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19-4781; Rev 1; 7/00
KIT
ATION
EVALU
BLE
AVAILA
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
General Description
Features
o
Ultra-High Efficiency
o
No Current-Sense Resistor (Lossless I
LIMIT
)
o
Quick-PWM with 100ns Load-Step Response
o
±1% V
OUT
Accuracy over Line and Load
o
4-Bit On-Board DAC (MAX1710)
o
5-Bit On-Board DAC (MAX1711/MAX1712)
o
0.925V to 2V Output Adjust Range
(MAX1711/MAX1712)
o
2V to 28V Battery Input Range
o
200/300/400/550kHz Switching Frequency
o
Remote GND and V
OUT
Sensing
o
Over/Undervoltage Protection
o
1.7ms Digital Soft-Start
o
Drive Large Synchronous-Rectifier FETs
o
2V ±1% Reference Output
o
Power-Good Indicator
o
Small 24-Pin QSOP Package
MAX1710/MAX1711/MAX1712
The MAX1710/MAX1711 step-down controllers are
intended for core CPU DC-DC converters in notebook
computers. They feature a triple-threat combination of
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 fre-
quency.
High DC precision is ensured by a 2-wire remote-sens-
ing scheme that compensates for voltage drops in both
the ground bus and supply rail. An on-board, digital-to-
analog converter (DAC) sets the output voltage in com-
pliance with Mobile Pentium II
®
CPU specifications.
The MAX1710 achieves high efficiency at a reduced
cost by eliminating the current-sense resistor found in
traditional current-mode PWMs. Efficiency is further
enhanced by an ability to drive very large synchronous-
rectifier MOSFETs.
Single-stage buck conversion allows these devices to
directly step down high-voltage batteries for the highest
possible efficiency. Alternatively, 2-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 MAX1710/MAX1711 are identical except that the
MAX1711 have 5-bit DACs and the MAX1710 has a 4-
bit DAC. Also, the MAX1711 has a fixed overvoltage
protection threshold at V
OUT
= 2.25V and undervoltage
protection at V
OUT
= 0.8V whereas the MAX1710 has
variable thresholds that track V
OUT
. The MAX1711 is
intended for applications where the DAC code may
change dynamically.
Ordering Information
PART
MAX1710EEG
MAX1711EEG
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
24 QSOP
24 QSOP
Minimal Operating Circuit
+5V INPUT
V
CC
SHDN
FBS
ILIM
GNDS
OVP*
V
DD
V+
BST
DH
OUTPUT
0.925V TO 2V
(MAX1711/MAX1712)
BATTERY
4.5V TO 28V
Applications
Notebook Computers
Docking Stations
CPU Core DC-DC Converters
Single-Stage (BATT to V
CORE)
Converters
Two-Stage (+5V to V
CORE
) Converters
MAX1710
MAX1711
REF
MAX1712
LX
CC
D0
DL
PGND
FB
SKIP
Quick-PWM is a trademark of Maxim Integrated Products.
Mobile Pentium II is a registered trademark of Intel Corp.
Pin Configurations appear at end of data sheet.
D/A
INPUTS
D1
D2
D3
D4** GND
*MAX1710 ONLY
**MAX1711/MAX1712 ONLY
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
MAX1710/MAX1711/MAX1712
ABSOLUTE MAXIMUM RATINGS
V+ to GND ..............................................................-0.3V to +30V
V
CC
, V
DD
to GND .....................................................-0.3V to +6V
PGND to GND.....................................................................±0.3V
SHDN,
PGOOD to GND ...........................................-0.3V to +6V
OVP,
ILIM, FB, FBS, CC, REF, D0–D4,
GNDS, TON to GND ..............................-0.3V to (V
CC
+ 0.3V)
SKIP
to GND (Note 1).................................-0.3V to (V
CC
+ 0.3V)
DL to PGND................................................-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 (T
A
= +70°C)
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 Range .............................-65°C to +165°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1:
SKIP
may be forced below -0.3V, temporarily exceeding the absolute maximum rating, for the purpose of debugging proto-
type breadboards using the no-fault test mode. Limit the current drawn to -5mA maximum.
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
BATT
= 15V, V
CC
= V
DD
= 5V,
SKIP
= GND,
T
A
=
0°C to +85°C,
unless otherwise noted.)
PARAMETER
Input Voltage Range
Battery voltage, V+
V
CC,
V
DD
DAC codes from 1.3V to 2V
V
BATT
= 4.5V to 28V, includes
DAC codes from 0.925V
load regulation error
to 1.275V
I
LOAD
= 0 to 7A
FB - FBS or GNDS - GND = 0 to 25mV
V
CC
= 4.5V to 5.5V, V
BATT
= 4.5V to 28V
FB (MAX1710 only) or FBS
-0.2
130
-1
Rising edge of
SHDN
to full I
LIM
TON = GND (550kHz)
V
BATT
= 24V, TON = REF (400kHz)
FB = 2V
TON = open (300kHz)
(Note 2)
TON = V
CC
(200kHz)
(Note 2)
Measured at V
CC
, FB forced above the regulation point
Measured at V
DD
, FB forced above the regulation point
SHDN
= 0
SHDN
= 0
SHDN
= 0, measured at V+ = 28V, V
CC
= V
DD
= 0 or 5V
V
CC
= 4.5V to 5.5V, no external REF load
I
REF
= 0 to 50µA
REF in regulation
Falling edge, hysteresis = 40mV
10
1.6
1.98
140
175
260
380
1.7
160
200
290
425
400
600
<1
25
<1
<1
<1
2
180
225
320
470
500
950
5
40
5
5
5
2.02
0.01
ns
µA
µA
µA
µA
µA
µA
V
V
µA
V
ns
180
CONDITIONS
MIN
2
4.5
-1
-1.2
9
3
5
0.2
240
1
TYP
MAX
28
5.5
1
1.2
%
mV
mV
mV
µA
kΩ
µA
ms
UNIT
V
DC Output Voltage Accuracy
Load Regulation Error
Remote-Sense Voltage Error
Line Regulation Error
FB Input Bias Current
FB Input Resistance
(MAX1711/MAX1712)
GNDS Input Bias Current
Soft-Start Ramp Time
On-Time
Minimum Off-Time
Quiescent Supply Current (V
CC
)
Quiescent Supply Current (V
DD
)
Shutdown Supply Current (V
CC
)
Shutdown Supply Current (V
DD
)
Shutdown Battery Supply
Current
Reference Voltage
Reference Load Regulation
REF Sink Current
REF Fault Lockout Voltage
2
Quiescent Battery Supply Current Measured at V+
_______________________________________________________________________________________
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
BATT
= 15V, V
CC
= V
DD
= 5V,
SKIP
= GND,
T
A
=
0°C to +85°C,
unless otherwise noted.)
PARAMETER
Overvoltage Trip Threshold
Overvoltage Fault Propagation
Delay
Output Undervoltage Protection
Threshold
Output Undervoltage Protection
Time
Current-Limit Threshold
(Positive Direction, Fixed)
Current-Limit Threshold
(Positive Direction, Adjustable)
Current-Limit Threshold
(Negative Direction)
Current-Limit Threshold
(Zero Crossing)
PGOOD Propagation Delay
PGOOD Output Low Voltage
PGOOD Leakage Current
Thermal Shutdown Threshold
V
CC
Undervoltage Lockout
Threshold
DH Gate-Driver On-Resistance
DL Gate-Driver On-Resistance
(Pullup)
DL Gate-Driver On-Resistance
(Pulldown)
DH Gate-Driver Source/Sink
Current
DL Gate-Driver Sink Current
DL Gate-Driver Source Current
Dead Time
SKIP
Input Current Logic
Threshold
PGOOD Trip Threshold
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
Logic Input Pullup Current
(MAX1711/MAX1712)
FB forced 2% above trip threshold
With respect to unloaded output voltage (MAX1710)
(MAX1711/MAX1712)
From
SHDN
signal going high
LX to PGND, ILIM tied to V
CC
LX to PGND
R
LIM
= 100kΩ
R
LIM
= 400kΩ
65
0.76
10
90
40
170
-150
100
50
200
-120
3
1.5
0.4
1
150
4.1
4.4
5
5
0.5
1
3
1
35
26
-1.5
-8
2.4
0.8
-1
3
5
1
10
-5
-0.1
-3
1.7
CONDITIONS
With respect to unloaded output voltage (MAX1710)
MIN
10.5
2.21
TYP
12.5
2.25
1.5
70
0.8
75
0.84
30
110
60
230
-80
MAX
14.5
2.29
UNIT
%
V
µs
%
V
ms
mV
mV
mV
mV
µs
V
µA
°C
V
Ω
Ω
Ω
A
A
A
ns
mA
%
V
V
µA
µA
3
MAX1710/MAX1711/MAX1712
LX to PGND, T
A
= +25°C
LX to PGND
FB forced 2% below PGOOD trip threshold, falling edge
I
SINK
= 1mA
High state, forced to 5.5V
Hysteresis = 10°C
Rising edge, hysteresis = 20mV,
PWM disabled below this level
BST-LX forced to 5V
DL, high state
DL, low state
DH forced to 2.5V, BST-LX forced to 5V
DL forced to 2.5V
DL forced to 2.5V
DL rising
DH rising
To enable no-fault mode, T
A
= +25°C
Measured at FB with respect to unloaded output voltage,
falling edge, hysteresis = 1%
D0–D4,
SHDN, SKIP, OVP
D0–D4,
SHDN, SKIP, OVP
SHDN, SKIP, OVP
D0–D4, each forced to GND
_______________________________________________________________________________________
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
MAX1710/MAX1711/MAX1712
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
BATT
= 15V, V
CC
= V
DD
= 5V,
SKIP
= GND,
T
A
=
0°C to +85°C,
unless otherwise noted.)
PARAMETER
TON V
CC
Level
TON Float Voltage
TON Reference Level
TON GND Level
TON Logic Input Current
CONDITIONS
TON logic input high level
TON logic input upper-midrange level
TON logic input lower-midrange level
TON logic input low level
TON only, forced to GND or V
CC
-3
MIN
V
CC
- 0.4
3.15
1.65
3.85
2.35
0.5
3
TYP
MAX
UNIT
V
V
V
V
µA
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
BATT
= 15V, V
CC
= V
DD
= 5V,
SKIP
= GND,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 3)
PARAMETER
Input Voltage Range
Battery voltage, V+
V
CC,
V
DD
V
BATT
= 4.5V to 28V, for all
D/A codes, includes load
regulation error
DAC codes from 1.32V to 2V
DAC codes from 0.925V to
1.275V
CONDITIONS
MIN
2
4.5
-1.5
-1.7
140
175
260
380
TYP
MAX
28
5.5
1.5
1.7
180
225
320
470
500
950
1.98
10
2.20
65
0.75
85
35
160
4.1
2.4
0.8
-1
3
1
10
2.02
15
2.30
75
0.85
115
65
240
4.4
ns
µA
V
%
V
%
V
mV
mV
V
V
V
µA
µA
ns
UNIT
V
%
%
DC Output Voltage Accuracy
TON = GND (550kHz)
On-Time
V
BATT
= 24V, TON = REF (400kHz)
FB = 2V
TON = open (300kHz)
(Note 2)
TON = V
CC
(200kHz)
(Note 2)
Measured at V
CC
, FB forced above the regulation point
V
CC
= 4.5V to 5.5V, no external REF load
With respect to unloaded output voltage (MAX1710)
(MAX1711/MAX1712)
With respect to unloaded output voltage (MAX1710)
(MAX1711/MAX1712)
LX to PGND, ILIM tied to V
CC
LX to PGND
R
LIM
= 100kΩ
R
LIM
= 400kΩ
Minimum Off-Time
Quiescent Supply Current (V
CC
)
Reference Voltage
Overvoltage Trip Threshold
Output Undervoltage
Protection Threshold
Current-Limit Threshold
(Positive Direction, Fixed)
Current-Limit Threshold
(Positive Direction, Adjustable)
V
CC
Undervoltage Lockout
Threshold
Logic Input High Voltage
Logic Input Low Voltage
Logic Input Current
Logic Input Pullup Current
Rising edge, hysteresis = 20mV, PWM disabled below
this level
D0–D4,
SHDN, SKIP, OVP
D0–D4,
SHDN, SKIP, OVP
SHDN, SKIP, OVP
D0–D4, each forced to GND
4
_______________________________________________________________________________________
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