Maxim MAX1630CAI, MAX1630EAI, MAX1631CAI, MAX1631EAI, MAX1632CAI Schematics
...
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________________General Description
The MAX1630–MAX1635 are buck-topology, step-down,
switch-mode, power-supply controllers that generate
logic-supply voltages in battery-powered systems. These
high-performance, dual/triple-output devices include onboard power-up sequencing, power-good signaling with
delay, digital soft-start, secondary winding control, lowdropout circuitry, internal frequency-compensation networks, and automatic bootstrapping.
Up to 96% efficiency is achieved through synchronous
rectification and Maxim’s proprietary Idle Mode™ control
scheme. Efficiency is greater than 80% over a 1000:1
load-current range, which extends battery life in systemsuspend or standby mode. Excellent dynamic response
corrects output load transients caused by the latest
dynamic-clock CPUs within five 300kHz clock cycles.
Strong 1A on-board gate drivers ensure fast external
N-channel MOSFET switching.
These devices feature a logic-controlled and synchronizable, fixed-frequency, pulse-width-modulation (PWM)
operating mode. This reduces noise and RF interference
in sensitive mobile communications and pen-entry applications. Asserting the
SKIP pin enables fixed-frequency
mode, for lowest noise under all load conditions.
The MAX1630–MAX1635 include two PWM regulators,
adjustable from 2.5V to 5.5V with fixed 5.0V and 3.3V
modes. All these devices include secondary feedback
regulation, and the MAX1630/MAX1632/MAX1633/
MAX1635 each contain 12V/120mA linear regulators. The
MAX1631/MAX1634 include a secondary feedback input
(SECFB), plus a control pin (STEER) that selects which
PWM (3.3V or 5V) receives the secondary feedback signal. SECFB provides a method for adjusting the secondary winding voltage regulation point with an external
resistor divider, and is intended to aid in creating auxiliary
voltages other than fixed 12V.
The MAX1630/MAX1631/MAX1632 contain internal output overvoltage and undervoltage protection features.
________________________Applications
Notebook and Subnotebook Computers
PDAs and Mobile Communicators
Desktop CPU Local DC-DC Converters
____________________________Features
♦ 96% Efficiency
♦ +4.2V to +30V Input Range
♦ 2.5V to 5.5V Dual Adjustable Outputs
♦ Selectable 3.3V and 5V Fixed or Adjustable
Outputs (Dual Mode™)
♦ 12V Linear Regulator
♦ Adjustable Secondary Feedback
(MAX1631/MAX1634)
♦ 5V/50mA Linear Regulator Output
♦ Precision 2.5V Reference Output
♦ Programmable Power-Up Sequencing
♦ Power-Good (RESET) Output
♦ Output Overvoltage Protection
(MAX1630/MAX1631/MAX1632)
♦ Output Undervoltage Shutdown
(MAX1630/MAX1631/MAX1632)
♦ 200kHz/300kHz Low-Noise, Fixed-Frequency
Operation
♦ Low-Dropout, 99% Duty-Factor Operation
♦ 2.5mW Typical Quiescent Power (+12V input, both
SMPSs on)
♦ 4µA Typical Shutdown Current
♦ 28-Pin SSOP Package
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
________________________________________________________________
Maxim Integrated Products
1
5V
LINEAR
12V
LINEAR
POWER-UP
SEQUENCE
POWER-
GOOD
3.3V
SMPS
5V
SMPS
RESETON/OFF
+5V (RTC)
+3.3V
INPUT
+5V
+12V
________________Functional Diagram
19-0480; Rev 3; 4/97
PART
MAX1630CAI
MAX1630EAI -40°C to +85°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
28 SSOP
28 SSOP
EVALUATION KIT
AVAILABLE
_______________Ordering Information
Ordering Information continued on last page.
Pin Configurations and Selector Guide appear at end of data
sheet.
Idle Mode and Dual Mode are trademarks of Maxim Integrated
Products.
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = 15V, both PWMs on, SYNC = VL, VL load = 0mA, REF load = 0mA, SKIP = 0V, TA= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°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.
V+ to GND..............................................................-0.3V to +36V
PGND to GND.....................................................................±0.3V
VL to GND ................................................................-0.3V to +6V
BST3, BST5 to GND ...............................................-0.3V to +36V
LX3 to BST3..............................................................-6V to +0.3V
LX5 to BST5..............................................................-6V to +0.3V
REF, SYNC, SEQ, STEER, SKIP, TIME/ON5,
SECFB, RESET to GND............................................-0.3V to +6V
V
DD
to GND............................................................-0.3V to +20V
RUN/ON3, SHDN to GND.............................-0.3V to (V+ + 0.3V)
12OUT to GND...........................................-0.3V to (V
DD
+ 0.3V)
DL3, DL5 to PGND........................................-0.3V to (VL + 0.3V)
DH3 to LX3...............................................-0.3V to (BST3 + 0.3V)
DH5 to LX5...............................................-0.3V to (BST5 + 0.3V)
VL, REF Short to GND ................................................Momentary
12OUT Short to GND..................................................Continuous
REF Current...........................................................+5mA to -1mA
VL Current.........................................................................+50mA
12OUT Current ...............................................................+200mA
V
DD
Shunt Current............................................................+15mA
Operating Temperature Ranges
MAX163_CAI.......................................................0°C to +70°C
MAX163_EAI....................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Continuous Power Dissipation (T
A
= +70°C)
SSOP (derate 9.52mW/°C above +70°C) ....................762mW
Lead Temperature (soldering, 10sec).............................+300°C
CONDITIONS
V4.2 30.0Input Voltage Range
UNITSMIN TYP MAXPARAMETER
Either SMPS
V+ = 4.2V to 30V, CSH3–CSL3 = 0V,
CSL3 tied to FB3
VREF 5.5
V2.42 2.5 2.58
3V Output Voltage in
Adjustable Mode
Output Voltage Adjust Range
Either SMPS, 5.2V < V+ < 30V %/V0.03
Either SMPS, 0V < CSH_–CSL_ < 80mV
Line Regulation
Dual Mode comparator
%-2
V0.5 1.1Adjustable-Mode Threshold Voltage
Load Regulation
SYNC = VL
From enable to 95% full current limit with respect to
f
OSC
(Note 1)
270 300 330
clks512
SKIP = 0V, not tested
Soft-Start Ramp Time
mV10 25 40Idle Mode Threshold
SYNC = 0V
kHz
170 200 230
Oscillator Frequency
V+ = 4.2V to 30V, 0mV < CSH3–CSL3 < 80mV,
FB3 = 0V
V3.20 3.39 3.473V Output Voltage in Fixed Mode
V+ = 4.2V to 30V, CSH5–CSL5 = 0V,
CSL5 tied to FB5
V2.42 2.5 2.58
5V Output Voltage in
Adjustable Mode
V+ = 5.2V to 30V, 0mV < CSH–CSL5 < 80mV,
FB5 = 0V
V4.85 5.13 5.255V Output Voltage in Fixed Mode
SYNC = VL 97 98
SYNC = 0V (Note 2)
%
98 99
Maximum Duty Factor
CSH3–CSL3 or CSH5–CSL5 80 100 120
SKIP = VL or VDD< 13V or SECFB < 2.44V
mV
-50 -100 -150
Current-Limit Threshold
MAIN SMPS CONTROLLERS
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 15V, both PWMs on, SYNC = VL, VL load = 0mA, REF load = 0mA, SKIP = 0V, TA= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°C.)
V+ = VL = 0V,
CSL3 = CSH3 = CSL5 = CSH5 = 5.5V
µA0.01 10
Not tested
Current-Sense Input Leakage Current
Not tested
Rising edge, hysteresis = 1% (Note 3)
VDD< 13V or SECFB < 2.44V
V18 20
µs1
Falling edge (MAX1631/MAX1634)
DL Pulse Width
Falling edge (Note 3)
VDDShunt Threshold
V2.44 2.60
V13 14
CONDITIONS
VDDRegulation Threshold
SECFB Regulation Threshold
VDD= 20V (Note 3)
VDD= 5V, off mode (Notes 3, 4) µA30VDDLeakage Current
mA10VDDShunt Sink Current
ns200
ns200SYNC Input High Pulse Width
SYNC Input Low Pulse Width
13V < VDD< 18V, 0mA < I
LOAD
< 120mA V11.65 12.1 12.5012OUT Output Voltage
UNITSMIN TYP MAXPARAMETER
Not tested ns200SYNC Rise/Fall Time
kHz240 350SYNC Input Frequency Range
VDD= 18V, run mode, no 12OUT load
12OUT forced to 11V, VDD= 13V
µA50 100
mA15012OUT Current Limit
Quiescent VDDCurrent
Rising edge of CSL5, hysteresis = 1%
Falling edge, hysteresis = 1%
V4.2 4.5 4.7
V3.5 3.6 3.7
VL Undervoltage Lockout
Fault Threshold
VL Switchover Threshold
SHDN = V+, RUN/ON3 = TIME/ON5 = 0V,
5.3V < V+ < 30V, 0mA < I
LOAD
< 50mA
V4.7 5.1VL Output Voltage
Falling edge V1.8 2.4
µA10REF Sink Current
REF Fault Lockout Voltage
V+ = 4V to 24V, SHDN = 0V
V+ = 4.2V to 5.5V, both SMPSs off,
includes current into SHDN
µA4 10
µA50 200
V+ Standby Supply Current
in Dropout
V+ Shutdown Supply Current
V+ = 5.5V to 30V, both SMPSs off,
includes current into SHDN
VL switched over to CSL5, 5V SMPS on
µA30 60
µA5 50V+ Operating Supply Current
V+ Standby Supply Current
0µA < I
LOAD
< 50µA
No external load (Note 5)
12.5
V2.45 2.5 2.55REF Output Voltage
2.5 4
Both SMPSs enabled, FB3 = FB5 = 0V,
CSL3 = CSH3 = 3.5V,
CSL5 = CSH5 = 5.3V
mW
1.5 4
Quiescent Power Consumption
(Note 3)
MAX1631/
MAX1634
0mA < I
LOAD
< 5mA
mV
100.0
REF Load Regulation
FLYBACK CONTROLLER
12V LINEAR REGULATOR (Note 3)
INTERNAL REGULATOR AND REFERENCE
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
4 _______________________________________________________________________________________
Note 1: Each of the four digital soft-start levels is tested for functionality; the steps are typically in 20mV increments.
Note 2: High duty-factor operation supports low input-to-output differential voltages, and is achieved at a lowered operating
frequency (see
Overload and Dropout Operation
section).
Note 3: MAX1630/MAX1632/MAX1633/MAX1635 only.
Note 4: Off mode for the 12V linear regulator occurs when the SMPS that has flyback feedback (V
DD
) steered to it is disabled. In
situations where the main outputs are being held up by external keep-alive supplies, turning off the 12OUT regulator prevents a leakage path from the output-referred flyback winding, through the rectifier, and into V
DD
.
Note 5: Since the reference uses VL as its supply, the reference’s V+ line-regulation error is insignificant.
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 15V, both PWMs on, SYNC = VL, VL load = 0mA, REF load = 0mA, SKIP = 0V, TA= T
MIN
to T
MAX
, unless otherwise noted.
Typical values are at T
A
= +25°C.)
Typical hysteresis = +10°C
From each SMPS enabled, with respect to f
OSC
°C150
clks5000 6144 7000
With respect to unloaded output voltage
Output Undervoltage Lockout Time
Thermal Shutdown Threshold
With respect to f
OSC
Falling edge, CSL_ driven 2%
below RESET trip threshold
clks27,000 32,000 37,000
µs1.5
With respect to unloaded output voltage,
falling edge; typical hysteresis = 1%
RESET Propagation Delay
RESET Delay Time
%-7 -5.5 -4
CONDITIONS
RESET Trip Threshold
RESET, I
SINK
= 4mA
RUN/ON3, SKIP, TIME/ON5 (SEQ = REF),
SHDN, STEER, SYNC, SEQ; V
PIN
= 0V or 3.3V
V0.4
µA±1Input Leakage Current
Logic Output Low Voltage
CSL_ driven 2% above overvoltage trip threshold µs
FB3, FB5; SECFB = 2.6V
1.5Overvoltage-Fault Propagation Delay
nA1 50
With respect to unloaded output voltage %60 70 80
Feedback Input Leakage Current
Output Undervoltage Threshold
%4 7 10Overvoltage Trip Threshold
RUN/ON3, SKIP, TIME/ON5 (SEQ = REF),
SHDN, STEER, SYNC
RUN/ON3, SKIP, TIME/ON5 (SEQ = REF),
SHDN, STEER, SYNC
V2.4
V0.6Logic Input Low Voltage
Logic Input High Voltage
UNITSMIN TYP MAXPARAMETER
High or low
DL3, DH3, DL5, DH5; forced to 2V
Ω1.5 7
A1Gate Driver Sink/Source Current
Gate Driver On-Resistance
RESET = 3.5V
mA1Logic Output High Current
TIME/ON5 = 0V, SEQ = 0V or VL
SEQ = 0V or VL
µA2.5 3 3.5
V2.4 2.6TIME/ON5 Input Trip Level
TIME/ON5 Source Current
TIME/ON5; RUN/ON3 = 0V, SEQ = 0V or VL Ω15 80TIME/ON5 On-Resistance
FAULT DETECTION (MAX1630/MAX1631/MAX1632)
INPUTS AND OUTPUTS
RESET
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
_______________________________________________________________________________________
5
100
50
0.001 0.01 0.1 1 10
EFFICIENCY vs. 5V OUTPUT CURRENT
60
MAX1630/35-01
5V OUTPUT CURRENT (A)
EFFICIENCY (%)
70
80
90
ON5 = 5V
ON3 = 0V
f = 300kHz
MAX1631/MAX1634
V+ = 6V
V+ = 15V
100
50
0.001 0.01 0.1 1 10
EFFICIENCY vs. 3.3V OUTPUT CURRENT
60
MAX1630/35-02
3.3V OUTPUT CURRENT (A)
EFFICIENCY (%)
70
80
90
ON3 = ON5 = 5V
f = 300kHz
MAX1631/MAX1634
V+ = 6V
V+ = 15V
800
0
15 20
MAX1632/MAX1635
MAXIMUM 15V V
DD
OUTPUT
CURRENT vs. SUPPLY VOLTAGE
600
MAX 1630/35-03
SUPPLY VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (mA)
0
200
10
400
5
VDD > 13V
5V REGULATING
5V LOAD = 0A
5V LOAD = 3A
500
0
15 20
MAX1630/MAX1633
MAXIMUM 15V V
DD
OUTPUT
CURRENT vs. SUPPLY VOLTAGE
400
MAX 1630/35-04
SUPPLY VOLTAGE (V)
MAXIMUM OUTPUT CURRENT (mA)
0
200
100
10
300
5
VDD > 13V
3.3V REGULATING
3.3V LOAD = 0A
3.3V LOAD = 3A
10,000
1
0 30
STANDBY INPUT CURRENT
vs. INPUT VOLTAGE
1000
MAX1630/35-07
INPUT VOLTAGE (V)
INPUT CURRENT (µA)
15
10
5 10 25
100
20
ON3 = ON5 = 0V
NO LOAD
30
0
5
0 30
PWM MODE INPUT CURRENT
vs. INPUT VOLTAGE
MAX1630/35-05
INPUT VOLTAGE (V)
INPUT CURRENT (mA)
15
10
15
5 10 25
20
25
20
ON3 = ON5 = 5V
SKIP = VL
NO LOAD
10
0.01
0 30
IDLE MODE INPUT CURRENT
vs. INPUT VOLTAGE
MAX1630/35-06
INPUT VOLTAGE (V)
INPUT CURRENT (mA)
15
0.1
5 10 25
1
20
ON3 = ON5 = 5V
SKIP = 0V
NO LOAD
10
0
0 30
SHUTDOWN INPUT CURRENT
vs. INPUT VOLTAGE
8
MAX1630/35-08
INPUT VOLTAGE (V)
INPUT CURRENT (µA)
15
4
2
5 10 25
6
20
SHDN = 0V
1000
1
0.001 0.1 101
MINIMUM VIN TO V
OUT
DIFFERENTIAL
vs. 5V OUTPUT CURRENT
10
100
MAX1630/35-09
5V OUTPUT CURRENT (A)
MIN V
IN
TO V
OUT
DIFFERENTIAL (mV)
0.01
5V, 3A CIRCUIT
V
OUT
> 4.8V
f = 300kHz
__________________________________________Typical Operating Characteristics
(Circuit of Figure 1, 3A Table 1 components, TA = +25°C, unless otherwise noted.)
__________________________________________________________________________Pin Description
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
6 _______________________________________________________________________________________
____________________________________Typical Operating Characteristics (continued)
(Circuit of Figure 1, 3A Table 1 components, TA = +25°C, unless otherwise noted.)
1000
0.1
0.1 10 1000100
SWITCHING FREQUENCY
vs. LOAD CURRENT
10
1
100
MAX1630/35-10
LOAD CURRENT (mA)
SWITCHING FREQUENCY (kHz)
1
+5V, VIN = 15V
+3.3V, VIN = 15V
+3.3V, VIN = 6V
+5V, VIN = 6V
5.00
4.90
50 60
VL REGULATOR OUTPUT VOLTAGE
vs. OUTPUT CURRENT
4.98
MAX 1630/35-11
OUTPUT CURRENT (mA)
VL OUTPUT VOLTAGE (V)
0
4.94
4.92
30 40
4.96
10 20
VIN = 15V
ON3 = ON5 = 0V
2.510
2.480
2.485
5 6
REF OUTPUT VOLTAGE
vs. OUTPUT CURRENT
2.505
MAX 1630/35-12
OUTPUT CURRENT (mA)
REF OUTPUT VOLTAGE (V)
0
2.495
2.490
3 4
2.500
1 2
VIN = 15V
ON3 = ON5 = 0V
2ms/div
START-UP WAVEFORMS
RUN
5V/div
3.3V OUTPUT
2V/div
TIME
5V/div
5V OUTPUT
5V/div
SEQ = VL, 0.015µF CAPACITOR ON-TIME
MAX1630/35-13
Feedback Input for the 3.3V SMPS; regulates at FB3 = REF (approx. 2.5V) in adjustable mode. FB3 is a
Dual Mode input that also selects the 3.3V fixed output voltage setting when tied to GND. Connect FB3
to a resistor divider for adjustable-output mode.
FB33
12V/120mA Linear Regulator Output. Input supply comes from VDD. Bypass 12OUT to GND with
1µF minimum.
12OUT
(MAX1630/
32/33/35)
Current-Sense Input. Also serves as the feedback input in fixed-output mode.CSL32
FUNCTIONNAMEPIN
Logic-Control Input for secondary feedback. Selects the PWM that uses a transformer and secondary
feedback signal (SECFB):
STEER = GND: 3.3V SMPS uses transformer
STEER = VL: 5V SMPS uses transformer
STEER
(MAX1631/
MAX1634)
Current-Sense Input for the 3.3V SMPS. Current-limit level is 100mV referred to CSL3.CSH31
4
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
_______________________________________________________________________________________ 7
_________________________________________________Pin Description (continued)
PIN FUNCTIONNAME
Dual-Purpose Timing Capacitor Pin and ON/OFF Control Input. See
Power-Up Sequencing and
ON/
OFF Controls
section.
TIME/ON57
Oscillator Synchronization and Frequency Select. Tie to VL for 300kHz operation; tie to GND for 200kHz
operation. Can be driven at 240kHz to 350kHz for external synchronization.
SYNC6
Active-Low Timed Reset Output. RESET swings GND to VL. Goes high after a fixed 32,000 clock-cycle
delay following power-up.
RESET
11
Logic-Control Input that disables Idle Mode when high. Connect to GND for normal use.
SKIP
10
2.5V Reference Voltage Output. Bypass to GND with 1µF minimum.REF9
Low-Noise Analog Ground and Feedback Reference PointGND8
Feedback Input for the 5V SMPS; regulates at FB5 = REF (approx. 2.5V) in adjustable mode. FB5 is a
Dual Mode input that also selects the 5V fixed output voltage setting when tied to GND. Connect FB5 to
a resistor divider for adjustable-output mode.
FB512
Gate-Drive Output for the 5V, high-side N-channel switch. DH5 is a floating driver output that swings
from LX5 to BST5, riding on the LX5 switching node voltage.
DH516
Pin-Strap Input that selects the SMPS power-up sequence:
SEQ = GND: 5V before 3.3V, RESET output determined by both outputs
SEQ = REF: Separate ON3/ON5 controls, RESET output determined by 3.3V output
SEQ = VL: 3.3V before 5V, RESET output determined by both outputs
SEQ15
Power GroundPGND20
Gate-Drive Output for the low-side synchronous-rectifier MOSFET. Swings 0V to VL.DL519
Boost capacitor connection for high-side gate drive (0.1µF)BST518
Switching Node (inductor) Connection. Can swing 2V below ground without hazard.LX517
Current-Sense Input for the 5V SMPS. Current-limit level is 100mV referred to CSL5.CSH514
Current-Sense Input for the 5V SMPS. Also serves as the feedback input in fixed-output mode, and as
the bootstrap supply input when the voltage on CSL5/VL is > 4.5V.
CSL513
Shutdown Control Input, active low. Logic threshold is set at approximately 1V. For automatic start-up,
connect SHDN to V+ through a 220kΩ resistor and bypass SHDN to GND with a 0.01µF capacitor.
SHDN
23
Battery Voltage Input, +4.2V to +30V. Bypass V+ to PGND close to the IC with a 0.22µF capacitor.
Connects to a linear regulator that powers VL.
V+22
5V Internal Linear-Regulator Output. VL is also the supply voltage rail for the chip. After the 5V SMPS
output has reached +4.5V (typical), VL automatically switches to the output voltage via CSL5 for bootstrapping. Bypass to GND with 4.7µF. VL supplies up to 25mA for external loads.
VL21
Supply Voltage Input for the 12OUT Linear Regulator. Also connects to an internal resistor divider for
secondary winding feedback, and to an 18V overvoltage shunt regulator clamp.
V
DD
(MAX1630/
32/33/35)
Secondary Winding Feedback Input. Normally connected to a resistor divider from an auxiliary output.
SECFB regulates at V
SECFB
= 2.5V (see
Secondary Feedback Regulation Loop
section). Tie to VL if not
used.
SECFB
(MAX1631/
MAX1634)
Boost Capacitor Connection for high-side gate drive (0.1µF) BST325
Gate-Drive Output for the low-side synchronous-rectifier MOSFET. Swings 0V to VL.DL324
ON/OFF Control Input. See
Power-Up Sequencing and ON/OFF Controls
section
.
RUN/ON328
Gate-Drive Output for the 3.3V, high-side N-channel switch. DH3 is a floating driver output that swings
from LX3 to BST3, riding on the LX3 switching node voltage.
DH327
Switching Node (inductor) Connection. Can swing 2V below ground without hazard.LX326
5
_______Standard Application Circuit
The basic MAX1631/MAX1634 dual-output 3.3V/5V
buck converter (Figure 1) is easily adapted to meet a
wide range of applications with inputs up to 28V by
substituting components from Table 1. These circuits
represent a good set of tradeoffs between cost, size,
and efficiency, while staying within the worst-case
specification limits for stress-related parameters, such
as capacitor ripple current. Don’t change the frequency
of these circuits without first recalculating component
values (particularly inductance value at maximum battery voltage). Adding a Schottky rectifier across each
synchronous rectifier improves the efficiency of these
circuits by approximately 1%, but this rectifier is otherwise not needed because the MOSFETs required for
these circuits typically incorporate a high-speed silicon
diode from drain to source. Use a Schottky rectifier
rated at a DC current equal to at least one-third of the
load current.
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
8 _______________________________________________________________________________________
MAX1631
MAX1634
V+ SHDN VLSECFB
INPUT
ON/OFF
C3
GND
REF
SEQ
1µF
+2.5V ALWAYS ON
*1A SCHOTTKY DIODE REQUIRED
FOR THE MAX1631 (SEE
OUTPUT
OVERVOLTAGE PROTECTION
SECTION).
+5V ALWAYS ON
Q1
5V ON/OFF
3.3V ON/OFF
Q4
0.1µF
0.1µF
L2 R2
+3.3V OUTPUT
C2
*
4.7µF
0.1µF
4.7µF
0.1µF
10Ω
0.1µF
Q3
0.1µF
DL3
CSH3
CSL3
FB3
RESET
RESET OUTPUT
SKIP
STEER
Q2
L1
R1
+5V OUTPUT
C1
DL5
LX5
DH5
BST5
BST3
SYNC
DH3
LX3
PGND
CSL5
CSH5
RUN/ON3
TIME/ON5
FB5
*
Figure 1. Standard 3.3V/5V Application Circuit (MAX1631/MAX1634)
MAX1630–MAX1635
Multi-Output, Low-Noise Power-Supply
Controllers for Notebook Computers
_______________________________________________________________________________________ 9
Input Range
Application
Table 1. Component Selection for Standard 3.3V/5V Application
Table 2. Component Suppliers
4.75V to 18V
PDA
2A
4.75V to 28V
Notebook
3A
4.75V to 24V
Workstation
4A
Frequency 300kHz
1/2 IR IRF7301;
1/2 Siliconix Si9925DQ; or
1/2 Motorola MMDF3N03HD or
MMDF4N01HD (10V max)
300kHz
IR IRF7403 or IRF7401 (18V
max); Siliconix Si4412DY; or
Motorola MMSF5N03HD or
MMSF5N02HD (18V max)
200kHz
IR IRF7413 or
Siliconix Si4410DYQ1, Q3 High-Side
MOSFETs
Q2, Q4 Low-Side
MOSFETs
1/2 IR IRF7301;
1/2 Siliconix Si9925DQ; or
1/2 Motorola MMDF3N03HD or
MMDF4N01HD (10V max)
10µF, 30V Sanyo OS-CON;
22µF, 35V AVX TPS; or
Sprague 594D
IR IRF7403 or IRF7401 (18V
max); Siliconix Si4412DY; or
Motorola MMSF5N03HD or
MMSF5N02HD (18V max)
2 x 10µF, 30V Sanyo OS-CON;
2 x 22µF, 35V AVX TPS; or
Sprague 594D
IR IRF7413 or
Siliconix Si4410DY
3 x 10µF, 30V Sanyo OS-CON;
4 x 22µF, 35V AVX TPS; or
Sprague 595D
C1, C2 Output Capacitors
220µF, 10V AVX TPS or
Sprague 595D
0.033Ω IRC LR2010-01-R033 or
Dale WSL2010-R033-F
2 x 220µF, 10V AVX TPS or
Sprague 595D
0.02Ω IRC LR2010-01-R020 or
Dale WSL2010-R020-F
4 x 220µF, 10V AVX TPS or
Sprague 595D
0.012Ω Dale WSL2512-R012-F
R1, R2 Resistors
C3 Input Capacitor
15µH, 2.4A Ferrite
Coilcraft DO3316P-153 or
Sumida CDRH125-150
10µH, 4A Ferrite
Coilcraft DO3316P-103 or
Sumida CDRH125-100
4.7µH, 5.5A Ferrite
Coilcraft DO3316-472 or
5.2µH, 6.5A Ferrite Sumida
CDRH127-5R2MC
L1, L2 Inductors
AVX (1) 803-626-3123
(1) 516-435-1824
FACTORY FAX
(COUNTRY CODE)
(803) 946-0690
(516) 435-1110
USA PHONE
Coilcraft (1) 847-639-1469 (847) 639-6400
Central
Semiconductor
COMPANY
Coiltronics (1) 561-241-9339
(1) 605-665-1627
(561) 241-7876
(605) 668-4131
International
Rectifier (IR)
(1) 310-322-3332 (310) 322-3331
Dale
IRC (1) 512-992-3377
(1) 714-960-6492
(512) 992-7900
(714) 969-2491Matsuo
Motorola (1) 602-994-6430
(81) 3-3494-7414
FACTORY FAX
(COUNTRY CODE)
(602) 303-5454
(805) 867-2555*
USA PHONE
Siliconix (1) 408-970-3950
(1) 603-224-1430
Sanyo (81) 7-2070-1174
(408) 988-8000
(619) 661-6835
(603) 224-1961
Sumida (81) 3-3607-5144 (847) 956-0666
Sprague
TDK (1) 847-390-4428
(1) 702-831-3521
(847) 390-4373
(702) 831-0140
Transpower
Technologies
NIEC
COMPANY
Murata-Erie (1) 814-238-0490 (814) 237-1431
*
Distributor
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