19-1636; Rev 3; 8/05
KIT
ATION
EVALU
BLE
AVAILA
Dynamically Adjustable, Synchronous
Step-Down Controller for Notebook CPUs
General Description
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) I
CC
Supply Current
2µA (typ) Shutdown Supply Current
2V ±1% Reference Output
VGATE Transition-Complete Indicator
Small 24-Pin QSOP Package
MAX1717
The MAX1717 step-down controller is intended for core
CPU DC-DC converters in notebook computers. It fea-
tures a dynamically adjustable output, ultra-fast tran-
sient 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 mini-
mizes 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 remote-
sensing 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 volt-
age-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 mini-
mum possible physical size.
The MAX1717 is available in a 24-pin QSOP package.
Ordering Information
PART
MAX1717EEG
MAX1717EEG+
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
24 QSOP
24 QSOP
+
Denotes lead-free package.
Minimal Operating Circuit
+5V INPUT
V
CC
MAX1717
V
DD
V+
BST
DH
BATTERY
2.5V TO 28V
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
Pin Configuration appears at end of data sheet.
†
P.
SKP/SDN
FBS
ILIM
GNDS
A/B
REF
TON
CC
D0
DAC
INPUTS
D1
D2
D3
D4
OUTPUT
0.925V TO 2V
LX
DL
GND
FB
TIME
VGATE
Quick-PWM is a trademark of Maxim Integrated Products.
SpeedStep is a trademark of Intel Corp.
________________________________________________________________
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.
Dynamically Adjustable, Synchronous
Step-Down Controller for Notebook CPUs
MAX1717
ABSOLUTE MAXIMUM RATINGS
V+ to GND ..............................................................-0.3V to +30V
V
CC
, V
DD
to 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
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
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
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
= 1.6V,
T
A
= 0°C to +85°C,
unless otherwise noted.)
PARAMETER
PWM CONTROLLER
Input Voltage Range
DC Output Voltage Accuracy
(Note 1)
Remote Sense Voltage Error
Line Regulation Error
FB Input Resistance
FBS Input Bias Current
GNDS Input Bias Current
TIME Frequency Accuracy
Battery voltage, V+
V
CC
, V
DD
V+ = 4.5V to 28V,
includes load
regulation error
DAC codes from 1.3V to 2V
DAC codes from 0.925V to 1.275V
2
4.5
-1
-1.2
3
5
180
28
5.5
1
1.2
V
%
%
mV
mV
kΩ
µA
µA
%
CONDITIONS
MIN
TYP
MAX
UNITS
FB to FBS or GNDS to GND = 0 to 25mV
V
CC
= 4.5V to 5.5V, V
BATT
= 4.5V to 28V
115
-0.2
-1
150kHz nominal, R
TIME
= 120kΩ
380kHz nominal, R
TIME
= 47kΩ
38kHz nominal, R
TIME
= 470kΩ
V+ = 5V, FB = 2V, TON = GND (1000kHz)
TON = REF (550kHz)
V+ = 24V, FB = 2V
TON = open (300kHz)
TON = V
CC
(200kHz)
-8
-12
-12
375
135
260
375
265
0.2
1
+8
+12
+12
425
155
289
418
400
300
700
<1
25
475
173
318
461
500
375
1200
5
40
5
5
5
2.02
ns
ns
µA
µA
µA
µA
µA
µA
V
ns
On-Time (Note 2)
Minimum Off-Time (Note 2)
Minimum Off-Time (Note 2)
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
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
2
<1
<1
2
_______________________________________________________________________________________
Dynamically Adjustable, Synchronous
Step-Down Controller for Notebook CPUs
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V+ = +15V, V
CC
= V
DD
= SKP/SDN = +5V, V
OUT
= 1.6V,
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
(Positive, Default)
Current-Limit Threshold
(Positive, Adjustable)
Current-Limit Threshold
(Negative)
Current-Limit Threshold
(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 Transition 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
1.3
4
3.5
3.5
1.0
Ω
Ω
A
A
3
Hysteresis = 10°C
Rising edge, hysteresis = 20mV, PWM disabled below
this level
Measured at FB with respect to unloaded output voltage,
rising edge, hysteresis = 1%
Measured at FB with respect to unloaded output voltage,
rising edge, hysteresis = 1%
FB forced 2% outside VGATE trip threshold
After X = Y, clock speed set by R
TIME
I
SINK
= 1mA
High state, forced to 5.5V
4.1
-8
+10
-6.5
+12
10
1
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
-110
4
V
CC
- 1 V
CC
- 0.4
150
4.4
-5
+14
65
2.20
2.25
10
70
10
256
100
110
115
65
230
-80
75
2.30
V
µs
%
µs
clks
mV
mV
mV
mV
V
°C
V
%
%
µs
clk
V
µA
I
REF
= 0 to 50µA
REF in regulation
10
CONDITIONS
MIN
TYP
MAX
0.01
UNITS
V
µA
MAX1717
_______________________________________________________________________________________
Dynamically Adjustable, Synchronous
Step-Down Controller for Notebook CPUs
MAX1717
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V+ = +15V, V
CC
= V
DD
= SKP/SDN = +5V, V
OUT
= 1.6V,
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, A/B
D0–D4, A/B
D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
A/B = GND
D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
A/B = GND
Entering B mode
D0–D4, A/B = 5V
A/B
For TON = V
CC
(200kHz operation)
TON Input Levels
For TON = open (300kHz operation)
For TON = REF (550kHz operation)
For TON = GND (1000kHz operation)
SKP/SDN and TON Input Current
SKP/SDN, 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
-3
2.8
1.8
12
Pull up
Pull down
-1
-1
V
CC
- 0.4
3.15
1.65
3.85
2.35
0.5
3
6
2.2
0.5
15
µA
V
95
40
8
1
1
2.4
0.8
1.05
kΩ
kΩ
µA
DL forced to 2.5V
DL rising
DH rising
CONDITIONS
MIN
TYP
1.3
35
26
MAX
UNITS
A
ns
SKP/SDN Input Levels
V
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V+ = +15V, V
CC
= V
DD
= SKP/SDN = +5V, V
OUT
= 1.6V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 3)
PARAMETER
DC Output Voltage Accuracy
(Note 1)
V+ = 4.5V to 28V,
includes load
regulation error
CONDITIONS
DAC codes from 1.3V to 2V
DAC codes from 0.925V to 1.275V
MIN
-1.5
-1.7
-8
-12
-12
375
136
260
365
TYP
MAX
1.5
%
1.7
+8
+12
+12
475
173
318
471
500
375
ns
ns
ns
ns
%
UNITS
150kHz nominal, R
TIME
= 120kΩ
TIME Frequency Accuracy
On-Time (Note 2)
On-Time (Note 2)
Minimum Off-Time (Note 2)
Minimum Off-Time (Note 2)
4
380kHz nominal, R
TIME
= 47kΩ
38kHz nominal, R
TIME
= 470kΩ
V+ = 5V, FB = 2V, TON = GND (1000kHz)
TON = REF (550kHz)
V+ = 24V, FB = 2V
TON = open (300kHz)
TON = V
CC
(200kHz)
TON = V
CC
, open, or REF (200kHz, 300kHz, or 550kHz)
TON = GND (1000kHz)
_______________________________________________________________________________________
Dynamically Adjustable, Synchronous
Step-Down Controller for Notebook CPUs
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V+ = +15V, V
CC
= V
DD
= SKP/SDN = +5V, V
OUT
=1.6V,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 3)
PARAMETER
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
Overvoltage Trip Threshold
Output Undervoltage Protection
Threshold
Current-Limit Threshold
(Positive, Default)
Current-Limit Threshold
(Positive, Adjustable)
Current-Limit Threshold
(Negative)
V
CC
Undervoltage Lockout
Threshold
DH Gate Driver On-Resistance
DL Gate Driver On-Resistance
Logic Input High Voltage
Logic Input Low Voltage
DAC B-Mode Programming
Resistor, Low
DAC B-Mode Programming
Resistor, High
VGATE Lower Trip Threshold
VGATE Upper Trip Threshold
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
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
BST - LX forced to 5V
DL, high state (pullup)
DL, low state (pulldown)
D0–D4, A/B
D0–D4, A/B
D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
A/B = GND
D0–D4, 0 to 0.4V or 2.6V to 5.5V applied through resistor,
A/B = GND
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%
100
-8.4
+10
-4.6
+15
2.4
0.8
1
ILIM = 0.5V
ILIM = REF (2V)
1.98
2.20
65
80
33
160
-140
4.1
CONDITIONS
Measured at V
CC
, FB forced above the regulation point
Measured at V
DD
, FB forced above the regulation point
MIN
TYP
MAX
1200
5
40
5
5
5
2.02
2.30
75
115
65
240
-80
4.4
3.5
3.5
1.0
UNITS
µA
µA
µA
µA
µA
µA
V
V
%
mV
mV
mV
V
Ω
Ω
Ω
V
V
kΩ
kΩ
%
%
MAX1717
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.
_______________________________________________________________________________________
5
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