lx1663 Microsemi Corporation, lx1663 Datasheet

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lx1663

Manufacturer Part Number
lx1663
Description
Single-chip Programmable Controllers With 5-bit
Manufacturer
Microsemi Corporation
Datasheet
T
H E
The LX1662/62A and LX1663/63A 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.
out Expensive Current Sense Resistors.
Current-sensing mechanism can use PCB
trace resistance or the parasitic resistance of
the main inductor.
LX1663A have reduced current sense com-
parator threshold for optimum perfor-
mance using a PCB trace. For applications
requiring a high degree of accuracy, a
conventional sense resistor can be used to
sense current.
fier Driver for CPU Core.
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
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
IMPORTANT: For the most current data, consult LinFinity's web site: http://www.linfinity.com.
Short-Circuit Current Limiting with-
Programmable Synchronous Recti-
I
N F I N I T E
Note: All surface-mount packages are available in Tape & Reel. Append the letter "T" to part number. (i.e. LX1662CDT)
11861 W
P
The LX1662A and
®
O W E R
Pro and Pentium II
VID0
VID1
VID2
VID3
VID4
N
ESTERN
Plastic DIP
14-pin
The main
O F
L
0.1µF
A
I N
C
VENUE
3
I
F
N N O V A T I O N
I N I T Y
, G
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).
available in a narrow body 14-pin surface
mount IC package for space sensitive appli-
cations. The LX1663 provides the additional
functions of Over Voltage Protection (OVP)
and Power Good (PWRGD) output drives
for applications requiring output voltage
monitoring and protection functions.
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.
Good Flag. The OVP output in the LX1663
& LX1663A 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 LX1663 & LX1663A also have a logic-
level Power Good Flag to signal when the
output voltage is out of specified limits.
ARDEN
14-pin, Narrow Body SOIC
Smallest Package Size. The LX1662 is
Ultra-Fast Transient Response Re-
Over-Voltage Protection and Power
1
2
3
4
5
6
7
SS
INV
V
VID0
VID1
VID2
VID3
N
CC_CORE
M
G
LX1662
Plastic DIP
16-pin
ROVE
U1
I C R O E L E C T R O N I C S
, CA. 92841, 714-898-8121, F
BDRV
TDRV
GND
VID4
V
V
C
CC
C1
T
14
13
12
11
10
9
8
12V
LX1662/62A, LX1663/63A
D
C
1µF
C
680pF
5
8
Plastic SOIC
14-pin
IRL3102
1µH
L
Q
2
1
5V
Q
IRL3303
L
2
I
6.3V
1500µF x3
1
, 2.5µH
N C
** Three capacitors for Pentium
AX
Four capacitors for Pentium II
I 5-bit Programmable Output For CPU Core
I No Sense Resistor Required For Short-
I Designed To Drive Either Synchronous Or
I Lowest System Cost Possible For Price-
I Soft-Start Capability
I Modulated, Constant Off-Time Architecture
I Available Over-Voltage Protection (OVP)
I Small, Surface-Mount Packages
I Socket 7 Microprocessor Supplies
I Pentium II and Deschutes Processor & L2-
I Voltage Regulator Modules
I General Purpose DC:DC Converter
C
6.3V, 1500µF x 3**
: 714-893-2570
.
2
Supply
Circuit Current Limiting
Non-Synchronous Output Stages
Sensitive Pentium And Pentium II Class
Applications
For Fast Transient Response And Simple
System Design
Crowbar Driver And Power Good Flag
(LX1663 only)
(including Intel Pentium Processor, AMD-
K6
Processors)
Cache Supplies
Applications
D
TM
And Cyrix
Plastic SOIC
16-pin
2.5m9
R
1
®
6x86
L I N D
Supply Voltage
for CPU Core
TM
C
, Gx86
1
O C
TM
and M2
# :
V
OUT
TM
1

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lx1663 Summary of contents

Page 1

... Over-Voltage Protection and Power Good Flag. The OVP output in the LX1663 & LX1663A 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 LX1663 & LX1663A also have a logic- level Power Good Flag to signal when the output voltage is out of specified limits ...

Page 2

... All of the above assume no ambient airflow 2 (Note 1) , VID0-VID4) ........................................... -0. 65°C/W JA 120°C θ PACKAGE — 14-Pin LX1662/1662A (Top View) N PACKAGE — 16-Pin LX1663/1663A (Top View) D PACKAGE — 14-Pin LX1662/1662A (Top View) D PACKAGE — 16-Pin LX1663/1663A (Top View) ...

Page 3

... SD SS Sat Voltage V OL Supply Current Section Dynamic Operating Current I CD Power Good / Over-Voltage Protection Section (LX1663 Only) Lower Threshold Hysteresis Power Good Voltage Low Over-Voltage Threshold OVP Sourcing Current LX1662/62A, LX1663/63A ≤ 70°C. Test conditions 12V 25°C. Use Application Circuit.) ...

Page 4

... LX1662/62A, LX1663/63A * Nominal = DAC setpoint voltage 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. ...

Page 5

... I (A) OUT FIGURE 2 — Efficiency Test Results: Non-Synchronous Operation FIGURE 4 — Efficiency Test Results: Synchronous Operation, V Note: Non-synchronous operation not recommended for 12V operation, due to power loss in Schottky diode. LX1662/62A, LX1663/63A 100 Output Set Point EFFICIENCY AT 3.1V EFFICIENCY AT 2.8V 75 EFFICIENCY AT 1 ...

Page 6

... FIGURE 5 — Block Diagram PWM Latch DOM R Q Break Before Make 0.7V SYNC EN Comp OV Comp UV Comp LX1663/1663A ONLY Note: Pin numbers are correct for LX1663/1663A, 16-pin package. * Not connected on the LX1662/1662A. ** 60mV in LX1662A & LX1663A TDRV 15 GND 14 BDRV OV* ...

Page 7

... FET is replaced by a Schottky diode). Both power and signal ground of the device. Gate drive for top MOSFET. This pin is a separate power supply input for the top drive. Can be connected to a charge pump when only 12V is available. LX1662/62A, LX1663/63A nd SB) input. rd SB) input. ...

Page 8

... The controller is inherently protected from an over-voltage condition due to its constant OFF-time architecture. However, should a failure occur at the power switch, an over-voltage drive pin is provided (on the LX1663 only) which can drive an external SCR crowbar (Q must be removed and power recycled for the LX1663 to resume normal operation (See Figure 9) ...

Page 9

... INV 3 V CC_CORE 4 VID0 VID0 5 VID1 VID1 6 VID2 VID2 7 VID3 VID3 VID4 14-pin, Narrow Body SOIC FIGURE 7 — LX1662 In A Non-Synchronous Pentium / Socket 7 Power Supply Application LX1662/62A, LX1663/63A 12V 1µH 6.3V 1500µ 1µ TDRV 1 IRL3102 ...

Page 10

... LX1662/62A, LX1663/63A C 3 0.1µ VID0 5 VID1 6 VID2 7 VID3 8 VID4 FIGURE 8 — Pentium II Processor Application With OVP, Power Good And Loss-Less Current Sensing (Synchronous 0.1µF LX1663 INV 3 V CC_CORE 4 VID0 VID0 5 VID1 VID1 6 VID2 VID2 7 VID3 VID3 8 VID4 ...

Page 11

... S OUT Where I is fixed at 200µA and f is the switching frequency DIS S (recommended to be around 200kHz for optimal operation and component selection). LX1662/62A, LX1663/63A Part Number / Manufacturer When using a 5V input voltage, the switching frequency (f can be approximated as follows: I DIS C = 0.621 * f T ...

Page 12

... The LX166x family offers two different comparator thresholds. The LX1662 & 1663 have a threshold of 100mV, while the LX1662A and LX1663A have a threshold of 60mV. The 60mV threshold is better suited to higher current loads, such as a Pentium II or Deschutes processor. ...

Page 13

... S Current R S2 Sense V CS Comparator FIGURE 11 — Current Sense Circuit LX1662/62A, LX1663/63A CURRENT LIMIT The current flowing through the inductor is a triangle wave. If the sensor components are selected such that: L The voltage across the capacitor will be equal to the current flowing through the resistor, i.e. ...

Page 14

... LX1662/62A, LX1663/63A CURRENT LIMIT (continued) In cases where large that the trip point current would L be lower than the desired short-circuit current limit, a resistor (R can be put in parallel with shown in Figure 11. The selection S of components is as follows (Required (Actual) ...

Page 15

... LinFinity. Product processing does not necessarily include testing of all parameters. Linfinity reserves the right to change the configuration and performance of the product and to discontinue product at any time. LX1662/62A, LX1663/63A LX166x All of these traces should be made as wide and thick as possible, in order to minimize resistance and hence power losses ...

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