19-0545; Rev 0; 6/06
KIT
ATION
EVALU
E
BL
AVAILA
12V PWM Controller with Hot-Swap
General Description
Features
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8V to 16V or 5V ±10% Input-Voltage Range
Integrated Hot-Swap Controller
Lossless Valley-Mode Current Sensing
Output Voltage Adjustable from 0.8V to 5.5V
Voltage-Mode Control
External Compensation for Maximum Flexibility
Digital Soft-Start
Sequencing or Ratiometric Tracking
Startup Synchronization
Programmable PGOOD Output
Programmable Switching Frequency from 100kHz
to 1MHz
External Frequency Synchronization
SYNCIN and SYNCOUT Enable 180° Out-of-Phase
Operation
Thermal Shutdown and Short-Circuit Protection
Space-Saving 5mm x 5mm, 32-Pin TQFN Package
MAX5950
The MAX5950 is a 12V pulse-width modulated (PWM),
step-down, DC-DC controller with integrated hot-swap
controller. The device operates over the 8V to 16V input-
voltage range or 5V ±10% and provides an adjustable
output from 0.8V to 5.5V. The device delivers up to 10A
of load current with excellent load-and-line regulation.
The MAX5950 is optimized for PCIe
®
ExpressModule™
power-management application.
The MAX5950 features a hot-swap controller that pro-
vides inrush current control during module insertion
and removal, as well as short-circuit protection during
normal operation. The MAX5950 features an internal
charge pump that provides the gate drive for an exter-
nal n-channel MOSFET. A DCENO logic output indi-
cates the completion of the inrush cycle.
The MAX5950 PWM section utilizes a voltage-mode con-
trol scheme for good noise immunity and offers external
compensation, allowing for maximum flexibility with a
wide selection of inductor values and capacitor types.
The device operates at a fixed switching frequency that
is programmable from 100kHz to 1MHz and can be syn-
chronized to an external clock signal through the
SYNCIN input. The device includes undervoltage lockout
(UVLO) and digital soft-start. Protection features include
lossless valley-mode current limit, hiccup-mode output
short-circuit protection, and thermal shutdown.
The MAX5950 is available in a space-saving 5mm x
5mm, 32-pin thin QFN package and is specified for
operation over the -40°C to +85°C extended tempera-
ture range. Refer to the MAX5951 data sheet for a pin-
compatible, general-purpose PWM controller.
Ordering Information
PART
MAX5950ETJ+
TEMP RANGE
-40°C to +85°C
PIN-
PACKAGE
32 TQFN-EP*
PKG
CODE
T3255-4
+Denotes
lead-free package.
*EP
= Exposed pad.
Applications
SENSE
ILIM
CS+
FB
Pin Configuration
TOP VIEW
STARTUP
18
PGOOD
COMP
RT
17
16
15
14
13
SYNCIN
SYNCOUT
AGND
THRESH
DCENI
DCENO
PGI
MPWRGD
12
11
10
9
1
PWM_IN
2
PUVLO
3
HSENSE
4
GATE
5
IN
6
HUVLO
7
PWREN
8
PWRFLT
PCIe ExpressModule
General 12V-Input PWM Controllers with
Hot-Swap
Blade Servers
RAID
Base Stations
Work Stations
24
CS- 25
PGND 26
DL 27
DREG 28
LX 29
DH 30
BST 31
REG 32
23
22
21
20
19
MAX5950
+
PCIe is a registered trademark and ExpressModule is a
trademark of PCI-SIG Corp.
TQFN
(5mm x 5mm)
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
12V PWM Controller with Hot-Swap
MAX5950
ABSOLUTE MAXIMUM RATINGS
IN to AGND.............................................................-0.3V to +24V
HSENSE, PWM_IN to AGND........................-0.3V to (V
IN
+ 0.3V)
GATE to AGND.......................................................-0.3V to +30V
GATE to PWM_IN ....................................................-0.3V to +6V
PWREN, PWRFLT, MPWRGD,
HUVLO, PGI, DCENO
to AGND ................................................................-0.3V to +6V
BST to AGND..........................................................-0.3V to +30V
BST to LX..................................................................-0.3V to +6V
CS- to AGND.......................................-0.3V to (V
PWM_IN
+ 0.3V)
REG, DREG, PUVLO, DCENI, SYNCIN, THRESH,
SENSE to AGND....................................................-0.3V to +6V
RT, ILIM, STARTUP, PGOOD, FB, CS+ to AGND ....-0.3V to +6V
SYNCOUT, COMP to AGND.....................-0.3V to (V
REG
+ 0.3V)
DL to PGND...............................................-0.3V to (V
DREG
+ 6V)
DH to LX ....................................................-0.3V to (V
BST
+ 0.3V)
PGND to AGND .....................................................-0.3V to +0.3V
Input Current (any pin) .....................................................±50mA
Continuous Power Dissipation
32-Pin TQFN (derate 34.5 mW/°C above +70°C) ...2758.6mW
32-Pin TQFN (θ
JA
) ......................................................+29°C/W
32-Pin TQFN (θ
JC
)........................................................2.1°C/W
Operating Ambient Temperature Range .............-40°C to +85°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°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
(V
IN
= V
PWM_IN
= 12V or V
IN
= V
PWM_IN
= V
REG
= 5V, V
DREG
= V
REG
, V
PGND
= 0V, V
SYNCIN
= 0V, R
RT
= 100kΩ, R
ILIM
= 60kΩ,
C
REG
= 2.2µF, T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= T
J
= +25°C.) (Note 1)
PARAMETER
Input-Voltage Range
Standby Supply Current
Quiescent Supply Current
Switching Supply Current
HOT-SWAP UVLO
Default Hot-Swap Undervoltage
Lockout Threshold
Hot-Swap UVLO Hysteresis
HUVLO Threshold
HUVLO Hysteresis
HUVLO Input Impedance
HOT-SWAP
PWREN
CONTROL
PWREN
Input High-Level Voltage
PWREN
Input Low-Level Voltage
PWREN
Input Hysteresis
PWREN
Input Pullup Resistance
PWREN
Clamp Voltage
PWREN
High-to-Low Deglitch Time
HOT-SWAP CIRCUIT-BREAKER COMPARATOR
Circuit-Breaker Threshold
HSENSE Input Bias Current
HOT-SWAP GATE CONTROL
GATE Charge Current
GATE High Voltage
I
GATE
V
GATE
- V
PWM_IN
, sourcing 1µA
4
4.7
5
5.4
6
6.1
µA
V
V
CB
V
IN
- V
HSENSE
V
HSENSE
= 12V
553
-1
613
673
+1
mV
µA
I
PWREN
= 1mA
6.5
50
260
100
4.8
10.5
15.0
160
2
0.8
V
V
mV
kΩ
V
ms
180
V
HUVLO
V
HUVLO
rising
1.202
V
IN
rising
6.7
0.7
1.220
122
310
500
1.238
7.3
V
V
V
mV
kΩ
SYMBOL
V
IN
CONDITIONS
V
IN
= V
PWM
_IN = V
REG
= V
DREG
(Note 2)
V
IN
= 16V, V
PWM_IN
= V
HUVLO
= 0V
V
IN
= V
PWM_IN
= 16V, V
FB
= 0.9V
V
IN
= V
PWM_IN
= 16V, V
FB
= 0V
MIN
8
4.5
1.0
2.3
6
TYP
MAX
16
5.5
1.6
3.7
9
V
mA
mA
mA
UNITS
2
_______________________________________________________________________________________
12V PWM Controller with Hot-Swap
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
PWM_IN
= 12V or V
IN
= V
PWM_IN
= V
REG
= 5V, V
DREG
= V
REG
, V
PGND
= 0V, V
SYNCIN
= 0V, R
RT
= 100kΩ, R
ILIM
= 60kΩ,
C
REG
= 2.2µF, T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= T
J
= +25°C.) (Note 1)
PARAMETER
GATE Pulldown Resistance
Hot-Swap FET Enhancement
Threshold
Hot-Swap FET Enhancement
Hysteresis
HOT-SWAP LOGIC OUTPUTS
DCENO Internal Pullup Current
PWRFLT, MPWRGD
Input
Leakage
PWRFLT, MPWRGD,
DCENO
Output Voltage Low
MPWRGD
Power-On-Reset Time
HOT-SWAP LOGIC INPUTS
PGI Input High-Level Voltage
PGI Input Low-Level Voltage
PGI Input Hysteresis
PGI Blanking Time from DCENO
High
PWM UVLO
Default PWM Undervoltage
Lockout Threshold
PWM Undervoltage Lockout
Hysteresis
PUVLO Threshold
PUVLO Hysteresis
PUVLO Input Impedance
PWM DCENI CONTROL
DCENI Comparator Input
Common-Mode Range
DCENI Comparator Offset
DCENI Comparator Hysteresis
DCENI Input Current
THRESH Operating Voltage Range
THRESH Input Current
Default DCENI Threshold
PWM PGOOD OUTPUT
SENSE Threshold
SENSE Hysteresis
V
SENSE
rising
788
800
100
812
mV
mV
V
THRESH
> 0.6V
V
THRESH
< 0.3V
V
THRESH
< 0.3V
-1
0.6
-1.5
-5
1.202
1.22
V
DCENI
- V
THRESH
0
-10
100
+1
2.5
+1.0
+1
1.238
3
+10
V
mV
mV
µA
V
µA
V
180
V
PUVLO
V
PUVLO
rising
1.202
V
PWM_IN
rising
6.7
0.7
1.22
122
310
500
1.238
7.3
V
V
V
mV
kΩ
100
260
165
250
2
0.8
V
V
mV
ms
Sinking 2.4mA
100
165
-1
10
+1
50
250
µA
µA
mV
ms
SYMBOL
CONDITIONS
Sinking 1mA to AGND
V
GATE
rising
3.45
4.0
70
MIN
TYP
MAX
40
4.65
UNITS
Ω
V
mV
MAX5950
_______________________________________________________________________________________
3
12V PWM Controller with Hot-Swap
MAX5950
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
PWM_IN
= 12V or V
IN
= V
PWM_IN
= V
REG
= 5V, V
DREG
= V
REG
, V
PGND
= 0V, V
SYNCIN
= 0V, R
RT
= 100kΩ, R
ILIM
= 60kΩ,
C
REG
= 2.2µF, T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= T
J
= +25°C.) (Note 1)
PARAMETER
SENSE Input Bias Current
PGOOD Internal Pullup Current
PGOOD Output-Voltage Low
INTERNAL VOLTAGE REGULATOR
Output-Voltage Set Point
Line Regulation
Load Regulation
PWM OSCILLATOR
Oscillator Frequency Range
f
SW
V
SYNCIN
= 0V, f
SW
= 5 x 10
10
/ R
RT
Hz
T
A
= T
J
= +25°C
Oscillator Accuracy
T
A
= T
J
=
-40°C to +85°C
RT Voltage
Maximum Duty Cycle
SYNCIN High Level Voltage
SYNCIN Low Level Voltage
SYNCIN Pulldown Resistor
SYNCIN Rising to SYNCOUT
Falling Delay
SYNCIN Falling to SYNCOUT
Rising Delay
Maximum SYNCIN Frequency
SYNCOUT Voltage High
SYNCOUT Voltage Low
PWM ERROR AMPLIFIER
FB Input Range
FB Input Current
COMP Output-Voltage Range
Open-Loop Gain
Unity-Gain Bandwidth
Reference Voltage
PWM COMPARATOR
Comparator Offset Voltage
Comparator Propagation Delay
PWM DIGITAL SOFT-START
Soft-Start Duration
Reference Voltage Steps
1024
128
6.3
Clocks
Steps
mV
0.3
40
V
ns
f
GBW
V
REF
I
COMP
= -500µA to +500µA
792
I
COMP
= -500µA to +500µA
0
-250
0.25
80
2.5
800
808
V
REF
+250
V
REG
- 0.5
V
nA
V
dB
MHz
mV
VH
SYNCOUT
I
SYNCOUT
= +1.2mA
VL
SYNCOUT
I
SYNCOUT
= -2.4mA
1
V
REG
- 0.1
50
50
100
10
30
V
RT
50kΩ
≤
R
RT
≤
500kΩ
V
SYNCIN
= 0V, V
PWM_IN
= 12V
82
2.1
0.8
150
f
SW
≤
500kHz
f
SW
> 500kHz
f
SW
≤
500kHz
f
SW
> 500kHz
100
-2.5
-4
-3.5
-5
2
88
1000
+2.5
+4
+3.5
+5
V
%
V
V
kΩ
ns
ns
MHz
V
mV
%
kHz
V
REG
V
PWM_IN
= 8V to 16V
I
REG
= 0 to 50mA
4.7
5.3
1
150
V
mV/V
mV
I
PGOOD
= -2.4mA
SYMBOL
CONDITIONS
MIN
-1
10
50
TYP
MAX
+1
UNITS
µA
µA
mV
4
_______________________________________________________________________________________
12V PWM Controller with Hot-Swap
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
PWM_IN
= 12V or V
IN
= V
PWM_IN
= V
REG
= 5V, V
DREG
= V
REG
, V
PGND
= 0V, V
SYNCIN
= 0V, R
RT
= 100kΩ, R
ILIM
= 60kΩ,
C
REG
= 2.2µF, T
A
= T
J
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= T
J
= +25°C.) (Note 1)
PARAMETER
PWM RAMP GENERATOR
Ramp Amplitude
PWM CURRENT-LIMIT COMPARATOR AND HICCUP MODE
Cycle-by-Cycle Valley Current-
Limit Threshold Adjustment Range
Cycle-by-Cycle Valley Current-
Limit Threshold Tolerance
ILIM Reference Current
ILIM Reference Current Tempco
CS+, CS- Input Bias Current
PWM HICCUP MODE
Number of Cumulative Current-
Limit Events to Hiccup
Number of Consecutive Non-
Current Limit Cycles to Clear N
CL
Hiccup Timeout
PWM STARTUP INPUT
STARTUP Threshold
STARTUP Threshold Hysteresis
Internal Pullup Current
STARTUP Output Voltage Low
PWM DH DRIVER
Peak Source Current
Peak Sink Current
DH Resistance Sourcing
DH Resistance Sinking
PWM DL DRIVER
Peak Source Current
Peak Sink Current
DL Resistance Sourcing
DL Resistance Sinking
Break-Before-Make Time
THERMAL SHUTDOWN
Thermal-Shutdown Temperature
Thermal-Shutdown Hysteresis
T
J
rising
+135
15
°C
°C
V
DL
= 0V, pulse width < 100ns, V
DREG
= 5V
V
DL
= 5V, pulse width < 100ns, V
DREG
= 5V
I
DL
= 50mA, V
DREG
= 5V
I
DL
= -50mA, V
DREG
= 5V
2
2
1
1
25
3
3
A
A
Ω
Ω
ns
V
DH,LX
= 0V, pulse width < 100ns, V
BST, LX
= 5V
V
DH,LX
= 5V, pulse width < 100ns, V
BST, LX
= 5V
I
DH
= 50mA, V
BST, LX
= 5V
I
DH
= -50mA, V
BST, LX
= 5V
2
2
1
1
3
3
A
A
Ω
Ω
I
START
I
STARTUP
= -2.4mA
V
SUT
V
SUT
rising
1.1
250
10
50
1.9
V
mV
µA
mV
N
CL
N
CLR
N
HT
8
3
512
Clocks
Clocks
Clocks
V
CS+
= 0V, V
CS-
= -0.3V, current out of the CS_
-1
Limit = V
ILIM
/ 10
V
ILIM
= 0.5V
V
ILIM
= 3.5V
V
ILIM
= 0 to 3.5V, T
A
= T
J
= +25°C
50
44.5
330
19
20
3333
+20
350
55.5
366
21
mV
mV
µA
ppm/°C
µA
1.8
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5950
Note 1:
Limits at -40°C are guaranteed by design and are not production tested.
Note 2:
For 5V applications, connect REG directly to PWM_IN.
_______________________________________________________________________________________
5
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