Rainbow Electronics MAX1717 User Manual

General Description

The MAX1717 step-down controller is intended for core CPU DC-DC converters in notebook computers. It features a dynamically adjustable output, ultra-fast transient response, high DC accuracy, and high efficiency needed for leading-edge CPU core power supplies. Maxim’s proprietary Quick-PWM™ quick-response, constant-on-time PWM control scheme handles wide input/output voltage ratios with ease and provides 100ns “instant-on” response to load transients while maintaining a relatively constant switching frequency.

The output voltage can be dynamically adjusted through the 5-bit digital-to-analog converter (DAC) inputs over a 0.925V to 2V range. A unique feature of the MAX1717 is an internal multiplexer (mux) that accepts two 5-bit DAC settings with only five digital input pins. Output voltage transitions are accomplished with a proprietary precision slew-rate control†that minimizes surge currents to and from the battery while guaranteeing “just-in-time” arrival at the new DAC setting.

High DC precision is enhanced by a two-wire remotesensing scheme that compensates for voltage drops in the ground bus and output voltage rail. Alternatively, the remote-sensing inputs can be used together with the MAX1717’s high DC accuracy to implement a voltage-positioned circuit that modifies the load-transient response to reduce output capacitor requirements and full-load power dissipation.

Single-stage buck conversion allows these devices to directly step down high-voltage batteries for the highest possible efficiency. Alternatively, two-stage conversion (stepping down the +5V system supply instead of the battery) at a higher switching frequency allows the minimum possible physical size.

The MAX1717 is available in a 24-pin QSOP package.

Applications

Notebook Computers with SpeedStep™ or Other Dynamically Adjustable Processors

2-Cell to 4-Cell Li+ Battery to CPU Core Supply Converters

5V to CPU Core Supply Converters

Features

♦ Quick-PWM Architecture

♦ ±1% V

OUT

Accuracy Over Line and Load

♦ 5-Bit On-Board DAC with Input Mux

♦ Precision-Adjustable V

OUT

Slew Control

♦ 0.925V to 2V Output Adjust Range

♦ Supports Voltage-Positioned Applications

♦ 2V to 28V Battery Input Range

♦ Requires a Separate +5V Bias Supply

♦ 200/300/550/1000kHz Switching Frequency

♦ Over/Undervoltage Protection

♦ Drives Large Synchronous-Rectifier FETs

♦ 700µA (typ) ICCSupply Current

♦ 2µA (typ) Shutdown Supply Current

♦ 2V ±1% Reference Output

♦ VGATE Transition-Complete Indicator

♦ Small 24-Pin QSOP Package

MAX1717

Dynamically Adjustable, Synchronous

Step-Down Controller for Notebook CPUs

________________________________________________________________ Maxim Integrated Products 1

19-1636; Rev 2; 2/02

PART

MAX1717EEG -40°C to +85°C

TEMP RANGE PIN-PACKAGE

24 QSOP

Ordering Information

Pin Configuration appears at end of data sheet.

†

Patent pending. Quick-PWM is a trademark of Maxim Integrated Products. SpeedStep is a trademark of Intel Corp.

TIME

VGATE

BST

+5V INPUT

ILIM

GNDS

FBS

REF

TON

GND

MAX1717

V+

SKP/SDN

OUTPUT

0.925V TO 2V

DAC

INPUTS

BATTERY

2.5V TO 28V

A/B

Minimal Operating Circuit

EVALUATION KIT

AVAILABLE

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.

MAX1717

Dynamically Adjustable, Synchronous Step-Down Controller for Notebook CPUs

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1, V+ = +15V, VCC= VDD= SKP/SDN = +5V, V

OUT

= 1.6V, TA= 0°C to +85°C, unless otherwise noted.)

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+ to GND ..............................................................-0.3V to +30V

, VDDto GND .....................................................-0.3V to +6V

D0–D4, A/B, VGATE, to GND ..................................-0.3V to +6V

SKP/SDN to GND ...................................................-0.3V to +16V

ILIM, FB, FBS, CC, REF, GNDS, TON,

TIME to GND ..........................................-0.3V to (V

+ 0.3V)

DL to GND..................................................-0.3V to (V

+ 0.3V)

BST to GND ............................................................-0.3V to +36V

DH to LX .....................................................-0.3V to (BST + 0.3V)

LX to BST..................................................................-6V to +0.3V

REF Short Circuit to GND ...........................................Continuous

Continuous Power Dissipation

24-Pin QSOP (derate 9.5mW/°C above +70°C)..........762mW

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

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

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

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

VCC= 4.5V to 5.5V, no REF load

SKP/SDN = 0, VCC= VDD= 0 or 5V

SKP/SDN = 0

VCC, V

Measured at VDD, FB forced above the regulation point

Battery voltage, V+

Measured at VCC, FB forced above the regulation point

TON = GND (1000kHz)

TON = VCC, open, or REF (200kHz, 300kHz, or 550kHz)

38kHz nominal, R

TIME

= 470kΩ

380kHz nominal, R

TIME

= 47kΩ

150kHz nominal, R

TIME

= 120kΩ

TON = VCC(200kHz)

FB to FBS or GNDS to GND = 0 to 25mV

VCC= 4.5V to 5.5V, V

BATT

= 4.5V to 28V

V+ = 24V, FB = 2V

V+ = 5V, FB = 2V, TON = GND (1000kHz)

CONDITIONS

1.98 2 2.02

DAC codes from 1.3V to 2V

Reference Voltage

µA

<1 5

Shutdown Battery Supply Current (V+)

µA

<1 5

-1 1

Shutdown Supply Current (VDD)

µA

Shutdown Supply Current (VCC)

µA

25 40

DAC codes from 0.925V to 1.275V

Quiescent Battery Supply Current (V+)

µA

<1 5

-1.2 1.2

Quiescent Supply Current (VDD)

µA

700 1200

TON = open (300kHz)

Quiescent Supply Current (VCC)

300 375

TON = REF (550kHz)

Minimum Off-Time (Note 2)

400 500

Minimum Off-Time (Note 2)

375 418 461

260 289 318

135 155 173

375 425 475

On-Time (Note 2)

4.5 5.5

228

Input Voltage Range

-12 +12

-8 +8

TIME Frequency Accuracy

µA

-1 1

GNDS Input Bias Current

Remote Sense Voltage Error

Line Regulation Error

kΩ

115 180 265

FB Input Resistance

UNITSMIN TYP MAXPARAMETER

µA

-0.2 0.2

FBS Input Bias Current

V+ = 4.5V to 28V, includes load regulation error

DC Output Voltage Accuracy (Note 1)

PWM CONTROLLER

BIAS AND REFERENCE

MAX1717

Dynamically Adjustable, Synchronous

Step-Down Controller for Notebook CPUs

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, V+ = +15V, VCC= VDD= SKP/SDN = +5V, V

OUT

= 1.6V, TA= 0°C to +85°C, unless otherwise noted.)

Current-Limit Threshold (Zero Crossing)

mVGND - LX

DH Gate Driver On-Resistance

1.0 3.5

ΩBST - LX forced to 5V

Current-Limit Default Switchover Threshold

3VCC-1 VCC- 0.4 V

TA= 0°C to +85°C

85 115

TA= +25°C to +85°C

ILIM = REF (2V)

ILIM = 0.5V

PARAMETER MIN TYP MAX UNITS

Output Undervoltage Fault Blanking Time

256

clks

Output Undervoltage Fault Propagation Delay

µs

Output Undervoltage Fault Protection Threshold

65 70 75

Overvoltage Fault Propagation Delay

µs

Current-Limit Threshold (Positive, Default)

90 100 110

Current-Limit Threshold (Positive, Adjustable)

35 50 65

165 200 230

REF Sink Current

Reference Load Regulation

0.01

µA

Overvoltage Trip Threshold

2.20 2.25 2.30

Current-Limit Threshold (Negative)

-140 -110 -80

Thermal Shutdown Threshold

150

°C

VCCUndervoltage Lockout Threshold

4.1 4.4

1.0 3.5

DL Gate Driver On-Resistance

0.4 1.0

Ω

DH Gate-Driver Source/Sink Current

1.3

DL Gate-Driver Sink Current

CONDITIONS

LX - GND, ILIM = V

From SKP/SDN signal going high, clock speed set by R

TIME

Hysteresis = 10°C

FB forced 2% below trip threshold

With respect to unloaded output voltage

FB forced 2% above trip threshold

GND - LX, ILIM = V

Rising edge, hysteresis = 20mV, PWM disabled below this level

GND - LX

DL, high state (pullup)

DL, low state (pulldown)

DH forced to 2.5V, BST - LX forced to 5V

REF

= 0 to 50µA

DL forced to 2.5V

REF in regulation

Measured at FB

VGATE Lower Trip Threshold

-8 -6.5 -5

Measured at FB with respect to unloaded output voltage, rising edge, hysteresis = 1%

VGATE Upper Trip Threshold

+10 +12 +14

Measured at FB with respect to unloaded output voltage, rising edge, hysteresis = 1%

VGATE Propagation Delay

µsFB forced 2% outside VGATE trip threshold

VGATE Output Low Voltage

0.4

SINK

= 1mA

VGATE Transition Delay

clkAfter X = Y, clock speed set by R

TIME

VGATE Leakage Current

µAHigh state, forced to 5.5V

GATE DRIVERS

FAULT PROTECTION

MAX1717

Dynamically Adjustable, Synchronous Step-Down Controller for Notebook CPUs

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, V+ = +15V, VCC= VDD= SKP/SDN = +5V, V

OUT

= 1.6V, TA= 0°C to +85°C, unless otherwise noted.)

ELECTRICAL CHARACTERISTICS

(Circuit of Figure 1, V+ = +15V, VCC= VDD= SKP/SDN = +5V, V

OUT

= 1.6V, TA= -40°C to +85°C, unless otherwise noted.) (Note 3)

PARAMETER MIN TYP MAX UNITS

On-Time (Note 2)

375 475

On-Time (Note 2)

136 173

260 318

365 471

Minimum Off-Time (Note 2)

500

Minimum Off-Time (Note 2)

TON = REF (550kHz)

375

TON = open (300kHz)

CONDITIONS

V+ = 5V, FB = 2V, TON = GND (1000kHz)

V+ = 24V, FB = 2V

TON = VCC(200kHz)

TON = VCC, open, or REF (200kHz, 300kHz, or 550kHz)

TON = GND (1000kHz)

TIME Frequency Accuracy

-8 +8

-12 +12 %

-12 +12

150kHz nominal, R

TIME

= 120kΩ

380kHz nominal, R

TIME

= 47kΩ

38kHz nominal, R

TIME

= 470kΩ

-1.7 1.7

DC Output Voltage Accuracy (Note 1)

-1.5 1.5 %

DAC codes from 1.3V to 2V

V+ = 4.5V to 28V, includes load regulation error

DAC codes from 0.925V to 1.275V

PARAMETER CONDITIONS MIN TYP MAX UNITS

1.3

DL forced to 2.5VDL Gate-Driver Source Current

D0–D4 Pullup/Pulldown Entering B mode

Pull up

Pull down

kΩ

µA

-1 1

D0–D4, A/B = 5V A/B

Logic Input Current

TON Input Levels

For TON = VCC(200kHz operation)

For TON = open (300kHz operation)

For TON = REF (550kHz operation)

For TON = GND (1000kHz operation)

VCC- 0.4

3.15 3.85

1.65 2.35

0.5

µA

-3 3

SKP/SDN, TON forced to GND or V

SKP/SDN and TON Input Current

SKP/SDN Input Levels

SKP/SDN = logic high (SKIP mode) SKP/SDN = open (PWM mode) SKP/SDN = logic low (shutdown mode) To enable no-fault mode

12 15

0.5

1.8 2.2

2.8 6

kΩ

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor, A/B = GND

DAC B-Mode Programming Resistor, High

1.05

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor, A/B = GND

DAC B-Mode Programming Resistor, Low

0.8

D0–D4, A/B

Logic Input Low Voltage

2.4

D0–D4, A/B

Logic Input High Voltage

DH rising

DL rising

Dead Time

LOGIC AND I/O

MAX1717

Dynamically Adjustable, Synchronous

Step-Down Controller for Notebook CPUs

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

(Circuit of Figure 1, V+ = +15V, VCC= VDD= SKP/SDN = +5V, V

OUT

=1.6V, TA= -40°C to +85°C, unless otherwise noted.) (Note 3)

VGATE Lower Trip Threshold

-8.4 -4.6

VGATE Upper Trip Threshold

+10 +15

Measured at FB with respect to unloaded output voltage, falling edge, hysteresis = 1%

Measured at FB with respect to unloaded output voltage, rising edge, hysteresis = 1%

ILIM = REF (2V)

ILIM = 0.5V

DAC B-Mode Programming Resistor, Low

kΩ

DAC B-Mode Programming Resistor, High

100

kΩ

Output Undervoltage Protection Threshold

65 75

Current-Limit Threshold (Positive, Default)

80 115

Current-Limit Threshold (Positive, Adjustable)

33 65

160 240

Overvoltage Trip Threshold

2.20 2.30

Current-Limit Threshold (Negative)

-140 -80

VCCUndervoltage Lockout Threshold

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor, A/B = GND

4.1 4.4

DH Gate Driver On-Resistance

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor, A/B = GND

3.5

Ω

DL Gate Driver On-Resistance

3.5

Ω

1.0

Ω

Logic Input High Voltage

2.4

Logic Input Low Voltage

0.8

LX - GND, ILIM = V

With respect to unloaded output voltage

GND - LX, ILIM = V

Rising edge, hysteresis = 20mV, PWM disabled below this level

BST - LX forced to 5V

GND - LX

DL, high state (pullup)

DL, low state (pulldown)

Measured at FB

D0–D4, A/B D0–D4, A/B

PARAMETER MIN TYP MAX UNITS

Quiescent Supply Current (VCC)

1200

µA

Shutdown Battery Supply Current (V+)

µA

Reference Voltage

1.98 2.02

CONDITIONS

Measured at VCC, FB forced above the regulation point

SKP/SDN = 0, VCC= VDD= 0 or 5V

VCC= 4.5V to 5.5V, no REF load

Note 1: Output voltage accuracy specifications apply to DAC voltages from 0.925V to 2V. Includes load-regulation error. Note 2: On-Time specifications are measured from 50% to 50% at the DH pin, with LX forced to 0, BST forced to 5V, and a 500pF

capacitor from DH to LX to simulate external MOSFET gate capacitance. Actual in-circuit times may be different due to MOSFET switching speeds.

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

Shutdown Supply Current (VCC)

µA

Shutdown Supply Current (VDD)

µA

SKP/SDN = 0 SKP/SDN = 0

Quiescent Battery Supply Current (V+)

µA

Quiescent Supply Current (VDD)

µAMeasured at VDD, FB forced above the regulation point

MAX1717

Dynamically Adjustable, Synchronous Step-Down Controller for Notebook CPUs

6 _______________________________________________________________________________________

Typical Operating Characteristics

(Circuit of Figure 1, components of Table 1, V+ = +12V, VDD= VCC= SKP/SDN = +5V, V

OUT

= 1.6V, TA= +25°C, unless otherwise noted.)

0.01 1010.1

EFFICIENCY vs. LOAD CURRENT

300kHz STANDARD APPLICATION,

CIRCUIT 1

100

MAX1717 toc01

LOAD CURRENT (A)

EFFICIENCY (%)

SKIP MODE, V+ = 7V

SKIP MODE, V+ = 12V

SKIP MODE, V+ = 20V

PWM MODE, V+ = 7V

PWM MODE, V+ = 12V

PWM MODE, V+ = 20V

0.01 1010.1

EFFICIENCY vs. LOAD CURRENT

300kHz VOLTAGE POSITIONED, CIRCUIT 2

100

MAX1717 toc02

LOAD CURRENT (A)

EFFICIENCY (%)

SKIP MODE, V+ = 7V

SKIP MODE, V+ = 12V

SKIP MODE, V+ = 20V

PWM MODE, V+ = 12V

PWM MODE, V+ = 20V

PWM MODE, V+ = 7V

0.01 1010.1

EFFECTIVE EFFICIENCY vs. LOAD CURRENT

300kHz VOLTAGE POSITIONED, CIRCUIT 2

100

MAX1717 toc03

NONPOSITIONED LOAD CURRENT (A)

EFFECTIVE EFFICIENCY (%)

SKIP MODE, V+ = 7V

SKIP MODE, V+ = 12V

SKIP MODE, V+ = 20V

PWM MODE, V+ = 7V

PWM MODE, V+ = 12V

PWM MODE, V+ = 20V

0.01 1010.1

EFFICIENCY vs. LOAD CURRENT

550kHz VOLTAGE POSITIONED, CIRCUIT 3

100

MAX1717 toc04

LOAD CURRENT (A)

EFFICIENCY (%)

SKIP MODE, V+ = 7V

SKIP MODE, V+ = 12V

SKIP MODE, V+ = 20V

PWM MODE, V+ = 12V

PWM MODE, V+ = 7V

PWM MODE, V+ = 20V

0.01 1010.1

EFFECTIVE EFFICIENCY vs. LOAD CURRENT

550kHz VOLTAGE POSITIONED, CIRCUIT 3

100

MAX1717 toc05

NONPOSITIONED LOAD CURRENT (A)

EFFECTIVE EFFICIENCY (%)

SKIP MODE, V+ = 7V

SKIP MODE, V+ = 12V

SKIP MODE, V+ = 20V

PWM MODE, V+ = 12V

PWM MODE, V+ = 7V

PWM MODE, V+ = 20V

0.01 1010.1

EFFICIENCY vs. LOAD CURRENT

1000kHz, +5V, CIRCUIT 4

100

MAX1717 toc06

LOAD CURRENT (A)

EFFICIENCY (%)

SKIP MODE

PWM MODE

0.01 1010.1

EFFECTIVE EFFICIENCY vs. LOAD CURRENT

1000kHz, +5V, CIRCUIT 4

100

MAX1717 toc07

NONPOSITIONED LOAD CURRENT (A)

EFFECTIVE EFFICIENCY (%)

SKIP MODE

PWM MODE

0.01 1010.1

EFFICIENCY vs. LOAD CURRENT

1000kHz VOLTAGE POSITIONED,

CIRCUIT 5

100

MAX1717 toc08

LOAD CURRENT (A)

EFFICIENCY (%)

SKIP MODE, V+ = 7V

SKIP MODE, V+ = 12V

SKIP MODE, V+ = 20V

PWM MODE, V+ = 20V

PWM MODE, V+ = 12V

PWM MODE, V+ = 7V

0.01 1010.1

EFFECTIVE EFFICIENCY vs. LOAD CURRENT

1000kHz VOLTAGE POSITIONED,

CIRCUIT 5

100

MAX1717 toc09

NONPOSITIONED LOAD CURRENT (A)

EFFECTIVE EFFICIENCY (%)

SKIP MODE, V+ = 7V

SKIP MODE, V+ = 12V

SKIP MODE, V+ = 20V

PWM MODE, V+ = 20V

PWM MODE, V+ = 12V

PWM MODE, V+ = 7V

MAX1717

Dynamically Adjustable, Synchronous

Step-Down Controller for Notebook CPUs

_______________________________________________________________________________________ 7

400

300

200

100

063912

FREQUENCY vs. LOAD CURRENT

MAX1717 toc10

LOAD CURRENT (A)

FREQUENCY (kHz)

300kHz VOLTAGE POSITIONED, CIRCUIT 2

SKIP MODE

PWM MODE

1250

1000

750

500

250

063912

FREQUENCY vs. LOAD CURRENT

MAX1717 toc11

LOAD CURRENT (A)

FREQUENCY (kHz)

1000kHz VOLTAGE POSITIONED, CIRCUIT 5

SKIP MODE

PWM MODE

400

350

300

250

200

51510 20 25

FREQUENCY vs. INPUT VOLTAGE

MAX1717 toc12

INPUT VOLTAGE (V)

FREQUENCY (kHz)

300kHz VOLTAGE POSITIONED, CIRCUIT 2

OUT

= 12A

OUT

= 0.3A

1200

1000

800

600

400

51510 20 25

FREQUENCY vs. INPUT VOLTAGE

MAX1717 toc13

INPUT VOLTAGE (V)

FREQUENCY (kHz)

1000kHz VOLTAGE POSITIONED, CIRCUIT 5

OUT

= 12A

OUT

= 0.3A

300

310

330

320

340

350

-40 0-20 20 40 60 80 85

FREQUENCY vs. TEMPERATURE

MAX1717 toc14

TEMPERATURE (°C)

FREQUENCY (kHz)

300kHz VOLTAGE POSITIONED, CIRCUIT 2

-40 0 20-20 40 60 8580

OUTPUT CURRENT AT CURRENT LIMIT

vs. TEMPERATURE

MAX1717 toc15

TEMPERATURE (°C)

CURRENT (A)

300kHz VOLTAGE POSITIONED, CIRCUIT 2

1.0

0.5

2.0

1.5

2.5

3.0

0105 152025

CONTINUOUS-TO-DISCONTINUOUS

INDUCTOR CURRENT POINT

MAX1717 toc16

INPUT VOLTAGE (V)

LOAD CURRENT (A)

300kHz VOLTAGE POSITIONED, CIRCUIT 2

513117 9 15 17 19 21 23 25

INDUCTOR CURRENT PEAKS AND

VALLEYS vs. INPUT VOLTAGE

MAX1717 toc17

INPUT VOLTAGE (V)

INDUCTOR CURRENT (A)

AT CURRENT-LIMIT POINT 300kHz VOLTAGE POSITIONED, CIRCUIT 2

PEAK

VALLEY

1000

800

600

400

200

51510 20 25

NO-LOAD SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX1717 toc18

INPUT VOLTAGE (V)

SUPPLY CURRENT (µA)

300kHz VOLTAGE POSITIONED, CIRCUIT 2, SKIP MODE

ICC + I

I+

Typical Operating Characteristics (continued)

(Circuit of Figure 1, components of Table 1, V+ = +12V, VDD= VCC= SKP/SDN = +5V, V

OUT

= 1.6V, TA= +25°C, unless otherwise noted.)

MAX1717

Dynamically Adjustable, Synchronous Step-Down Controller for Notebook CPUs

8 _______________________________________________________________________________________

1000

800

600

400

200

51510 20 25

NO-LOAD SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX1717 toc19

INPUT VOLTAGE (V)

SUPPLY CURRENT (µA)

1000kHz VOLTAGE POSITIONED, CIRCUIT 5, SKIP MODE

ICC + I

I+

51510 20 25

NO-LOAD SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX1717 toc20

INPUT VOLTAGE (V)

SUPPLY CURRENT (mA)

300kHz VOLTAGE POSITIONED, CIRCUIT 2, PWM MODE

ICC + I

I+

51510 20 25

NO-LOAD SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX1717 toc21

INPUT VOLTAGE (V)

SUPPLY CURRENT (mA)

550kHz VOLTAGE POSITIONED, CIRCUIT 3, PWM MODE

ICC + I

I+

51510 20 25

NO-LOAD SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX1717 toc22

INPUT VOLTAGE (V)

SUPPLY CURRENT (mA)

1000kHz VOLTAGE POSITIONED, CIRCUIT 5, PWM MODE

ICC + I

I+

10µs/div

LOAD-TRANSIENT RESPONSE

MAX1717 toc23

A = V

OUT

, 50mV/div, AC-COUPLED

B = INDUCTOR CURRENT, 10A/div

300kHz STANDARD APPLICATION, CIRCUIT 1, PWM MODE

10µs/div

LOAD-TRANSIENT RESPONSE

MAX1717 toc24

A = V

OUT

, 50mV/div, AC-COUPLED

B = INDUCTOR CURRENT, 10A/div

300kHz VOLTAGE POSITIONED, CIRCUIT 2, PWM MODE

5µs/div

LOAD-TRANSIENT RESPONSE

MAX1717 toc25

A = V

OUT

, 50mV/div, AC-COUPLED

B = INDUCTOR CURRENT, 10A/div

550kHz VOLTAGE POSITIONED, CIRCUIT 3, PWM MODE

4µs/div

LOAD-TRANSIENT RESPONSE

MAX1717 toc26

A = V

OUT

, 50mV/div, AC-COUPLED

B = INDUCTOR CURRENT, 10A/div

1000kHz +5V, CIRCUIT 4, PWM MODE

4µs/div

LOAD-TRANSIENT RESPONSE

MAX1717 toc27

A = V

OUT

, 50mV/div, AC-COUPLED

B = INDUCTOR CURRENT, 10A/div

1000kHz VOLTAGE POSITIONED, CIRCUIT 5, PWM MODE

Typical Operating Characteristics (continued)

(Circuit of Figure 1, components of Table 1, V+ = +12V, VDD= VCC= SKP/SDN = +5V, V

OUT

= 1.6V, TA= +25°C, unless otherwise noted.)

MAX1717

Dynamically Adjustable, Synchronous

Step-Down Controller for Notebook CPUs

_______________________________________________________________________________________ 9

100µs/div

STARTUP WAVEFORM

MAX1717 toc28

A = V

OUT

, 1V/div

B = INDUCTOR CURRENT, 10A/div C = SKP/SDN, 5V/div

300kHz VOLTAGE POSITIONED, CIRCUIT 2, PWM MODE, NO LOAD

100µs/div

STARTUP WAVEFORM

MAX1717 toc29

A = V

OUT

, 1V/div

B = INDUCTOR CURRENT, 10A/div C = SKP/SDN, 5V/div

300kHz VOLTAGE POSITIONED, CIRCUIT 2, I

OUT

=12A

50µs/div

DYNAMIC OUTPUT VOLTAGE TRANSITION

MAX1717 toc30

300kHz STANDARD APPLICATION, CIRCUIT 1, PWM MODE, V

OUT

= 1.35V TO 1.6V, I

OUT

= 0.3A,

TIME

= 120kΩ

A = V

OUT

, 200mV/div, AC-COUPLED B = INDUCTOR CURRENT, 10A/div C = VGATE, 5V/div D = A/B, 5V/div

50µs/div

DYNAMIC OUTPUT VOLTAGE TRANSITION

MAX1717 toc31

300kHz STANDARD APPLICATION, CIRCUIT 1, PWM MODE, V

OUT

= 1.35V TO 1.6V,

OUT

= 12A, R

TIME

= 120kΩ

A = V

OUT

, 200mV/div, AC-COUPLED B = INDUCTOR CURRENT, 10A/div C = VGATE, 5V/div D = A/B, 5V/div

20µs/div

DYNAMIC OUTPUT VOLTAGE TRANSITION

MAX1717 toc32

A = V

OUT

, 200mV/div, AC-COUPLED B = INDUCTOR CURRENT, 10A/div C = VGATE, 5V/div D = A/B, 5V/div

1000kHz +5V, CIRCUIT 4, PWM MODE, V

OUT

= 1.35V TO 1.6V,

OUT

= 0.3A, R

TIME

= 51kΩ

40µs/div

OUTPUT OVERLOAD WAVEFORM

MAX1717 toc33

A = V

OUT

, 500mV/div

B = INDUCTOR CURRENT, 10A/div

300kHz VOLTAGE POSITIONED, CIRCUIT 2,

PWM MODE

Typical Operating Characteristics (continued)

(Circuit of Figure 1, components of Table 1, V+ = +12V, VDD= VCC= SKP/SDN = +5V, V

OUT

= 1.6V, TA= +25°C, unless otherwise noted.)

MAX1717

Dynamically Adjustable, Synchronous Step-Down Controller for Notebook CPUs

10 ______________________________________________________________________________________

Pin Description

Typical Operating Characteristics (continued)

(Circuit of Figure 1, components of Table 1, V+ = +12V, VDD= VCC= SKP/SDN = +5V, V

OUT

= 1.6V, TA= +25°C, unless otherwise noted.)

100µs/div

SHUTDOWN WAVEFORM

MAX1717 toc34

300kHz VOLTAGE POSITIONED, CIRCUIT 2, PWM MODE, NO LOAD

A = V

OUT

, 1V/div B = INDUCTOR CURRENT, 10A/div C = SKP/SDN, 5V/div

100µs/div

SHUTDOWN WAVEFORM

MAX1717 toc35

300kHz VOLTAGE POSITIONED, CIRCUIT 2, PWM MODE, I

OUT

= 12A

A = V

OUT

, 1V/div B = INDUCTOR CURRENT, 10A/div C = SKP/SDN, 5V/div

Feedback Remote-Sense Input. For nonvoltage-positioned circuits, connect FBS to V

OUT

directly at the load. FBS internally connects to the integrator that fine tunes the DC output voltage. For voltage-positioned circuits, connect FBS directly to FB near the IC to disable the FBS remote-sense integrator amplifier. To disable all three integrator amplifiers, connect FBS to V

FBS5

Integrator Capacitor Connection. Connect a 100pF to 1000pF (470pF typ) capacitor from CC to GND to set the integration time constant. CC can be left open if FBS is tied to VCC.

CC6

Analog Supply Voltage Input for PWM Core. Connect VCCto the system supply voltage (4.5V to 5.5V) with a series 20Ω resistor. Bypass to GND with a 0.22µF (min) capacitor.

Fast Feedback Input. Connect FB to the junction of the external inductor and output capacitor for nonvoltage-positioned circuits (Figure 1). For voltage-positioned circuits, connect FB to the junction of the external inductor and the positioning resistor (Figure 3).

FB4

Slew-Rate Adjustment Pin. Connect a resistor from TIME to GND to set the internal slew-rate clock. A 470kΩ to 47kΩ resistor sets the clock from 38kHz to 380kHz, f

SLEW

= 150kHz x 120kΩ / R

TIME

TIME3

Combined Shutdown and Skip-Mode Control. Drive SKP/SDN to GND for shutdown. Leave SKP/SDN open for low-noise forced-PWM mode, or drive to V

for normal pulse-skipping operation. Low-noise forced-PWM mode

causes inductor current recirculation at light loads and suppresses pulse-skipping operation. SKP/SDN can also be used to disable over/undervoltage protection circuits and clear the fault latch by forcing it to 12V < SKP/SDN < 15V (with otherwise normal PFM/PWM operation). Do not connect SKP/SDN to > 15V.

SKP/SDN

Battery Voltage Sense Connection. Connect V+ to input power source. V+ is used only for PWM one-shot timing. DH on-time is inversely proportional to input voltage over a range of 2V to 28V.

V+1

FUNCTIONNAME

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