19-1960; Rev 4; 8/05
Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP -II)
General Description
The MAX1718 step-down controller is intended for core
CPU DC-DC converters in notebook computers. It fea-
tures a dynamically adjustable output, ultra-fast transient
response, high DC accuracy, and high efficiency need-
ed 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) over a 0.6V to
1.75V range. The MAX1718 has an internal multiplexer
that accepts three unique 5-bit VID DAC codes corre-
sponding 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 tran-
sitions.
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. Voltage-
positioning 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 bat-
tery) at a higher switching frequency allows the mini-
mum possible physical size.
The MAX1718 is available in a 28-pin QSOP package.
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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
MAX1718
Ordering Information
PART
MAX1718EEI
MAX1718BEEI+
MAX1718BEEI
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 QSOP
28 QSOP
28 QSOP
28 QSOP
MAX1718BEEIB+
-40°C to +85°C
+Denotes
lead-free package.
Minimal Operating Circuit
5V INPUT
BATT 2V TO 28V
V
CC
SKP/SDN
SHUTDOWN
ILIM
V
DD
V+
BST
MAX1718
DH
D0
D1
DUAL MODE VID
MUX INPUTS
D2
D3
D4
ZMODE
SUS
S0
S1
TIME
CC
REF
TON
VGATE
OVP
FB
NEG
POS
LX
DL
GND
OUTPUT
0.6V TO 1.75V
Applications
IMVP-II™ Notebook Computers
2-Cell to 4-Cell Li+ Battery to CPU Core Supply
Converters
5V to CPU Core Supply Converters
Pin Configuration appears at end of data sheet.
MUX CONTROL
SUSPEND
INPUT
DECODER
VCC
†
Patent pending.
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
IMVP-II is a trademark of Intel Corp.
POWER-GOOD
OUTPUT
________________________________________________________________
Maxim Integrated Products
1
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.
Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP -II)
MAX1718
ABSOLUTE MAXIMUM RATINGS
V+ to GND ..............................................................-0.3V to +30V
V
CC
, V
DD
to 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
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.
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V+ = 15V, V
CC
= V
DD
= SKP/SDN
= 5V, V
OUT
= 1.25V,
T
A
= 0°C to +85°C,
unless otherwise noted.)
PARAMETER
PWM CONTROLLER
Input Voltage Range
Battery voltage, V+
V
CC
, V
DD
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
2
4.5
-1
-1.5
5
-0.2
0.4
-80
0.81
-8
-12
-12
230
165
320
465
260
190
355
515
400
300
700
<1
25
SKP/SDN = GND
SKP/SDN = GND
SKP/SDN = GND, V
CC
= V
DD
= 0V or 5V
V
CC
= 4.5V to 5.5V, no REF load
1.98
2
<1
<1
2
+0.2
2.5
+80
0.91
+8
+12
+12
290
215
390
565
500
375
1200
5
40
5
5
5
2.02
ns
ns
%
28
5.5
+1
+1.5
V
%
%
mV
µA
V
mV
V/V
CONDITIONS
MIN
TYP
MAX
UNITS
DC Output Voltage Accuracy
Line Regulation Error
Input Bias Current
POS, NEG Common-Mode Range
POS, NEG Differential Range
POS, NEG Offset Gain
TIME Frequency Accuracy
V
CC
= 4.5V to 5.5V, V
BATT
= 4.5V to 28V
FB, POS, NEG
POS - NEG
∆V
FB
/ (POS - NEG); POS - NEG = 50mV
150kHz nominal, R
TIME
= 120kΩ
380kHz nominal, R
TIME
= 47kΩ
38kHz nominal, R
TIME
= 470kΩ
V+ = 5V, FB = 1.2V, TON = GND (1000kHz)
TON = REF (550kHz)
V+ = 12V, FB = 1.2V
TON = open (300kHz)
TON = V
CC
(200kHz)
0.86
On-Time (Note 1)
Minimum Off-Time (Note 1)
BIAS AND REFERENCE
Quiescent Supply Current (V
CC
)
Quiescent Supply Current (V
DD
)
Quiescent Battery Supply
Current (V+)
Shutdown Supply Current (V
CC
)
Shutdown Supply Current (V
DD
)
Shutdown Battery Supply
Current (V+)
Reference Voltage
2
TON = V
CC
, open, or REF (200kHz, 300kHz, or 550kHz)
TON = GND (1000kHz)
Measured at V
CC
, FB forced above the regulation point
Measured at V
DD
, FB forced above the regulation point
µA
µA
µA
µA
µA
µA
V
_______________________________________________________________________________________
Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP -II)
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V+ = 15V, V
CC
= V
DD
= SKP/SDN = 5V, V
OUT
= 1.25V,
T
A
= 0°C to +85°C,
unless otherwise noted.)
PARAMETER
Reference Load Regulation
REF Sink Current
FAULT PROTECTION
Overvoltage Trip Threshold
Overvoltage Fault Propagation
Delay
Output Undervoltage Fault
Protection Threshold
Output Undervoltage Fault
Propagation Delay
Output Undervoltage Fault
Blanking Time
Current-Limit Threshold Voltage
(Positive, Default)
Current-Limit Threshold Voltage
(Positive, Adjustable)
Current-Limit Threshold Voltage
(Negative)
Current-Limit Threshold Voltage
(Zero Crossing)
Current-Limit Default
Switchover Threshold
Thermal Shutdown Threshold
V
CC
Undervoltage Lockout
Threshold
VGATE Lower Trip Threshold
VGATE Upper Trip Threshold
VGATE Propagation Delay
VGATE Output Low Voltage
VGATE Leakage Current
GATE DRIVERS
DH Gate Driver On-Resistance
DL Gate Driver On-Resistance
DH Gate-Driver Source/Sink
Current
DL Gate-Driver Sink Current
BST - LX forced to 5V
DL, high state (pullup)
DL, low state (pulldown)
DH forced to 2.5V, BST - LX forced to 5V
DL forced to 2.5V
1.0
1.0
0.4
1.6
4
3.5
3.5
1.0
Ω
Ω
A
A
Hysteresis = 10°C
Rising edge, hysteresis = 20mV, PWM disabled below
this level
Measured at FB with respect to unloaded output voltage
Measured at FB with respect to unloaded output voltage
FB forced 2% outside VGATE trip threshold
I
SINK
= 1mA
High state, forced to 5.5V
4.1
-12
+8
-10
+10
10
0.4
1
Measured at FB
FB forced 2% above trip threshold
With respect to unloaded output voltage
FB forced 2% below trip threshold
From SKP/SDN signal going high, clock speed set by R
TIME
GND - LX, ILIM = V
CC
GND - LX
LX - GND, ILIM = V
CC
GND - LX
3
T
A
= +25°C to +85°C
T
A
= 0°C to +85°C
ILIM = 0.5V
ILIM = REF (2V)
90
85
35
165
-140
50
200
-117
4
V
CC
- 1 V
CC
- 0.4
150
4.4
-8
+12
65
1.95
2.00
10
70
10
256
100
110
115
65
230
-95
mV
mV
mV
mV
V
°C
V
%
%
µs
V
µA
75
2.05
V
µs
%
µs
I
REF
= 0µA to 50µA
REF in regulation
10
CONDITIONS
MIN
TYP
MAX
0.01
UNITS
V
µA
MAX1718
clks
_______________________________________________________________________________________
3
Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP -II)
MAX1718
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V+ = 15V, V
CC
= V
DD
= SKP/SDN = 5V, V
OUT
= 1.25V,
T
A
= 0°C to +85°C,
unless otherwise noted.)
PARAMETER
DL Gate-Driver Source Current
Dead Time
LOGIC AND I/O
Logic Input High Voltage
Logic Input Low Voltage
DAC B-Mode Programming
Resistor, Low
DAC B-Mode Programming
Resistor, High
D0–D4 Pullup/Pulldown
Logic Input Current
D0–D4, ZMODE, SUS,
OVP
D0–D4, ZMODE, SUS,
OVP
D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
ZMODE = V
CC
D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
ZMODE = V
CC
Entering impedance mode
D0–D4, ZMODE = GND
ZMODE, SUS,
OVP
For high
4 Level Input Logic Levels
(TON, S0, S1)
For open
For REF
For low
SKP/SDN, S0, S1, and TON Input
Current
SKP/SDN, S0, S1, TON forced to GND or V
CC
SKP/SDN = logic high (SKIP mode)
SKP/SDN = open (PWM mode)
SKP/SDN = logic low (shutdown mode)
To enable no-fault mode
I
SKP/SDN
= 0µA
-3
2.8
1.4
12
1.8
Pullup
Pulldown
-1
-1
V
CC
- 0.4
3.15
1.65
3.85
2.35
0.5
+3
6
2.2
0.5
15
2.2
µA
V
95
40
8
+1
+1
2.4
0.8
1.05
V
V
kΩ
kΩ
kΩ
µA
DL forced to 2.5V
DL rising
DH rising
CONDITIONS
MIN
TYP
1.6
35
26
MAX
UNITS
A
ns
SKP/SDN Input Levels
V
SKP/SDN Float Level
V
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V+ = 15V, V
CC
= V
DD
= SKP/SDN = 5V, V
OUT
= 1.25V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
PWM CONTROLLER
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
-1.5
-2.0
-8
-12
-12
230
165
320
465
+1.5
%
+2.0
+8
+12
+12
290
215
390
565
ns
%
CONDITIONS
MIN
TYP
MAX
UNITS
150kHz nominal, R
TIME
= 120kΩ
TIME Frequency Accuracy
380kHz nominal, R
TIME
= 47kΩ
38kHz nominal, R
TIME
= 470kΩ
V+ = 5V, FB = 1.2V, TON = GND (1000kHz)
On-Time (Note 1)
TON = REF (550kHz)
V+ = 12V, FB = 1.2V
TON = open (300kHz)
TON = V
CC
(200kHz)
4
_______________________________________________________________________________________
Notebook CPU Step-Down Controller for Intel
Mobile Voltage Positioning (IMVP -II)
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V+ = 15V, V
CC
= V
DD
= SKP/SDN = 5V, V
OUT
= 1.25V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 2)
PARAMETER
Minimum Off-Time (Note 1)
BIAS AND REFERENCE
Quiescent Supply Current (V
CC
)
Quiescent Supply Current (V
DD
)
Quiescent Battery Supply
Current (V+)
Shutdown Supply Current (V
CC
)
Shutdown Supply Current (V
DD
)
Shutdown Battery Supply
Current (V+)
Reference Voltage
FAULT PROTECTION
Overvoltage Trip Threshold
Output Undervoltage Protection
Threshold
Current-Limit Threshold Voltage
(Positive, Default)
Current-Limit Threshold Voltage
(Positive, Adjustable)
Current-Limit Threshold Voltage
(Negative)
V
CC
Undervoltage Lockout
Threshold
VGATE Lower Trip Threshold
VGATE Upper Trip Threshold
GATE DRIVERS
DH Gate Driver On-Resistance
DL Gate Driver On-Resistance
BST - LX forced to 5V
DL, high state (pullup)
DL, low state (pulldown)
3.5
3.5
1.0
Ω
Ω
Measured at FB
With respect to unloaded output voltage
GND - LX, ILIM = V
CC
GND - LX
LX - GND, ILIM = V
CC
Rising edge, hysteresis = 20mV, PWM disabled below this
level
Measured at FB with respect to unloaded output voltage
Measured at FB with respect to unloaded output voltage
ILIM = 0.5V
ILIM = REF (2V)
1.95
65
80
33
160
-145
4.1
-12.5
+7.5
2.05
75
115
65
240
-90
4.4
-7.5
+12.5
V
%
mV
mV
mV
V
%
%
SKP/SDN = 0
SKP/SDN = 0
SKP/SDN = 0, V
CC
= V
DD
= 0 or 5V
V
CC
= 4.5V to 5.5V, no REF load
1.98
Measured at V
CC
, FB forced above the regulation point
Measured at V
DD
, FB forced above the regulation point
1300
5
40
5
5
5
2.02
µA
µA
µA
µA
µA
µA
V
CONDITIONS
TON = V
CC
, open, or REF (200kHz, 300kHz, or 550kHz)
TON = GND (1000kHz)
MIN
TYP
MAX
500
375
UNITS
ns
MAX1718
_______________________________________________________________________________________
5
