LIN D O C #: 8584
LX8584-xx/8584A-xx/8584B-xx
7A L OW D ROPOUT P OSITIVE R E G U L AT O R S
T
H E
I
P
N F I N I T E
O W E R
I
O F
P
N N O VA T I O N
D
R O D U C T I O N
DESCRIPTION
The LX8584/84A/84B series ICs are low dropout three-terminal positive regulators with a
nominal 7A output current. This product
family is ideally suited for Pentium® Processor and Power PCTM applications requiring
fast transient response. The LX8584A is guaranteed to have < 1.2V at 7A and the
LX8584/84B < 1.4V at 7A dropout voltage,
making them ideal to provide well regulated
outputs of 2.5V to 3.6V using a 5V input
supply. In addition, the LX8584B also offers ±1% maximum voltage reference accuracy over temperature. Fixed versions
are also available and are specified in the
Available Options table below.
■ THREE-TERMINAL ADJUSTABLE OR FIXED
OUTPUT
■ GUARANTEED 1% VOLTAGE ACCURACY
OVER TEMPERATURE (LX8584B)
■ GUARANTEED ≤ 1.2V HEADROOM AT 7A
(LX8584A)
■ GUARANTEED ≤ 1.4V HEADROOM AT 7A
(LX8584/84B)
■ OUTPUT CURRENT OF 7A
p FAST TRANSIENT RESPONSE
p 1% VOLTAGE REFERENCE INITIAL
ACCURACY
p OUTPUT SHORT CIRCUIT PROTECTION
p BUILT-IN THERMAL SHUTDOWN
■ EVALUATION BOARD AVAILABLE:
REQUEST LXE9001 EVALUATION KIT
Current limit is trimmed above 7.1A to
ensure adequate output current and controlled short-circuit current. On-chip thermal limiting provides protection against any
combination of overload that would create
excessive junction temperatures.
The LX8584/84A series products are available in both the through-hole versions of
the industry standard 3-pin TO-220 and
TO-247 power packages.
The LX1431 Programmable Reference in
conjunction with the LX8584 7A LDO products offer precision output voltage (see application below) and are ideal for use in VRE
applications.
A P P L I C AT I O N S
T HE APPLICATION OF THE LX8584A & LX1431 IN A
75 & 166MH Z P54C PROCESSORS U SING 3.3V C ACHE
VIN
VO 7A
(See Table Below)
2
VOUT
LX8584A
1kW
ADJ
0.01µF
1kW
1
PLACE IN µP SOCKET CAVITY
3x
330µF, 6.3V
Low ESR
Oscon Type
from Sanyo
100µF x 6
10V
AVX TYPE
TPS
250pF
1
2
3
220µF
10V
Low ESR
from
Sanyo
COL
V+
REF
LX1431
0.1µF
50V
SGND
VOUT
3.50
3.38
2.84kW
0.1%
21k
1%
1µF x 10
SMD
JP1
FGND
5
1k
0.1%
8
6
JP1
Short
Open
■
■
■
■
■
TYPICAL APPLICATION
120/166MHz, VRE, 3.3V Cache
75/90/100/133MHz, STND, 3.3V Cache
PENTIUM PROCESSOR SUPPLIES
POWER PC SUPPLIES
MICROPROCESSOR SUPPLIES
LOW VOLTAGE LOGIC SUPPLIES
POST REGULATOR FOR SWITCHING SUPPLY
D R O P O U T V O L TA G E V S .
OUTPUT C URRENT
1.5
µP
Load
TJ = 125°C
LX8584/84A
Input / Output Differential - (V)
3
H E E T
K E Y F E AT U R E S
PRODUCT HIGHLIGHT
5V
S
A T A
LX8584
1.0
LX8584A
0.5
Thick traces represent high current traces which must be low resistance /
low inductance in order to achieve good transient response.
PA C K A G E O R D E R I N F O R M AT I O N
TA (°C)
0 to 125
Dropout
Voltage
1.4V
1.2V
P
Plastic TO-220
3-pin
V
Plastic TO-247
3-terminal
LX8584-xxCP
LX8584-xxCV
LX8584B-xxCP
LX8584A-xxCP
LX8584B-xxCV
LX8584A-xxCV
0
1.75
3.5
5.25
7
Output Current - (A)
A VA I L A B L E O P T I O N S
Part #
PER
PART #
Output Voltage
LX8584/A/B-00
Adjustable
LX8584/A/B-33
3.3V
Other voltage options may be available —
Please contact factory for details.
"xx" refers to output voltage, please see table above.
F O R F U R T H E R I N F O R M AT I O N C A L L ( 7 1 4 ) 8 9 8 - 8 1 2 1
Copyright © 1997
Rev. 1.2 4/97
11861 WESTERN A VENUE , G ARDEN G ROVE , CA. 92841
1
PRODUCT DATABOOK 1996/1997
LX8584-xx/8584A-xx/8584B-xx
7 A L O W D R O P O U T P O S I T I V E R E G U L AT O R S
P
R O D U C T I O N
A B S O L U T E M A X I M U M R AT I N G S
D
A T A
S
H E E T
PACKAGE PIN OUTS
(Note 1)
Power Dissipation .................................................................................. Internally Limited
Input Voltage ................................................................................................................ 10V
Input to Output Voltage Differential ........................................................................... 10V
Maximum Output Current ............................................................................................. 8A
Operating Junction Temperature
Plastic (P 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.
TAB IS V OUT
3
VIN
VOUT
ADJ / GND*
2
1
P PACKAGE
(Top View)
* Pin 1 is GND for fixed voltage versions.
TAB ON REVERSE SIDE IS VOUT
3
T H E R MAL DATA
2
1
P PACKAGE:
THERMAL RESISTANCE-JUNCTION TO TAB, θJT
2.7°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ JA
60°C/W
VIN
VOUT
ADJ / GND*
V PACKAGE
(Top View)
* Pin 1 is GND for fixed voltage versions.
V PACKAGE:
THERMAL RESISTANCE-JUNCTION TO TAB, θJT
1.6°C/W
THERMAL RESISTANCE-JUNCTION TO AMBIENT, θ JA
35°C/W
Junction Temperature Calculation: TJ = TA + (PD x θJA).
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 © 1997
Rev. 1.2 4/97
PRODUCT DATABOOK 1996/1997
LX8584-xx/8584A-xx/8584B-xx
7A L OW D ROPOUT P OSITIVE R E G U L AT O R S
P
R O D U C T I O N
D
A T A
S
H E E T
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, these specifications apply over the operating ambient temperatures for the LX8584-xxC/84A-xxC/84B-xxC with 0°C ≤ TA ≤ 125°C;
VIN - VOUT = 3V; IOUT = 7A. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.)
LX8584-00/84A-00/84B-00 (Adjustable)
Parameter
Reference Voltage
LX8584/84A-00
LX8584B-00
Line Regulation (Note 2)
Load Regulation (Note 2)
Thermal Regulation
Ripple Rejection (Note 3)
Adjust Pin Current
Adjust Pin Current Change
Dropout Voltage
LX8584A
LX8584/84B
LX8584/84B
Minimum Load Current
Maximum Output Current
Temperature Stability
Long Term Stability
RMS Output Noise (% of VOUT)
Symbol
LX8584/84A/84B-00
Min. Typ.
Max.
Test Conditions
1.238
1.225
1.240
1.238
VREF
IOUT = 10mA, TA = 25°C
10mA ≤ IOUT ≤ 7A, 1.5V ≤ (VIN - VOUT), VIN ≤ 7V, P ≤ PMAX
IOUT = 10mA, TA = 25°C
10mA ≤ IOUT ≤ 7A, 1.5V ≤ (VIN - VOUT), VIN ≤ 7V, P ≤ PMAX
∆VREF (V IN) IOUT = 10mA, 1.5V ≤ (VIN - VOUT ), VIN ≤ 7V
∆V REF (IOUT) VIN - V OUT = 3V, 10mA ≤ IOUT ≤ 7A
∆VOUT (Pwr) TA = 25°C, 20ms pulse
VOUT = 3.3V, f =120Hz, COUT = 100µf Tantalum, VIN = 5V
CADJ = 10µF, I OUT = 7A
I ADJ
∆IADJ
10mA ≤ IOUT ≤ 7A, 1.5V ≤ (VIN - VOUT), VIN ≤ 7V
∆V
∆VREF = 1%, IOUT = 7A
∆VREF = 1%, IOUT = 7A
∆VREF = 1%, IOUT = 6A
IOUT(MIN) VIN ≤ 7V
IOUT (MAX) 1.4V ≤ (V IN - VOUT), VIN ≤ 7V
∆VOUT (T)
∆VOUT (t) TA = 125°C, 1000 hrs
VOUT (RMS) TA = 25°C, 10Hz ≤ f ≤ 10kHz
65
7
Units
1.250
1.250
1.250
1.250
0.035
0.1
0.01
83
1.263
1.275
1.260
1.263
0.2
0.5
0.02
V
V
V
V
%
%
%/W
dB
55
0.2
1.1
1.2
1.1
2
8
0.25
0.3
0.003
100
5
1.2
1.4
1.3
10
µA
µA
V
V
V
mA
A
%
%
%
1
LX8584-33/84A-33/84B-33 (3.3V Fixed)
Parameter
Output Voltage
LX8584/84A-33
Symbol
LX8584/84A/84B-33
Min. Typ.
Max.
Test Conditions
VIN = 5V, IOUT = 0mA, TA = 25°C
4.75V ≤ V IN ≤ 10V, 0mA ≤ IOUT ≤ 7A, P ≤ PMAX
LX8584B-33
VIN = 5V, IOUT = 0mA, TA = 25°C
4.75V ≤ V IN ≤ 10V, 0mA ≤ IOUT ≤ 7A, P ≤ PMAX
Line Regulation (Note 2)
∆VOUT
4.75V ≤ V IN ≤ 7V
(VIN )
4.75V ≤ VIN ≤ 10V
Load Regulation (Note 2)
∆VOUT (IOUT)
VIN = 5V, 0mA ≤ IOUT ≤ IOUT (MAX)
Thermal Regulation
∆VOUT (Pwr) TA = 25°C, 20ms pulse
Ripple Rejection (Note 3)
COUT = 100µF (Tantalum), IOUT = 7.5V
Quiescent Current
IQ
0mA ≤ IOUT ≤ IOUT (MAX) , 4.75V ≤ VIN ≤ 10V
Dropout Voltage
LX8584-xx
∆V
∆VOUT = 1%, IOUT = IOUT (MAX)
LX8584A-xx
∆VOUT = 1%, IOUT = IOUT (MAX)
LX8584B-xx
∆VOUT = 1%, IOUT = IOUT (MAX)
Maximum Output Current
IOUT (MAX)
VIN ≤ 7V
Temperature Stability (Note 3)
∆VOUT (T)
Long Term Stability (Note 3)
∆VOUT (t) TA = 125°C, 1000 hours
RMS Output Noise (% of VOUT) (Note 3) VOUT (RMS) TA = 25°C, 10Hz ≤ f ≤ 10kHz
3.267
3.234
3.274
3.267
VOUT
60
`
7
3.30
3.30
3.30
3.30
1
2
5
0.01
83
4
8
0.25
0.3
0.003
3.333
3.366
3.326
3.333
6
10
15
0.02
10
1.4
1.2
1.4
1
Units
V
V
V
V
mV
mV
mV
%/W
dB
mA
V
V
V
A
%
%
%
Note 2. Regulation is measured at constant junction temperature, using pulse testing with a low duty cycle. Changes in output voltage due to
heating effects are covered under the specification for thermal regulation.
Note 3. These parameters, although guaranteed, are not tested in production.
Copyright © 1997
Rev. 1.2 4/97
3
PRODUCT DATABOOK 1996/1997
LX8584-xx/8584A-xx/8584B-xx
7 A L O W D R O P O U T P O S I T I V E R E G U L AT O R S
P
R O D U C T I O N
D
A T A
S
H E E T
A P P L I C AT I O N N O T E S
The LX8584/84A/84B series ICs are easy to use Low-Dropout (LDO)
voltage regulators. They have all of the standard self-protection
features expected of a voltage regulator: short circuit protection,
safe operating area protection and automatic thermal shutdown if
the device temperature rises above approximately 165°C.
Use of an output capacitor is REQUIRED with the LX8584/84A/
84B series. Please see the table below for recommended minimum
capacitor values.
These regulators offer a more tightly controlled reference voltage
tolerance and superior reference stability when measured against
the older pin-compatible regulator types that they replace.
STABILITY
The output capacitor is part of the regulator’s frequency compensation system. Many types of capacitors are available, with different
capacitance value tolerances, capacitance temperature coefficients,
and equivalent series impedances. For all operating conditions,
connection of a 220µF aluminum electrolytic capacitor or a 47µF
solid tantalum capacitor between the output terminal and ground
will guarantee stable operation.
If a bypass capacitor is connected between the output voltage
adjust (ADJ) pin and ground, ripple rejection will be improved
(please see the section entitled “RIPPLE REJECTION”). When ADJ
pin bypassing is used, the required output capacitor value increases.
Output capacitor values of 220µF (aluminum) or 47µF (tantalum)
provide for all cases of bypassing the ADJ pin. If an ADJ pin bypass
capacitor is not used, smaller output capacitor values are adequate.
The table below shows recommended minimum capacitance values
for stable operation.
RECOMMENDED CAPACITOR VALUES
INPUT
OUTPUT
ADJ
10µF
10µF
15µF Tantalum, 100µF Aluminum
47µF Tantalum, 220µF Aluminum
None
15µF
In order to ensure good transient response from the power supply
system under rapidly changing current load conditions, designers
generally use several output capacitors connected in parallel. Such
an arrangement serves to minimize the effects of the parasitic
resistance (ESR) and inductance (ESL) that are present in all
capacitors. Cost-effective solutions that sufficiently limit ESR and
ESL effects generally result in total capacitance values in the range
of hundreds to thousands of microfarads, which is more than
adequate to meet regulator output capacitor specifications. Output
capacitance values may be increased without limit.
The circuit shown in Figure 1 can be used to observe the transient
response characteristics of the regulator in a power system under
changing loads. The effects of different capacitor types and values
on transient response parameters, such as overshoot and undershoot, can be quickly compared in order to develop an optimum
solution.
4
Power Supply
IN
LX8584/84A
/84B
OUT
ADJ
Minumum Load
(Larger resistor)
Full Load
(Smaller resistor)
RDSON