EVALUATION KIT AVAILABLE
MAX20734
Integrated, Step-Down Switching
Regulator with PMBus
General Description
The MAX20734 is a fully integrated, highly efficient switch-
ing regulator with PMBus™ for applications operating from
4.5V to 16V and requiring up to 40A (max) load. This
single-chip regulator provides extremely compact, high-
efficiency power-delivery solutions with high-precision
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 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 output 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
•
90.7% 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 the 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
Typical System Efficiency vs.
Load Current (V
DDH
= 12V)
100
95
90
85
EFFICIENCY (%)
Applications
●
●
●
●
●
●
●
Communications Equipment
Networking Equipment
Servers and Storage Equipment
Point-of-Load Voltage Regulators
µP Chipsets
Memory V
DDQ
I/O
CURRENT
INPUT
RATING* VOLTAGE
40A
35A
22A
4.5V to 16V
12V
12V
OUTPUT
VOLTAGE
0.6V to 5.5V
1V
1V
80
75
70
65
V
OUT
=
Vout = 5V
5V
V
OUT
=
Vout = 3.3V
3.3V
V
OUT
=
Vout = 1.8V
1.8V
V
OUT
=
Vout = 1.2V
1.2V
V
OUT
=
Vout = 1V
1V
V
OUT
=
Vout = 0.8V
0.8V
0
5
10
15
20
I
OUT
(A)
25
30
35
V
OUT
= 0.65V
Vout = 0.65V
40
DESCRIPTION
Electrical rating
Thermal rating,
T
A
= 55°C, 200LFM
Thermal rating,
T
A
= 85°C, 0LFM
60
55
50
Order 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.
19-8585; Rev 0; 1/17
MAX20734
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 (V
DDH_MAX
) (Note 3) .........6A
Maximum Average Output Current (I
MAX
) ............................40A
Peak Output Current (I
PK
).....................................................90A
Package Information
PACKAGE TYPE: 15 FCQFN
Package Code
Outline Number
Land Pattern Number
THERMAL RESISTANCE
Junction to Ambient (θJA)
(Note 4; Still Air, No Heatsink)
Junction to Case (θJC)
12°C/W
0.42°C/W
P154A9F+1
21-100027
90-100025
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 GND pin immediately 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
guidelines.
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 may
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 Maxim’s evaluation kit (MAX20734EVKIT#). The PCB has four layers of 2oz copper.
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Maxim Integrated
│
2
MAX20734
Integrated, Step-Down Switching
Regulator with PMBus
Electrical Characteristics
(Circuit of
Figure 6,
V
DDH
= 4.5V to 16V, T
A
= +25°C, unless otherwise noted. Typical values are at T
A
= +25°C. All devices 100%
tested at T
A
= +25°C. Limits over temperature guaranteed by design.)
PARAMETER
SUPPLY VOLTAGE
Supply-Voltage Range
OUTPUT VOLTAGE (Note 5)
Output-Voltage Range
Programmable V
OUT
Slew Rates
V
REF
V
BOOT
Values
V
REF
Selected by C_SELA (Note 7)
V
REF
= 0.6484V, 0.8984V, and 1.0V
(Notes 6, 8),
referred to V
SENSE+/-
pins
See Table 8 for accuracy vs. V
REF
(Note 7)
t
REC
R
GAIN
Selected by R_SELB or
PMBus (Notes 6, 7, 8, 9)
(Notes 6, 8, 9)
-20
400
Switching Frequency
400kHz/600kHz/800kHz selected by
C_SEL_B; other values are set through
PMBus (Note 7)
500
600
700
800
900
Switching Frequency Accuracy
INPUT PROTECTION
Rising V
DDH
UVLO Threshold
Hysteresis
Falling V
DDH
UVLO Threshold
V
DDH
UVLO
(Note 6)
4.25
3.7
3.9
350
4.47
V
mV
(Notes 6, 8, 9)
-20
+20
%
kHz
V
DDH
V
OUT
T
J
= -40°C to +125°C
(Note 6)
Default is 1mV/μs; other values are set
through PMBus; measured at V
SENSE+/-
pins
4.5
0.6
1
2
4
0.6484
0.8984
1.0
-1.0
+1.0
%
V
mV/μs
16
5.5
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
V
REF
Tolerance
Programmable V
REF
Range
FEEDBACK LOOP
Integrator Recovery Time Constant
Gain (see the
Control Loop Stability
section for details)
Gain Accuracy
SWITCHING FREQUENCY
0.6016
1.0
V
20
0.8
1.6
3.2
+20
μs
mV/A
%
f
SW
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Maxim Integrated
│
3
MAX20734
Integrated, Step-Down Switching
Regulator with PMBus
Electrical Characteristics (continued)
(Circuit of
Figure 6,
V
DDH
= 4.5V to 16V, T
A
= +25°C, unless otherwise noted. Typical values are at T
A
= +25°C. All devices 100%
tested at T
A
= +25°C. Limits over temperature guaranteed by design.)
PARAMETER
Overvoltage-Protection, Rising
Threshold
OVP Deglitch Filter Time
Power-Good Protection, Falling
Threshold
Power-Good Protection Rising
Threshold
Power-Good Deglitch Filter Time
OVERCURRENT PROTECTION (OCP)
Positive OCP Inception
Threshold (Inductor Valley Current)
OCP
Negative OCP Inception
Threshold (Inductor Valley Current)
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
STARTUP TIMING
Enable Time from OE Rise to Start
of BST Charge
t
OE
After t
INIT
3 or 1.5 can be bet by R_SELA; any
value can be set by PMBus (Note 7)
16
0.75
Soft-Start Ramp Time
BST Charging Time
t
SS
t
BST
1.5
3
6
8
µs
ms
µs
(Note 9)
OE
Full V
CC
supply range; measured at the
OE pin (Note 6)
V
DDH
-
2.5
0.83
200
0.9
0.9
0.2
275
350
2.2
kΩ
µs
0.97
OTP
Default is 150, 130 is set through PMBus
(Notes 7, 8, 9)
120
140
130
150
10
140
160
°C
Selected by R_
SELB or PMBus
Selected by
R_SELB or
PMBus
(Notes 6, 7, 8, 9)
OCP Setting 0
OCP Setting 1
OCP Setting 2
OCP Setting 3
OCP Setting 0
OCP Setting 1
OCP Setting 2
OCP Setting 3
Hysteresis applies only to positive OCP
16.3
20.8
24.6
30.6
21
27
32
38
-28
-33
-39
-44
15
%
A
26.1
33.0
39.9
45.5
A
PWRGD
Relative to programmed V
OUT
6
3
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
OUTPUT-VOLTAGE PROTECTION (OVP)
OVP
Relative to programmed V
OUT
9.5
13
8
9
6
8
12
9
16.5
%
µs
%
%
µs
V
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Maxim Integrated
│
4
MAX20734
Integrated, Step-Down Switching
Regulator with PMBus
Electrical Characteristics (continued)
(Circuit of
Figure 6,
V
DDH
= 4.5V to 16V, T
A
= +25°C, unless otherwise noted. Typical values are at T
A
= +25°C. All devices 100%
tested at T
A
= +25°C. Limits over temperature guaranteed by design.)
PARAMETER
STAT PIN
Allowable Pullup Voltage
VOH
STAT
3.6
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)
Status Output High Leakage Current
Time from V
OUT
Ramp Completion
to STAT Pin Released
I
STAT
t
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
1.78
±1
0
±20
20
1000
162
kΩ
%
pF
%
pF
0.4
0.65
0.75
7
µA
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Status Output Low
VOL
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
Reading Range
Reading Update Interval
Reading Averaging Interval
Referred to SENSE Pins (V
OUT
may
be scaled by divider in feedback)
Reading Resolution
Reading Range
Reading Update Interval
Reading Averaging Interval
Reading Error
Reading Resolution
I
OUT
Readback
T
A
= -40°C to T
J
= +125°C
(Notes 8, 9, 10, 11)
0
5
1
±3
0.07
V
SENSE
Readback
T
A
= -40°C to T
J
= +125°C
(Notes 8, 9, 10, 11)
0
5
1
-25
1.95
25
+25
V
DDH
Readback
T
A
= -40°C to T
J
= +125°C
(Notes 8, 9, 10, 11)
4.5
5
1
-3
28
1.25
+3
16
V
ms
ms
%
mV
V
ms
ms
mV
mV
A
ms
ms
A
A
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
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