MAX20743
Integrated, Step-Down Switching
Regulator with PMBus
General Description
The MAX20743 is a fully integrated, highly efficient switch-
ing regulator with PMBus™ for applications operating
from 4.5V to 16V and requiring up to 35A maximum load.
This single-chip regulator provides extremely compact,
high-efficiency power delivery solutions with high-preci-
sion output voltages and excellent transient response for
networking, datacom and telecom equipment.
The IC offers a broad range of programmable features
through either the PMBus or through a capacitor and
resistor connected to a dedicated programming pin.
Using this feature, the operation can be optimized for a
specific application, reducing the component count and/
or setting appropriate trade-offs between the regulator’s
performance and system cost. Ease of programming
enables using the same design for multiple applications.
The IC includes protection and telemetry features. Positive
and negative cycle-by-cycle overcurrent protection and
overtemperature protection ensure a rugged design. Input
undervoltage lockout shuts down the device to prevent
operation when the input voltage is out of specification. A
status pin provides an output signal to show that the out-
put voltage is within range and the system is regulating.
Benefits and Features
●
High-Power Density and Low Component Count
• Overall Solution Size 509mm
2
Including Inductor
and Output Capacitors
• 90.8% Peak Efficiency with V
DDH
= 12V and
V
OUT
= 1V
• Fast Transient Response: Supports Up to 300A/μs
Load-Step Transients
●
Optimized Component Performance and Efficiency
with Reduced Design-In Time
• PMBus-Compliant Interface for Telemetry and
Power Management
• Voltage, Current and Temperature Reporting
through Digital Bus
●
Increased Power-Supply Reliability with System and
IC Self-Protection Features
• Differential Remote Sense with Open-Circuit
Detection
• Hiccup Overcurrent Protection
• Programmable Thermal Shutdown
Applications
Typical System Efficiency vs.
Load Current (V
DDH
= 12V)
100
95
90
85
EFFICIENCY (%)
●
Communication Equipment
●
Networking Equipment
●
Servers and Storage Equipment
●
Point-of-Load Voltage Regulators
● μP Chipset
●
Memory V
DDQ
●
I/O
DESCRIPTION
Electrical Rating
Thermal Rating
T
A
= 55°C, 200LFM
Thermal Rating
T
A
= 85°C, 0LFM
CURRENT
RATING*
35A
34A
22A
INPUT
VOLTAGE
4.5V to 16V
12V
12V
OUTPUT
VOLTAGE
0.6V to 5.5V
1V
1V
80
75
70
65
60
55
50
0
5
10
15
20
I
OUT
(A)
V
OUT
Vout = 5V
= 5V
V
OUT
=
Vout = 3.3V
3.3V
V
OUT
=
Vout = 1.8V
1.8V
Vout = 1.2V
1.2V
V
OUT
=
Vout = 1V
= 1V
V
OUT
Vout = 0.8V
0.8V
V
OUT
=
Vout = 0.65V
V
OUT
= 0.65V
25
30
35
Ordering Information
appears at end of data sheet.
PMBus is a trademark of SMIF, Inc.
*For
specific operating conditions, refer to the SOA curves in
the
Typical Operating Characteristics
section.
19-8582; Rev 1; 10/16
MAX20743
Integrated, Step-Down Switching
Regulator with PMBus
Absolute Maximum Ratings
Input Pin Voltage (V
DDH
) (Note 1) ........................-0.3V to +18V
V
CC
..........................................................................-0.3V to +2V
STAT, OE, CLK, DATA, and
SMALERT Pin Voltages .......................................-0.3V to +4V
PGMA, PGMB, V
SENSE+
and
V
SENSE-
Pin Voltages .........................................-0.3V to +2V
Switching Node Voltage (VX) DC ..........................-0.3V to +18V
Switching Node Voltage (VX) 25ns (Note 2) ..........-10V to +23V
(BST - VX) Pin Differential ...................................-0.3V to +2.5V
Junction Temperature (T
J
)...............................................+150°C
Storage Temperature Range ............................ -65°C to +150°C
Peak Reflow Temperature Lead-Free ............................. +260°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.
Operating Ratings
Input Voltage (V
DDH
) ................................................ 4.5V to 16V
Junction Temperature (T
J
)................................ -40°C to +125°C
Maximum Average Input Current (I
VDDH
) (Note 3) .................6A
Maximum Average Output Current (I
OUT
) ............................35A
Peak Output Current (I
PK
).....................................................60A
Package Information
PACKAGE CODE
Outline Number
Land Pattern Number
THERMAL RESISTANCE, FOUR-LAYER BOARD
Junction to Ambient (θ
JA
)
Junction to Case (θ
JC
)
(Still Air, No Heatsink; Note 4)
13°C/W
0.47°C/W
21-100031
90-100022
P154A8F+1
For the latest package outline information and land patterns (footprints), go to
www.maximintegrated.com/packages.
Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
Note 1:
As measured at the V
DDH
pin referenced to the GND pin immediatly adjacent using a high-frequency scope probe with I
LOAD
at I
MAX
. A high-frequency input bypass capacitor must be located less than 60 mils from the V
DDH
pin per our design guide-
lines.
Note 2:
The 25ns rating is the allowable voltage on the VX node in excess of the -0.3V to +18V DC ratings. The VX voltage can exceed
the DC rating in either the positive or negative direction for up to 25ns per cycle.
Note 3:
See the
Average Input Current Limit
section.
Note 4:
Data taken using the MAX20743 evaluation kit (MAX20743EVKIT#). The PCB has 4 layers of 2oz copper.
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MAX20743
Integrated, Step-Down Switching
Regulator with PMBus
Electrical Characteristics
PARAMETER
SUPPLY VOLTAGE
Supply Voltage Range
OUTPUT VOLTAGE (Note 5)
Output-Voltage Range
Slew Rate when V
OUT
is
Changed through PMBus
V
REF
(Circuit of
Figure 6,
V
DDH
= 4.5V to 16V, T
A
= +32°C, unless otherwise noted. Typical values are at T
A
= +32°C. All devices 100%
tested at room temperature. Limits over temperature guaranteed by design.)
SYMBOL
V
DDH
V
OUT
CONDITIONS
T
J
= -40°C to +125°C
(Note 6)
Default is 1mV/μs; other values are set
through PMBus; measured at V
SENSE+/-
pins
MIN
4.5
0.6
1
2
4
0.6484
V
BOOT
Values
Selected by C_SELA (Note 7)
Referred to
V
SENSE+/-
pins
(Notes 6, 8)
0.6484V V
REF
0.8984V V
REF
1V V
REF
-1.2
-1.0
-1.0
0.6016
0.8984
1.0
V
REF
Tolerance
Values Available through PMBus
Command
FEEDBACK LOOP
Integrator Recovery Time
Constant
Gain (see the
Control Loop
section for details)
SWITCHING FREQUENCY
400
400kHz/600kHz/800kHz selected by C_
SELB; other values are set through PMBus
(Note 7)
500
600
700
800
900
Switching Frequency Accuracy
INPUT PROTECTION
V
DDH
UVLO Threshold (Rising)
V
DDH
UVLO Threshold (Falling)
Hysteresis
V
DDH_UVLO
(Note 6)
4.25
3.75
3.9
350
4.47
V
mV
(Notes 6, 8, 9)
-15
+15
%
kHz
t
REC
Selected by R_SELB or PMBus
(Notes 6, 7, 8, 9)
0.72
1.4
2.9
20
0.9
1.8
3.6
1.1
2.2
4.4
mV/A
μs
V
REF
+1.2
+1.0
+1.0
1.0
V
%
V
mV/μs
TYP
MAX
16
5.5
UNITS
V
V
See Table 8 for accuracy vs. V
REF
(Note 7)
R
GAIN
Switching Frequency
f
SW
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MAX20743
Integrated, Step-Down Switching
Regulator with PMBus
Electrical Characteristics (continued)
PARAMETER
Overvoltage-Protection Threshold
(Rising)
OVP Deglitch Filter Time
Power-Good Protection Threshold
(Falling)
Power-Good Protection Threshold
(Rising)
Power-Good Deglitch Filter Time
OVERCURRENT PROTECTION (OCP)
PWRGD
SYMBOL
(Circuit of
Figure 6,
V
DDH
= 4.5V to 16V, T
A
= +32°C, unless otherwise noted. Typical values are at T
A
= +32°C. All devices 100%
tested at room temperature. Limits over temperature guaranteed by design.)
CONDITIONS
MIN
TYP
MAX
UNITS
OUTPUT-VOLTAGE PROTECTION (OVP)
OVP
Relative to programmed V
OUT
10
13
8
Relative to programmed V
OUT
6
3
9
6
8
12
9
16
%
µs
%
%
µs
OCP Setting 0
Positive OCP Inception
Threshold (Inductor Valley
Current)
Selected by R_SELB OCP Setting 1
or PMBus
(Notes 6, 7, 8, 9)
OCP Setting 2
OCP Setting 3
OCP
OCP Setting 0
OCP Setting 1
Selected by R_SELB
or PMBus
OCP Setting 2
OCP Setting 3
Hysteresis
OVERTEMPERATURE PROTECTION (OTP)
OTP Inception Threshold
Hysteresis
OE MAXIMUM VOLTAGE
OE Maximum Voltage
Rising Threshold
Hysteresis
OE Pin Input Resistance
OE Deglitch Filter Time
(Note 9)
OE
Full V
CC
supply range; measured at the
OE pin; keep OE ≤ V
DDH
– 2.5V and ≤
3.6V (Note 6)
OTP
Default is 150°C; 130°C is set through
PMBus (Notes 7, 8, 9)
Hysteresis applies only to positive OCP
11.8
16.0
19.8
24.5
18.9
24.1
29.2
34.1
-26.4
-31.3
-36.0
-40.8
20
26.0
32.2
A
38.6
43.8
Negative OCP Inception
Threshold (Inductor Valley
Current)
A
%
140
160
°C
120
140
130
150
10
3.6
0.83
0.9
0.2
200
0.9
275
350
2.2
kΩ
µs
0.97
V
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MAX20743
Integrated, Step-Down Switching
Regulator with PMBus
Electrical Characteristics (continued)
PARAMETER
STARTUP TIMING
Enable Time from OE Rise to
Start of BST Charge
t
OE
SYMBOL
(Circuit of
Figure 6,
V
DDH
= 4.5V to 16V, T
A
= +32°C, unless otherwise noted. Typical values are at T
A
= +32°C. All devices 100%
tested at room temperature. Limits over temperature guaranteed by design.)
CONDITIONS
MIN
TYP
MAX
UNITS
After t
INIT
16
0.75
µs
Soft-Start Ramp Time
t
SS
3ms or 1.5ms can be bet by R_SELA; any
value can be set by PMBus (Note 7)
1.5
3
6
8
3.6
ms
BST Charging Time
STAT PIN
Pullup Voltage
t
BST
VOH
STAT
I
STAT
= 2.5mA
I
STAT
= 0.2mA, 0V < V
CC
< UVLO and
0V < V
DDH
< UVLO (Note 6)
I
STAT
= 1.3mA, 0V < V
CC
< UVLO and
0V < V
DDH
< UVLO (Note 6)
µs
V
0.4
0.65
0.75
7
µA
V
Status Output Low
VOL
STAT
Status Output High Leakage
Current
Time from V
OUT
Ramp
Completion to STAT Pin Released
I
STAT
STAT pulled up to 3.3V through 20kΩ
(Note 6)
STAT output low to high, default is 125;
2000 can be set through PMBus (Note 7)
125
2000
t
STAT
µs
PGMA AND PGMB PINS (see Tables 2–5)
Allowable R_SEL Resistor Range
R_SEL Resistor Required
Accuracy
Allowable C_SEL Capacitor
Range
C_SEL Capacitor Required
Accuracy
Allowable External Capacitance
PMBus TELEMETRY
Reading Range
Reading Update Interval
Reading Averaging Interval
Reading Error
Reading Resolution
V
DDH
Readback
4.5
5
1
T
A
= -40°C to T
J
= 125°C (Notes 8, 9, 10)
-3
28
+3
16
V
ms
ms
%
mV
12 resistor values detected
EIA standard resistor values only
3 options (0pF, 220pF, or 1000pF)
Use X7R or better
Load and stray capacitance in addition to
C_SELA/B
0
±20
20
1.78
±1
1000
162
kΩ
%
pF
%
pF
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