LX1664/64A, LX1665/65A
D
UAL
O
UTPUT
PWM C
ONTROLLERS
T
H E
WITH
5-B
IT
DAC
I
N F I N I T E
P
O W E R
O F
I
N N O VA T I O N
P
R O D U C T I O N
D
A T A
S
H E E T
DESCRIPTION
The LX1664/64A and LX1665/65A are
monolithic switching regulator con-
troller 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 with-
out 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 com-
parator threshold for optimum perfor-
mance using a sense resistor. For applica-
tions requiring a high degree of accuracy, a
conventional sense resistor can be used to
sense current.
Programmable Synchronous Recti-
fier 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-syn-
chronous 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 regu-
lator suitable for powering a 1.5V GTL+ bus
or 2.5V clock supply.
(continued next page)
K E Y F E AT U R E S
I
5-bit Programmable Output For CPU Core
Supply
I
Adjustable Linear Regulator Driver Output
I
No Sense Resistor Required For Short-
Circuit Current Limiting
I
Designed To Drive Either Synchronous Or
Non-Synchronous Output Stages
I
Soft-Start Capability
I
Modulated, Constant Off-Time Architecture
For Fast Transient Response And Simple
System Design
I
Available Over-Voltage Protection (OVP)
Crowbar Driver And Power Good Flag
(LX1665 only)
A P P L I C AT I O N S
I
Socket 7 (Pentium Class) Microprocessor
Supplies (including Intel Pentium Processor,
AMD-K6
TM
And Cyrix
®
6x86
TM
, Gx86
TM
and
M2
TM
Processors)
I
Pentium II and Deschutes Processor & L2-
Cache Supplies
I
Voltage Regulator Modules
IMPORTANT:
For the most current data, consult LinFinity's web site:
http://www.linfinity.com.
PRODUCT HIGHLIGHT
LX1665
IN A
P
E N T I U M
I I S
I N G L E
-C
H I P
P
O W E R
S
U P P L Y
S
O L U T I O N
F
1
20A
L
2
1µH
Q
1
12V
C
3
0.1µF
1
2
3
5V
6.3V
1500µF x3
C
2
L
1
2.5µH
U1
LX1665
SS
INV
V
CC_CORE
VID0
VID1
VID2
VID3
VID4
L
FB
V
C1
TDRV
GND
BDRV
V
CC
C
T
OV
L
DRV
PWRGD
18
17
16
15
14
13
12
11
10
C
5
1µF
IRL3102
R
1
0.0025
Supply Voltage
for CPU Core
V
OUT
VID0
VID1
VID2
VID3
VID4
4
5
6
7
8
9
Q
2
IRL3303
6.3V, 1500µF x 3**
C
1
C
8
680pF
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
18-pin
Wide-Body SOIC
OV
PWRGD
C
7
330µF
T
A
(°C)
0 to 70
N
Plastic DIP
16-pin
LX1664CN
LX1664ACN
N
Plastic DIP
18-pin
LX1665CN
LX1665ACN
D
Plastic SOIC
16-pin
LX1664CD
LX1664ACD
DW
Plastic SOIC Wide
18-pin
LX1665CDW
LX1665ACDW
Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (e.g. LX1664CDT)
Copyright © 1999
Rev. 1.2 11/99
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
Selection Guide
PA C K A G E O R D E R I N F O R M AT I O N
See next page
for
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
N PACKAGE — 16-Pin
LX1664/1664A
(Top View)
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
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
Pentium-class (<10A)
Pentium II (> 10A)
Pentium-class (<10A)
Pentium II (> 10A)
V
C1
TDRV
GND
BDRV
V
CC
C
T
OV
L
DRV
PWRGD
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)
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
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
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)
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
T H E R M A L D ATA
N (16-PIN DIP) PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
N (18-PIN DIP) PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
D PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
DW PACKAGE:
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
θ
JA
90°C/W
120°C/W
60°C/W
65°C/W
V
C1
TDRV
GND
BDRV
V
CC
C
T
OV
L
DRV
PWRGD
DW PACKAGE — 18-Pin
LX1665/1665A
(Top View)
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. 1.2 11/99
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
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
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
180
0.9
0.37
240
1.1
0.47
Error Comparator Section
Input Bias Current
Input Offset Voltage
E
C
Delay to Output
I
B
V
IO
36
10% Overdrive
I
B
V
CLP
1.3V < V
INV
= V
CC_CORE
< 3.5V
Initial Accuracy
Initial Accuracy
10% Overdrive
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
2
46
Current Sense Section
Input Bias Current (V
CC_CORE
Pin)
Pulse By Pulse C
L
LX1664/1665
LX1664A/1665A
C
S
Delay to Output
85
50
35
115
70
Output Drivers Section
Drive Rise Time
Drive Fall Time
Drive High
Drive Low
Output Pull Down
T
R
T
F
V
DH
V
DL
V
PD
V
ST
V
HYST
I
SD
V
OL
I
CD
0.1
1.2
1.4
10.4
UVLO and S.S. Section
Start-Up Threshold
Hysteresis
SS Sink Current
SS Sat Voltage
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
2
0.6
27
Supply Current Section
Dynamic Operating Current
Lower Threshold
Hysteresis
Power Good Voltage Low
Over-Voltage Threshold
OVP Sourcing Current
Power Good / Over-Voltage Protection Section
(LX1665 Only)
88
90
1
0.5
117
45
92
0.7
125
110
30
1.5
-1.5
Linear Regulator Section
Output Voltage
Setpoint Accuracy
Output Temperature Drift
Load Regulation
Cummulative Accuracy
Op-Amp Output Current
3.6
1.5
40
1.5
3
Open Loop
50
70
Copyright © 1999
Rev. 1.2 11/99
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
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.
Note:
Adaptive Transient Voltage Output
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.
Output Load
0A
5A/Div.
0 to 14A
Time - 100µs/Div.
FIGURE 1
— Output Transient Response
(using 5mΩ sense resistor and 5µH output inductor)
4
Copyright © 1999
Rev. 1.2 11/99
Output Voltage
2.8V
100mV/Div.
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
85
EFFICIENCY (%)
_
_
Output Set Point
85
80
80
Output Set Point
75
EFFICIENCY AT 3.1V
EFFICIENCY AT 2.8V
EFFICIENCY AT 1.8V
75
EFFICIENCY AT 3.1V
EFFICIENCY AT 2.8V
EFFICIENCY AT 1.8V
70
1
2
3
4
5
6
7
8
9
10
11
12
13
14
70
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
85
80
75
70
Output Set Point
1.8V EFFICIENCY
65
2.8V EFFICIENCY
3.3V EFFICIENCY
60
1
2
3
4
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.
Copyright © 1999
Rev. 1.2 11/99
5
嵌入式系统
