Semiconductor NCP5388 Specifications

Page 1
NCP5388
2/3/4 Phase Buck Controller for VR10 and VR11 Pentium IV Processor Applications
A high performance operational error amplifier is provided, which allows for easy compensation of the system. The proprietary method of Dynamic Reference Injection (Patent Pending) makes the error amplifier compensation virtually independent of the system response to VID changes, eliminating the need for tradeoffs between load transients and Dynamic VID performance.
Features
• Meets Intel’s VR 10.0, 10.1, 10.2, and 11.0 Specifications
• Dual−Edge PWM for Fastest Initial Response to Transient Loading
• High Performance Operational Error Amplifier
• Supports both VR11 and Legacy VR10 Soft−Start Modes
• Dynamic Reference Injection (Patent Pending)
• 8−Bit DAC per Intel’s VR11 Specifications
• DAC Range from 0.5 V to 1.6 V
• "0.75% System Voltage Accuracy
• Remote Temperature Sensing per VR11
• 2, 3, or 4−Phase Operation
• True Differential Remote Voltage Sensing Amplifier
• Phase−to−Phase Current Balancing
• “Lossless” Differential Inductor Current Sensing
• Differential Current Sense Amplifiers for each Phase
• Adaptive Voltage Positioning (AVP)
• Fixed No−Load Voltage Positioning at –19 mV
• Frequency Range: 100 kHz–1.0 MHz
• Latched Overvoltage Protection (OVP)
• Threshold Sensitive Enable Pin for VTT Sensing
• Power Good Output with Internal Delays
• Programmable Soft−Start Time
• Operates from 12 V
• This is a Pb−Free Device*
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MARKING DIAGRAM
1
1
40
40 PIN QFN, 7x7
MN SUFFIX
CASE 488AG
NCP5388 = Specific Device Code AA = Assembly Location WL = Wafer Lot YY = Year WW = Work Week G/G = Pb−Free Package
*Pin 41 is the thermal pad on the bottom of the device.
ORDERING INFORMATION
Device Package Shipping
NCP5388MNR2G QFN−40
(Pb−Free)
†For information on tape and reel specifications,
including part orientation and tape sizes, please refer to our Tape and Reel Packaging Specification Brochure, BRD8011/D.
NCP5388
AAWLYYWWG
†
2500 / Tape & Reel
Applications
• Pentium IV Processors
• VRM Modules
• Graphics Cards
• Low Voltage, High Current Power Supplies
© Semiconductor Components Industries, LLC, 2010
June, 2010 − Rev. 11
*For additional information on our Pb−Free strategy
and soldering details, please download the ON Semiconductor Soldering and Mounting Techniques Reference Manual, SOLDERRM/D.
1 Publication Order Number:
NCP5388/D
Page 2
NCP5388
PIN CONNECTIONS
40
39
38
37
36
35
34G433G332G231
NTC
VCC
VREF
1
EN
2
VID0
3
VID1
4
VID2
5
VID3
6
VID4
7
VID5
8
VID6
9
VID7
10
VR10/11
VR_FAN
VR_HOT
SS11ROSC12ILIM13AGND14VS+15VS−16DIFFOUT17COMP18VFB19VDRP
VR_RDY
NCP5388
DGND
DRVON
20
(Top View)
CS4
CS4N
CS3
CS3N
CS2
CS2N
CS1
CS1N
G1
30
29
28
27
26
25
24
23
22
21
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NCP5388
VR10/11
VID0 VID1 VID2 VID3 VID4 VID5 VID6 VID7
SS
VS−
VS+
DIFFOUT
VFB
COMP
VDRP
CS1
CS1N
CS2
CS2N
CS3
CS3N
CS4
CS4N
1.3 V
VR10/11
DAC
DAC
Droop
Amplifier
+
-
Gain = 6
+
-
Gain = 6
+
-
Gain = 6
+
-
Gain = 6
Oscillator
-
+
Diff Amp
+
-
Error Amp
+ −
1.3 V
NCP5388
Fault
+
-
+
-
+
-
+
-
OVER
+
-
+
-
4OFF
Fault
ENB
ENB
ENB
ENB
VREF
NTC
VR_FAN
NTC
VR_HOT
DGND
G1
G2
G3
G4
ROSC
ILIM
EN
VCC
AGND
DAC
VS+
VS−
+
-
Current Limit
+
-
9.0 V
UVLO
Figure 1. Simplified Block Diagram
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3
Fault Logic
3 Phase
Detect
and Monitor Circuits
DRVON
VR_RDY
Page 4
NCP5388
VID0
VID1
VID2
VID3
VID4
VID5
VID6
VID7
VID8
VR_EN
VR_RDY
VR_HOT
VR_FAN
VTT
680 PULLUPS
RISO1
RT2
CFB1 RFB1
RFB
RDRP
CF RF
CH
RISO2
RVCC
2
3
4
5
6
7
8
9
10
1
37
40
39
16
15
17
19
20
18
+12 V
U20
VID0
VID1
VID2
VID3
VID4
VID5
VID6
VID7
VR10/VR11
EN
VR_RDY
VR_HOT
VR_FAN
VS−
VS+
NCP5388
DIFFOUT
VFB
VDRP
COMP
ILIM
13
RLIM1
36
VCC
CVCC1
DGND
AGND
DRVON
SSROSC
VREF
NTC
CS1
CS1N
CS2
CS2N
CS3
CS3N
CS4
CS4N
1112
CSS
G1
G2
G3
G4
12 V_FILTER
35
14
RNTC1
34
38
30
22
21
31
24
23
32
26
25
33
28
27
29
RT1
RNTC2
3
2
C1
12 V_FILTER
3
2
12 V_FILTER
3
2
BAT54HT1
NCP3418B
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
D1
C3
1
8
7
5
6
NTD85N02RT4
1
8
7
5
6
1
8
7
5
6
12 V_FILTER
NTD60N02RT4
R2
C2
12 V_FILTER
12 V_FILTER
C4
L1
RS1
CS1
RLIM2
RT2 LOCATED NEAR OUTPUT INDUCTORS
VCCP
VSSP
Figure 2. Application Schematic for Four Phases
12 V_FILTER
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4
VCC4BST
3
OD
2
IN
DRVH
SW
DRVL
PGND
12 V_FILTER
1
8
7
5
6
+
CPU GND
Page 5
NCP5388
VID0
VID1
VID2
VID3
VID4
VID5
VID6
VID7
VID8
VR_EN
VR_RDY
VR_HOT
VR_FAN
VTT
RISO1
680 PULLUPS
RISO2
RT2
CFB1 RFB1
RFB
RDRP
CF
RF
CH
RVCC
2
3
4
5
6
7
8
9
10
1
37
40
39
16
15
17
19
20
18
+12 V
36
U1
VCC
VID0
VID1
VID2
VID3
VID4
VID5
VID6
VID7
VR10/VR11
EN
VR_RDY
VR_HOT
VR_FAN
VS−
VS+
NCP5388
DIFFOUT
VFB
VDRP
COMP
ILIM
13
RLIM1
CVCC1
DGND
AGND
DRVON
SSROSC
VREF
NTC
CS1
CS1N
CS2
CS2N
CS3
CS3N
CS4
CS4N
1112
CSS
G1
G2
G3
G4
12 V_FILTER
35
29
14
34
38
30
22
21
31
24
23
32
26
25
33
28
27
RT1
RNTC2
RNTC1
3
2
C1
12 V_FILTER
3
2
12 V_FILTER
3
2
BAT54HT1
NCP3418B
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
D1
C3
1
8
7
5
6
NTD85N02RT4
1
8
7
5
6
1
8
7
5
6
12 V_FILTER
NTD60N02RT4
R2
C2
12 V_FILTER
12 V_FILTER
C4
L1
RS1
CS1
RLIM2
RT2 LOCATED NEAR OUTPUT INDUCTORS
VCCP
VSSP
Figure 3. Application Schematic for Three Phases
+
CPU GND
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NCP5388
VID0
VID1
VID2
VID3
VID4
VID5
VID6
VID7
VID8
VR_EN
VR_RDY
VR_HOT
VR_FAN
VTT
RISO1
680 PULLUPS
RISO2
RT2
CFB1 RFB1
RFB
RVCC
2
3
4
5
6
7
8
9
10
1
37
40
39
16
15
17
19
+12 V
U21
VID0
VID1
VID2
VID3
VID4
VID5
VID6
VID7
VR10/VR11
EN
VR_RDY
VR_HOT
VR_FAN
VS−
VS+
NCP5388
DIFFOUT
VFB
36
VCC
CVCC1
DGND
AGND
VREF
NTC
CS1
CS1N
CS2
CS2N
CS3
CS3N
CS4
CS4N
G1
G2
G3
G4
12 V_FILTER
35
14
34
38
30
22
21
31
24
23
32
26
25
33
28
27
RT1
RNTC2
RNTC1
3
2
C1
12 V_FILTER
3
2
BAT54HT1
NCP3418B
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
VCC4BST
DRVH
OD
SW
DRVL
IN
PGND
D1
C3
1
8
7
5
6
NTD85N02RT4
1
8
7
5
6
12 V_FILTER
NTD60N02RT4
R2
C2
12 V_FILTER
C4
L1
RS1
CS1
RDRP
CF RF
CH
VCCP
VSSP
20
VDRP
18
COMP
ILIM
13
RLIM1
RLIM2
RT2 LOCATED NEAR OUTPUT INDUCTORS
DRVON
SSROSC
1112
CSS
29
Figure 4. Application Schematic for Two Phases
+
CPU GND
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NCP5388
PIN DESCRIPTIONS
Pin No. Symbol Description
1 EN Pull this pin high to enable controller. Pull this pin low to disable controller. Either an open−collector output
2 – 9 VID0–VID7 Voltage ID DAC inputs.
10 VR10/VR11 VR select bit. Connect this pin to VTT (1.25 V) to select the VR11 DAC table. Ground this pin to select the
11 SS A capacitor from this pin to ground programs the soft−start time.
12 ROSC A resistance from this pin to ground programs the oscillator frequency. Also, this pin supplies a regulated
13 ILIM Over current shutdown threshold. To program the shutdown threshold, connect this pin to the R
14 AGND Power supply return for the analog circuits that control output voltage.
15 VS+ Non−inverting input to the internal differential remote V
16 VS− Inverting input to the internal differential remote V
17 DIFFOUT Output of the differential remote sense amplifier.
18 COMP Output of the error amplifier.
19 VFB Error amplifier inverting input. Connect a resistor from this pin to DIFFOUT. The value of this resistor and the
20 VDRP Current signal output for Adaptive Voltage Positioning (AVP). The voltage of this pin minus 1.3 V is
21, 23,
CSxN Inverting input to current sense amplifier #x, x = 1, 2, 3, 4.
25, 27
22, 24,
CSx Non−inverting input to current sense amplifier #x, x = 1, 2, 3, 4.
26, 28
29 DRVON Gate Driver enable output. This pin produces a logic HIGH to enable gate drivers and a logic LOW to disable
30 – 33 G1 – G4 PWM control signal outputs to gate drivers.
34 VREF Voltage reference pin. This pin may be used to implement remote NTC temperature sensing as shown in the
35 DGND Power supply return for the digital circuits. Connect to AGND.
36 VCC Power for the internal control circuits.
37 VR_RDY Voltage Regulator Ready (PowerGood) output. Open drain type output with internal delays that will transition
38 NTC Remote temperature sense connection. Connect an NTC thermistor from this pin to GND and a resistor from
39 VR_FAN Open drain type of output that will be low impedance when the voltage at the NTC pin is above 1.416 V.
40 VR_HOT Open drain type of output that will be low impedance when the voltage at the NTC pin is above 1.086 V.
41 THPAD Copper pad on the bottom of the IC for heatsinking. This pin should be connected to the ground plane under
(with a pull−up resistor) or a logic gate (CMOS or totem−pole output) may be used to drive this pin. A Low to High transition on this pin will initiate a soft start. If the Enable function is not required, this pin should be tied directly to VREF.
VR10 DAC table with VR11 type startup. Connect this pin to V legacy VR10 type startup.
(4 V) to select VR10 DAC table with
REF
2.0 V which may be used with a voltage divider to the ILIM pin to set the over current shutdown threshold as shown in the Applications Schematics.
pin via a resistor divider as shown in the Applications Schematics. To disable the over current feature connect this pin directly to the R generated by the R
amount of current from the droop resistor (R load.
pin. To guarantee correct operation, this pin should only be connected to the voltage
OSC
pin – do not connect this pin to any externally generated voltages.
OSC
sense amplifier.
CORE
sense amplifier.
CORE
) will set the amount of output voltage droop (AVP) during
DRP
OSC
proportional to the output current. Connect a resistor from this pin to VFB to set the amount of AVP current into the feedback resistor (RFB) to produce an output voltage droop. Leave this pin open for no AVP.
gate drivers and has an internal 70 k to ground.
Applications Schematic.
High when V and Low when V mV until VCC is removed.
this pin to V
is higher than 300 mV below DAC, Low when V
CORE
REF
is higher than DAC+185 mV. This output is latched Low if V
CORE
. As the NTC’s temperature increases the voltage on this pin will decrease.
is lower than 380 mV below DAC,
CORE
exceeds DAC+185
CORE
This pin will transition to a high impedance state when the voltage at the NTC pin decreases below 1.176 V.
This pin will transition to a high impedance state when the voltage at the NTC pin decreases below 0.846 V.
the IC.
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NCP5388
MAXIMUM RATINGS
Rating Value Unit
Operating Ambient Temperature Range 0 to 70 °C
Operating Junction Temperature Range 0 to 85 °C
Storage Temperature Range −55 to 150 °C
Lead Temperature Soldering, Reflow (60 to 120 seconds minimum above 237°C): 260 °C
Thermal Resistance, Junction−to−Ambient (R
JEDEC Moisture Sensitivity Level ≤ 3 MSL
Maximum Voltage – VCC pin with respect to AGND 15 V
Maximum Voltage – all other pins with respect to AGND 5.5 V
Minimum Voltage – all pins with respect to AGND −0.3 V
Maximum Current into pins: COMP, VDRP, DIFFOUT, VREF 3.0 mA
Maximum Current into pins: VR_RDY, G1, G2, G3, G4, SS, VR_FAN, VR_HOT, DRVON 20 mA
Maximum Current out of pins: COMP, VDRP, DIFFOUT, ROSC, VREF 3.0 mA
Maximum Current out of pins: G1, G2, G3, G4 20 mA
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect device reliability.
NOTE: ESD Senstive Device.
) on a thermally conductive PCB in free air 83 °C/W
θ
JA
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter Test Conditions Min Ty p Max Units
Error Amplifier
Input Bias Current −200 −50 −10 nA
Inverting Input Voltage 1.0 kbetween VFB and COMP Pins − 1.3 − V
Input Offset Voltage (Note 1) −1.0 − 1.0 mV
Open Loop DC Gain (Note 1) CL = 60 pF to GND,
Open Loop Unity Gain Bandwidth (Note 1)
Open Loop Phase Margin (Note 1) CL = 60 pF to GND,
Slew Rate (Note 1) Vin = 100 mV, G = −1.0 V/V,
Maximum Output Voltage I
Minimum Output Voltage I
Output Source Current (Note 1) V
Output Sink Current (Note 1) V
Remote Sense Differential Amplifier
VS+ Input Resistance (Note 1) DRVON = High
VS+ Input Open Circuit Voltage (Note 1)
VS− Input Resistance (Note 1) VS+ = DAC Voltage
VS− Input Open Circuit Voltage (Note 1)
Input Voltage Range −0.3 − 3.0 V
Input Offset Voltage (Note 1) −1.0 − 1.0 mV
−3dB Bandwidth (Note 1) CL = 80 pF to GND,
DC Gain I
Slew Rate (Note 1) Vin = 1.0 V,
Maximum Output Voltage I
Minimum Output Voltage I
Output Source Current (Note 1) V
Output Sink Current (Note 1) V
1. Guaranteed by design. Not tested in production.
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
RL = 10 k to GND
CL = 60 pF to GND, RL = 10 k to GND
RL = 10 k to GND
1.2 V < V
< 2.2 V,
out
CL = 60 pF, DC Load = ±125 A
= 1.0 mA 3.0 3.3 − V
SOURCE
= 1.0 mA − 0.9 1.0 V
SINK
= 3.0 V − 2.0 − mA
out
= 1.0 V − 2.0 − mA
out
DRVON = Low
DRVON = High DRVON = Low
DRVON = High
DRVON = High VS+ = DAC Voltage
RL = 10 k to GND
= 100 A 0.982 1.000 1.018 V/V
DIFFOUT
V
= 1.0 V to 2.0 V,
out
CL = 80 pF to GND, Load = ±125 A
= 1.0 mA 3.0 − − V
SOURCE
= 1.0 mA − − 0.5 V
SINK
= 2.1 V − 25 − mA
out
= 1.0 V − 1.4 − mA
out
= 0.1 F, FSW = 400 kHz, unless otherwise stated)
VCC
− 78 − dB
− 15 − MHz
− 65 − deg
− 5.0 − V/s
−
−
−
−
17
0.5
0.67
0.05
−
−
−
−
− 10 − k
=
0.333*DA C
+ 0.433
− 12 − MHz
− 10 − V/s
k
V
V
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter UnitsMaxTypMinTest Conditions
V
Adaptive Voltage Positioning Amplifier
DRP
Current Sense Input to V
Current Sense Input to V
−3dB Bandwidth (Note 1)
Current Sense Input to V Slew Rate (Note 1)
Current Summing Amp Output Offset Voltage
Maximum V
Minimum V
Output Voltage CSx − CSxN = 0.12 V
DRP
Output Voltage CSx − CSxN = −0.12 V
DRP
Output Source Current (Note 1) VDRP = 2.9 V − 9.0 − mA
Output Sink Current (Note 1) VDRP = 1.0 V − 2.0 − mA
Current Sense Amplifiers
Input Bias Current CSx = CSxN = 1.4 V −200 −100 − nA
Common Mode Input Voltage Range (Note 1)
Differential Mode Input Voltage Range −120 − 120 mV
Input Offset Voltage (Note 1) CSx = CSxN = 1.0 V −3.0 − 3.0 mV
Current Sense Input to PWM Comparator Input Gain
Oscillator
Switching Frequency Range (Note 1) 100 − 1000 kHz
Switching Frequency Accuracy (Note 1)
Switching Frequency Accuracy R
Switching Frequency Accuracy R
Switching Frequency Accuracy R
Switching Frequency Accuracy (Note 1)
Switching Frequency Accuracy R
Switching Frequency Accuracy R
Switching Frequency Accuracy R
R
Output Voltage 10 k < R
OSC
R
Output Voltage (Note 1) 49.9 k < R
OSC
1. Guaranteed by design. Not tested in production.
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
Gain −60 mV < (CSx−CSxN)
DRP
DRP
Output
< +60 mV, T
CL = 330 pF to GND,
= 25°C
A
RL = 10 k to GND
DRP
Output
V(CSx−CSxN) = 25 mV (all phases),
1.3 V < V
< 1.9 V,
out
CL = 330 pF to GND, Load = ±400 A
CSx – CSxN = 0, CSx =1.0 V −40 − +40 mV
(all phases), I
SOURCE
= 1.0 mA
(all phases), I
= 1.0 mA
SINK
0 mV < (CSx−CSxN) < 25 mV T
= 25°C
A
R
= 100 k, 2 or 4−phase 93.6 104 114.4 kHz
OSC
= 49.9 k, 2 or 4−phase 184.5 205 225.5 kHz
OSC
= 24.9 k, 2 or 4−phase 360 400 440 kHz
OSC
= 10 k, 2 or 4−phase 829 921 1013 kHz
OSC
R
= 100 k, 3−phase 90 100 11 0 kHz
OSC
= 49.9 k, 3−phase 178.2 198 217.8 kHz
OSC
= 24.9 k, 3−phase 351 390 429 kHz
OSC
= 10 k, 3−phase 818 909 1000 kHz
OSC
< 49.9 k 1.92 2.00 2.08 V
OSC
< 100 k − 2.00 − V
OSC
= 0.1 F, FSW = 400 kHz, unless otherwise stated)
VCC
5.7 6.0 6.3 V/V
− 7.2 − MHz
− 3.7 − V/s
3.02 − − V
− − 0.5 V
−0.3 − 2.0 V
5.7 6.0 6.3 V/V
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter UnitsMaxTypMinTest Conditions
Modulators (PWM Comparators)
Minimum Pulse Width Fs = 400 kHz − 30 40 ns
Magnitude of the PWM Ramp − 1.0 − V
0% Duty Cycle COMP voltage when the PWM
100% Duty Cycle COMP voltage when the PWM
Minimum PWM Linear Duty Cycle (Note 1)
PWM Comparator Offset Mismatch (Note 1)
Phase Angle Error Between adjacent phases,
Propagation Delay (Note 1) Ramp/Comp crossing to Gx high − 20 − ns
Propagation Delay (Note 1) Ramp/Comp crossing to Gx low − 20 − ns
PWM Outputs
Output High Voltage Sourcing 500 A 3.3 4.0 4.7 V
Output Low Voltage Sinking 500 A − 25 100 mV
Rise Time CL = 20 pF, Vo = 0.3 to 2.0 V − 10 − ns
Fall Time CL = 20 pF, Vo = Vmax to 0.7 V − 10 − ns
Output Impedance – LO State Resistance to GND (Gx = LO) − 50 −
G4 Gate Pin Source Current during Phase Detect
Phase Detection Period − 50 − s
G4 Phase Detect Threshold Resistance
Gate Driver Enable (DRVON)
Output High Voltage Sourcing 500 A 4.0 5.3 5.5 V
Output Low Voltage Sinking 500 A − 50 200 mV
Rise Time CL (PCB) = 20 pF,
Fall Time CL (PCB) = 20 pF,
Internal Pulldown Resistance VCC < UVLO Threshold − 70 140 k
1. Guaranteed by design. Not tested in production.
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
outputs remain LO
outputs remain HI
FS = 400 kHz − 90 − %
Between any 2 phases, FS = 400 kHz
FS = 400 kHz
Vo = 10% to 90%
Vo = 10% to 90%
= 0.1 F, FSW = 400 kHz, unless otherwise stated)
VCC
− 1.2 − V
− 2.3 − V
− − 40 mV
−15 − 15 °
− 70 − A
− − 1.0 k
− 25 − ns
− 25 − ns
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter UnitsMaxTypMinTest Conditions
VR_RDY (Power Good) Output
Saturation Voltage I
Rise Time External pullup of 1.0 k to 1.25 V,
Output Voltage at Power−up (Note 1) External VR_RDY pullup resistor of 2.0
High – Output Leakage Current VR_RDY = 5.5 V via 1.0 K − − 1.0 A
Threshold Voltage VCORE increasing,
Rising Delay VCORE increasing 0.3 1.40 2.0 ms
Falling Delay VCORE decreasing − 5.0 − s
VR_FAN AND VR_HOT
NTC Pin Bias Current 0 V < NTC < 5.0 V −1.0 − 1.0 A
VR_FAN Upper Voltage Threshold Fraction of VREF voltage above which
VR_FAN Lower Voltage Threshold Fraction of VREF voltage below which
VR_FAN Hysteresis 210 240 270 mV
VR_FAN Output Voltage at Powerup (Note 1)
VR_FAN Output Saturation Voltage I
VR_FAN Output Leakage Current High Impedance State,
VR_HOT Upper Voltage Threshold Fraction of VREF voltage above which
VR_HOT Lower Voltage Threshold Fraction of VREF voltage below which
VR_HOT Hysteresis 210 240 270 mV
VR_HOT Output Voltage at Powerup (Note 1)
VR_HOT Saturation Output Voltage I
VR_HOT Output Leakage Current High Impedance State,
1. Guaranteed by design. Not tested in production.
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
= 10 mA − − 0.4 V
SINK
C
= 20 pF,
LOAD
Vo = 10% to 90%
k to 5.0 V, t
≤ 3 x t
R_VCC
100 s ≤ t
R_5V
R_VCC
,
≤ 20 ms
DAC = 1.3 V
VR_FAN output pulls low
VR_FAN output is open
External Pullup resistor of 2.0 k to 5.0 V, t
≤ 3 x t
R_VCC
100 s ≤ t
= 4.0 mA − − 0.3 V
SINK
R_5V
R_VCC
,
≤ 20 ms
VR_FAN = 5.0 V
VR_HOT output pulls low
VR_HOT output is open
External Pullup resistor of 2.0 k to 5.0 V, t
≤ 3 x t
R_VCC
100 s ≤ t
= 4.0 mA − − 0.3 V
SINK
R_5V
R_VCC
,
≤ 20 ms
VR_HOT = 5.0 V
= 0.1 F, FSW = 400 kHz, unless otherwise stated)
VCC
− − 150 ns
− − 1.0 V
− 300 − mV below
0.3518 0.3625 0.3737
0.2892 0.3025 0.3112
− − 1.0 V
− − 1.0 A
0.2732 0.2815 0.2897
0.2107 0.2190 0.2272
− − 1.0 V
− − 1.0 A
DAC
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter UnitsMaxTypMinTest Conditions
Soft−Start
SS Pin Source Current ENABLE = HI, V
SS Pin Source Current ENABLE = HI, V
Soft−Start Ramp Time CSS = 0.01 F, DRVON = HI to V
SS Pin Discharge Voltage ENABLE = LO − − 50 mV
Soft−Start Discharge Time From ENABLE = LO to V
VR11 V
Threshold Voltage − 1.081 − V
BOOT
VR11 Dwell Time at V
Enable Input
Enable High Input Leakage Current EN = 3.0 V − − 10 A
Upper Threshold V
Lower Threshold V
Total Hysteresis V
Enable Delay Time Enable transitioning HI to start of SS
Disable Delay Time Enable transitioning Low to
Current Limit
Current Sense Inputs to I
ILIM Pin Input Bias Current V
ILIM Pin Working Voltage Range 0.3 − 2.0 V
ILIM Input Offset Voltage −50 − 50 mV
Overvoltage Protection
Overvoltage Threshold DAC+160 DAC+180 DAC+200 mV
Undervoltage Protection
UVLO Start Threshold 8.2 9.0 9.5 V
UVLO Stop Threshold 7.2 8.0 8.5 V
UVLO Hysteresis − 1.0 − V
VID Inputs
Upper Threshold V
Lower Threshold V
Input Bias Current V
Delay before Latching VID Change (VID De−Skewing)
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
< 1.1 V − 5.0 − A
SS PIN
> 1.15 V, VR11
SS mode only
SS PIN
= 1.1 V
Discharge Voltage,
SS PIN
SS PIN
< max
= 0.1 F, FSW = 400 kHz, unless otherwise stated)
VCC
125 − − A
1.5 2.2 3.0 ms
− 5.0 − s
CSS = 0.01 F
(Note 1) 50 225 900 s
BOOT
UPPER
LOWER
UPPER
– V
LOWER
0.80 0.85 0.90 V
0.67 0.75 0.83 V
70 100 130 mV
0.5 1.5 3.0 ms
voltage rise
− − 200 ns
DRVON = Low
Gain 20 mV < (CSx−CSxN) < 60 mV
LIM
T
= 25°C
A
(all CS channels together)
= 2.0 V − 0.1 1.0 A
ILIM
UPPER
LOWER
= 1.25 V − 100 500 nA
VIDX
Measured from the 1st edge of a VID
5.7 6.0 6.3 V/V
− − 800 mV
400 − − mV
500 − 1000 ns
change
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter UnitsMaxTypMinTest Conditions
VR10/VR11 Select
VR10/VR11 DAC Table Threshold 0.4 − 0.775 V
VR10 w/ Legacy SS/VR11 Threshold 2.7 − 3.1 V
Internal DAC Slew Rate Limiter
Positive Slew Rate Limit VID step range of +10mV to +500mV − 7.3 − mV/s
Negative Slew Rate Limit VID step range of −10mV to −500mV − 7.3 − mV/s
Voltage Reference (V
V
Output Voltage 0 < I
REF
Input Supply Current
VCC Operating Current FSW = 400 kHz − 20 − mA
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
)
REF
< 250 A 3.92 4.00 4.08 V
VREF
= 0.1 F, FSW = 400 kHz, unless otherwise stated)
VCC
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter UnitsMaxTypMinTest Conditions
VR10 DAC
System Voltage Accuracy 1.0 V < DAC < 1.6 V
No−Load Offset Voltage from Nominal DAC Specification
VR10 VID Codes
VID4
400 mV
0 1 0 1 0 1 1 1.60000
0 1 0 1 0 1 0 1.59375
0 1 0 1 1 0 1 1.58750
0 1 0 1 1 0 0 1.58125
0 1 0 1 1 1 1 1.57500
0 1 0 1 1 1 0 1.56875
0 1 1 0 0 0 1 1.56250
0 1 1 0 0 0 0 1.55625
0 1 1 0 0 1 1 1.55000
0 1 1 0 0 1 0 1.54375
0 1 1 0 1 0 1 1.53750
0 1 1 0 1 0 0 1.53125
0 1 1 0 1 1 1 1.52500
0 1 1 0 1 1 0 1.51875
0 1 1 1 0 0 1 1.51250
0 1 1 1 0 0 0 1.50625
0 1 1 1 0 1 1 1.50000
0 1 1 1 0 1 0 1.49375
0 1 1 1 1 0 1 1.48750
0 1 1 1 1 0 0 1.48125
0 1 1 1 1 1 1 1.47500
0 1 1 1 1 1 0 1.46875
1 0 0 0 0 0 1 1.46250
1 0 0 0 0 0 0 1.45625
1 0 0 0 0 1 1 1.45000
1 0 0 0 0 1 0 1.44375
1 0 0 0 1 0 1 1.43750
1 0 0 0 1 0 0 1.43125
1 0 0 0 1 1 1 1.42500
1 0 0 0 1 1 0 1.41875
1 0 0 1 0 0 1 1.41250
1 0 0 1 0 0 0 1.40625
1 0 0 1 0 1 1 1.40000
1 0 0 1 0 1 0 1.39375
1 0 0 1 1 0 1 1.38750
1 0 0 1 1 0 0 1.38125
1 0 0 1 1 1 1 1.37500
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
0.8 V < DAC < 1.0 V
0.5 V < DAC < 0.8 V
With CS Input Vin = 0 V −19 mV
VID3
200 mV
VID2
100 mV
VID1
50 mV
VID0
25 mV
= 0.1 F, FSW = 400 kHz, unless otherwise stated)
VCC
− − ±0.75 ±7.0 ±8.0
VID5
12.5 mV
VID6
6.25 mV
% mV mV
Nominal DAC
Voltage (V)
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NCP5388
VR10 VID Codes
VID4
400 mV
1 0 0 1 1 1 0 1.36875
1 0 1 0 0 0 1 1.36250
1 0 1 0 0 0 0 1.35625
1 0 1 0 0 1 1 1.35000
1 0 1 0 0 1 0 1.34375
1 0 1 0 1 0 1 1.33750
1 0 1 0 1 0 0 1.33125
1 0 1 0 1 1 1 1.32500
1 0 1 0 1 1 0 1.31875
1 0 1 1 0 0 1 1.31250
1 0 1 1 0 0 0 1.30625
1 0 1 1 0 1 1 1.30000
1 0 1 1 0 1 0 1.29375
1 0 1 1 1 0 1 1.28750
1 0 1 1 1 0 0 1.28125
1 0 1 1 1 1 1 1.27500
1 0 1 1 1 1 0 1.26875
1 1 0 0 0 0 1 1.26250
1 1 0 0 0 0 0 1.25625
1 1 0 0 0 1 1 1.25000
1 1 0 0 0 1 0 1.24375
1 1 0 0 1 0 1 1.23750
1 1 0 0 1 0 0 1.23125
1 1 0 0 1 1 1 1.22500
1 1 0 0 1 1 0 1.21875
1 1 0 1 0 0 1 1.21250
1 1 0 1 0 0 0 1.20625
1 1 0 1 0 1 1 1.20000
1 1 0 1 0 1 0 1.19375
1 1 0 1 1 0 1 1.18750
1 1 0 1 1 0 0 1.18125
1 1 0 1 1 1 1 1.17500
1 1 0 1 1 1 0 1.16875
1 1 1 0 0 0 1 1.16250
1 1 1 0 0 0 0 1.15625
1 1 1 0 0 1 1 1.15000
1 1 1 0 0 1 0 1.14375
1 1 1 0 1 0 1 1.13750
1 1 1 0 1 0 0 1.13125
1 1 1 0 1 1 1 1.12500
1 1 1 0 1 1 0 1.11875
1 1 1 1 0 0 1 1.11250
1 1 1 1 0 0 0 1.10625
1 1 1 1 0 1 1 1.10000
1 1 1 1 0 1 0 1.09375
1 1 1 1 1 0 1 OFF
1 1 1 1 1 0 0 OFF
VID3
200 mV
VID2
100 mV
VID1
50 mV
VID0
25 mV
VID5
12.5 mV
VID6
6.25 mV
Nominal DAC
Voltage (V)
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NCP5388
VR10 VID Codes
VID4
400 mV
1 1 1 1 1 1 1 OFF
1 1 1 1 1 1 0 OFF
0 0 0 0 0 0 1 1.08750
0 0 0 0 0 0 0 1.08125
0 0 0 0 0 1 1 1.07500
0 0 0 0 0 1 0 1.06875
0 0 0 0 1 0 1 1.06250
0 0 0 0 1 0 0 1.05625
0 0 0 0 1 1 1 1.05000
0 0 0 0 1 1 0 1.04375
0 0 0 1 0 0 1 1.03750
0 0 0 1 0 0 0 1.03125
0 0 0 1 0 1 1 1.02500
0 0 0 1 0 1 0 1.01875
0 0 0 1 1 0 1 1.01250
0 0 0 1 1 0 0 1.00625
0 0 0 1 1 1 1 1.00000
0 0 0 1 1 1 0 0.99375
0 0 1 0 0 0 1 0.98750
0 0 1 0 0 0 0 0.98125
0 0 1 0 0 1 1 0.97500
0 0 1 0 0 1 0 0.96875
0 0 1 0 1 0 1 0.96250
0 0 1 0 1 0 0 0.95625
0 0 1 0 1 1 1 0.95000
0 0 1 0 1 1 0 0.94375
0 0 1 1 0 0 1 0.93750
0 0 1 1 0 0 0 0.93125
0 0 1 1 0 1 1 0.92500
0 0 1 1 0 1 0 0.91875
0 0 1 1 1 0 1 0.91250
0 0 1 1 1 0 0 0.90625
0 0 1 1 1 1 1 0.90000
0 0 1 1 1 1 0 0.89375
0 1 0 0 0 0 1 0.88750
0 1 0 0 0 0 0 0.88125
0 1 0 0 0 1 1 0.87500
0 1 0 0 0 1 0 0.86875
0 1 0 0 1 0 1 0.86250
0 1 0 0 1 0 0 0.85625
0 1 0 0 1 1 1 0.85000
0 1 0 0 1 1 0 0.84375
0 1 0 1 0 0 1 0.83750
0 1 0 1 0 0 0 0.83125
VID3
200 mV
VID2
100 mV
VID1
50 mV
VID0
25 mV
VID5
12.5 mV
VID6
6.25 mV
Nominal DAC
Voltage (V)
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NCP5388
ELECTRICAL CHARACTERISTICS
(0°C < T
< 70°C; 0°C < T
A
Parameter Test Conditions Min Ty p Max Units
VR 11 DAC
System Voltage Accuracy 1.0 V < DAC < 1.6 V
No−Load Offset Voltage from Nominal DAC Specification
Table 2: VR11 VID Codes
VID7
800 mV
0 0 0 0 0 0 0 0 OFF 00
0 0 0 0 0 0 0 1 OFF 01
0 0 0 0 0 0 1 0 1.60000 02
0 0 0 0 0 0 1 1 1.59375 03
0 0 0 0 0 1 0 0 1.58750 04
0 0 0 0 0 1 0 1 1.58125 05
0 0 0 0 0 1 1 0 1.57500 06
0 0 0 0 0 1 1 1 1.56875 07
0 0 0 0 1 0 0 0 1.56250 08
0 0 0 0 1 0 0 1 1.55625 09
0 0 0 0 1 0 1 0 1.55000 0A
0 0 0 0 1 0 1 1 1.54375 0B
0 0 0 0 1 1 0 0 1.53750 0C
0 0 0 0 1 1 0 1 1.53125 0D
0 0 0 0 1 1 1 0 1.52500 0E
0 0 0 0 1 1 1 1 1.51875 0F
0 0 0 1 0 0 0 0 1.51250 10
0 0 0 1 0 0 0 1 1.50625 11
0 0 0 1 0 0 1 0 1.50000 12
0 0 0 1 0 0 1 1 1.49375 13
0 0 0 1 0 1 0 0 1.48750 14
0 0 0 1 0 1 0 1 1.48125 15
0 0 0 1 0 1 1 0 1.47500 16
0 0 0 1 0 1 1 1 1.46875 17
0 0 0 1 1 0 0 0 1.46250 18
0 0 0 1 1 0 0 1 1.45625 19
0 0 0 1 1 0 1 0 1.45000 1A
0 0 0 1 1 0 1 1 1.44375 1B
0 0 0 1 1 1 0 0 1.43750 1C
0 0 0 1 1 1 0 1 1.43125 1D
0 0 0 1 1 1 1 0 1.42500 1E
0 0 0 1 1 1 1 1 1.41875 1F
0 0 1 0 0 0 0 0 1.41250 20
0 0 1 0 0 0 0 1 1.40625 21
0 0 1 0 0 0 1 0 1.40000 22
0 0 1 0 0 0 1 1 1.39375 23
0 0 1 0 0 1 0 0 1.38750 24
VID6
400 mV
< 85°C; 10.8 V < VCC < 13.2 V; All DAC Codes; C
J
0.8 V < DAC < 1.0 V
0.5 V < DAC < 0.8 V
With CS Input Vin = 0 V −19 mV
VID5
200 mV
VID4
100 mV
VID3
50 mV
VID2
25 mV
= 0.1 F, unless otherwise stated)
VCC
− − ±0.75
VID1
12.5 mV
VID0
6.25 mV
±7.0 ±8.0
Nominal
DAC
Voltage (V)
% mV mV
HEX
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NCP5388
Table 2: VR11 VID Codes
VID7
800 mV
0 0 1 0 0 1 0 1 1.38125 25
0 0 1 0 0 1 1 0 1.37500 26
0 0 1 0 0 1 1 1 1.36875 27
0 0 1 0 1 0 0 0 1.36250 28
0 0 1 0 1 0 0 1 1.35625 29
0 0 1 0 1 0 1 0 1.35000 2A
0 0 1 0 1 0 1 1 1.34375 2B
0 0 1 0 1 1 0 0 1.33750 2C
0 0 1 0 1 1 0 1 1.33125 2D
0 0 1 0 1 1 1 0 1.32500 2E
0 0 1 0 1 1 1 1 1.31875 2F
0 0 1 1 0 0 0 0 1.31250 30
0 0 1 1 0 0 0 1 1.30625 31
0 0 1 1 0 0 1 0 1.30000 32
0 0 1 1 0 0 1 1 1.29375 33
0 0 1 1 0 1 0 0 1.28750 34
0 0 1 1 0 1 0 1 1.28125 35
0 0 1 1 0 1 1 0 1.27500 36
0 0 1 1 0 1 1 1 1.26875 37
0 0 1 1 1 0 0 0 1.26250 38
0 0 1 1 1 0 0 1 1.25625 39
0 0 1 1 1 0 1 0 1.25000 3A
0 0 1 1 1 0 1 1 1.24375 3B
0 0 1 1 1 1 0 0 1.23750 3C
0 0 1 1 1 1 0 1 1.23125 3D
0 0 1 1 1 1 1 0 1.22500 3E
0 0 1 1 1 1 1 1 1.21875 3F
0 1 0 0 0 0 0 0 1.21250 40
0 1 0 0 0 0 0 1 1.20625 41
0 1 0 0 0 0 1 0 1.20000 42
0 1 0 0 0 0 1 1 1.19375 43
0 1 0 0 0 1 0 0 1.18750 44
0 1 0 0 0 1 0 1 1.18125 45
0 1 0 0 0 1 1 0 1.17500 46
0 1 0 0 0 1 1 1 1.16875 47
0 1 0 0 1 0 0 0 1.16250 48
0 1 0 0 1 0 0 1 1.15625 49
0 1 0 0 1 0 1 0 1.15000 4A
0 1 0 0 1 0 1 1 1.14375 4B
0 1 0 0 1 1 0 0 1.13750 4C
0 1 0 0 1 1 0 1 1.13125 4D
0 1 0 0 1 1 1 0 1.12500 4E
0 1 0 0 1 1 1 1 1.11875 4F
0 1 0 1 0 0 0 0 1.11250 50
0 1 0 1 0 0 0 1 1.10625 51
0 1 0 1 0 0 1 0 1.10000 52
VID6
400 mV
VID5
200 mV
VID4
100 mV
VID3
50 mV
VID2
25 mV
VID1
12.5 mV
VID0
6.25 mV
DAC
Voltage (V)
HEXNominal
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NCP5388
Table 2: VR11 VID Codes
VID7
800 mV
0 1 0 1 0 0 1 1 1.09375 53
0 1 0 1 0 1 0 0 1.08750 54
0 1 0 1 0 1 0 1 1.08125 55
0 1 0 1 0 1 1 0 1.07500 56
0 1 0 1 0 1 1 1 1.06875 57
0 1 0 1 1 0 0 0 1.06250 58
0 1 0 1 1 0 0 1 1.05625 59
0 1 0 1 1 0 1 0 1.05000 5A
0 1 0 1 1 0 1 1 1.04375 5B
0 1 0 1 1 1 0 0 1.03750 5C
0 1 0 1 1 1 0 1 1.03125 5D
0 1 0 1 1 1 1 0 1.02500 5E
0 1 0 1 1 1 1 1 1.01875 5F
0 1 1 0 0 0 0 0 1.01250 60
0 1 1 0 0 0 0 1 1.00625 61
0 1 1 0 0 0 1 0 1.00000 62
0 1 1 0 0 0 1 1 0.99375 63
0 1 1 0 0 1 0 0 0.98750 64
0 1 1 0 0 1 0 1 0.98125 65
0 1 1 0 0 1 1 0 0.97500 66
0 1 1 0 0 1 1 1 0.96875 67
0 1 1 0 1 0 0 0 0.96250 68
0 1 1 0 1 0 0 1 0.95625 69
0 1 1 0 1 0 1 0 0.95000 6A
0 1 1 0 1 0 1 1 0.94375 6B
0 1 1 0 1 1 0 0 0.93750 6C
0 1 1 0 1 1 0 1 0.93125 6D
0 1 1 0 1 1 1 0 0.92500 6E
0 1 1 0 1 1 1 1 0.91875 6F
0 1 1 1 0 0 0 0 0.91250 70
0 1 1 1 0 0 0 1 0.90625 71
0 1 1 1 0 0 1 0 0.90000 72
0 1 1 1 0 0 1 1 0.89375 73
0 1 1 1 0 1 0 0 0.88750 74
0 1 1 1 0 1 0 1 0.88125 75
0 1 1 1 0 1 1 0 0.87500 76
0 1 1 1 0 1 1 1 0.86875 77
0 1 1 1 1 0 0 0 0.86250 78
0 1 1 1 1 0 0 1 0.85625 79
0 1 1 1 1 0 1 0 0.85000 7A
0 1 1 1 1 0 1 1 0.84375 7B
0 1 1 1 1 1 0 0 0.83750 7C
0 1 1 1 1 1 0 1 0.83125 7D
0 1 1 1 1 1 1 0 0.82500 7E
0 1 1 1 1 1 1 1 0.81875 7F
1 0 0 0 0 0 0 0 0.81250 80
VID6
400 mV
VID5
200 mV
VID4
100 mV
VID3
50 mV
VID2
25 mV
VID1
12.5 mV
VID0
6.25 mV
DAC
Voltage (V)
HEXNominal
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NCP5388
Table 2: VR11 VID Codes
VID7
800 mV
1 0 0 0 0 0 0 1 0.80625 81
1 0 0 0 0 0 1 0 0.80000 82
1 0 0 0 0 0 1 1 0.79375 83
1 0 0 0 0 1 0 0 0.78750 84
1 0 0 0 0 1 0 1 0.78125 85
1 0 0 0 0 1 1 0 0.77500 86
1 0 0 0 0 1 1 1 0.76875 87
1 0 0 0 1 0 0 0 0.76250 88
1 0 0 0 1 0 0 1 0.75625 89
1 0 0 0 1 0 1 0 0.75000 8A
1 0 0 0 1 0 1 1 0.74375 8B
1 0 0 0 1 1 0 0 0.73750 8C
1 0 0 0 1 1 0 1 0.73125 8D
1 0 0 0 1 1 1 0 0.72500 8E
1 0 0 0 1 1 1 1 0.71875 8F
1 0 0 1 0 0 0 0 0.71250 90
1 0 0 1 0 0 0 1 0.70625 91
1 0 0 1 0 0 1 0 0.70000 92
1 0 0 1 0 0 1 1 0.69375 93
1 0 0 1 0 1 0 0 0.68750 94
1 0 0 1 0 1 0 1 0.68125 95
1 0 0 1 0 1 1 0 0.67500 96
1 0 0 1 0 1 1 1 0.66875 97
1 0 0 1 1 0 0 0 0.66250 98
1 0 0 1 1 0 0 1 0.65625 99
1 0 0 1 1 0 1 0 0.65000 9A
1 0 0 1 1 0 1 1 0.64375 9B
1 0 0 1 1 1 0 0 0.63750 9C
1 0 0 1 1 1 0 1 0.63125 9D
1 0 0 1 1 1 1 0 0.62500 9E
1 0 0 1 1 1 1 1 0.61875 9F
1 0 1 0 0 0 0 0 0.61250 A0
1 0 1 0 0 0 0 1 0.60625 A1
1 0 1 0 0 0 1 0 0.60000 A2
1 0 1 0 0 0 1 1 0.59375 A3
1 0 1 0 0 1 0 0 0.58750 A4
1 0 1 0 0 1 0 1 0.58125 A5
1 0 1 0 0 1 1 0 0.57500 A6
1 0 1 0 0 1 1 1 0.56875 A7
1 0 1 0 1 0 0 0 0.56250 A8
1 0 1 0 1 0 0 1 0.55625 A9
1 0 1 0 1 0 1 0 0.55000 AA
1 0 1 0 1 0 1 1 0.54375 AB
1 0 1 0 1 1 0 0 0.53750 AC
1 0 1 0 1 1 0 1 0.53125 AD
1 0 1 0 1 1 1 0 0.52500 AE
VID6
400 mV
VID5
200 mV
VID4
100 mV
VID3
50 mV
VID2
25 mV
VID1
12.5 mV
VID0
6.25 mV
DAC
Voltage (V)
HEXNominal
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NCP5388
Table 2: VR11 VID Codes
VID7
800 mV
1 0 1 0 1 1 1 1 0.51875 AF
1 0 1 1 0 0 0 0 0.51250 B0
1 0 1 1 0 0 0 1 0.50625 B1
1 0 1 1 0 0 1 0 0.50000 B2
1 1 1 1 1 1 1 0 OFF FE
1 1 1 1 1 1 1 1 OFF FF
VID6
400 mV
VID5
200 mV
VID4
100 mV
VID3
50 mV
VID2
25 mV
VID1
12.5 mV
VID0
6.25 mV
DAC
Voltage (V)
OFF B3 to FD
HEXNominal
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NCP5388
TYPICAL CHARACTERISTICS
13.6
13.4
13.2
13.0
12.8
, IC QUIESCENT CURRENT (mA)
CC
I
12.6 0
10 20 30 40
TA, AMBIENT TEMPERATURE (°C)
Figure 5. IC Quiescent Current vs. Ambient
Temperature
0.0198
0.0196
0.0194
0.0192
0.0190
0.0188
DAC OFFSET
0.0186
0.0184
0.0182
0.0180
10
9
8
, UNDERVOLTAGE LOCKOUT
THRESHOLD VOLTAGE (V)
CC
V
50 60 70
7
0 20 3040506070
Figure 6. VCC Undervoltage Lockout
Threshold Voltage vs. Ambient Temperature
25°C
0°C
70°C
0.6
0.5 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4
VID
VCC Increasing Voltage
VCC Decreasing Voltage
10
TA, AMBIENT TEMPERATURE (°C)
1.5 1.6
Figure 7. Typical DAC Voltage Offset vs.
Temperature
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NCP5388
FUNCTIONAL DESCRIPTION
General
The NCP5388 dual edge modulated multiphase PWM controller is specifically designed with the necessary features for a high current VR10 or VR11 CPU power system. The IC consists of the following blocks: Precision Programmable DAC, Differential Remote Voltage Sense Amplifier, High Performance Voltage Error Amplifier, Differential Current Feedback Amplifiers, Precision Oscillator and Triangle Wave Generators, and PWM Comparators. Protection features include Undervoltage Lockout, Soft−Start, Overcurrent Protection, Overvoltage Protection, and Power Good Monitor.
Remote Output Sensing Amplifier (RSA)
A true differential amplifier allows the NCP5388 to measure Vcore voltage feedback with respect to the Vcore ground reference point by connecting the Vcore reference point to VS+, and the Vcore ground reference point to VS−. This configuration keeps ground potential differences between the local controller ground and the Vcore ground reference point from affecting regulation of Vcore between Vcore and Vcore ground reference points. The RSA also subtracts the DAC (minus VID offset) voltage, thereby producing an unamplified output error voltage at the DIFFOUT pin. This output also has a 1.3 V bias voltage to allow both positive and negative error voltages.
Precision Programmable DAC
A precision programmable DAC is provided. This DAC has 0.75% accuracy over the entire operating temperature range of the part. The DAC can be programmed to support either VR10 or VR11 specifications. A program selection pin is provided to accomplish this. This pin also sets the startup mode of operation. Connect this pin to 1.25 V to select the VR11 DAC table, and the VR11 startup mode. Connect this pin to ground to select the VR10 DAC table and the VR11 startup mode. Connect this pin to VREF to select the VR10 DAC table and the VR10 startup mode.
High Performance Voltage Error Amplifier
The error amplifier is designed to provide high slew rate and bandwidth. Although not required when operating as a voltage regulator for VR10 or VR11, a capacitor from COMP to VFB is required for stable unity gain test configurations.
Gate Driver Outputs and 2/3/4 Phase Operation
The part can be configured to run in 2−, 3−, or 4−phase mode. In 2−phase mode, phases 1 and 3 should be used to drive the external gate drivers as shown in the 2−phase Applications Schematic. In 3−phase mode, gate output G4 must be grounded as shown in the 3−phase Applications Schematic. In 4−phase mode all 4 gate outputs are used as
shown in the 4−phase Applications Schematic. The following truth table summarizes the modes of operation:
Gate Output Connections
Mode
2−Phase Normal OPEN Normal OPEN
3−Phase Normal Normal Normal GND
4−Phase Normal Normal Normal Normal
G1 G2 G3 G4
These are the only allowable connection schemes to
program the modes of operation.
Differential Current Sense Amplifiers
Four differential amplifiers are provided to sense the output current of each phase. The inputs of each current sense amplifier must be connected across the current sensing element of the phase controlled by the corresponding gate output (G1, G2, G3, or G4). If a phase
is unused, the differential inputs to that phase’s current sense amplifier must be shorted together and connected to V
as shown in the 2− and 3−phase Application
CCP
Schematics.
A voltage is generated across the current sense element (such as an inductor or sense resistor) by the current flowing in that phase. The output of the current sense amplifiers are used to control three functions. First, the output controls the adaptive voltage positioning, where the output voltage is actively controlled according to the output current. In this function, all of the current sense outputs are summed so that the total output current is used for output voltage positioning. Second, the output signal is fed to the current limit circuit. This again is the summed current of all phases in operation. Finally, the individual phase current is connected to the PWM comparator. In this way current balance is accomplished.
Oscillator and Triangle Wave Generator
A programmable precision oscillator is provided. The oscillator ’s frequency is programmed by the resistance connected from the ROSC pin to ground. The user will usually form this resistance from two resistors in order to create a voltage divider that uses the ROSC output voltage as the reference for creating the current limit setpoint voltage. The oscillator frequency range is 100 kHz/phase to 1.0 MHz/phase. The oscillator generates up to 4 triangle waveforms (symmetrical rising and falling slopes) between 1.3 V and 2.3 V. The triangle waves have a phase delay between them such that for 2−, 3−, and 4−phase operation the PWM outputs are separated by 180, 120, and 90 angular degrees, respectively.
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PWM Comparators with Hysteresis
Four PWM comparators receive the error amplifier output signal at their noninverting input. Each comparator receives one of the triangle waves offset by 1.3 V at it’s inverting input. The output of the comparator generates the PWM outputs G1, G2, G3, and G4.
During steady state operation, the duty cycle will center on the valley of the triangle waveform, with steady state duty cycle calculated by V
. During a transient event,
out/Vin
both high and low comparator output transitions shift phase to the points where the error amplifier output intersects the down and up ramp of the triangle wave.
PROTECTION FEATURES
Undervoltage Lockout
An undervoltage lockout (UVLO) senses the VCC input. During powerup, the input voltage to the controller is monitored, and the PWM outputs and the soft−start circuit are disabled until the input voltage exceeds the threshold voltage of the UVLO comparator. The UVLO comparator incorporates hysteresis to avoid chattering, since VCC is likely to decrease as soon as the converter initiates soft−start.
Overcurrent Shutdown
A programmable overcurrent function is incorporated within the IC. A comparator and latch makeup this function. The inverting input of the comparator is connected to the ILIM pin. The voltage at this pin sets the maximum output current the converter can produce. The ROSC pin provides a convenient and accurate reference voltage from which a resistor divider can create the overcurrent setpoint voltage. Although not actually disabled, tying the ILIM pin directly to the ROSC pin sets the limit above useful levels – effectively disabling overcurrent shutdown. The comparator noninverting input is the summed current information from the current sense amplifiers. The overcurrent latch is set when the current
information exceeds the voltage at the ILIM pin. The outputs are immediately disabled, the VR_RDY and DRVON pins are pulled low, and the soft−start is pulled low. The outputs will remain disabled until the VCC voltage is removed and re−applied, or the ENABLE input is brought low and then high.
Overvoltage Protection and Power Good Monitor
An output voltage monitor is incorporated. During normal operation, if the voltage at the DIFFOUT pin exceeds 1.3 V, the VR_RDY pin goes low, the DRVON signal remains high, the PWM outputs are set low. The outputs will remain disabled until the VCC voltage is removed and reapplied. During normal operation, if the output voltage falls more than 300 mV below the DAC setting, the VR_RDY pin will be set low until the output rises.
Soft−Start
The NCP5388 incorporates an externally programmable soft−start. The soft−start circuit works by controlling the ramp−up of the DAC voltage during powerup. The initial soft−start pin voltage is 0 V. The soft−start circuitry clamps the DAC input of the Remote Sense Amplifier to the SS pin voltage until the SS pin voltage exceeds the DAC setting minus VID offset. The soft−start pin is pulled to 0 V if there is an overcurrent shutdown, if the ENABLE pin is low, if VCC is below the UVLO threshold, or if an overvoltage condition exists.
There are two possible soft−start modes: Legacy VR10 and VR11. VR10 mode simply ramps Vcore from 0 V directly to the DAC setting at the rate set by the capacitor connected to the SS pin. The VR11 mode ramps Vcore to
1.1 V at the SS capacitor charge rate, pauses at 1.1 V for 170 s, reads the VID pins to determine the DAC setting, then ramps Vcore to the final DAC setting at the Dynamic VID slew rate of 7.3 mV/s. Typical VR10 and VR11 soft−start sequences are shown in the following graphs.
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NCP5388
2.4
2.2
2.0
1.8
1.6
1.4
1.2
VOLTAGE
1.0
0.8
0.6
0.4
0.2
0
0
TIME
Figure 8. Typical VR10 Soft−Start Sequence to Vcore = 1.3 V
2.4
2.2
2.0
1.8
1.6
1.4
1.2
VOLTAGE
1.0
0.8
0.6
0.4
0.2
0
0
Boot Voltage
Boot
Dwell Time
TIME
VID Setting
Vcore Voltage SS Pin Voltage
VID Setting
NCP5388 Internal Dynamic VID Rate Limit
Vcore Voltage SS Pin Voltage
Figure 9. Typical VR11 Soft−Start Sequence to Vcore = 1.3 V
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NCP5388
APPLICATION INFORMATION
The NCP5388 is a high performance multiphase controller optimized to meet the Intel VR11 Specifications. The demo board for the NCP5388 is available by request. It is configured as a four phase solution with decoupling designed to provide a 1.0 m load line under a 100 A step load. A schematic is available upon request from ON Semiconductor.
Startup Procedure
The demo board comes with a Socket 775 and requires an Intel dynamic load tool (VTT Tool) available through a third party supplier, Cascade Systems. The web page is http://www.cascadesystems.net/.
Start by installing the test tool software. It’s best to power the test tool from a separate ATX power supply. The test tool should be set to a valid VID code of 0.5 V or above in−order for the controller to start. Consult the VTT help manual for more detailed instructions.
Startup Sequence
1. Make sure the VTT software is installed.
2. Powerup the PC or Laptop do not start the VTT software.
3. Insert the VTT Test Tool adapter into the socket and lock it down.
4. Inset the socket saver pin field into the bottom of the VTT test tool.
5. Carefully line up the tool with the socket in the board and press tool into the board.
6. Connect the scope probe, or DMM to the voltage sense lines on the test tool. When using a scope probe it is best to isolate the scope from the AC ground. Make the ground connection on the scope probe as short as possible.
7. Connect the first ATX supply to the VTT tool.
8. Powerup the first ATX supply to the VTT tool.
9. Start the VTT tool software in VR11 mode with the current limit set to 150 A.
10. Using the VTT tool software, select a VID code that is 0.5 V or above.
11. Connect the second ATX supply to the demo board.
12. Set the VID DIP switches. All the VID switches should be up or open.
13. Set the VR_ENABLE DIP switch down or closed.
14. Set the VR10 DIP switch up or open.
15. Set the VID_SEL switch up or open.
16. Start the second ATX supply by turning it on and setting the PSON DIP switch low. The green VID lights should light up to match the VTT tool VID setting.
17. Set the VR_ENABLE DIP switch up to start the NCP5388.
18. Check that the output voltage is about 19 mV below the VID setting.
Step Load Testing
The VTT tool is used to generate the high di/dt step load. Select the dynamic loading option in the VTT test tool software. Set the desired step load size, frequency, duty, and slew rate. See Figures 10 and 11.
Figure 10. Typical Step Load Response
Figure 11. Typical Load Release Event
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Dynamic VID Testing
The VTT tool provides for VID stepping based on the Intel Requirements. Select the Dynamic VID option. Before enabling the test set the lowest VID to 0.5 V or greater and set the highest VID to a value that is greater than the lowest VID selection, then enable the test. See Figures 12 through 14.
Figure 12. 1.6 to 0.5 Dynamic VID Response
Design Methodology
Decoupling the VCC Pin on the IC
An RC input filter is required as shown in the VCC pin to minimize supply noise on the IC. The resistor should be sized such that it does not generate a large voltage drop between the 12 V supply and the IC. See the schematic values.
Understanding Soft−Start
The controller supports two different startup routines. A legacy VR10 ramp to the initial VID code, or a VR11 Ramp to the 1.1 V VID code, with a pause to capture the VID code then resume ramping to target value based on an internal slew rate limit. See Figures 15 and 16. The controller is designed to regulate to the voltage on the SS pin until it reaches the internal DAC voltage. The soft−start cap sets the initial ramp rate using a typical 5.0 A current. The typical value to use for the soft−start cap (SS), is typically set to 0.01 F. This results in a ramp time to 1.1 V of 2.2 ms based on equation 1.
dt
Css^ i
1.1 · V
2.2 · ms
Css+ 0.01 · F
ss
+
ss
dv
ss
dv
ss
and iss+ 5·A
dt
ss
(eq. 1)
Figure 13. Dynamic VID Settling Time Rising
Figure 14. Dynamic VID Settling Time Falling
Figure 15. VR11 Startup
Figure 16. VR10 Legacy Startup
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Programming the Current Limit and the Oscillator Frequency
The demo board is set for an operating frequency of approximately 300 kHz. The OSC pin provides a 2.0 V reference voltage which is divided down with a resistor divider and fed into the current limit pin ILIM. Calculate the total series resistance to set the frequency and then calculate the individual values for current limit divider.
The series resistors RLIM1 and RLIM2 sink current to ground. This current is internally mirrored into a capacitor to create an oscillator. The period is proportional to the resistance and frequency is inversely proportional to the resistance. The resistance may be estimated by equation 2 or 3 depending on the phase count.
100
90
80
70
60
50
40
ROSC (kOhms)
30
20
10
0
100
200
300
400
500
600
700
32.36 k^
ROSC +
ROSC +
4 Phase Mode
3 Phase Mode
800
10.14 10 300 · k
4 Phase Mode
10.14 10 Frequency
3 Phase Mode
9.711 10 Frequency
900
1000
9
* 1440
9
* 1440
9
* 1111
(eq. 2)
(eq. 3)
Frequency (kHz)
Figure 17. ROSC vs. Phase Frequency
The current limit function is based on the total sensed current of all phases multiplied by a gain of 5.94. DCR sensed inductor current is function of the winding temperature. The best approach is to set the maximum
Calculate the current limit voltage:
V
ILIMIT
^ 5.94 ·ǒI
MIN_OCP
· DCR
Tmax
)
Solve for the individual resistors:
V
RLIM2 +
Final Equation for the Current Limit Threshold
I
LIMIT(Tinductor
) ^
5.94 · (DCR
ILIMIT·ROSC
2·V
2·V·RLIM2
ǒ
RLIM1)RLIM2
·(1) 0.00393 · C−1(T
25C
Ǔ
) 0.02
The inductors on the demo board have a DCR at 25°C of
0.75 m. Selecting the closest available values of 16.9 k for RLIM1 and 15.8 k for RLIM2 yield a nominal operating frequency of 305 kHz and an approximate current limit of 180 A at 100°C. The total sensed current can be observed as a scaled voltage at the VDRP pin added to a positive, no−load offset of approximately 1.3 V.
current limit based on the expected average maximum temperature of the inductor windings.
DCR
50C
2·Vin·F
Inductor
· Vout
s
−25 · C)))
DCR
(1 ) 0.00393 · C−1(T
Vin−Vout
ǒ
·
RLIM1 + R
*
Tmax
* (N−1) ·
L
Vout
2·Vin·F
+ DCR
OSC−RLIM2
·
s
25C
Vout
Vin−Vout
ǒ
·
Tmax
Ǔ
L
L
−25 · C))
Ǔ
* 0.02
* (N−1) ·
Inductor Selection
When using inductor current sensing it is recommended that the inductor does not saturate by more than 10% at maximum load. The inductor also must not go into hard saturation before current limit trips. The demo board includes a four phase output filter using the T50−8 core from Micrometals with 4turns and a DCR target of 0.75 m @ 25°C. Smaller DCR values can be used, however, current sharing accuracy and droop accuracy decrease as DCR decreases. Use the excel spreadsheet for regulation accuracy calculations for a specific value of DCR.
(eq. 4)
(eq. 5)
(eq. 6)
Vout
L
(eq. 7)
Ǔ
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NCP5388
Inductor Current Sense Compensation
The NCP5388 uses the inductor current sensing method. This method uses an RC filter to cancel out the inductance of the inductor and recover the voltage that is the result of
Rsense(T) +
Figure 18.
0.47 · F · DCR
The demoboard inductor measured 350 nH and 0.75 m at room temp. The actual value used for Rsense was 953 which matches the equation for Rsense at approximately 50C. Because the inductor value is a function of load and
the current flowing through the inductor’s DCR. This is done by matching the RC time constant of the current sense filter to the L/DCR time constant. The first cut approach is to use a 0.47 F capacitor for C and then solve for R.
L
·(1) 0.00393 · C−1·(T−25 · C))
25C
inductor temperature final selection of R is best done experimentally on the bench by monitoring the Vdroop pin and performing a step load test on the actual solution.
It is desirable to keep the Rsense resistor value below
1.0 k whenever possible by increasing the capacitor values in the inductor compensation network. The bias current flowing out of the current sense pins is approximately 100 nA. This current flows through the current sense resistor and creates an offset at the capacitor which will appear as a load current at the Vdroop pin. A 1.0 k resistor will keep this offset at the droop pin below 2.5 mV.
Simple Average PSPICE Model
A simple state average model shown in Figure 19 can be used to determine a stable solution and provide insight into the control system.
(eq. 8)
−
+
−
+
VRamp_min
1.3 V
−
+
1E3
Vin 12
0
4
4.3 kCF1.5 n
Unity Gain
BW = 15 MHz
C3
10.6 n
0
E1
+
+
−
−
E
0
GAIN = 6
CFB1
680 p
Voff
DCR
(0.85e−3/4)
RFB1
100
RFB
1 k
12
0
CH
22 p
RF
R6
1 k
L
12
(250e−9/4)
Voff
RDRP
5.11 k
−
+
LBRD
12
100 p CBulk (560e−6*10)
ESRBulk (7e−3/10)
2
ESLBulk (3.5e−9/10)
1
+
1.3
−
RBRD
0.75 m
Voffset
0
+
−
+
−
CCer (22e−6*18)
ESRCer (1.5e−3/18)
2
ESLCer (1.5e−9/18)
1
VDAC
1.25 V
0
1Aac 0Adc
+
−
I1 = 10 I2 = 110 TD = 10u TR = 50n TF = 50n PW = 40u PER = 80u
Vout
I2
+
−
0
Figure 19.
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A complex switching model is available by request which includes a more detailed board parasitic for this demo board.
Compensation and Output Filter Design
The values shown on the demo board are a good place to start for any similar output filter solution. The dynamic performance can then be adjusted by swapping out various individual components.
If the required output filter and switching frequency are significantly different, it’s best to use the available PSPICE models to design the compensation and output filter from scratch.
The design target for this demo board was 1.0 m out to
2.0 MHz. The phase switching frequency is currently set to 300 kHz. It can easily be seen that the board impedance of
0.75 m between the load and the bulk capacitance has a large effect on the output filter. In this case the ten 560 F
80
1/(2*PI*CFB1*(RFB1+RFB))
1/(2*PI*CF*RF)
1/(2*PI*(RBRD+ESRBulk)*CBulk)
dB
60
40
20
−20
RF/RFB
0
bulk capacitors have an ESR of 7.0 m. Thus the bulk ESR plus the board impedance is 0.7 m+ 0.75 m or
1.45 m. The actual output filter impedance does not drop to 1.0 m until the ceramic breaks in at over 375 kHz. The controller must provide some loop gain slightly less than one out to a frequency in excess 300 kHz. At frequencies below where the bulk capacitance ESR breaks with the bulk capacitance, the DC−DC converter must have sufficiently high gain to control the output impedance completely. Standard Type−3 compensation works well with the NCP5388. RFB1 should be kept above 50 for amplifier stability reasons.
The goal is to compensate the system such that the resulting gain generates constant output impedance from DC up to the frequency where the ceramic takes over holding the impedance below 1.0 m. See the example of the locations of the poles and zeros that were set to optimize the model above.
Zout Open Loop
Zout Closed Loop
Open Loop Gain with Current loop Closed
Voltage Loop Compensation Gain
1/(2*PI*RF*CF)
RF/RFB1
Error Amp Open Loop Gain
−40
−60
−80
1mOhm
1/(2*PI*SQRT(ESL_Cer*CCer))
1/(2*PI*CCer*(RBRD+ESRBulk))
−100 100 1000 10000 100000 1000000 10000000
Frequency
Figure 20.
By matching the following equations a good set of starting compensation values can be found for a typical mixed bulk
and ceramic capacitor type output filter.
1
2·CF·RF
2·CFBI·(RFBI) RFB)
+
2· (RBRD ) ESRBulk) · CBulk
1
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1
+
2· CCer * (RBRD ) ESRBulk)
31
1
(eq. 9)
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NCP5388
RFB is always set to 1.0 k and RFB1 is usually set to 100 for maximum phase boost. The value of RF is typically set to 4.0 k.
Droop Injection and Thermal Compensation
The VDRP signal is generated by summing the sensed output currents for each phase and applying a gain of approximately six. VDRP is externally summed into the feedback network by the resistor RDRP. This induces an
RRDP determines the target output impedance by the
basic equation:
Vout
+ Zout +
Iout
RDRP +
The value of the inductor’s DCR varies with temperature
according to the following equation 10:
offset which is proportional to the output current thereby forcing the controlled resistive output impedance.
DCR
The system can be thermally compensated to cancel this effect out to a great degree by adding an NTC (negative temperature coefficient resistor) in parallel with RFB to reduce the droop gain as the temperature increases. The NTC device is nonlinear. Putting a resistor in series with the
Tmax
+ DCR
·(1) 0.00393 · C−1(T
25C
NTC helps make the device appear more linear with temperature. The series resistor is split and inserted on both sides of the NTC to reduce noise injection into the feedback loop. The recommended value for RISO1 and RISO2 is approximately 1.0 k.
Tmax
−25 · C))
The output impedance varies with inductor temperature by the equation:
Zout(T) +
RFB · DCR
·(1) 0.00393 · C−1(T
25C
Rdroop
−25C)) · 5.94
max
By including the NTC RT2 and the series isolation resistors the new equation becomes:
Zout(T) +
RFB · (RISO1)RT2(T))RISO2)
RFB)RISO1)RT2(T))RISO2
· DCR
·(1) 0.00393 · C−1(T
25C
Rdroop
RFB · DCR · 5.94
RDRP
RFB · DCR · 5.94
Zout
−25C)) · 5.94
max
(eq.
10)
(eq. 11)
(eq. 12)
(eq. 13)
The typical equation of a NTC is based on a curve fit equation 13.
RT2(T) + RT2
25C
·e
ƪǒ
1
273 )T
1
298
Ǔ
ƫ
(eq. 14)
ǒ
Ǔ
*
The demo board is populated with a 10 k NTC with a Beta of 4300. Figure 21 shows the uncompensated and compensated output impedance versus temperature.
Figure 21. Uncompensated and Compensated Output
Impedance vs. Temperature
ON Semiconductor provides an excel spreadsheet to help with the selection of the NTC. The actual selection of the NTC will be effected by the location of the output inductor with respect to the NTC and airflow, and should be verified with an actual system thermal solution.
VRHOT and VRFAN
Thermal monitoring provides two threshold sensitive comparators for thermal monitoring. The circuit consists of two comparators that compare the voltage on the NTC pin to an internal resistor divider connected to VREF. By powering the external temperature sense divider with VREF the tolerance of the VREF voltage is canceled out. The data sheet specifications for the thresholds are shown as ratios with respect to VREF.
VR_FAN Upper Threshold Ratio = 0.3625
VR_FAN Lower Threshold Ratio = 0.3025
VR_HOT Upper Threshold Ratio = 0.2815
VR_HOT Lower Threshold Ratio = 0.2190
The following equations can be used to find the temperature trip points.
RT1(T) + RT1
Ratio
NTC
(T) :
25C
RNTC1 )RNTC2 ) RT1(T)
273 )T
RNTC2 ) RT1(T)
1
ƪǒ
·e
1
298
Ǔ
ƫ
(eq. 15)
(eq. 16)
ǒ
Ǔ
*
The demo board contains a 68 K NTC for RT1 with a Beta of 4750. RNTC1 is populated with 15 k and RNTC2 is populated with a zero ohm resistor. Figure 22 is a plot of equation 15. The horizontal trip thresholds intersect the Ratio
NTC
curve.
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Figure 22.
OVP
The overvoltage protection threshold is not adjustable. OVP protection is enabled as soon as soft−start begins and is disabled when the part is disabled. When OVP is tripped, the controller commands all four gate drivers to enable their low side MOSFETs, and VR_RDY transitions low. In order to recover from an OVP condition, VCC must fall below the UVLO threshold. See the state diagram for
further details. The OVP circuit monitors the output of DIFFOUT. If the DIFFOUT signal reaches 180 mV above the nominal 1.3 V offset the OVP will trip. The DIFFOUT signal is the difference between the output voltage and the DAC voltage plus the 1.3 V internal offset. This results in the OVP tracking the DAC voltage even during a dynamic change in the VID setting during operation.
Gate Driver and MOSFET Selection
ON Semiconductor provides the companion gate driver IC (NCP3418B). The NCP3418B driver is optimized to work with a range of MOSFETs commonly used in CPU applications. The NCP3418B provides special functionality and is required for the high performance dynamic VID operation of the part. Contact your local ON Semiconductor applications engineer for MOSFET recommendations.
Board Stack−Up
The demo board follows the recommended Intel Stack−up and copper thickness as shown.
Figure 23.
Board Layout
A complete Allegro ATX and BTX demo board layout file and schematics are available by request at www.onsemi.com and can be viewed using the Allegro Free Physical Viewer 15.x from the Cadence website http://www.cadence.com/.
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Close attention should be paid to the routing of the sense traces and control lines that propagate away from the controller IC. Routing should follow the demo board example. For further information or layout review contact ON Semiconductor.
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2 X
a
LOCATION
0.15 C
2 X
PIN ONE
0.15 C
D
TOP VIEW
NCP5388
PACKAGE DIMENSIONS
40 PIN QFN, 7x7
MN SUFFIX
CASE 488AG−01
ISSUE O
A
B
E
NOTES:
1. DIMENSIONS AND TOLERANCING PER ASME Y14.5M, 1994.
2. CONTROLLING DIMENSIONS: MILLIMETER.
3. DIMENSION b APPLIES TO PLATED TERMINAL AND IS MEASURED BETWEEN
0.25 AND 0.30 MM TERMINAL
4. COPLANARITY APPLIES TO THE EXPOSED PAD AS WELL AS THE TERMINALS.
MILLIMETERS
DIM MIN MAX
A 0.80 1.00 A1 0.00 0.05 A3 0.20 REF
b 0.18 0.30
D 7.00 BSC D2 5.50 5.70
E 7.00 BSC
e 0.50 BSC
L 0.30 0.50
k 0.20 −−−
5.70E2 5.50
0.10 C
(A3)
A
40 X
0.08 C
SEATING PLANE
L
40 X
SIDE VIEW
A1
C
D2
11
10
20
EXPOSED PAD
k
40 X
21
E2
40 X
1
40
b
30
31
e
A0.10 BC
0.05 C
BOTTOM VIEW
Pentium is a registered trademark of Intel Corporation.
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