88.5

89.0

89.5

90.0

90.5

91.0

87.0

-40

RSET = 12.1kI

MAX16990 EFFICIENCY

MAX16990 toc22

SUPPLY VOLTAGE (V)

EFFICIENCY (%)

765

100

4 8

IOUT = 100mA

IOUT = 2A

IOUT = 1A

MAX16992 EFFICIENCY

MAX16990 toc23

SUPPLY VOLTAGE (V)

EFFICIENCY (%)

765

100

4 8

IOUT = 100mA

IOUT = 1A

IOUT = 2A

MAX16992 INTERNAL OSCILLATOR

FREQUENCY vs. RSET

MAX16990 toc24

RSET (kI)

INTERNAL OSCILLATOR FREQUQNCY (kHz)

252015

1000

1200

1400

1600

1800

2000

2200

2400

2600

800

10 30

Typical Operating Characteristics (continued)

Maxim Integrated

│

www.maximintegrated.com

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

MAX16990AUBA/B,

MAX16992AUBA/B

MAX16990ATCC/D,

MAX16992ATCC/D

MAX16990ATCE/F,

MAX16992ATCE/F NAME FUNCTION

μMAX-EP TQFN-EP TQFN-EP

1 1 1 SUP Power-Supply Input. Place a bypass capacitor of at

least 1µF between this pin and ground.

2 3 3 EN

Active-High Enable Input. This input is high-voltage-

capable or can alternatively be driven from a logic-

level signal.

3 2 2 GND Ground Connection

4 4 4 DRV

Drive Output for Gate of nMOS Boost Switch. The

nominal voltage swing of this output is between PVL

and GND.

5 5 5 PVL

Output of 5V Internal Regulator. Connect a ceramic

capacitor of at least 2.2µF from this pin to ground,

placing it as close as possible to the pin.

6 6 6 ISNS

Current-Sense Input to Regulator. Connect a sense

resistor between the source of the external switching

FET and GND. Then connect another resistor

between ISNS and the source of the FET for slope

compensation adjustment.

GND

SUP

REFIN

SYNCO

PGOOD

COMP

987

ISNS

PVL

DRV

FSET/SYNC

TQFN

(3mm x 3mm)

MAX16990ATCE/F

MAX16992ATCE/F

TOP VIEW

GND

SUP

REFIN

OVP

PGOOD

COMP

987

ISNS

PVL

DRV

FSET/SYNC

TQFN

(3mm x 3mm)

MAX16990ATCC/D

MAX16992ATCC/D

TOP VIEW

COMP

FSET/SYNC

PGOODDRV

GND

SUP

µMAX

TOP VIEW

ISNSPVL EPEP

MAX16990AUBA/B

MAX16992AUBA/B

Pin Congurations

Pin Descriptions

www.maximintegrated.com Maxim Integrated

│

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

MAX16990AUBA/B,

MAX16992AUBA/B

MAX16990ATCC/D,

MAX16992ATCC/D

MAX16990ATCE/F,

MAX16992ATCE/F NAME FUNCTION

μMAX-EP TQFN-EP TQFN-EP

— — 7 SYNCO

Open-Drain Synchronization Output. SYNCO outputs

a square-wave signal which is 180° out-of-phase

with the device’s operational clock. Connect a pullup

resistor from this pin to PVL or to a 5V or lower supply

when used.

— 7 — OVP

Overvoltage Protection Input. When this pin goes

above 110% of the FB regulation voltage, all switching

is disabled. Operation resumes normally when OVP

drops below 107.5% of the FB regulation point.

Connect a resistor divider between the output, OVP,

and GND to set the overvoltage protection level.

— 8 8 REFIN

Reference Input. When using the internal reference,

connect REFIN to PVL. Otherwise, drive this pin with

an external voltage between 0.5V and 2V to set the

boost output voltage.

7 9 9 PGOOD

Open-Drain Power-Good Output. Connect a resistor

from this pin to PVL or to another voltage less than or

equal to 5V. PGOOD goes high after soft-start when

the output exceeds 90% of its final value. When EN is

low, PGOOD is also low. After soft-start is complete,

if PGOOD goes low and 16 consecutive current-limit

cycles occur, the devices enter hiccup mode and a

new soft-start is initiated after a delay of 44ms.

8 10 10 FSET/

SYNC

Frequency Set/Synchronization. To set a switching

frequency between 100kHz and 1000kHz

(MAX16990) or between 1000kHz and 2500kHz

(MAX16992), connect a resistor from this pin to

GND. To synchronize the converter, connect a logic

signal in the range 220kHz to 1000kHz (MAX16990)

or 1000kHz to 2500kHz (MAX16992) to this input.

The external n-channel MOSFET is turned on (i.e.,

DRV goes high) after a short delay (60ns for 2.2MHz

operation, 125ns for 400kHz) when SYNC transitions

low.

911 11 COMP Output of Error Amplifier. Connect the compensation

network between COMP and GND.

10 12 12 FB

Boost Converter Feedback. This pin is regulated to

1V when REFIN is tied to PVL or otherwise regulated

to REFIN during boost operation. Connect a resistor

divider between the boost output, the FB pin, and

GND to set the boost output voltage. In a two-phase

converter, connect the FB pin of the slave IC to PVL.

Pin Descriptions (continued)

www.maximintegrated.com Maxim Integrated

│

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

MAX16990AUBA/B,

MAX16992AUBA/B

MAX16990ATCC/D,

MAX16992ATCC/D

MAX16990ATCE/F,

MAX16992ATCE/F NAME FUNCTION

μMAX-EP TQFN-EP TQFN-EP

— — — EP

Exposed Pad. Internally connected to GND. Connect

to a large ground plane to maximize thermal

performance. Not intended as an electrical connection

point.

5V REGULATOR

+ REFERENCE

UVLO

PVLSUP

(OVP)

FSET/SYNC

(SYNCO)

PGOOD

DRV

GND

THERMAL

ISNS

REF.

250mV

CONTROL

LOGIC

OSCILLATOR

THERMAL

50µA x fSW

BLANKING

TIME

VPVL - 0.4V

COMP

(REFIN)

PGOOD

COMPARATOR OTA

MAX16990

MAX16992

Pin Descriptions (continued)

Functional Diagram

www.maximintegrated.com Maxim Integrated

│

MAX16990/MAX16992 36V, 2.5MHz Automotive Boost/

SEPIC Controllers

Detailed Description

The MAX16990/MAX16992 are high-performance,

current-mode PWM controllers for wide input voltage

range boost/SEPIC converters. The input operating volt-

age range of 4.5V to 36V makes these devices ideal in

automotive applications such as for front-end “preboost”

or “SEPIC” power supplies and for the first boost stage

in high-power LED lighting applications. An internal

low-dropout regulator (PVL regulator) with an output volt-

age of 5V enables the devices to operate directly from an

automotive battery input. The input operating range can

be as low as 2.5V when the converter output supplies

the SUP input.

The input undervoltage lockout (UVLO) circuit monitors

the PVL voltage and turns off the converter when the volt-

age drops below 3.6V (typ). An external resistor programs

the switching frequency in two ranges from 100kHz to

1000kHz (MAX16990) or between 1000kHz and 2500kHz

(MAX16992). The FSET/SYNC input can also be used

for synchronization to an external clock. The SYNC pulse

width should be greater than 70ns.

Inductor current information is obtained by means of an

external sense resistor connected from the source of the

external n-channel MOSFET to GND.

The devices include an internal transconductance error

amplifier with 1% accurate reference. At startup, the

internal reference is ramped in a time of 9ms to obtain

soft-start.

The devices also include protection features such as

hiccup mode and thermal shutdown, as well as an optional

overvoltage-detection circuit (OVP pin, C and D versions).

Current-Mode Control Loop

The MAX16990/MAX16992 offers peak current-mode

control operation for best load-step performance and

simpler compensation. The inherent feed-forward

characteristic is especially useful in automotive appli-

cations where the input voltage changes quickly

during cold-crank and load-dump conditions. While the

current-mode architecture offers many advantages, there

are some shortcomings. In high duty-cycle operation, sub-

harmonic oscillations can occur. To avoid this, the device

offers programmable slope compensation using a single

resistor between the ISNS pin and the current-sense

resistor. To avoid premature turn-off at the beginning

of the on-cycle, the current-limit and PWM comparator

inputs have leading-edge blanking.

Startup Operation/UVLO/EN

The devices feature undervoltage lockout on the PVL-

regulator and turn on the converter once PVL rises

above 4V. The internal UVLO circuit has about 400mV

hysteresis to avoid chattering during turn-on. Once the

converter is operating and if SUP is fed from the output,

the converter input voltage can drop below 4.5V. This

feature allows operation at cold-crank voltages as low as

2.5V or even lower with careful selection of external com-

ponents. The EN input can be used to disable the device

and reduce the standby current to less than 4µA (typ).

Soft-Start

The devices are provided with an internal soft-start time

of 9ms. At startup, after voltage is applied and the UVLO

threshold is reached, the device enters soft-start. During

soft-start, the reference voltage ramps linearly to its final

value in 9ms.

Oscillator Frequency/External Synchronization/

Spread Spectrum

Use an external resistor at FSET/SYNC to program

the MAX16990 internal oscillator frequency from 100kHz

to 1MHz and the MAX16992 frequency between 1MHz

and 2.5MHz. See TOCs 24 and 25 in the Typical Operat-

ing Characteristics section for resistor selection.

The SYNCO output is a 180° phase-shifted version

of the internal clock, and can be used to synchro-

nize other converters in the system or to implement a

two-phase boost converter with a second MAX16990/

MAX16992. The advantages of a two-phase boost topol-

ogy are lower input and output ripple and simpler thermal

management as the power dissipation is spread over more

components. See the Multiphase Operation section for

further details.

The devices can be synchronized using an external clock

at the FSET/SYNC input. A falling clock edge on FSET/

SYNC turns on the external MOSFET by driving DRV high

after a short delay.

The B, D, and F versions of the devices have spread-spec-

trum oscillators. In these parts, the internal oscillator

frequency is varied dynamically ±6% around the switch-

ing frequency. Spread spectrum can improve system

EMI performance by reducing the height of peaks due

to the switching frequency and its harmonics in the

spectrum. The SYNCO output includes spread-spectrum

modulation when the internal oscillator is used on the B,

D, and F versions. Spread spectrum is not active when an

external clock is applied to the FSET/SYNC pin.

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n-Channel MOSFET Driver

DRV drives the gate of an external n-channel MOSFET.

The driver is powered by the internal regulator (PVL),

which provides approximately 5V. This makes both the

devices suitable for use with logic-level MOSFETs. DRV

can source 750mA and sink 1000mA peak current. The

average current sourced by DRV depends on the switch-

ing frequency and total gate charge of the external

MOSFET (see the Power Dissipation section).

Error Amplier

The devices include an internal transconductance error

amplifier. The noninverting input of the error amplifier is

connected to the internal 1V reference and feedback is

provided at the inverting input. High 700µS open-loop

transconductance and 50MΩ output impedance allow

good closed-loop bandwidth and transient response.

Moreover, the source and sink current capability of 140µA

provides fast error correction during output load tran-

sients.

Slope Compensation

The devices use an internal current-ramp generator for

slope compensation. The internal ramp signal resets at

the beginning of each cycle and slews at a typical rate of

50µA x fSW. The amount of slope compensation needed

depends on the slope of the current ramp in the inductor.

See the Current-Sense Resistor Selection and Setting

Slope Compensation section for further information.

Current Limit

The current-sense resistor (RCS) connected between the

source of the MOSFET and ground sets the current limit.

The ISNS input has a voltage trip level (VCS) of 250mV.

When the voltage produced by the current in the induc-

tor exceeds the current-limit comparator threshold, the

MOSFET driver (DRV) quickly terminates the on-cycle.

In some cases, a short time-constant RC filter could be

required to filter out the leading-edge spike on the sense

waveform in addition to the internal blanking time. The

amplitude and width of the leading edge spike depends

on the gate capacitance, drain capacitance, and switching

speed (MOSFET turn-on time).

Hiccup Operation

The devices incorporate a hiccup mode to protect the

external power components when there is an output

short-circuit. If PGOOD is low (i.e., the output voltage is

less than 85% of its set value) and there are 16 consec-

utive current-limit events, switching is stopped. There is

then a waiting period of 44ms before the device tries to

restart by initiating a soft-start. Note that a short-circuit

on the output places considerable stress on all the power

components even with hiccup mode, so that careful com-

ponent selection is important if this condition is encoun-

tered. For more complete protection against output

short-circuits, a series pMOS switch driven from PGOOD

through a level-shifter can be employed (see Figure 1).

Applications Information

Inductor Selection

Using the following equation, calculate the minimum

inductor value so that the converter remains in continuous

mode operation at minimum output current (IOMIN):

LMIN = (VIN2 x D x η)/(2 x fSW x VOUT x IOMIN)

where:

D = (VOUT + VD - VIN)/(VOUT + VD - VDS)

and:

IOMIN is between 10% and 25% of IOUT

A higher value of IOMIN reduces the required inductance,

but it increases the peak and RMS currents in the switch-

ing MOSFET and inductor. Select IOMIN between 10%

to 25% of the full load current. VD is the forward voltage

drop of the external Schottky diode, D is the duty cycle,

and VDS is the voltage drop across the external switch.

Select an inductor with low DC resistance and with a sat-

uration current (ISAT) rating higher than the peak switch

current limit of the converter.

Input and Output Capacitors

The input current to a boost converter is almost

continuous and the RMS ripple current at the input capac-

itor is low. Calculate the minimum input capacitor value

and maximum ESR using the following equations:

CIN = DIL x D/(4 x fSW x DVQ)

ESRMAX = DVESR/DIL

where DIL = ((VIN - VDS) x D)/(L x fSW).

VDS is the total voltage drop across the external

MOSFET plus the voltage drop across the inductor

ESR. DIL is peak-to-peak inductor ripple current as

calculated above. DVQ is the portion of input ripple due

to the capacitor discharge and DVESR is the contribution

due to ESR of the capacitor. Assume the input capacitor

ripple contribution due to ESR (DVESR) and capacitor

discharge (DVQ) are equal when using a combination of

ceramic and aluminium capacitors. During the converter

turn-on, a large current is drawn from the input source,

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especially at high output-to-input differential. The devices

have an internal soft-start, but a larger input capacitor

than calculated above could be necessary to avoid chat-

tering due to finite hysteresis during turn-on.

In a boost converter, the output capacitor supplies the

load current when the main switch is on. The required out-

put capacitance is high, especially at lower duty cycles.

Also, the output capacitor ESR needs to be low enough

to minimize the voltage drop due to ESR while supporting

the load current. Use the following equations to calculate

the output capacitor for a specified output ripple. All ripple

values are peak-to-peak.

ESR = DVESR/IOUT

COUT = (IOUT x DMAX)/(DVQ x fSW)

where IOUT is the output current, DVQ is the portion of the

ripple due to the capacitor discharge, and DVESR is the

ripple contribution due to the ESR of the capacitor. DMAX

is the maximum duty cycle (i.e., the duty cycle at the

minimum input voltage). Use a combination of low-ESR

ceramic and high-value, low-cost aluminium capacitors

for lower output ripple and noise.

Current-Sense Resistor Selection and Setting

Slope Compensation

Set the current-limit threshold 20% higher than the peak

switch current at the rated output power and minimum

input voltage. Use the following equation to calculate an

initial value for RCS:

RCS = 0.2/{1.2 x [((VOUT x IOUT)/η)/VINMIN + 0.5 x

((VOUT - VINMIN)/VOUT) x (VINMIN/(fSW x L))]}

where η is the estimated efficiency of the converter (use

0.85 as an initial value or consult the graph in the Typical

Operating Characteristics section); VOUT and IOUT are the

output voltage and current, respectively; VINMIN is the min-

imum value of the input voltage; fSW is the switching fre-

quency; and L is the minimum value of the chosen inductor.

The devices use an internal ramp generator for slope

compensation to stabilize the current loop when oper-

ating at duty cycles above 50%. The amount of slope

Figure 1. Application with Output Short-Circuit Protection

MAX16990

MAX16992AUBA

DRV

SUP

GND

INPUT

PGOOD

PVL

FSET/SYNC

COMP

ISNS

VOUT

PVL

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compensation required depends on the down-slope of the

inductor current when the main switch is off. The inductor

down-slope in turn depends on the input to output volt-

age differential of the converter and the inductor value.

Theoretically, the compensation slope should be equal to

50% of the inductor downslope; however, a little higher

than 50% slope is advised. Use the following equation to

calculate the required compensating slope (mc) for the

boost converter:

mc = 0.5 x (VOUT – VIN)/L A/s

The internal ramp signal resets at the beginning of each

cycle and slews at the rate of 50µA x fSW. Adjust the

amount of slope compensation by choosing RSCOMP to

satisfy the following equation:

RSCOMP = (mc x RCS)/(50e-6 x fSW)

In some applications, a filter could be needed between

the current-sense resistor and the ISNS pin to augment

the internal blanking time. Set the RC time constant

just long enough to suppress the leading edge spike of

the MOSFET current. For a given design, measure the

leading spike at the lowest input and rated output load to

determine the value of the RC filter which can be formed

from the slope-compensation resistor and an added

capacitor from ISNS to GND.

MOSFET Selection

The devices drive a wide variety of logic-level n-channel

power MOSFETs. The best performance is achieved

with low-threshold n-channel MOSFETs that specify

on-resistance with a gate-source voltage (VGS) of 5V or

less. When selecting the MOSFET, key parameters can

include:

1) Total gate charge (Qg).

2) Reverse-transfer capacitance or charge (CRSS).

3) On-resistance (RDS(ON)).

4) Maximum drain-to-source voltage (VDS(MAX)).

5) Maximum gate frequencies threshold voltage (VTH(MAX)).

At high switching frequencies, dynamic characteristics

(parameters 1 and 2 of the above list) that predict switch-

ing losses have more impact on efficiency than RDS(ON),

which predicts DC losses. Qg includes all capacitances

associated with charging the gate. The VDS(MAX) of the

selected MOSFET must be greater than the maximum

output voltage setting plus a diode drop (or the maximum

input voltage if greater) plus an additional margin to allow

for spikes at the MOSFET drain due to the inductance in

the rectifier diode and output capacitor path. In addition,

Qg determines the current needed to drive the gate at the

selected operating frequency using the PVL linear regula-

tor and therefore determines the power dissipation of the

IC (see the Power Dissipation section).

Low-Voltage Operation

The devices operate down to a voltage of 4.5V or less on

their SUP pins. If the system input voltage is lower than

this, the circuit can be operated from its own output as

shown in the Typical Application Circuit. At very low input

voltages, it is important to remember that input current will

be high and the power components (inductor, MOSFET

and diode) must be specified for this higher input current.

In addition, the current limit of the devices must be set

high enough so that the limit is not reached during the on-

time of the MOSFET, which would result in output-power

limitation and eventually, entering hiccup mode. Estimate

the maximum input current using the following equation:

IINMAX = ((VOUT x IOUT)/η)/VINMIN + 0.5 x

((VOUT – VINMIN)/VOUT) x (VINMIN/(fSW x L))

where IINMAX is the maximum input current; VOUT and

IOUT are the output voltage and current, respectively; η

is the estimated efficiency (which is lower at low input

voltages due to higher resistive losses); VINMIN is the

minimum value of the input voltage; fSW is the switching

frequency; and L is the minimum value of the chosen

inductor.

Boost Converter Compensation

Refer to Application Note 5587: Selecting External

Components and Compensation for Automotive Step-Up

DC-DC Regulator with Preboost Reference Design.

SEPIC Operation

For a reference example of using the devices in SEPIC

mode, see Figure 2.

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Figure 2. SEPIC Bootstrapped 400kHz Application with Low Operating Voltage

Figure 3. Application with Independent Output Overvoltage Protection

MAX16990AUBA

MAX16990AUBB

DRV

SUP

GND

1µF

BATTERY INPUT

2.5V-40V

PVL

PGOOD

PVL

FSET/SYNC

ENABLE

COMP

ISNS

470Ω

22mΩ

69kΩ

3kΩ

330pF

5V/2A

10kΩ

12kΩ

10µH

22µF

27µH 33µF

24x7µF

CERAMIC

2.2µF

SYNCO

REFIN

MAX16990/2_ATC

DRV

SUP

GND

VOUT

INPUT

OVP

PVL

FSET/SYNC

EN ENABLE

COMP

ISNS

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Overvoltage Protection

The “C” and “D” variants of the devices include the over-

voltage protection input. When the OVP pin goes above

110% of the FB regulation voltage, all switching is dis-

abled. For an example application circuit, see Figure 3.

Multiphase Operation

Two boost phases can be implemented with no extra

components, using two ICs as shown in Figure 4. In this

circuit, the SYNCO output of the master device drives the

SYNC input of the slave, forcing it to operate 180° out of

phase. The FB pin of the slave device is connected to

PVL, thus disabling its error amplifier. In this way, the error

amplifier of the master controls both devices by means of

the COMP signal, and good current-sharing is attained

between the two phases. When designing the PCB for a

multiphase converter, it is important to protect the COMP

trace in the layout from noisy signals by placing it on an

inner layer and surrounding it with ground traces.

Using REFIN to Adjust the Output Voltage

The REFIN pin can be used to directly adjust the

reference voltage of the boost converter, thus altering

the output voltage. When not used, REFIN should be

connected to PVL. Because REFIN is a high-impedance

pin, it is simple to drive it by means of an external digital-

to-analog converter (DAC) or a filtered PWM signal.

Figure 4. Two-Phase 400kHz Boost Application with Minimum Component Count

SUP

DRV

VIN

50V/1A

SYNCO

MAX16990

(SLAVE)

ISNS

PVL

GND

SUP DRV

FSET/SYNC

ISNS

PVL

GND

ENABLE

COMP

PGOOD

REFIN

PGOOD

10µH

CERAMIC

20mΩ

75kΩ

1500Ω

22µF

1µF

MAX16990

(MASTER)

1µF

22µF

10kΩ

2.2µF

FSET/SYNC

69kΩ

2200Ω

10µH

20mΩ

2200Ω

2 x 47µF

REFIN

2.2µF

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Power Dissipation

The power dissipation of the IC comes from two sources:

the current consumption of the IC itself and the current

required to drive the external MOSFET, of which the latter

is usually dominant. The total power dissipation can be

estimated using the following equation:

PIC = VSUP x ICC + (VSUP – 5) x (Qg x fSW)

where VSUP is the voltage at the SUP pin of the IC,

ICC is the IC quiescent current consumption or typically

0.75mA (MAX16990) or 1.25mA (MAX16992), Qg is the

total gate charge of the chosen MOSFET at 5V, and fSW

is the switching frequency. PIC reaches its maximum at

maximum VSUP.

/V denotes an automotive qualified part.

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

*EP = Exposed pad.

**Future product—contact factory for availability.

PART FREQUENCY

RANGE

OVP/

SYNCO

SPREAD

SPECTRUM TEMP RANGE PIN-PACKAGE

MAX16990AUBA/V+ 220kHz to 1MHz None Off -40°C to +125°C 10 μMAX-EP*

MAX16990AUBB/V+ 220kHz to 1MHz None On -40°C to +125°C 10 μMAX-EP*

MAX16990ATCC/V+ 220kHz to 1MHz OVP Off -40°C to +125°C 12 TQFN-EP*

MAX16990ATCD/V+ 220kHz to 1MHz OVP On -40°C to +125°C 12 TQFN-EP*

MAX16990ATCD/VY+ 220kHz to 1MHz OVP On -40°C to +125°C 12 SWTQFN-EP*

MAX16990ATCE/V+ 220kHz to 1MHz SYNCO Off -40°C to +125°C 12 TQFN-EP*

MAX16990ATCF/V+ 220kHz to 1MHz SYNCO On -40°C to +125°C 12 TQFN-EP*

MAX16992AUBA/V+ 1MHz to 2.5MHz None Off -40°C to +125°C 10 μMAX-EP*

MAX16992AUBB/V+ 1MHz to 2.5MHz None On -40°C to +125°C 10 μMAX-EP*

MAX16992ATCC/V+ 1MHz to 2.5MHz OVP Off -40°C to +125°C 12 TQFN-EP*

MAX16992ATCD/V+ 1MHz to 2.5MHz OVP On -40°C to +125°C 12 TQFN-EP*

MAX16992ATCD/VY+ 1MHz to 2.5MHz OVP On -40°C to +125°C 12 SWTQFN-EP*

MAX16992ATCE/V+ 1MHz to 2.5MHz SYNCO Off -40°C to +125°C 12 TQFN-EP*

MAX16992ATCF/VY+** 1MHz to 2.5MHz SYNCO On -40°C to +125°C 12 SWTQFN-EP*

PACKAGE

TYPE

PKG

CODE

OUTLINE

NO.

LAND

PATTERN

NO.

12 SWTQFN-EP T1233Y+4 21-100171 90-100060

12 TQFN-EP T1233+4 21-0136 90-0019

10 μMAX-EP U10E+3 21-0109 90-0148

Ordering Information

Chip Information

PROCESS: BiCMOS

Package Information

For the latest package outline information and land patterns (foot-

prints), go to www.maximintegrated.com/packages. Note that

a “+”, “#”, or “-” in the package code indicates RoHS status only.

Package drawings may show a different suffix character, but the

drawing pertains to the package regardless of RoHS status.

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REVISION

NUMBER

REVISION

DATE DESCRIPTION PAGES

CHANGED

0 3/13 Initial release —

1 4/13 Added EP to µMAX package in Pin Descriptions 9–11

2 4/13 Corrected errors in TOCs 21 and 29 7, 8

3 7/13 Removed future product asterisks from Ordering Information 18

4 2/15 Update the Benefits and Features section 1

5 7/15 Corrected value in Figure 2, changing inductor value from 22mF to 22mH16

6 8/15 Corrected part number in Typical Application Circuit 1

7 2/17

Replaced toc18 in Typical Operating Characteristics, added MAX16992ATCF/VY+ in

Ordering Information as a future product, and added SWTQFN-EP (package code

T1233Y+4) in Package Information sections

7, 18

8 7/17 Added Note 3 to SUP Operating Supply Range in the Electrical Characteristics table 2

9 9/17 Deleted Note 3 in and after the Electrical Characteristics table 2, 4

10 5/18 Replaced Figure 4 and added MAX16990ATCD/VY+** to Ordering Information 17,18

11 8/18 Added MAX16992ATCD/VY+ to Ordering Information as a future product 18

12 10/18 Removed future product status from MAX16990ATCD/VY+ in Ordering Information 18

Revision History

Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses

are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)

shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.

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