MAX1710-MAX1712.pdf

(438 KB) Pobierz
323064273 UNPDF
19-4781; Rev 1; 7/00
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
General Description
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.
Features
Ultra-High Efficiency
No Current-Sense Resistor (Lossless I LIMIT )
Quick-PWM with 100ns Load-Step Response
±1% V OUT Accuracy over Line and Load
4-Bit On-Board DAC (MAX1710)
5-Bit On-Board DAC (MAX1711/MAX1712)
0.925V to 2V Output Adjust Range
(MAX1711/MAX1712)
2V to 28V Battery Input Range
200/300/400/550kHz Switching Frequency
1.7ms Digital Soft-Start
Drive Large Synchronous-Rectifier FETs
2V ±1% Reference Output
Power-Good Indicator
Small 24-Pin QSOP Package
Ordering Information
PART
MAX1710 EEG
TEMP. RANGE
PIN-PACKAGE
24 QSOP
-40°C to +85°C
MAX1711 EEG
-40°C to +85°C
24 QSOP
Minimal Operating Circuit
+5V INPUT
BATTERY
4.5V TO 28V
Applications
V CC OVP* V DD
SHDN
V+
Notebook Computers
Docking Stations
CPU Core DC-DC Converters
Single-Stage (BATT to V CORE) Converters
Two-Stage (+5V to V CORE ) Converters
FBS
BST
ILIM
GNDS
DH
OUTPUT
0.925V TO 2V
(MAX1711/MAX1712)
MAX1710
MAX1711
MAX1712
REF
CC
LX
DL
D0
D1
D2
D3
D4**
PGND
Quick-PWM is a trademark of Maxim Integrated Products.
Mobile Pentium II is a registered trademark of Intel Corp.
D/A
INPUTS
FB
SKIP
Pin Configurations appear at end of data sheet.
*MAX1710 ONLY
**MAX1711/MAX1712 ONLY
GND
________________________________________________________________ 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.
Remote GND and V OUT Sensing
Over/Undervoltage Protection
323064273.012.png 323064273.013.png 323064273.014.png 323064273.015.png 323064273.001.png 323064273.002.png 323064273.003.png 323064273.004.png 323064273.005.png 323064273.006.png 323064273.007.png
High-Speed, Digitally Adjusted
Step-Down Controllers for Notebook CPUs
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
CONDITIONS
MIN
TYP
MAX
UNIT
Input Voltage Range
Battery voltage, V+
2
28
V
V CC, V DD
4.5
5.5
DAC codes from 1.3V to 2V
-1
1
V BATT = 4.5V to 28V, includes
load regulation error
DC Output Voltage Accuracy
DAC codes from 0.925V
to 1.275V
-1.2
1.2
%
Load Regulation Error
I LOAD = 0 to 7A
9
mV
Remote-Sense Voltage Error
FB - FBS or GNDS - GND = 0 to 25mV
V CC = 4.5V to 5.5V, V BATT = 4.5V to 28V
3
mV
Line Regulation Error
5
mV
FB Input Bias Current
FB (MAX1710 only) or FBS
-0.2
0.2
µA
FB Input Resistance
(MAX1711/MAX1712)
130
180
240
k
Ω
GNDS Input Bias Current
-1
1
µA
Soft-Start Ramp Time
Rising edge of SHDN to full I LIM
1.7
ms
TON = GND (550kHz)
140
160
180
V BATT = 24V,
FB = 2V
(Note 2)
On-Time
TON = REF (400kHz)
175
200
225
ns
TON = open (300kHz)
260
290
320
TON = V CC (200kHz)
380
425
470
Minimum Off-Time
(Note 2)
400
500
ns
Quiescent Supply Current (V CC )
Measured at V CC , FB forced above the regulation point
600
950
µA
Quiescent Supply Current (V DD )
Measured at V DD , FB forced above the regulation point
<1
5
µA
Quiescent Battery Supply Current
Measured at V+
25
40
µA
Shutdown Supply Current (V CC )
SHDN = 0
<1
5
µA
Shutdown Supply Current (V DD )
SHDN = 0
<1
5
µA
Shutdown Battery Supply
Current
SHDN = 0, measured at V+ = 28V, V CC = V DD = 0 or 5V
<1
5
µA
Reference Voltage
V CC = 4.5V to 5.5V, no external REF load
1.98
2
2.02
V
Reference Load Regulation
I REF = 0 to 50µA
0.01
V
REF Sink Current
REF in regulation
10
µA
REF Fault Lockout Voltage
Falling edge, hysteresis = 40mV
1.6
V
2 _______________________________________________________________________________________
323064273.008.png
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.)
CONDITIONS
MIN
TYP
MAX
UNIT
Overvoltage Trip Threshold
With respect to unloaded output voltage (MAX1710)
10.5
12.5
14.5
%
(MAX1711/MAX1712)
2.21
2.25
2.29
V
Overvoltage Fault Propagation
Delay
FB forced 2% above trip threshold
1.5
µs
Output Undervoltage Protection
Threshold
With respect to unloaded output voltage (MAX1710)
(MAX1711/MAX1712)
65
70
75
%
0.76
0.8
0.84
V
Output Undervoltage Protection
Time
From SHDN signal going high
10
30
ms
Current-Limit Threshold
(Positive Direction, Fixed)
LX to PGND, ILIM tied to V CC
90
100
110
mV
Current-Limit Threshold
(Positive Direction, Adjustable)
LX to PGND
R LIM = 100k
Ω
40
50
60
mV
R LIM = 400k
Ω
170
200
230
Current-Limit Threshold
(Negative Direction)
LX to PGND, T A = +25°C
-150
-120
-80
mV
Current-Limit Threshold
(Zero Crossing)
LX to PGND
3
mV
PGOOD Propagation Delay
FB forced 2% below PGOOD trip threshold, falling edge
1.5
µs
PGOOD Output Low Voltage
I SINK = 1mA
0.4
V
PGOOD Leakage Current
High state, forced to 5.5V
1
µA
Thermal Shutdown Threshold
Hysteresis = 10°C
150
°C
V CC Undervoltage Lockout
Threshold
Rising edge, hysteresis = 20mV,
PWM disabled below this level
4.1
4.4
V
DH Gate-Driver On-Resistance
BST-LX forced to 5V
5
Ω
DL Gate-Driver On-Resistance
(Pullup)
DL, high state
5
Ω
DL Gate-Driver On-Resistance
(Pulldown)
DL, low state
0.5
1.7
Ω
DH Gate-Driver Source/Sink
Current
DH forced to 2.5V, BST-LX forced to 5V
1
A
DL Gate-Driver Sink Current
DL forced to 2.5V
3
A
DL Gate-Driver Source Current
DL forced to 2.5V
1
A
Dead Time
DL rising
35
ns
DH rising
26
SKIP Input Current Logic
Threshold
To enable no-fault mode, T A = +25°C
-1.5
-0.1
mA
PGOOD Trip Threshold
Measured at FB with respect to unloaded output voltage,
falling edge, hysteresis = 1%
-8
-5
-3
%
Logic Input High Voltage
D0–D4, SHDN, SKIP, OVP
2.4
V
Logic Input Low Voltage
D0–D4, SHDN, SKIP, OVP
0.8
V
Logic Input Current
SHDN, SKIP, OVP
-1
1
µA
Logic Input Pullup Current
D0–D4, each forced to GND
3
5
10
µA
_______________________________________________________________________________________ 3
PARAMETER
With respect to unloaded output voltage
323064273.009.png
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.)
CONDITIONS
TON logic input high level
PARAMETER
MIN
TYP
MAX
UNIT
TON V CC Level
V CC - 0.4
V
TON Float Voltage
TON logic input upper-midrange level
3.15
3.85
V
TON Reference Level
TON logic input lower-midrange level
1.65
2.35
V
TON GND Level
TON logic input low level
0.5
V
TON Logic Input Current
TON only, forced to GND or V CC
-3
3
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
CONDITIONS
MIN
TYP
MAX
UNIT
Input Voltage Range
Battery voltage, V+
2
28
V
V CC, V DD
4.5
5.5
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
-1.5
1.5
%
DC Output Voltage Accuracy
-1.7
1.7
%
TON = GND (550kHz)
140
180
V BATT = 24V,
FB = 2V
(Note 2)
On-Time
TON = REF (400kHz)
175
225
ns
TON = open (300kHz)
260
320
TON = V CC (200kHz)
380
470
Minimum Off-Time
(Note 2)
500
ns
Quiescent Supply Current (V CC )
Measured at V CC , FB forced above the regulation point
950
µA
Reference Voltage
V CC = 4.5V to 5.5V, no external REF load
1.98
2.02
V
Overvoltage Trip Threshold
With respect to unloaded output voltage (MAX1710)
(MAX1711/MAX1712)
10
15
%
2.20
2.30
V
Output Undervoltage
Protection Threshold
With respect to unloaded output voltage (MAX1710)
65
75
%
(MAX1711/MAX1712)
0.75
0.85
V
Current-Limit Threshold
(Positive Direction, Fixed)
LX to PGND, ILIM tied to V CC
85
115
mV
Current-Limit Threshold
(Positive Direction, Adjustable)
LX to PGND
R LIM = 100k
Ω
35
65
mV
R LIM = 400k
Ω
160
240
V CC Undervoltage Lockout
Threshold
Rising edge, hysteresis = 20mV, PWM disabled below
this level
4.1
4.4
V
Logic Input High Voltage
D0–D4, SHDN, SKIP, OVP
2.4
V
Logic Input Low Voltage
D0–D4, SHDN, SKIP, OVP
0.8
V
Logic Input Current
SHDN, SKIP, OVP
-1
1
µA
Logic Input Pullup Current
D0–D4, each forced to GND
3
10
µA
4 _______________________________________________________________________________________
323064273.010.png
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 = -40°C to +85°C, unless otherwise noted.) (Note 3)
PARAMETER
CONDITIONS
Measured at FB with respect to unloaded output voltage,
falling edge, hysteresis = 1%
MIN
TYP
MAX
UNIT
PGOOD Trip Threshold
-8.5
-2.5
%
PGOOD Output Low Voltage
I SINK = 1mA
0.4
V
PGOOD Leakage Current
High state, forced to 5.5V
1
µA
Note 2: On-Time and Off-Time specifications are measured from 50% point to 50% point at the DH pin with LX forced to 0V, BST
forced to 5V, and a 250pF capacitor connected from DH to LX. Actual in-circuit times may differ due to MOSFET switching
speeds.
Note 3: Specifications from -40°C to 0°C are guaranteed but not production tested.
__________________________________________Typical Operating Characteristics
(7A CPU supply circuit of Figure 1, T A = +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
(V O = 2.0V, f = 300kHz)
EFFICIENCY vs. LOAD CURRENT
(V O = 1.6V, f = 300kHz)
EFFICIENCY vs. LOAD CURRENT
(V O = 1.3V, f = 300kHz)
100
100
100
V IN = 4.5V
V IN = 4.5V
V IN = 4.5V
90
90
V IN = 7V
90
V IN = 7V
80
80
80
V IN = 7V
70
V IN = 15V
70
V IN = 15V
70
V IN = 15V
60
V IN = 24V
60
V IN = 24V
60
V IN = 24V
50
50
50
40
40
40
0.01
0.1
1
10
0.01
0.1
1
10
0.01
0.1
1
10
LOAD CURRENT (A)
LOAD CURRENT (A)
LOAD CURRENT (A)
EFFICIENCY vs. LOAD CURRENT
(V O = 1.6V, f = 550kHz)
FREQUENCY vs. LOAD CURRENT
(V O = 1.6V)
FREQUENCY vs. INPUT VOLTAGE
(I O = 7A)
100
350
320
V IN = 4.5V
318
300
90
V IN = 7V
V IN = 15V, PWM MODE
316
250
80
314
200
V IN = 4.5V, SKIP MODE
312
V O = 2.0V
70
310
150
V O = 1.6V
V IN = 15V
308
V IN = 15V, SKIP MODE
60
100
306
304
302
50
V IN = 24V
50
TON = OPEN
TON = OPEN
40
0
300
0.01
0.1
1
10
0.01
0.1
1
10
0
5
10
15
20
25
30
LOAD CURRENT (A)
LOAD CURRENT (A)
INPUT VOLTAGE (V)
_______________________________________________________________________________________ 5
323064273.011.png

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin