April 2006
FAN5032 8-Bit Programmable 2 to 4 Phase Synchronous Buck Controller
©2006 Fairchild Semiconductor Corporation
1
www.fairchildsemi.com
FAN5032 Rev. 1.0.0
FAN5032
8-Bit Programmable 2 to 4 Phase Synchronous Buck
Controller
Features
■
Selectable 2, 3, or 4 phase operation at up to 1MHz
per phase
■
±7.7mV worst-case differential sensing error over
temperature
■
Active current balancing between the output phases
■
Power good and crowbar blanking supports on-the-fly
VID code changes
■
0.5V to 1.6V output
■
Fully compliant to Intel
®
VR10 and VR11
specifications
■
Selectable VR10 extended (7 bit) and VR11 (8 bit)
VID tables
■
Programmable soft-start ramp
■
Programmable short-circuit protection and latch-off
delay
Special Features
■
300mV OVP and crowbar threshold
Applications
■
Desktop PC/server processor power supplies for
existing and next-generation Intel processors
■
VRM modules
Description
The FAN5032 is a controller for a multi-phase buck
switching regulator optimized to convert a 12V input
supply to the processor core voltage required by
high-
performance Intel processors. It has an internal 8-bit
digital to analog converter (DAC) that converts a digital
voltage identification (VID) code, sent from the processor
to set the output voltage between 0.5V and 1.6V in
6.25mV steps. It outputs a pulse-width modulated (PWM)
signal to external MOSFET drivers that, in turn, drive the
switching power MOSFETs. The switching frequency of
the design is programmable by a single resistor value
and the number of phases can be programmed to sup-
port 2, 3, or 4 phase applications.
The FAN5032 also includes programmable no-load off-
set and droop functions to adjust the output voltage as a
function of the load current, as required by the Intel spec-
ifications. The FAN5032 also provides an accurate and
reliable short-circuit protection function with an adjust-
able over-current set point.
The FAN5032 is specified over the commercial tempera-
ture range of 0°C to 85°C and is available in a 40-lead
MLP package.
Ordering Information
Product
Number Package Type Pb-Free Operating
Temperature Range Packing Meathod Quantity
per Reel
FAN5032MPX MLP-40 Yes 0°C to 85°C Tape and Reel 3,000
FAN5032 8-Bit Programmable 2 to 4 Phase Synchronous Buck Controller
2
www.fairchildsemi.com
FAN5032 Rev. 1.0.0
FAN5032 Block Diagram
Figure 1. Block Diagram
VCC
PRECISION
REFERENCE
DELAY
UVLO
SHUTDOWN
& BIAS
–
+
GND
18
EN
1
DELAY
7
ILIMIT
11
PWRGD
2
31
RAMPADJ
13
RT
12
PWM2
29
PWM3
28
PWM4
27
SW3
23
SW2
24
SW1
25
CSREF
15
CSCOMP
SW4
22
CSSUM
16
PWM1
OD
VID5
34
VID7
32 VID6
33 VID4
35 VID3
36 VID2
37 VID0
39
VID1
38
3
COMP
FBRTN
40
VIDSEL
5
VID
DAC
DAC+150mV
–
+
850mV
–
+
DAC-250mV
+
–
CSREF
CURRENT
LIMIT
CIRCUIT
CROWBAR CURRENT
LIMIT
+
–
CMP
+
–
CMP
+
–
CMP
+
–
+
–
CMP
NC
26
NC
21
CURRENT
BALANCING
CIRCUIT
2 / 3 / 4-PHASE
DRIVER LOGIC
ENSET
RESET
RESET
RESET
RESET
30
19
17
THERMAL
THROTTLING
CONTROL
TTSENSE
10
VRHOT
9
VRFAN
8
OSCILLATOR
–
+
SS
6
Boot Control
LLSET
14
DAC
BUFF
FB
4
+
–
Z
STARTUP
CONTROL
FAN5032 8-Bit Programmable 2 to 4 Phase Synchronous Buck Controller
3
www.fairchildsemi.com
FAN5032 Rev. 1.0.0
FAN5032 Pin Assignment
Figure 2. Pin Assignment
Pin Assignments
Pin # Pin Name Pin Description
1EN
Power Supply Enable Input.
Analog comparator input with hysteresis. If input voltage
is higher than the internal threshold, the controller is enabled. If lower, the controller is
disabled.
2 PWRGD
Power Good Output.
Open drain output that pulls to GND when the output voltage is
outside the proper operating range.
3 FBRTN
Feedback Return.
VID DAC and error amplifier reference for remote sensing of output
voltage.
4FB
Feedback Input.
Error amplifier input for remote sensing of output voltage. A positive
internal current source is connected to this pin to allow the output voltage to be offset
lower than the DAC voltage.
5 COMP
Error Amplifier Output.
For loop compensation.
6SS
Soft-Start Input.
An external capacitor connected between this pin and GND sets the
soft-start ramp time.
7 DELAY
Delay Timer Input.
An external capacitor connected between this pin and GND sets the
over-current latch-off delay time, BOOT voltage hold time, EN delay time, and PWRGD
delay time.
8 VRFAN
VR Fan Output.
Open drain output that goes high when the TTSENSE voltage goes
below the internal VRFAN threshold.
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
15
14
13
12
11
31
32
33
34
35
36
37
38
39
40
1
2
3
4
5
6
7
8
9
10
VCC
VID7
VID6
VID5
VID4
VID3
VID2
VID1
VID0
VIDSEL
NC
OD
GND
CSCOMP
CSSUM
CSREF
LLSET
RAMPADJ
RT
ILIMIT
EN
PWRGD
FBRTN
FB
COMP
SS
DELAY
VRFAN
VRHOT
TTSENSE
PWM1
PWM2
PWM3
PWM4
NC
SW1
SW2
SW3
SW4
NC
(Top View)
Exposed paddle on
bottom of package
FAN5032 8-Bit Programmable 2 to 4 Phase Synchronous Buck Controller
4
www.fairchildsemi.com
FAN5032 Rev. 1.0.0
9 VRHOT
VR Hot Output.
Open drain output that goes high when the TTSENSE voltage goes
below the internal VRHOT threshold.
10 TTSENSE
Thermal Sense Input.
A positive internal current source is connected to this pin.
Connecting an external NTC thermistor between this pin and GND produces a positive
input voltage that is proportional to temperature.
11 ILIMIT
Current Limit Set.
An external resistor from this pin to GND sets the current limit
threshold of the converter.
12 RT
Frequency Set Input.
An external resistor connected between this pin and GND sets
the oscillator frequency of the device.
13 RAMPADJ
PWM Ramp Set Input.
An external resistor connected between this pin and the
converter input voltage sets the internal PWM ramp.
14 LLSET
Load Line Set Input.
This pin can be directly connected to CSCOMP or connected to
the center point of a resistor divider between CSCOMP and CSREF. Connecting LLSET
to CSREF disables positioning.
15 CSREF
Current Sense Amplifier Positive Input.
The voltage on this pin is used as the
reference for the current sense amplifier. The power good and crowbar functions are
also internally connected to this pin.
16 CSSUM
Current Sense Amplifier Negative Input
17 CSCOMP
Current Sense Amplifier Compensation Output
18 GND
Ground.
All internal biasing and logic output signals of the device are ref erenced to this
ground.
19 OD
Output Disable.
This pin is actively pulled lo w when the EN input is lo w or when VCC is
below its UVLO threshold, to disable the external MOSFET drivers.
20 to 21 NC
No Connection
22 to 25 SW4 to SW1
Switching Node Current Balance Inputs.
Sense the s witching side of the inductor and
are used to measure the current level in each phase. The SW pins of unused phases
should be left open.
26 NC
No Connection
27 to 30 PWM4 to PWM1
PWM Outputs.
Each output is connected to the input of an external MOSFET driver,
such as the FAN5109. Connecting the PWM3 and/or PWM4 outputs to VCC disables
that phase, allowing the FAN5032 to operate as a 2, 3, or 4 phase controller.
31 VCC
Supply Voltage for the Device
32 to 39 VID7 to VID0
Voltage Identification Code Inputs.
These digital inputs are connected to the internal
DAC and are used to program the output voltage. These pins have 1µA internal pull-
down; left open, the input state is decoded as logic low.
40 VIDSEL
VID Table Select Input.
A logic low selects the extended VR10 DAC table and a logic
high selects the VR11 DAC table. This pin has a 1µA internal pull-down; left open, the
input state is decoded as logic low.
– Exposed Paddle
Internally connected to die ground.
May be connected to ground or left floating.
Connect to ground for lowest package thermal resistance.
Pin Assignments
(Continued)
Pin # Pin Name Pin Description
FAN5032 8-Bit Programmable 2 to 4 Phase Synchronous Buck Controller
5
www.fairchildsemi.com
FAN5032 Rev. 1.0.0
Mechanical Dimensions
40-Lead MLP
FAN5032 8-Bit Programmable 2 to 4 Phase Synchronous Buck Controller
DISCLAIMER
FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY LIABILITY
ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER DOES IT
CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.
TRADEMARKS
The following are registered and unregistered trademarks Fairchild Semiconductor owns or is authorized to use and is
not intended to be an exhaustive list of all such trademarks.
LIFE SUPPORT POLICY
FAIRCHILDíS PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF FAIRCHILD SEMICONDUCTOR CORPORATION.
As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant into
the body, or (b) support or sustain life, or (c) whose
failure to perform when properly used in accordance
with instructions for use provided in the labeling, can be
reasonably expected to result in significant injury to the
user.
2. A critical component is any component of a life
support device or system whose failure to perform can
be reasonably expected to cause the failure of the life
support device or system, or to affect its safety or
effectiveness.
PRODUCT STATUS DEFINITIONS
Definition of Terms
Datasheet Identification Product Status Definition
Advance Information
Preliminary
No Identification Needed
Obsolete
This datasheet contains the design specifications for
product development. Specifications may change in
any manner without notice.
This datasheet contains preliminary data, and
supplementary data will be published at a later date.
Fairchild Semiconductor reserves the right to make
changes at any time without notice in order to improve
design.
This datasheet contains final specifications. Fairchild
Semiconductor reserves the right to make changes at
any time without notice in order to improve design.
This datasheet contains specifications on a product
that has been discontinued by Fairchild semiconductor.
The datasheet is printed for reference information only.
Formative or
In Design
First Production
Full Production
Not In Production
ISOPLANAR™
LittleFET™
MICROCOUPLER™
MicroFET™
MicroPak™
MICROWIRE™
MSX™
MSXPro™
OCX™
OCXPro™
OPTOLOGIC®
OPTOPLANAR™
PACMAN™
POP™
Power247™
PowerEdge™
FAST®
FASTr™
FPS™
FRFET™
GlobalOptoisolator™
GTO™
HiSeC™
I2C™
i-Lo™
ImpliedDisconnect™
IntelliMAX™
Rev. I18
ACEx™
ActiveArray™
Bottomless™
Build it Now™
CoolFET™
CROSSVOLT™
DOME™
EcoSPARK™
E2CMOS™
EnSigna™
FACT™
FACT Quiet Series™
PowerSaver™
PowerTrench®
QFET®
QS™
QT Optoelectronics™
Quiet Series™
RapidConfigure™
RapidConnect™
µSerDes™
ScalarPump™
SILENT SWITCHER®
SMART START™
SPM™
Stealth™
SuperFET™
SuperSOT™-3
SuperSOT™-6
SuperSOT™-8
SyncFET™
TCM™
TinyLogic®
TINYOPTO™
TruTranslation™
UHC™
UltraFET®
UniFET™
VCX™
Wire™
Across the board. Around the world.™
The Power Franchise®
Programmable Active Droop™
6
www.fairchildsemi.com
FAN5032 Rev. 1.0.0
