FAN5240 Multi-Phase PWM Controller for AMD Mobile Athlon™ and Duron™
March 2006
FAN5240
Multi-Phase PWM Controller for AMD Mobile Athlon
™
and Duron
™
Features
■
CPU Core power: 0.925V to 2.0V output range
■
±1% reference precision over temperature
■
Dynamic voltage setting with 5-bit DAC
■
6V to 24V input voltage range
■
2 phase interleaved switching
■
Active droop to reduce output capacitor size
■
Differential remote voltage sense
■
High efficiency:
General Description
The FAN5240 is a single output 2-Phase synchronous
buck controller to power AMD’s mobile CPU core. The
FAN5240 includes a 5-bit digital-to-analog converter
(DAC) that adjusts the core PWM output voltage from
0.925VDC to 2.0VDC, which may be changed during
operation. Special measures are taken to allow the out-
put to transition with controlled slew rate to comply with
AMD’s Power Now
technology. The FAN5240 includes
a precision reference, and a proprietary architecture with
integrated compensation providing excellent static and
dynamic core voltage regulation. The regulator includes
special circuitry which balances the 2 phase currents for
maximum efficiency.
At light loads, when the filter inductor current becomes
discontinuous, the controller operates in a hysteretic
mode, dramatically improving system efficiency. The hys-
teretic mode of operation can be inhibited by the FPWM
control pin.
The FAN5240 monitors the output voltage and issues a
PGOOD (Power-Good) when soft start is completed and
the output is in regulation. A pin is provided to add delay
to PGOOD with an external capacitor.
A built-in over-voltage protection (OVP) forces the lower
MOSFET on to prevent the output from exceeding a set
voltage. The PWM controller's overcurrent circuitry moni-
tors the converter load by sensing the voltage drop
across the lower MOSFET. The overcurrent threshold is
set by an external resistor. If precision overcurrent pro-
tection is required, an optional external current-sense
resistor may be used.
■
■
■
■
■
■
>90% efficiency over wide load range
>80% efficiency at light load
Excellent dynamic response with Voltage
Feed-Forward and Average Current Mode control
Dynamic duty cycle clamp minimizes inductor current
build up
Lossless current sensing on low-side MOSFET or
Precision current sensing using sense resistor
Fault protections: Over-voltage, Over-current, and
Thermal Shut-down
Controls: Enable, Forced PWM, Power Good, Power
Good Delay
QSOP28, TSSOP28
Applications
■
AMD Mobile Athlon
CPU V
CORE
Regulator
■
Graphic chip V
CORE
Regulator
Ordering Information
Part Number
FAN5240QSC
FAN5240QSCX
FAN5240MTC
FAN5240MTCX
Temperature Range
-10°C to 85°C
-10°C to 85°C
-10°C to 85°C
-10°C to 85°C
Package
QSOP-28
QSOP-28
TSSOP-28
TSSOP-28
Packing
Rails
Tape and Reel
Rails
Tape and Reel
©2006 Fairchild Semiconductor Corporation
1
www.fairchildsemi.com
FAN5240 Rev. 1.2.0
FAN5240 Multi-Phase PWM Controller for AMD Mobile Athlon™ and Duron™
Typical Application
VIN (BATTERY)
= 5 to 24V
+5
C3
C4
24
VIN
21
28
25
C1
BOOT1
C7
Q1
HDRV1
SW1
Q2
27
C2
D2
+5
C8
VCC
+5
R1
PGOOD
EN
C5
FPWM
VID0
VID1
VID2
VID3
VID4
C11
C10
SS
12
11
10
9
8
7
19
14
Phase 1
23
Q3
L1
LDRV1
R2
ISNS1
VCORE +
VCORE D
BOOT2
VIN
C9
Q4
HDRV2
SW2
Q6
R3
PGND2
ISNS2
C6
D1
+5
R6
C12
C13
C14
C15
26
PGND1
22
18
17
3
V
CORE
C16
L2
4
Phase 2
20
16
13
15
5
DELAY
ILIM
AGND
1
2
6
Q5
LDRV2
R4
Figure 1. AMD Mobile Athlon/Duron CPU Core Supply
Table 1. BOM for Figure 1
Description
Capacitor 22µF, Ceramic X7R 25V
Capacitor 1µF, Ceramic
Capacitor 0.1µF, Ceramic
Capacitor 0.22µF, Ceramic
Capacitor 270µF, 2V, ESR 15m
Ω
10K
Ω
, 5% Resistor
1K
Ω
, 1% Resistor
56.2K
Ω
, 1% Resistor
Schottky Diode 40V
Inductor 1.6µH, 20A, 2.4m
Ω
N-Channel SO-8 MOSFET, 11m
Ω
N-Channel SO-8 SyncFET™ MOSFET, 6m
Ω
Qty
2
3
6
1
4
2
1
2
2
1
1
1
C1, C2
Ref.
C3, C7, C9
C4–C6, C8, C11, C12
C10
C13–C16
R1
R2, R3, R6
R4
D1, D2
L1, L2
Q1, Q4
Q2, Q3, Q5, Q6
Vendor
TDK
Any
Any
Any
Panasonic
Any
Any
Any
Fairchild
Panasonic
Fairchild
Fairchild
Part Number
EEFUE0D271R
MBR0540
ETQP6F0R8LFA
FDS6694
FDS6676S
2
FAN5240 Rev. 1.2.0
www.fairchildsemi.com
FAN5240 Multi-Phase PWM Controller for AMD Mobile Athlon™ and Duron™
Pin Configuration
LDRV2
PGND2
BOOT2
HDRV2
SW2
ISNS2
VID4
VID3
VID2
VID1
VID0
FPWM
ILIM
EN
1
2
3
4
5
6
28
27
26
25
24
23
VCC
LDRV1
PGND1
BOOT1
HDRV1
SW1
ISNS1
VIN
SS
PGOOD
VCORE+
VCORED
DELAY
AGND
7
22
FAN5240
21
8
9
10
11
12
13
14
20
19
18
17
16
15
QSOP-28 or TSSOP-28
θ
JA
= 90°C/W
Pin Assignments
Pin
Number
1
27
2
26
3
25
4
24
5
23
6
22
7 –11
12
13
14
15
16
18
17
Pin
Name
LDRV2
LDRV1
PGND2
PGND1
BOOT2
BOOT1
HDRV2
HDRV1
SW2
SW1
ISNS2
ISNS1
Pin Function Description
Low-Side Drive.
The low-side (lower) MOSFET driver output.
Power Ground.
The return for the low-side MOSFET driver.
BOOT.
The positive supply for the upper MOSFET driver. Connect as shown in Figure 1.
High-Side Drive.
The high-side (upper) MOSFET driver output.
Switching node.
The return for the high-side MOSFET driver.
Current Sense input.
Monitors the voltage drop across the lower MOSFET or external
sense resistor for current feedback.
VID4–VID0
Voltage Identification Code.
Input to VID DAC. Sets the output voltage according to the
codes set as defined in Table Figure . These inputs have 1
µ
A internal pull-up.
FPWM
ILIM
EN
AGND
DELAY
VCORE+
VCORE–
Forced PWM mode.
When logic high, inhibits the chip from entering hysteretic operating
mode. If tied low, hysteretic mode will be allowed.
Current Limit.
A resistor from this pin to GND sets the current limit.
ENABLE.
This pin enables IC operation when either left open, or pulled up to V
CC
. Toggling
EN will also reset the chip after a latched fault condition.
Analog Ground.
This is the signal ground reference for the IC. All voltage levels are
measured with respect to this pin.
Power Good / Over-Current Delay.
A capacitor to GND on this pin delays the PGOOD
from going high as well delaying the over-current shutdown.
VCORE Output Sense.
Differential sensing of the output voltage. Used for regulation as
well as PGOOD, under-voltage and over-voltage protection and monitoring. A resistor in
series with this VCORE+ sets the output voltage droop.
3
FAN5240 Rev. 1.2.0
www.fairchildsemi.com
FAN5240 Multi-Phase PWM Controller for AMD Mobile Athlon™ and Duron™
Pin Assignments
(Continued)
Pin
Number
19
Pin
Name
PGOOD
Pin Function Description
Power Good Flag.
An open-drain output that will pull LOW when the core output below
825mV. PGOOD delays its low to high transition for a time determined by CDELAY when
VCORE rises above 875mV.
Soft Start.
A capacitor from this pin to GND programs the slew rate of the converter during
initialization as well as in operation. This pin is used as the reference against which the
output is compared. During initialization, this pin is charged with a 25
µ
A current source.
Once this pin reaches 0.5V, its function changes, and it assumes the value of the voltage as
set by the VID programming. The current driving this pin is then limited to ±500
µ
A, that
together with C
SS
sets a controlled slew rate for VID code changes.
Input voltage from battery.
This voltage is used by the oscillator for feed-forward
compensation of input voltage variation.
V
CC
.
This pin powers the chip. The IC starts to operate when voltage on this pin exceeds
4.6V (UVLO rising) and shuts down when it drops below 4.3V (UVLO falling).
20
SS
21
28
V
IN
V
CC
Absolute Maximum Ratings
The “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. The
device should not be operated at these limits. The parametric values defined in the Electrical Characteristics tables
are not guaranteed at the absolute maximum ratings. The “Recommended Operating Conditions” table will define the
conditions for actual device operation.
Parameter
V
CC
Supply Voltage
V
IN
BOOT, SW, HDRV Pins
BOOT to SW
All Other Pins
Junction Temperature (T
J
)
Storage Temperature
Lead Soldering Temperature, 10 seconds
Min.
Typ.
Max.
6.5
27
33
6.5
Units
V
V
V
V
V
°C
°C
°C
–0.3
–10
–65
V
CC
+ 0.3
150
150
300
Recommended Operating Conditions
Parameter
Supply Voltage V
CC
Supply Voltage V
IN
Ambient Temperature (T
A
)
Conditions
Min.
4.75
6
–20
Typ.
5
Max.
5.25
24
85
Units
V
V
°C
4
FAN5240 Rev. 1.2.0
www.fairchildsemi.com
FAN5240 Multi-Phase PWM Controller for AMD Mobile Athlon™ and Duron™
Electrical Specifications
(V
CC
= 5V, V
IN
= 6V–24V, and T
A
= recommended operating ambient temperature range using circuit of Figure 1,
unless otherwise noted.)
Parameter
Power Supplies
V
CC
Current
V
IN
Current
UVLO Threshold
Regulator / Control Functions
Output voltage
Error Amplifier Gain
Error Amplifier GBW
Error Amplifier Slew Rate
VCORE+ Input Current
ILIM Voltage
ILIM T
HOLDOFF
Over-voltage Threshold
Over-voltage Protection delay
EN, input threshold
Phase to Phase current mismatch
Over-Temperature Shut-down
Over-Temperature Hysteresis
Output
Drivers
(1)
Sourcing
Sinking
LDRV Output Resistance
Oscillator
Frequency
Ramp Amplitude, pk–pk
Ramp Offset
Ramp Gain
Reference, DAC and Soft-Start
VID input threshold
VID pull-up current
DAC output accuracy
Soft Start Charging current (I
SS
)
Logic LOW
Logic HIGH
to V
CC
V
IN
= 16V
Sourcing
Sinking
HDRV Output Resistance
Logic LOW
Logic HIGH
Conditions
Operating, C
L
= 10pF
Shut-down (EN=0)
Operating
Shut-down (EN=0)
Rising V
CC
Falling V
CC
per Table Figure
Min.
Typ.
Max.
2
Units
mA
µ
A
µ
A
µ
A
V
V
V
dB
MHz
V/
µ
S
1
10
25
1
4.3
3.8
0.925
4.45
3.95
4.6
4.10
2.00
86
2.7
1
25
R
ILIM
= 30K
Ω
C
DELAY
= 22nF
2.2
0.89
1.16
2.35
2
0.8
2
±5
150
25
3.8
1.6
3.8
0.8
255
300
2
0.5
RampAmplitude
----------------------------------------------
V
IN
125
5
3
5
1.5
345
2.5
30
35
0.91
µ
A
V
mS
V
µ
S
V
V
%
°C
°C
Ω
Ω
Ω
Ω
KHz
V
V
mV/V
IC contribution only
Guaranteed by design
0.8
2.0
1
–1
1
27
500
34
650
20
350
V
V
µ
A
%
µ
A
µ
A
V
SS
< 90% of Programmed output
V
SS
> 90% of Programmed output
5
FAN5240 Rev. 1.2.0
www.fairchildsemi.com
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