Microsemi Corporation LX1670CD Datasheet
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LX1670
1670
THE INFINITE POWER OF INNOVATION
DESCRIPTION KEY FEATURES
The LX1670 is a complete precision
reference and voltage monitor circuit
for the Intel Pentium
®
Pro Processor
and other high-end microprocessor
supplies. It is designed for use in
conjunction with the LX1660/1661 PWM
controller. The LX1670 reads a 5-bit
voltage identification (VID) code from
the microprocessor and sets the output
voltage reference to be used by the
LX1660/61 controller. Together, they
convert +5 or 12V input power to an
adjustable output ranging from 1.8VDC
to 3.5VDC in 100mV steps (50mV steps
below 2.1V) with 1% DC system
accuracy.
PRODUCT HIGHLIGHT
TYPICAL APPLICATION OF THE LX1670
V
CC
5-BIT P
ROGRAMMABLE VOLTAGE REFERENCE
P RODUCTION DAT A SHEET
p 1% TOTAL OUTPUT ERROR
p POWER GOOD, UV, 0V COMPARATORS
p 0V COMPARATOR HAS SCR DRIVE
p UNDER-VOLTAGE LOCKOUT CAPABILITY
p 5-BIT INPUT FOR ADVANCED PENTIUM PRO
PROCESSOR APPLICATIONS (5TH BIT IS FOR
AUTOMATIC GAIN AND OFFSET SCALING)
p IMPLEMENTS 1% DC ACCURATE CONTROL
SYSTEM
p 14-PIN NARROW BODY SOIC PACKAGE
APPLICATIONS
■ PENTIUM II & PENTIUM PRO VOLTAGE
REGULATOR MODULES
■ PROGRAMMABLE POWER SUPPLIES
■ VOLTAGE REFERENCE
■ ADVANCED MICROPROCESSOR SUPPLIES
5-Bit
Digital
Input
Word
BIT 0
BIT 1
BIT 2
BIT 3
BIT 4
Enable
Blank Enable
D0
D1
D2
D3
D4
ENABLE
BLKEN
GND
V
CC
To PWM
Error Amplifier
SCR Drive
Power Good
LX1670
V
SENSE
VIDO
OV
P
GOOD
OUT
System Output
Volta
e
PACKAGE ORDER INFO
T
(°C)
A
Plastic SOIC
D
14-pin
0 to 70 LX1670CD
Note: All surface-mount packages are available in Tape & Reel.
Append the letter "T" to part number. (i.e. LX1670CDT)
Copyright © 1997
Rev. 1.0 7/97
FOR FURTHER INFORMATION CALL (714) 898-8121
11861 WESTERN AVENUE, GARDEN GROVE, CA. 92841
1
LX1670
PRODUCT DATABOOK 1996/1997
5-BIT P
ROGRAMMABLE VOLTAGE REFERENCE
RODUCTION DATA SHEET
P
ABSOLUTE MAXIMUM RATINGS (Note 1)
Supply Voltage (VCC) .................................................................................... -0.3V to +15V
P
, D0-D3, D4, ENABLE, BLKEN ....................................................... -0.3V to VCC+0.3
GOOD
VIDO, OV
OV
OUT
VIDO........................................................................................................................... -5mA
, V
OUT
........................................................................................................................ -35mA
....................................................................................... -0.3V to +5V
SENSE
Operating Junction Temperature
Plastic (D Package) ............................................................................................... 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.
THERMAL DATA
D PACKAGE:
D
x θ
θθ
θ
θθ
JA
).
JA
THERMAL RESISTANCE-JUNCTION TO AMBIENT,
Junction Temperature Calculation: T
The θ
numbers are guidelines for the thermal performance of the device/pc-board system.
JA
All of the above assume no ambient airflow
= TA + (P
J
120°C/W
PACKAGE PIN OUTS
VIDO
V
SENSE
P
GOOD
OV
ENABLE
BLKEN
GND
OUT
D PACKAGE
(Top View)
1 14
213
312
411
510
69
78
V
D4B
D4
D3
D2
D1
D0
CC
2
Copyright © 1997
Rev. 1.0 7/97
PRODUCT DATABOOK 1996/1997
LX1670
5-BIT P
ROGRAMMABLE VOLTAGE REFERENCE
P RODUCTION DATA SHEET
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for LX1670C with 0°C ≤ TA ≤ 70°C ;
10.8V < V
positive. Current maximums are currents with the highest possible value.)
Power Supply Current and Power Section
Positive 12V Supply Current I
Digital-to-Analog Converter Section
Voltage Set Point Accuracy VSPA D0-D3 = X, D4 = Open, 2.00 ≤ VIDO ≤ 3.50V
LSB VSTP D4 = Open
Coding Binary, D0 = LSB, D3 = MSB
Under-Voltage Lockout Section
Power-up Reset V
Threshold UVLOT VCC = 5V, Supply ramping down
Hysteresis UVLOH V
Under/Over-Voltage Comparator Section
Percent of VIDO Threshold UOVTH
P
GOOD
Over-Voltage Protection Comparator Section
Percent of VIDO Threshold OVPTH
OVP Sourcing Current IOVP OVP = 3.0V
OVP Output Low VLOVP IOVP = 100µA
TTL Inputs Section
Input Low Voltage V
Input High Voltage V
Input Low Current I
Input High Current I
Open Drain Inputs Section
Input Low Current I
Input High Voltage V
< 13.2V, D0-D3 = Open, D4 = Open, ENABLE = 1, BLKEN = 1. Nominal conditions: VCC = 12.0V, T = 25°C. Currents flowing into chip are
CC
Parameter
Symbol
All outputs, inputs unloaded
CC
(Includes DAC, I-V Converter and output scaling amplifier. R
Test Conditions
LOAD
> 1k, C
< 100pF)
LOAD
LX1670
Min. Typ. Max.
5mA
-1.0 1.0 %
D0-D3 = X, D4 = GND, 1.80 ≤ VIDO ≤ 2.05V
-1.5 1.5 %
100 m V
D4 = GND
RESIGOOD
= 5mA
50 mV
4.27 4.37 4.47 V
= 5V, Supply ramping up
CC
50 mV
±5.5 ±7 ±8.5 %
Low Voltage VLG I
GOOD
= 5mA
0.2 0.4 V
10 15 20 %
-20 mA
(D0-D3, D4)
IL
IH
IL
IH
IL
IH
VIL = 0.8V
VIH = 2.0V
Pin Ground
Pin Open
2.0 V
-10 µA
0µA
-37.5 µA
2.0 V
Units
1.0 V
100 m V
0.8 V
Copyright © 1997
Rev. 1.0 7/97
3
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