Rainbow Electronics MAX1718 User Manual

MAX1718

Notebook CPU Step-Down Controller for Intel

Mobile Voltage Positioning (IMVP-II)

________________________________________________________________ Maxim Integrated Products 1

19-1960; Rev 3; 8/02

Ordering Information

†

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

V

CC

V

CC

5V INPUT

BATT 2V TO 28V

POWER-GOOD
OUTPUT

SKP/SDN

ILIM

OUTPUT

0.6V TO 1.75V
D0
D1

D2

SHUTDOWN

DL

LX

V+

DH

BST

GND

FB

NEG

POS

VGATE

OVP

V

DD

D3
D4

S1

S0

SUS

MUX CONTROL

SUSPEND

INPUT

DECODER

ZMODE

TIME

CC

REF

TON

DUAL MODE VID

MUX INPUTS

MAX1718

Minimal Operating Circuit

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.

General Description

The MAX1718 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-on­time 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) over a 0.6V to

1.75V range. The MAX1718 has an internal multiplexer
that accepts three unique 5-bit VID DAC codes corre­sponding to Performance, Battery, and Suspend modes.
Precision slew-rate control†provides “just-in-time” arrival
at the new DAC setting, minimizing surge currents to
and from the battery.

The internal DAC of the MAX1718B is synchronized to
the slew-rate clock for improved operation under
aggressive power management of newer chipsets and
operating systems that can make incomplete mode tran­sitions.

A pair of complementary offset control inputs allows
easy compensation for IR drops in PC board traces or
creation of a voltage-positioned power supply. Voltage­positioning modifies the load-transient response to
reduce output capacitor requirements and total system
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 MAX1718 is available in a 28-pin QSOP package.

Applications

IMVP-II™ Notebook Computers
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 Muxes
♦ Precision-Adjustable V

OUT

Slew Control

♦ 0.6V to 1.75V Output Adjust Range
♦ Precision Offset Control
♦ 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) I

CC

Supply Current

♦ 2µA (typ) Shutdown Supply Current
♦ 2V ±1% Reference Output
♦ VGATE Blanking During Transition
♦ Small 28-Pin QSOP Package

Pin Configuration appears at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX1718EEI -40°C to +85°C 28 QSOP

MAX1718BEEI -40°C to +85°C 28 QSOP

MAX1718

Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP-II)

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

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

OUT

= 1.25V, 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

V

CC

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

D0–D4, ZMODE, VGATE, OVP, SUS, to GND .........-0.3V to +6V

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

ILIM, CC, REF, POS, NEG, S1, S0,

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

CC

+ 0.3V)

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

DD

+ 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

28-Pin QSOP (derate 10.8mW/°C above +70°C).........860mW

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

PARAMETER CONDITIONS MIN TYP MAX UNITS

V

228

4.5 5.5

Battery voltage, V+

VCC, V

DD

Input Voltage Range

DC Output Voltage Accuracy

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

DAC codes from 0.9V to 1.75V

DAC codes from 0.6V to 0.875V

-1 +1

-1.5 +1.5

%

%

Line Regulation Error VCC= 4.5V to 5.5V, V

BATT

= 4.5V to 28V

5

mV

Input Bias Current FB, POS, NEG

-0.2 +0.2

µA

V

0.4 2.5

POS, NEG Common-Mode Range

TIME Frequency Accuracy

150kHz nominal, R

TIME

= 120kΩ

380kHz nominal, R

TIME

= 47kΩ

38kHz nominal, R

TIME

= 470kΩ

V+ = 5V, FB = 1.2V, TON = GND (1000kHz)

-8 +8

-12 +12

-12 +12

230 260 290

%

ns

165 190 215

320 355 390

465 515 565

TON = REF (550kHz)

TON = open (300kHz)

TON = VCC(200kHz)

V+ = 12V, FB = 1.2V

On-Time (Note 1)

Minimum Off-Time (Note 1)

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

TON = GND (1000kHz)

400 500

300 375

ns

µA

700 1200

Measured at VCC, FB forced above the regulation pointQuiescent Supply Current (VCC)

Quiescent Supply Current (VDD) Measured at VDD, FB forced above the regulation point

<1 5

µA

µA

25 40

Quiescent Battery Supply
Current (V+)

Shutdown Supply Current (VCC)

Shutdown Supply Current (VDD)

SKP/SDN = GND
SKP/SDN = GND

25

<1 5

µA

µA

µA

<1 5

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

Shutdown Battery Supply
Current (V+)

Reference Voltage VCC= 4.5V to 5.5V, no REF load

1.98 2 2.02

V

mV

-80 +80

POS - NEGPOS, NEG Differential Range

V/V

0.81 0.86 0.91

∆V

FB

/ (POS - NEG); POS - NEG = 50mVPOS, NEG Offset Gain

PWM CONTROLLER

BIAS AND REFERENCE

MAX1718

Notebook CPU Step-Down Controller for Intel

Mobile Voltage Positioning (IMVP-II)

_______________________________________________________________________________________ 3

Current-Limit Threshold Voltage
(Zero Crossing)

4

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

10

µs

Output Undervoltage Fault
Protection Threshold

65 70 75

%

Overvoltage Fault Propagation
Delay

10

µs

Current-Limit Threshold Voltage
(Positive, Default)

90 100 110

Current-Limit Threshold Voltage
(Positive, Adjustable)

35 50 65

mV

165 200 230

REF Sink Current

Reference Load Regulation

0.01

V

10

µA

Overvoltage Trip Threshold

1.95 2.00 2.05

V

Current-Limit Threshold Voltage
(Negative)

-140 -117 -95

mV

Thermal Shutdown Threshold

150

°C

VCCUndervoltage Lockout
Threshold

4.1 4.4

V

1.0 3.5

DL Gate Driver On-Resistance

0.4 1.0

Ω

DH Gate-Driver Source/Sink
Current

1.6

A

DL Gate-Driver Sink Current

4

A

CONDITIONS

LX - GND, ILIM = V

CC

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

CC

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

I

REF

= 0µA to 50µA

DL forced to 2.5V

REF in regulation

Measured at FB

mV

VGATE Lower Trip Threshold

-12 -10 -8

%Measured at FB with respect to unloaded output voltage

VGATE Upper Trip Threshold

+8 +10 +12

%Measured at FB with respect to unloaded output voltage

VGATE Propagation Delay

10

µsFB forced 2% outside VGATE trip threshold

VGATE Output Low Voltage

0.4

VI

SINK

= 1mA

VGATE Leakage Current

1

µAHigh state, forced to 5.5V

ELECTRICAL CHARACTERISTICS (continued)

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

OUT

= 1.25V, TA= 0°C to +85°C, unless otherwise noted.)

FAULT PROTECTION

GATE DRIVERS

MAX1718

Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP-II)

4 _______________________________________________________________________________________

ELECTRICAL CHARACTERISTICS

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

OUT

= 1.25V, TA= -40°C to +85°C, unless otherwise noted.) (Note 2)

ELECTRICAL CHARACTERISTICS (continued)

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

OUT

= 1.25V, TA= 0°C to +85°C, unless otherwise noted.)

-8 +8

-2.0 +2.0

-1.5 +1.5

MIN TYP MAX

-12 +12

-12 +12

230 290

165 215

320 390

465 565

TON = VCC(200kHz)

TON = open (300kHz)

TON = REF (550kHz)

V+ = 12V, FB = 1.2V

On-Time (Note 1)

V+ = 5V, FB = 1.2V, TON = GND (1000kHz)

38kHz nominal, R

TIME

= 470kΩ

380kHz nominal, R

TIME

= 47kΩ

150kHz nominal, R

TIME

= 120kΩ

TIME Frequency Accuracy

DAC codes from 0.6V to 0.875V

DAC codes from 0.9V to 1.75V

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

CONDITIONS

DC Output Voltage Accuracy

PARAMETER UNITS

%

%

ns

PWM CONTROLLER

V

SKP/SDN Float Level

I

SKP/SDN

= 0µA

1.8 2.2

PARAMETER CONDITIONS MIN TYP MAX UNITS

A

1.6

DL forced to 2.5VDL Gate-Driver Source Current

D0–D4 Pullup/Pulldown Entering impedance mode

Pullup

Pulldown

40

8

kΩ

µA

-1 +1

-1 +1

D0–D4, ZMODE = GND
ZMODE, SUS, OVP

Logic Input Current

4 Level Input Logic Levels
(TON, S0, S1)

For high

For open

For REF

For low

VCC- 0.4

3.15 3.85

1.65 2.35

0.5

V

µA

-3 +3

SKP/SDN, S0, S1, TON forced to GND or V

CC

SKP/SDN, S0, S1, 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

V

12 15

0.5

1.4 2.2

2.8 6

kΩ

95

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
ZMODE = V

CC

DAC B-Mode Programming
Resistor, High

kΩ

1.05

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
ZMODE = V

CC

DAC B-Mode Programming
Resistor, Low

V

0.8

D0–D4, ZMODE, SUS, OVP

Logic Input Low Voltage

V

2.4

D0–D4, ZMODE, SUS, OVP

Logic Input High Voltage

26

DH rising

ns

35

DL rising

Dead Time

LOGIC AND I/O

MAX1718

Notebook CPU Step-Down Controller for Intel

Mobile Voltage Positioning (IMVP-II)

_______________________________________________________________________________________ 5

ELECTRICAL CHARACTERISTICS (continued)

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

OUT

= 1.25V, TA= -40°C to +85°C, unless otherwise noted.) (Note 2)

Measured at VDD, FB forced above the regulation point µA

5

Quiescent Supply Current (VDD)

µA

40

Quiescent Battery Supply
Current (V+)

SKP/SDN = 0

SKP/SDN = 0

µA

5

Shutdown Supply Current (VDD)

µA

5

Shutdown Supply Current (VCC)

VCC= 4.5V to 5.5V, no REF load

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

CONDITIONS

V

1.98 2.02

Reference Voltage

µA

5

Shutdown Battery Supply
Current (V+)

UNITSMIN TYP MAXPARAMETER

Measured at FB

DL, low state (pulldown)

DL, high state (pullup)

GND - LX

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

GND - LX, ILIM = V

CC

With respect to unloaded output voltage

LX - GND, ILIM = V

CC

Ω

1.0

3.5

DL Gate Driver On-Resistance

V

4.1 4.4

VCCUndervoltage Lockout
Threshold

mV

-145 -90

Current-Limit Threshold Voltage
(Negative)

V

1.95 2.05

Overvoltage Trip Threshold

160 240

mV

33 65

Current-Limit Threshold Voltage
(Positive, Adjustable)

mV

80 115

Current-Limit Threshold Voltage
(Positive, Default)

%

65 75

Output Undervoltage Protection
Threshold

ILIM = 0.5V

ILIM = REF (2V)

Measured at VCC, FB forced above the regulation point µA

1300

Quiescent Supply Current (VCC)

BST - LX forced to 5V Ω

3.5

DH Gate Driver On-Resistance

TON = GND (1000kHz)

ns

375

Minimum Off-Time (Note 1)

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

500

Measured at FB with respect to unloaded output voltage %

-12.5 -7.5

VGATE Lower Trip Threshold

Measured at FB with respect to unloaded output voltage %

+7.5 +12.5

VGATE Upper Trip Threshold

BIAS AND REFERENCE

FAULT PROTECTION

GATE DRIVERS

MAX1718

Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP-II)

6 _______________________________________________________________________________________

Typical Operating Characteristics

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

OUT

= 1.25V, TA= +25°C, unless otherwise noted.)

95

50-

0.01 0.1 1 10 100

EFFICIENCY vs. LOAD CURRENT

300kHz VOLTAGE POSITIONED

MAX1718 toc01

LOAD CURRENT (A)

EFFICIENCY (%)

65

75

85

80

70

60

55

90

SKIP MODE
V+ = 7V

SKIP MODE
V+ = 20V

PWM MODE
V+ = 12V

PWM MODE
V+ = 20V

SKIP MODE
V+ = 12V

PWM MODE
V+ = 7V

400

300

200

100

0

01051520

FREQUENCY vs. LOAD CURRENT

MAX1718 toc02

LOAD CURRENT (A)

FREQUENCY (kHz)

PWM MODE

SKIP MODE

250

280

270

260

290

300

310

320

330

340

350

7.0 13.810.4 17.2 20.6 24.0

FREQUENCY vs. INPUT VOLTAGE

MAX1718 toc03

INPUT VOLTAGE (V)

FREQUENCY (kHz)

I

OUT

= 18A

I

OUT

= 3A

323.0

324.0

323.5

325.0

324.5

325.5

326.0

-40 10-15 35 60 85

FREQUENCY vs. TEMPERATURE

MAX1718 toc04

TEMPERATURE (°C)

FREQUENCY (kHz)

I

OUT

= 19A

20

30

25

40

35

45

50

-40 10-15 35 60 85

OUTPUT CURRENT AT CURRENT LIMIT

vs. TEMPERATURE

MAX1718 toc05

TEMPERATURE (°C)

CURRENT (A)

0

300

200

100

400

500

600

700

800

900

1000

5 10152025

NO-LOAD SUPPLY CURRENT

vs. INPUT VOLTAGE

MAX1718\ toc06

INPUT VOLTAGE (V)

SUPPLY CURRENT (µA)

ICC + I

DD

I+

Note 1: On-Time specifications are measured from 50% to 50% at the DH pin, with LX forced to 0V, 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 2: Specifications to T

A

= -40°C are guaranteed by design and not production tested.

ELECTRICAL CHARACTERISTICS (continued)

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

OUT

= 1.25V, TA= -40°C to +85°C, unless otherwise noted.) (Note 2)

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
ZMODE = V

CC

kΩ

95

DAC B-Mode Programming
Resistor, High

D0–D4, ZMODE, SUS, OVP

V

0.8

Logic Input Low Voltage

CONDITIONS UNITSMIN TYP MAXPARAMETER

D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
ZMODE = V

CC

kΩ

1.05

DAC B-Mode Programming
Resistor, Low

D0–D4, ZMODE, SUS, OVP

V

2.4

Logic Input High Voltage

LOGIC AND I/O

MAX1718

Notebook CPU Step-Down Controller for Intel

Mobile Voltage Positioning (IMVP-II)

_______________________________________________________________________________________ 7

Typical Operating Characteristics (continued)

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

OUT

= 1.25V, TA= +25°C, unless otherwise noted.)

NO-LOAD SUPPLY CURRENT

40

35

30

25

20

15

SUPPLY CURRENT (mA)

10

5

0

5 10152025

A

vs. INPUT VOLTAGE

ICC + I

I+

INPUT VOLTAGE (V)

STARTUP WAVEFORM

(PWM MODE, NO LOAD)

DD

MAX1718 toc09

MAX1718 toc07

A

B

A = V

OUT

B = INDUCTOR CURRENT, 10A/div

A

LOAD-TRANSIENT RESPONSE

(SKIP MODE)

40

µs/div

, 50mV/div, AC-COUPLED

MAX1718 toc08a

A

B0A

0A

STARTUP WAVEFORM

(PWM MODE, I

OUT

= 12A)

MAX1718 toc10

A

LOAD-TRANSIENT RESPONSE

(PWM MODE)

40

µs/div

A = V

, 50mV/div, AC-COUPLED

OUT

B = INDUCTOR CURRENT, 10A/div

MAX1718 toc08b

DYNAMIC OUTPUT VOLTAGE TRANSITION

(PWM MODE)

MAX1718 toc11

B0A

C

100

µs/div

, 1V/div

A = V

OUT

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

BOA

C

100

µs/div

A = V

, 1V/div

OUT

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

BOA

C

D

= 1.15V TO 1.25V

V

OUT

= 3A, R

I

OUT

A = V

OUT

B = INDUCTOR CURRENT, 10A/div
C = VGATE, 5V/div
D = ZMODE, 5V/div

40µs/div

= 62kΩ

TIME

, 100mV/div, AC-COUPLED

MAX1718

Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP-II)

8 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

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

OUT

= 1.25V, TA= +25°C, unless otherwise noted.)

40µs/div

DYNAMIC OUTPUT VOLTAGE TRANSITION

(PWM MODE)

A

MAX1718 toc12

B0A

A = V

OUT

, 500mV/div, AC-COUPLED
B = INDUCTOR CURRENT, 10A/div
C = VGATE, 5V/div
D = SUS, 5V/div

C

D

V

OUT

= 0.7V TO 1.25V

I

OUT

= 3A, R

TIME

= 62kΩ

0.750

0.800

0.775

0.850

0.825

0.900

0.875

0.925

0.5 0.9 1.10.7 1.3 1.5 1.7 1.9

OFFSET FUNCTION SCALE FACTOR

vs. DAC SETTING

MAX1718 toc15

DAC SETTING (V)

POS-NEG SCALE FACTOR

MEASURED

THEORETICAL

1.00

1.10

1.05

1.25

1.20

1.15

1.40

1.35

1.30

1.45

-300 -100-200 0 100 200

OUTPUT VOLTAGE

vs. POS-NEG DIFFERENTIAL

MAX1718 toc16

POS-NEG (mV)

OUTPUT VOLTAGE (V)

SHUTDOWN WAVEFORM

(PWM MODE, NO LOAD)

A

B0A

C

100µs/div

, 1V/div

A = V

OUT

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

MAX1718 toc13

A

B0A

C

SHUTDOWN WAVEFORM

(PWM MODE, I

, 1V/div

A = V

OUT

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

OUT

100µs/div

= 12A)

MAX1718 toc14

MAX1718

Notebook CPU Step-Down Controller for Intel

Mobile Voltage Positioning (IMVP-II)

_______________________________________________________________________________________ 9

Typical Operating Characteristics (continued)

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

OUT

= 1.25V, TA= +25°C, unless otherwise noted.)

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.

V

CC

9

Suspend-Mode Voltage Select Input. S0 and S1 are four-level digital inputs that select the suspend-mode
VID code for the suspend-mode multiplexer inputs. If SUS is high, the suspend-mode VID code is delivered
to the DAC (see the Internal Multiplexers (ZMODE/SUS) section).

S0, S17, 8

6 CC

Integrator Capacitor Connection. Connect a 47pF to 1000pF (47pF typ) capacitor from CC to GND to set the
integration time constant (see the Integrator Amplifiers/Output Voltage Offsets section).

Feedback Offset Adjust Negative Input. The output shifts by an amount equal to the difference between POS
and NEG multiplied by a scale factor that depends on the DAC codes (see the Integrator Amplifiers/Output
Voltage Offsets section). Connect both POS and NEG to REF if the offset function is not used.

NEG5

4 FB Feedback Input. Connect FB to the junction of the external inductor and the positioning resistor (Figure 1).

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 ✕120kΩ / R

TIME

.

TIME3

2

SKP/SDN

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

CC

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

es inductor current recirculation at light loads and suppresses pulse-skipping operation. Forcing SKP/SDN to
12V to 15V disables both the overvoltage protection and undervoltage protection circuits and clears the fault
latch, with otherwise normal pulse-skipping operation. Do not connect SKP/SDN to > 15V.

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

PIN NAME FUNCTION

Pin Description

OUTPUT VOLTAGE DISTRIBUTION

25

20

15

10

SAMPLE PERCENTAGE (%)

5

0

-0.48

-0.24 0.480.240.00
OUTPUT VOLTAGE ERROR (%)

V

OUT

= 1.25V

REFERENCE VOLTAGE DISTRIBUTION

25

MAX1718 toc17

20

15

10

SAMPLE PERCENTAGE (%)

5

0

1.995

1.998 2.0052.0022.000
REFERENCE VOLTAGE (V)

MAX1718 toc18

MAX1718

Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP-II)

10 ______________________________________________________________________________________

Pin Description (continued)

Supply Voltage Input for the DL Gate Driver, 4.5V to 5.5V. Bypass to GND with a 1µF capacitor. V

DD

17

Low-Side Gate Driver Output. DL swings GND to VDD.DL16

Analog and Power Ground. Also connects to the current-limit comparator.GND15

Open-Drain Power-Good Output. VGATE is normally high when the output is in regulation. If VFBis not within
a ±10% window of the DAC setting, VGATE is asserted low. During DAC code transitions, VGATE is forced
high until 1 clock period after the slew-rate controller finishes the transition. VGATE is low during shutdown.

VGATE14

Feedback Offset Adjust Negative Input. The output shifts by an amount equal to the difference between POS
and NEG multiplied by a scale factor that depends on the DAC codes (see the Integrator Amplifiers/Output
Voltage Offsets section). Connect both POS and NEG to REF if the offset function is not used.

POS13

Current-Limit Adjustment. The GND - LX current-limit threshold defaults to 100mV if ILIM is connected to
VCC. In adjustable mode, the current-limit threshold voltage is 1/10th the voltage seen at ILIM over a 0.5V to
3V range. The logic threshold for switchover to the 100mV default value is approximately VCC- 1V. Connect
ILIM to REF for a fixed 200mV threshold.

ILIM12

2V Reference Output. Bypass to GND with 0.22µF (min) capacitor. Can source 50µA for external loads.
Loading REF degrades FB accuracy according to the REF load-regulation error.

REF11

On-Time Selection Control Input. This is a four-level input that sets the K factor (Table 2) to determine
DH on-time. Connect TON to the following pins for the indicated operation:

GND = 1000kHz
REF = 550kHz
Open = 300kHz
V

CC

= 200kHz

TON10

PIN NAME FUNCTION

Suspend-Mode Control Input. When SUS is high, the suspend-mode VID code, as programmed by S0 and
S1, is delivered to the DAC. Connect SUS to GND if the Suspend-mode multiplexer is not used (see the
Internal Multiplexers (ZMODE/SUS) section).

SUS18

Performance-Mode MUX Control Input. If SUS is low, ZMODE selects between two different VID DAC codes.
If ZMODE is low, the VID DAC code is set by the logic-level voltages on D0–D4. On the rising edge of
ZMODE, during power-up with ZMODE high, or on the falling edge of SUS when ZMODE is high, the VID
DAC code is determined by the impedance at D0–D4 (see the Internal Multiplexers (ZMODE/SUS) section).

ZMODE19

Overvoltage Protection Control Input. Connect OVP low to enable overvoltage protection. Connect OVP high
to disable overvoltage protection. The overvoltage trip threshold is approximately 2V. The state of OVP does
not affect output undervoltage fault protection or thermal shutdown.

OVP

20

VID DAC Code Inputs. D0 is the LSB, and D4 is the MSB of the internal 5-bit VID DAC (Table 3). If ZMODE
is low, D0–D4 are high-impedance digital inputs, and the VID DAC code is set by the logic-level voltages on
D0–D4. On the rising edge of ZMODE, during power-up with ZMODE high, or on the falling edge of SUS
when ZMODE is high, the VID DAC code is determined by the impedance at D0–D4 as follows:
Logic low = source impedance is ≤1kΩ + 5%.
Logic high = source impedance is ≥100kΩ - 5%.

D4–D021–25

Boost Flying Capacitor Connection. Connect BST to the external boost diode and capacitor as shown in
Figure 1. An optional resistor in series with BST allows the DH pullup current to be adjusted (Figure 8).

BST26

Inductor Connection. LX is the internal lower supply rail for the DH high-side gate driver. It also connects to
the current-limit comparator and the skip-mode zero-crossing comparator.

LX27

High-Side Gate-Driver Output. DH swings LX to BST.DH28

MAX1718

Notebook CPU Step-Down Controller for Intel

Mobile Voltage Positioning (IMVP-II)

______________________________________________________________________________________ 11

Figure 1. Standard Application Circuit

SHUTDOWN

V

CC

MUX CONTROL

SUSPEND

INPUT

DECODER

C7

1µF

R2

100kΩ

R3

100kΩ

REF

R4

62kΩ

C6

47pF

C5

0.22µF

R18

24.9kΩ

R19

27.4kΩ

10

25

24

23

22

21

19

18

11

12

2

7

8

3

6

9

V

CC

SKP/SDN

TON

D0

D1

D2

D3

D4

ZMODE

SUS

S0

S1

TIME

CC

REF

ILIM

R1

20Ω

MAX1718

V

DD

BST

GND

NEG

POS

VGATE

OVP

5V INPUT

D1
CMPSH-3

IRF7811A

C3

0.1µF

C1
1µF

2x

Q1

2x

Q2

R7

4.75kΩ

BATT 7V TO 24V

L1

0.68µH

SUMIDA

CEP125#4712-TO11

D2
CENTRAL
SEMICONDUCTOR
CMSH5-40

C2, 25V, X5R
5 x 10µF

5V

R5
100kΩ

R8

0.004Ω

POWER-GOOD
OUTPUT

OUTPUT

0.6V TO 1.75V

C4
6 x 270µF, 2V
PANASONIC SP
EEFUE0D271R

17

1

V+

26

28

DH

27

LX

FDS7764A

16

DL

15

4

FB

5

13

R6

511kΩ

14

20