19-4118; Rev 2; 2/09
KIT
ATION
EVALU
BLE
AVAILA
Dual Quick-PWM Step-Down Controller
with Low-Power LDO, RTC Regulator
General Description
The MAX17020 is a dual Quick-PWM™ step-down
power-supply (SMPS) controller with synchronous rec-
tification, intended for main 5V/3.3V or I/O 1.5V/1.05V
power generation in battery-powered systems. Low-
side MOSFET sensing provides a simple low-cost,
highly efficient current sense for valley current-limit
protection. Combined with the output overvoltage and
undervoltage protection features, this current limit
ensures robust output supplies.
The 5V/3.3V or 1.5V/1.05V SMPS outputs can save
power by operating in pulse-skipping mode or in ultra-
sonic mode to avoid audible noise. Ultrasonic mode
forces the controller to maintain switching frequencies
greater than 20kHz at light loads.
An internal 100mA linear regulator can be used to
either generate the 5V bias needed for power-up or
other lower power “always-on” suspend supplies. An
independent bypass input allows automatic bypassing
of the linear regulator when the SMPS is active.
This main controller also includes a secondary feed-
back input that triggers an ultrasonic pulse (DL1 turned
on) if the SECFB voltage drops below its threshold volt-
age. This refreshes an external charge pump driven by
DL1 without overcharging the output voltage.
The device includes independent shutdown controls to
simplify power-up and power-down sequencing. To
prevent current surges at startup, the internal voltage
target is slowly ramped up from zero to the final target
over a 1ms period. To prevent the output from ringing
below ground in shutdown, the internal voltage target
is ramped down from its previous value to zero over a
1ms period. Two independent power-good outputs
simplify the interface with external controllers.
The MAX17020 is a pin-for-pin replacement of the
MAX8778.
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Features
Dual Quick-PWM
Internal 100mA 5V or Adjustable Linear Regulator
Independent LDO Bypass Input
Internal Boost Diodes
Secondary Feedback Input Maintains Charge Pump
3.3V 5mA RTC Power (Always On)
OUT1: 5V or 1.5V Fixed or 0.7V Adjustable
Feedback
OUT2: 3.3V or 1.05V Fixed or Dynamic Adjustable
Dynamic 0V to 2V REFIN2 Input on Second SMPS
2V ±1% 50µA Reference
6V to 24V Input Range (28V max)
Ultrasonic Mode
Independent SMPS and LDO Enable Controls
Independent SMPS Power-Good Outputs
Minimal Component Count
MAX17020
Ordering Information
PART
MAX17020ETJ+
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
32 TQFN
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
Pin Configuration
PGND
SECFB
AGND
BST2
DL2
DL1
18
V
DD
TOP VIEW
24
LX2
25
DH2
26
ON2
27
PGOOD2
28
SKIP
29
OUT2
30
ILIM2
31
REFIN2
32
23
22
21
20
19
17
16
15
14
13
LX1
DH1
ON1
PGOOD1
ILIM1
FB1
OUT1
BYP
Applications
Notebook Computers
Main System Supply (5V and 3.3V Supplies)
I/O System Supply (1.5V and 1.05V Supplies)
Graphic Cards
DDR1, DDR2, DDR3 Power Supplies
Game Consoles
Low-Power I/O and Chipset Supplies
Two-to-Four Li+ Cell Battery-Powered Devices
PDAs and Mobile Communicators
Telecommunication
MAX17020
BST1
12
11
10
9
8
LDOREFIN
+
1
REF
2
TON
3
V
CC
4
ONLDO
5
RTC
6
IN
7
LDO
THIN QFN (T3255-4)
5mm x 5mm
A "+" SIGN FIRST-PIN INDICATOR DENOTES A LEAD-FREE PACKAGE.
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
1
________________________________________________________________
Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Dual Quick-PWM Step-Down Controller
with Low-Power LDO, RTC Regulator
MAX17020
ABSOLUTE MAXIMUM RATINGS
IN, ONLDO to GND ................................................-0.3V to +28V
V
DD
, V
CC
to GND .....................................................-0.3V to +6V
RTC, LDO to GND ....................................................-0.3V to +6V
OUT_ to GND ...........................................................-0.3V to +6V
ON1, ON2 to GND....................................................-0.3V to +6V
PGOOD_ to GND........................................-0.3V to (V
CC
+ 0.3V)
REF, ILIM_, TON,
SKIP
to GND ..................-0.3V to (V
CC
+ 0.3V)
FB1, REFIN2, LDOREFIN to GND ............................-0.3V to +6V
SECFB to GND .........................................................-0.3V to +6V
BYP to GND..............................................-0.3V to (V
LDO
+ 0.3V)
GND to PGND .......................................................-0.3V to +0.3V
DL_ to PGND ..............................................-0.3V to (V
DD
+ 0.3V)
BST_ to GND ..........................................................-0.3V to +34V
BST_ to V
DD
............................................................-0.3V to +28V
DH1 to LX1 ..............................................-0.3V to (V
BST1
+ 0.3V)
BST1 to LX1..............................................................-0.3V to +6V
DH2 to LX2 ..............................................-0.3V to (V
BST2
+ 0.3V)
BST2 to LX2..............................................................-0.3V to +6V
LDO, RTC, REF Short Circuit to GND.........................Momentary
RTC Current Continuous.....................................................+5mA
LDO Current (Internal Regulator)
Continuous..................................................................+100mA
LDO Current (Switched Over) Continuous .....................+200mA
Continuous Power Dissipation (T
A
= +70°C)
32-Pin 5mm x 5mm TQFN
(derate 34.5mW/°C above +70°C) .................................2.76W
Operating Temperature Range ...........................-40°C to +85°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°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.
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, no load on LDO, RTC, OUT1, OUT2, and REF, V
IN
= 12V, V
DD
= V
CC
= V
SECFB
= 5V, V
REFIN2
= 1.0V, BYP =
LDOREFIN = GND, ONLDO = IN, ON1 = ON2 = V
CC
,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
(Note 3)
PARAMETER
INPUT SUPPLIES
IN Standby Supply Current
IN Shutdown Supply Current
I
IN(STBY)
I
IN(SHDN)
V
IN
= 6V to 24V, ON1 = ON2 = GND,
ONLDO = V
CC
V
IN
= 4.5V to 24V,
ON1 = ON2 = ONLDO = GND
ON1 = ON2 = REFIN2 = V
CC
,
SKIP
= FB1 = GND,
V
OUT2
= 3.5V, V
OUT1
= 5.3V
ON1 = ON2 = REFIN2 = V
CC
,
SKIP
= FB1 = GND,
V
OUT2
= 3.5V, V
OUT1
= 5.3V
5V preset output: FB1 = GND,
V
IN
= 12V,
SKIP
= V
CC
1.5V preset output: FB1 = V
CC
(5V),
V
IN
= 12V,
SKIP
= V
CC
Adjustable feedback output,
V
IN
= 12V,
SKIP
= V
CC
Low
FB1 Dual-Mode™ Threshold
Voltage Levels
FB1 Input Bias Current
I
FB1
High
V
FB1
= 0.8V, T
A
= +25°C
85
50
175
70
µA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
IN Supply Current
I
IN
0.1
0.2
mA
V
CC
Supply Current
PWM CONTROLLERS
I
CC
1.0
1.5
mA
4.95
1.485
0.693
0.7
0.04
V
CC
-
1.6V
-0.2
5.00
1.50
0.700
5.05
1.515
0.707
5.5
0.110
V
CC
-
0.7V
+0.2
V
µA
V
V
OUT1 Output Voltage Accuracy
(Note 1)
V
OUT1
V
FB1
OUT1 Voltage Adjust Range
Dual Mode is a trademark of Maxim Integrated Products, Inc.
2
_______________________________________________________________________________________
Dual Quick-PWM Step-Down Controller
with Low-Power LDO, RTC Regulator
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, no load on LDO, RTC, OUT1, OUT2, and REF, V
IN
= 12V, V
DD
= V
CC
= V
SECFB
= 5V, V
REFIN2
= 1.0V, BYP =
LDOREFIN = GND, ONLDO = IN, ON1 = ON2 = V
CC
,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
(Note 3)
PARAMETER
SYMBOL
CONDITIONS
3.3V preset output: REFIN2 = V
CC
(5V),
V
IN
= 12V,
SKIP
= V
CC
1.05V preset output: REFIN2 = RTC (3.3V),
V
IN
= 12V,
SKIP
= V
CC
Tracking output: V
REFIN2
= 1.0V,
V
IN
= 12V,
SKIP
= V
CC
MIN
3.267
1.040
0.995
0
0
I
REFIN2
V
REFIN2
= 2.2V, T
A
= +25°C
V
REFIN2
= 0, T
A
= +25°C
Low (REFIN2 = RTC)
High (REFIN2 = V
CC
)
Either SMPS,
SKIP
= V
CC
, I
LOAD
= 0 to 5A
Load Regulation Error
Line Regulation Error
DH1 On-Time
t
ON1
Either SMPS,
SKIP
= REF, I
LOAD
= 0 to 5A
Either SMPS,
SKIP
= GND, I
LOAD
= 0 to 5A
Either SMPS, V
IN
= 6V to 24V
V
IN
= 12V,
V
OUT1
= 5.0V
(Note 2)
V
IN
= 12V,
V
OUT2
= 3.3V
(Note 2)
(Note 2)
Rising/falling edge on ON1 or ON2 (preset)
Rising/falling edge on ON2 (REFIN2 ADJ)
Rising edge on REFIN2
20
1.94
V
SECFB
= 2.2V, T
A
= +25°C
-0.2
TON = GND or REF
(400kHz)
TON = V
CC
(200kHz)
TON = GND (500kHz)
TON = REF or V
CC
(300kHz)
895
1895
475
833
-0.1
-0.5
2.2
V
CC
-
1.0V
-0.1
-1.7
-1.5
0.005
1052
2105
555
925
250
1
1
8
27
2.0
2.06
+0.2
1209
2315
635
1017
400
ns
ns
ms
mV/µs
mV/µs
kHz
V
µA
%/V
ns
%
TYP
3.30
1.050
1.00
MAX
3.333
1.060
1.005
2
2
+0.1
+0.1
3.0
V
CC
-
0.4V
V
V
V
µA
V
UNITS
MAX17020
OUT2 Output Voltage Accuracy
(Note 1)
V
OUT2
OUT2 Voltage-Adjust Range
REFIN2 Voltage-Adjust Range
REFIN2 Input Bias Current
REFIN2 Dual-Mode Threshold
Voltage Levels
DH2 On-Time
Minimum Off-Time
Soft-Start/Stop Slew Rate
Soft-Start/Stop Slew Rate
Dynamic REFIN2 Slew Rate
SECFB Threshold Voltage
SECFB Input Bias Current
LINEAR REGULATOR (LDO)
t
ON2
t
OFF(MIN)
t
SS
t
SS
t
DYN
V
SECFB
I
SECFB
Ultrasonic Operating Frequency f
SW(USONIC)
SKIP
= open (REF)
LDO Output-Voltage Accuracy
LDOREFIN Input Range
LDOREFIN Leakage Current
LDOREFIN Dual-Mode
Threshold Voltage
V
IN
= 24V, LDOREFIN = BYP = GND,
0mA < I
LDO
< 100mA
V
IN
= 24V, LDOREFIN = V
CC
, BYP = GND,
V
LDO
0mA < I
LDO
< 100mA
V
IN
= 24V, BYP = GND, V
LDOREFIN
= 0.5V,
0mA < I
LDO
< 100mA
V
LDOREFIN
V
LDO
= 2 x V
LDOREFIN
I
LDOREFIN
V
LDOREFIN
= 0 or 2V, T
A
= +25°C
LDOREFIN low threshold
LDOREFIN high threshold
4.90
3.23
0.960
0.3
-0.5
0.1
V
CC
-
2V
5.0
3.3
1.0
5.10
3.37
1.040
2.0
+0.5
V
µA
V
V
0.15
V
CC
-
1.5V
0.20
V
CC
-
0.9V
_______________________________________________________________________________________
3
Dual Quick-PWM Step-Down Controller
with Low-Power LDO, RTC Regulator
MAX17020
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, no load on LDO, RTC, OUT1, OUT2, and REF, V
IN
= 12V, V
DD
= V
CC
= V
SECFB
= 5V, V
REFIN2
= 1.0V, BYP =
LDOREFIN = GND, ONLDO = IN, ON1 = ON2 = V
CC
,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
(Note 3)
PARAMETER
LDO Short-Circuit Current
LDO Regulation Reduction/
Bypass Switchover Threshold
LDO Bypass Switchover
Threshold
LDO Bypass Switchover
Startup Timeout
LDO Bypass Switch Resistance
V
CC
Undervoltage-Lockout
(UVLO) Threshold
Thermal-Shutdown Threshold
t
BYP
SYMBOL
I
ILIM(LDO)
LDO = GND
With respect to the LDO voltage,
falling edge of BYP
With respect to the LDO voltage,
rising edge of BYP
Rising edge of BYP to bypass gate pulled low
LDO to BYP, V
BYP
= 5V (Note 4)
Falling edge of V
CC
,
V
UVLO(VCC)
PWM disabled below this threshold
Rising edge of V
CC
T
SHDN
Hysteresis = 10°C
ON1 = ON2 = GND, V
IN
= 6V to 24V,
0 < I
RTC
< 5mA
ON1 = ON2 = ONLDO = GND,
V
IN
= 6V to 24V, 0 < I
RTC
< 5mA
RTC = GND
V
CC
= 4.5V to 5.5V, I
REF
= 0
I
REF
= -20μA to 50μA
3.8
CONDITIONS
MIN
100
-11.0
-8.5
-6.5
500
1.2
4.0
4.2
+160
°C
4.5
4.3
TYP
MAX
260
-6.0
UNITS
mA
%
%
μs
Ω
V
3.3V ALWAYS-ON LINEAR REGULATOR (RTC)
3.23
3.19
5
1.980
-10
1.95
2.00
3.33
3.43
V
3.47
30
2.020
+10
mA
V
mV
V
RTC Output-Voltage Accuracy
V
RTC
RTC Short-Circuit Current
REFERENCE (REF)
Reference Voltage
Reference Load-Regulation Error
REF Lockout Voltage
OUT1 FAULT DETECTION
OUT1 Overvoltage Trip
Threshold
OUT1 Overvoltage Fault-
Propagation Delay
OUT1 Undervoltage-Protection
Trip Threshold
OUT1 Output-Undervoltage
Fault-Propagation Delay
PGOOD1 Lower Trip Threshold
PGOOD1 Propagation Delay
PGOOD1 Output Low Voltage
PGOOD1 Leakage Current
I
ILIM(RTC)
V
REF
ΔV
REF
V
REF(UVLO)
Rising edge, 350mV (typ) hysteresis
V
OVP(OUT1)
With respect to error-comparator threshold
t
OVP
FB1 forced 50mV above trip threshold
13
16
10
19
%
μs
V
UVP(OUT1)
With respect to error-comparator threshold
t
UVP
With respect to error-comparator threshold,
falling edge, hysteresis = 1%
t
PGOOD1
FB1 forced 50mV beyond PGOOD1 trip
threshold, falling edge
V
FB1
= 0.56V (PGOOD1 low impedance),
I
SINK
= 4mA
I
PGOOD1
V
FB1
= 0.70V (PGOOD1 high impedance),
PGOOD1 forced to 5.5V, T
A
= +25°C
65
70
10
75
%
μs
-19
-16
10
-13
%
μs
0.3
1
V
μA
4
_______________________________________________________________________________________
Dual Quick-PWM Step-Down Controller
with Low-Power LDO, RTC Regulator
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, no load on LDO, RTC, OUT1, OUT2, and REF, V
IN
= 12V, V
DD
= V
CC
= V
SECFB
= 5V, V
REFIN2
= 1.0V, BYP =
LDOREFIN = GND, ONLDO = IN, ON1 = ON2 = V
CC
,
T
A
= 0°C to +85°C,
unless otherwise noted. Typical values are at T
A
= +25°C.)
(Note 3)
PARAMETER
OUT2 FAULT DETECTION
Preset mode (REFIN2 = RTC or V
CC
): with
respect to error-comparator threshold
OUT2 Overvoltage Trip
Threshold
V
OVP(OUT2)
Dynamic transition,
SKIP
= REF or V
CC
and OUT2 > REFIN2
Tracking mode: with respect to REFIN2 voltage
Minimum overvoltage threshold
OUT2 Overvoltage
Fault-Propagation Delay
OUT2 Undervoltage-Protection
Trip Threshold
OUT2 Overvoltage
Fault-Propagation Delay
OUT2 Output Undervoltage
Fault-Propagation Delay
Dynamic REFIN2 Transition
PGOOD Blanking Threshold
t
OVP
OUT2 forced 50mV above trip threshold
65
-250
13
16
V
REF
+
0.20
200
0.7
10
70
-300
10
10
75
-350
19
%
V
230
mV
V
µs
%
mV
µs
µs
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX17020
170
Preset mode: with respect to
V
UVP(OUT2)
error-comparator threshold
Tracking mode: with respect to REFIN2 voltage
t
OVP
t
UVP
OUT2 forced 50mV above trip threshold
OUT2 forced 50mV below trip threshold
Blanking initiated; REFIN2 deviation from the
internal target voltage (error-comparator
threshold); hysteresis = 5mV
Preset mode: with respect to error-comparator
threshold, falling edge, hysteresis = 1%
Tracking mode: with respect to REFIN2
voltage, falling edge, hysteresis = 12mV
t
PGOOD2
OUT2 forced 50mV beyond PGOOD1 trip
threshold, falling edge
V
OUT2
= V
REFIN2
- 150mV (PGOOD2 low
impedance), I
SINK
= 4mA
I
PGOOD2
OUT2 = REFIN2 (PGOOD2 high impedance),
PGOOD2 forced to 5.5V, T
A
= +25°C
±25
mV
-19
-175
-16
-150
10
-13
-125
%
mV
µs
PGOOD2 Lower Trip Threshold
PGOOD2 Propagation Delay
PGOOD2 Output-Low Voltage
PGOOD2 Leakage Current
CURRENT LIMIT
ILIM_ Adjustment Range
ILIM_ Current
Valley Current-Limit Threshold
(Adjustable)
Current-Limit Threshold
(Negative)
Ultrasonic Current-Limit Threshold
Current-Limit Threshold
(Zero Crossing)
0.3
1
V
µA
V
ILIM
I
ILIM
R
ILIM
_ = 100k
V
VALLEY
V
AGND
- V
LX
_
R
ILIM
_ = 200k
R
ILIM
_ = 400k
V
NEG
V
NEG(US)
V
ZX
With respect to valley current-limit threshold,
SKIP
= V
CC
V
OUT1
= V
OUT2
= V
FB1
= 0.77V, V
REFIN2
= 0.70V
V
AGND
- V
LX
_,
SKIP
= GND or OPEN/REF
0.2
5
44
90
180
50
100
200
-120
25
3
2.0
56
110
220
V
µA
mV
%
mV
mV
_______________________________________________________________________________________
5
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