Not Recommended For New Design
LX1664 / 64A, LX1665 / 65A
D
UAL
O
UTPUT
PWM C
ONTROLLER WITH
5-BIT DAC
T
H E
I
N F I N I T E
P
O W E R
O F
I
N N O V A T I O N
P
R O D U C T I O N
D
A T A
S
H E E T
DESCRIPTION
KEY FEATURES
5-bit Programmable Output For
CPU Core Supply
Adjustable Linear Regulator
Driver Output
No Sense Resistor Required For
Short-Circuit Current Limiting
Designed To Drive Either
Synchronous Or Non-
Synchronous Output Stages
Soft-Start Capability
Modulated, Constant Off-Time
Architecture For Fast Transient
Response And Simple System
Design
Available Over-Voltage
Protection (OVP) Crowbar Driver
And Power Good Flag (LX1665
only)
ol
e
PRODUCT HIGHLIGHT
12V
F
1
20A
5V
6.3V
1500µF x3
C
2
L
1
2.5µH
The LX1664/64A and LX1665/65A are
monolithic switching regulator controller
IC’s
designed to provide a low cost, high
performance adjustable power supply for
advanced microprocessors and other
applications requiring a very fast transient
response and a high degree of accuracy.
Short-circuit Current Limiting without
Expensive Current Sense Resistors.
Current-sensing mechanism can use PCB
trace resistance or the parasitic resistance of
the main inductor. The
LX1664A
and
LX1665A
have reduced current sense
comparator threshold for optimum
performance using a sense resistor. For
applications requiring a high degree of
accuracy, a conventional sense resistor can be
used to sense current.
Programmable Synchronous Rectifier
Driver for CPU Core.
The main output is
adjustable from 1.3V to 3.5V using a 5-bit
code. The IC can read a VID signal set by
a DIP switch on the motherboard, or
hardwired into the processor’s package (as
in the case of Pentium
®
Pro and Pentium II
processors). The 5-bit code adjusts the
output voltage between 1.30 and 2.05V in
50mV increments and between 2.0 and 3.5V
in 100mV increments, conforming to the
Intel Corporation specification. The device
can drive dual MOSFET’s resulting in
typical efficiencies of 85 - 90% even with
loads in excess of 10 amperes. For cost
sensitive applications, the bottom MOSFET
can be replaced with a Schottky diode (non-
synchronous operation).
Linear Regulator Driver.
The LX1664/ 65
family of devices have a secondary regulator
output. This can drive a MOSFET or bipolar
transistor as a pass element to construct a
low-cost adjustable linear regulator suitable
for powering a 1.5V GTL+ bus or 2.5V
clock supply.
IMPORTANT:
For the most current data, consult
MICROSEMI’s
website:
http://www.microsemi.com
bs
C
3
0.1µF
LX1665 in a Pentium II Single-Chip Power Supply Solution
U1
LX1665
C
5
1µF
L
2
1µH
1
2
3
4
5
6
7
SS
V
C1
18
17
Q
1
IRL3102
INV
TDRV
GND
V
CC_CORE
VID0
VID1
VID2
VID3
VID4
L
FB
16
15
O
VID1
VID2
VID3
VID4
VID0
BDRV
V
CC
C
T
OV
L
DRV
PWRGD
Q
2
14
13
12
11
10
IRL3303
8
9
C
8
680pF
18-pin
Wide-Body SOIC
OV
PWRGD
T
A
(°C)
0 to 70
N
Plastic DIP
16-Pin
N
PACKAGE ORDER INFO
Plastic DIP
Plastic SOIC
D
16-Pin
18-Pin
RoHS Compliant / Pb-free
Transition DC: 0440
RoHS Compliant / Pb-free
Transition DC: 0503
LX1664CN
LX1664ACN
LX1665CN
LX1665ACN
Note: Available in Tape & Reel. Append the letters ‘TR’ to the part number. (i.e. LX1664CD-TR)
Copyright
©
1999
Rev. 1.3a,2005-03-17
L
IN
F
INITY
M
ICROELECTRONICS
I
NC
.
11861 W
ESTERN
A
VENUE
, G
ARDEN
G
ROVE
, CA. 92841, 714-898-8121, F
AX
: 714-893-2570
te
R
1
0.0025
Supply Voltage
for CPU Core
APPLICATIONS
Socket 7 (Pentium Class)
Microprocessor Supplies
(including Intel Pentium
Processor, AMD-K6TM And
Cyrix® 6x86TM, Gx86TM and
M2TM Processors)
Pentium II and Deschutes
Processor & L2-Cache Supplies
Voltage Regulator Modules
V
OUT
6.3V, 1500µF x 3**
C
1
C
9
330µF
Q
4
IRLZ44
R
5
R
6
** Three capacitors for Pentium
Four capacitors for Pentium II
Supply Voltage
For I/O Chipset or GTL+ Bus
C
7
330µF
DW
Plastic SOIC Wide
18-Pin
LX1665CDW
LX1665ACDW
RoHS Compliant / Pb-free
Transition DC: 0516
LX1664CD
LX1664ACD
1
PRODUCT DATABOOK 1996/1997
LX1664/64A, LX1665/65A
D
UAL
O
UTPUT
PWM C
ONTROLLERS
P
R O D U C T I O N
WITH
5-B
IT
DAC
D
A T A
S
H E E T
PACKAGE PIN OUTS
SS
INV
V
CC_CORE
VID0
VID1
VID2
VID3
VID4
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
D E S C R I P T I O N
(con't.)
Smallest Package Size.
The LX1664 is
available in a narrow body 16-pin surface
mount IC package for space sensitive appli-
cations. The LX1665 provides the additional
functions of Over Voltage Protection (OVP)
and Power Good (PWRGD) output drives
for applications requiring output voltage
monitoring and protection functions.
Ultra-Fast Transient Response re-
duces system cost.
The modulated off-
time architecture results in the fastest tran-
sient response for a given inductor, reduc-
ing output capacitor requirements, and re-
ducing the total regulator system cost.
Over-Voltage Protection and Power
Good Flag.
The OVP output in the LX1665
& LX1665A can be used to drive an SCR
crowbar circuit to protect the load in the
event of a short-circuit of the main MOSFET.
The LX1665 & LX1665A also have a logic-
level Power Good Flag to signal when the
output voltage is out of specified limits.
V
C1
TDRV
GND
BDRV
V
CC
C
T
L
DRV
L
FB
te
SS
INV
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
N PACKAGE — 16-Pin
LX1664/1664A
(Top View)
V
C1
TDRV
GND
BDRV
V
CC
C
T
OV
L
DRV
PWRGD
DEVICE SELECTION GUIDE
DEVICE
LX1664
LX1664A
LX1665
LX1665A
Packages
16-pin SOIC
& DIP
18-pin SOIC
& DIP
OVP and
Power Good
No
Yes
Current-Sense
Comp. Thresh. (mV)
100
60
100
60
Optimal Load
ol
e
65°C/W
60°C/W
120°C/W
90°C/W
Pentium-class (<10A)
Pentium II (> 10A)
Pentium-class (<10A)
Pentium II (> 10A)
V
CC_CORE
VID0
VID1
VID2
VID3
VID4
L
FB
N PACKAGE — 18-Pin
LX1665/1665A
(Top View)
A B S O L U T E M A X I M U M R AT I N G S
(Note 1)
bs
T H E R M A L D ATA
Supply Voltage (V
C1
) .................................................................................................... 25V
Supply Voltage (V
CC
) .................................................................................................... 15V
Output Drive Peak Current Source (500ns) ............................................................... 1.5A
Output Drive Peak Current Sink (500ns) ................................................................... 1.5A
Input Voltage (SS, INV, V
CC_CORE
, C
T
, VID0-VID4) ........................................... -0.3V to 6V
Operating Junction Temperature
Plastic (N, D & DW Packages) ............................................................................. 150°C
Storage Temperature Range .................................................................... -65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) ............................................................. 300°C
Peak Package Solder Reflow Temp (40 second max. exposure)............................................260°C(+0, -5)
SS
INV
V
CC_CORE
VID0
VID1
VID2
VID3
VID4
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
V
C1
TDRV
GND
BDRV
V
CC
C
T
L
DRV
L
FB
D PACKAGE — 16-Pin
LX1664/1664A
(Top View)
Note 1. Exceeding these ratings could cause damage to the device. All voltages are with respect
to Ground. Currents are positive into, negative out of the specified terminal. Pin
numbers refer to DIL packages only.
SS
INV
V
CC_CORE
VID0
VID1
VID2
VID3
VID4
L
FB
1
2
3
4
5
6
7
8
9
18
17
16
15
14
13
12
11
10
O
N (16-PIN DIP) PACKAGE:
N (18-PIN DIP) PACKAGE:
D PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
V
C1
TDRV
GND
BDRV
V
CC
C
T
OV
L
DRV
PWRGD
DW PACKAGE — 18-Pin
LX1665/1665A
(Top View)
RoHS / Pb-free 100% Matte Tin Lead Finish
DW PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
Junction Temperature Calculation: T
J
= T
A
+ (P
D
x
θ
JA
).
The
θ
JA
numbers are guidelines for the thermal performance of the device/pc-board system.
All of the above assume no ambient airflow
2
Copyright © 1999
Rev. 1.3a
11/04
PRODUCT DATABOOK 1996/1997
LX1664/1664A, LX1665/65A
D
UAL
O
UTPUT
PWM C
ONTROLLERS
P
R O D U C T I O N
WITH
5-B
IT
DAC
D
A T A
S
H E E T
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, 10.8 < V
CC
< 13.2, 0°C
≤
T
A
≤
70°C. Test conditions: V
CC
= 12V, T = 25°C. Use Application Circuit.)
Parameter
Reference & DAC Section
Regulation Accuracy
Symbol
Test Conditions
LX1664/1665 (A)
Min. Typ.
Max.
-30
-1
2
1
40
210
2
1
0.42
100
0.8
41
200
27
100
60
200
70
70
11
10
0.06
0.8
0.8
9.9
2
10.1
0.31
5.5
0.15
30
1
Units
mV
%
µs
µs
ppm
µA
V
V
V
ns
µA
mV
ns
µA
mV
mV
ns
ns
ns
V
V
V
V
V
V
V
mA
V
mA
%
%
V
%
mA
V
%
ppm
%
%
mA
(See Table 1 - Next Page)
Regulation Accuracy
(See Table 1)
(Less 40mV output adaptive positioning)
, V
CC
= 12V, I
LOAD
= 6A
1.8V
≤
V
OUT
≤
2.8V
OT
V
CC_CORE
= 1.3V, C
T
= 390pF
V
CC_CORE
= 3.5V, C
T
= 390pF
V
CC_CORE
= 1.3V to 3.5V
V
CC_CORE
= 1.3V, V
CT
= 1.5V
V
CC_CORE
= 1.3V
V
CC_CORE
= 3.5V
10% Overdrive
1.3V < V
SS
= V
INV
< 3.5V
10% Overdrive
Timing Section
Off Time Initial
Off Time Temp Stability
Discharging Current
Ramp Peak
Ramp Peak-Valley
Ramp Valley Delay to Output
I
DIS
V
P
V
RPP
Error Comparator Section
Input Bias Current
Input Offset Voltage
E
C
Delay to Output
I
B
V
IO
ol
e
I
B
V
CLP
1.3V < V
INV
= V
CC_CORE
< 3.5V
Initial Accuracy
Initial Accuracy
10% Overdrive
T
R
T
F
V
DH
V
DL
V
PD
V
C1
= V
CC
= 12V, C
L
= 3000pF
V
C1
= V
CC
= 12V, C
L
= 3000pF
V
CC
= V
CC
= 12V, I
SOURCE
= 20mA
V
CC
= V
CC
= 12V, I
SINK
= 200mA
V
CC
= V
CC
= 12V, I
SOURCE
= 20mA
V
CC
= V
CC
= 12V, I
SINK
= 200mA
V
CC
= V
C
= 0, I
PULL UP
= 2mA
V
ST
V
HYST
I
SD
V
OL
I
CD
V
C1
= 10.1V
V
C1
= 9V, I
SD
= 200µA
V
CC
= V
C1
= 12V, Out Freq = 200kHz, C
L
= 0
(V
CC_CORE
/ DAC
OUT
)
I
PWRGD
= 5mA
(V
CC_CORE
/ V
DAC
)
V
OV
= 5V
Set by external resistors
I
L
= 0.5A using 0.5% resistors
Open Loop
Current Sense Section
Input Bias Current (V
CC_CORE
Pin)
Pulse By Pulse C
L
LX1664/1665
LX1664A/1665A
C
S
Delay to Output
Output Drivers Section
Drive Rise Time
Drive Fall Time
Drive High
Drive Low
bs
Output Pull Down
UVLO and S.S. Section
Start-Up Threshold
Hysteresis
SS Sink Current
SS Sat Voltage
O
Supply Current Section
Dynamic Operating Current
Lower Threshold
Hysteresis
Power Good Voltage Low
Over-Voltage Threshold
OVP Sourcing Current
Output Voltage
Setpoint Accuracy
Output Temperature Drift
Load Regulation
Cummulative Accuracy
Op-Amp Output Current
Power Good / Over-Voltage Protection Section
(LX1665 Only)
88
90
1
0.5
117
45
92
0.7
125
Linear Regulator Section
1.5
-1.5
40
1.5
3
50
70
3.6
1.5
Copyright © 1999
Rev. 1.3a
11/04
te
180
0.9
0.37
36
85
50
110
30
240
1.1
0.47
2
46
35
115
70
0.1
1.2
1.4
10.4
0.6
27
3
PRODUCT DATABOOK 1996/1997
LX1664/64A, LX1665/65A
D
UAL
O
UTPUT
PWM C
ONTROLLERS
P
R O D U C T I O N
WITH
5-B
IT
DAC
D
A T A
S
H E E T
ELECTRICAL CHARACTERISTICS
Table 1 - Adaptive Transient Voltage Output
Processor Pins
0 = Ground, 1 = Open (Floating)
(Output
Voltage Setpoint Typical)
Output Voltage (V
CC_CORE
)
VID0
0.0A
Nominal Output*
VID4
VID3
VID2
VID1
Note:
Adaptive Transient Voltage Output
bs
0A
5A/Div.
2.8V
100mV/Div.
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
* Nominal =
1
1
1
1
1
1
1
1
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
0
1
0
1
0
1
0
0
1
0
1
0
1
0
1
0
0
0
0
0
0
0
0
DAC setpoint voltage
1
1
1.34V
1.30V
1
0
1.39V
1.35V
0
1
1.44V
1.40V
0
0
1.49V
1.45V
1
1
1.54V
1.50V
1
0
1.59V
1.55V
0
1
1.64V
1.60V
0
0
1.69V
1.65V
1
1
1.74V
1.70V
1
0
1.79V
1.75V
0
1
1.84V
1.80V
0
0
1.89V
1.85V
1
1
1.94V
1.90V
1
0
1.99V
1.95V
0
1
2.04V
2.00V
0
0
2.09V
2.05V
1
1
2.04V
2.00V
1
0
2.14V
2.10V
0
1
2.24V
2.20V
0
0
2.34V
2.30V
1
1
2.44V
2.40V
1
0
2.54V
2.50V
0
1
2.64V
2.60V
0
0
2.74V
2.70V
1
1
2.84V
2.80V
1
0
2.94V
2.90V
0
1
3.04V
3.00V
0
0
3.14V
3.10V
1
1
3.24V
3.20V
1
0
3.34V
3.30V
0
1
3.44V
3.40V
0
0
3.54V
3.50V
with no adaptive output voltage positioning.
ol
e
Output Load
Time - 100µs/Div.
FIGURE 1
— Output Transient Response
(using 5mΩ sense resistor and 5µH output inductor)
4
Copyright © 1999
Rev. 1.3a
11/04
Output Voltage
In order to improve transient response a 40mV
offset is built into the Current Sense comparator.
At high currents, the peak output voltage will be
lower than the nominal set point, as shown in
Figure 1. The actual output voltage will be a
function of the sense resistor, the output current
and output ripple.
O
te
0 to 14A
PRODUCT DATABOOK 1996/1997
LX1664/1664A, LX1665/65A
D
UAL
O
UTPUT
PWM C
ONTROLLERS
P
R O D U C T I O N
WITH
5-B
IT
DAC
D
A T A
S
H E E T
CHARACTERISTICS CURVES
95
100
90
95
EFFICIENCY (%)
_
_
90
80
Output Set Point
75
EFFICIENCY AT 3.1V
EFFICIENCY AT 2.8V
EFFICIENCY AT 1.8V
70
1
2
3
4
5
6
7
8
ol
e
70
9
10
11
12
13
14
te
85
80
85
EFFICIENCY (%)
_
_
Output Set Point
75
EFFICIENCY AT 3.1V
EFFICIENCY AT 2.8V
EFFICIENCY AT 1.8V
1
2
3
4
5
6
7
8
9
10
11
12
13
14
I
OUT
(A)
I
OUT
(A)
FIGURE 2
— Efficiency Test Results:
Non-Synchronous Operation, V
IN
= 5V
FIGURE 3
— Efficiency Test Results:
Synchronous Operation, V
IN
= 5V
90
O
70
65
60
1
2
3
4
Copyright © 1999
Rev. 1.3a
11/04
bs
85
80
75
Output Set Point
1.8V EFFICIENCY
2.8V EFFICIENCY
3.3V EFFICIENCY
5
6
7
8
9
10
11
12
13
14
I
OUT
(A)
FIGURE 4
— Efficiency Test Results: Synchronous Operation, V
IN
= 12V.
Note: Non-synchronous operation not recommended for 12V operation, due to power loss in Schottky diode.
5
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