www.fairchildsemi.com
REV. 1.0.3 2/25/02
Features
Fast transient response
Low dropout voltage at up to 2.7A
Load regulation: 0.05% typical
Trimmed current limit
On-chip thermal limiting
Standard TO-220, TO-263, TO-263 center cut and
TO-252 (DPAK) packages
Applications
A GTL+ bus supply for VRM 8.5
Low voltage logic supply
Post regulator for switching supply
Description
The FAN1589 is a low dropout three-terminal regulator with
2.7A output current capability. This device has been optimized
for V
TT
bus termination, where transient response and mini-
mum input voltage are critical. The FAN1589 offers fixed
1.2V with 2.7A current capability for a GTL+ bus V
TT
termination.
Current limit is trimmed to ensure specified output current and
controlled short-circuit current. On-chip thermal limiting pro-
vides protection against any combination of overload and
ambient temperature that would create excessive junction
temperatures.
The FAN1589 is available in the industry-standard TO-220,
TO-263, TO-263 center cut and TO-252 (DPAK) power
packages.
Typical Application
10
F
22
F
V
IN
= 3.3V
1.2V at 2.7A
+
+
V
IN
GND
V
OUT
FAN1589
FAN1589
2.7A, 1.2V Low Dropout Linear Regulator for VRM8.5
FAN1589
PRODUCT SPECIFICATION
2
REV. 1.0.3 2/25/02
Pin Assignments
*With package soldered to 0.5 square inch copper area over backside ground plane or internal power plane,
JA
can vary from
30C/W to more than 40C/W. Other mounting techniques can provide a thermal resistance lower than 30C/W.
Absolute Maximum Ratings
Parameter
Min.
Max.
Unit
V
IN
7
V
Operating Junction Temperature Range
0
125
C
Storage Temperature Range
-65
150
C
Lead Temperature (Soldering, 10 sec.)
300
C
3-Lead Plastic TO-220
JC = 3C/W
3-Lead Plastic TO-263
JC = 3C/W*
GND OUT
OUT
FRONT VIEW
IN
1
2
3
GND OUT
FRONT VIEW
FAN1589M
FAN1589T
IN
1
2
3
3-Lead Plastic TO-263 Center Cut
JC = 3C/W*
Tab is OUT
Tab is OUT
Tab is OUT
Tab is OUT
GND
FRONT VIEW
FAN1589MC
IN
1
2
3
3-Lead Plastic TO-252
JC = 3C/W*
GND
FRONT VIEW
FAN1589D
IN
1 2
3
PRODUCT SPECIFICATION
FAN1589
REV. 1.0.3 2/25/02
3
Electrical Characteristics
Tj = 25C unless otherwise specified.
The
denotes specifications which apply over the specified operating temperature range.
Notes:
1. See thermal regulation specifications for changes in output voltage due to heating effects. Load and line regulation are
measured at a constant junction temperature by low duty cycle pulse testing.
2. Line and load regulation are guaranteed up to the maximum power dissipation (18W). Power dissipation is determined by
input/output differential and the output currrent. Guaranteed maximum output power will not be available over the full input/
output voltage range.
Parameter
Conditions
Min.
Typ.
Max
Units
Output Voltage
3.3V
V
IN
7V
10mA
I
OUT
2.7A
1.176
1.200
1.224
V
Line Regulation
1, 2
(V
OUT
+ 1.5V)
V
IN
7V,
I
OUT
=
10mA
0.005
0.2
%
Load Regulation
1, 2
(V
IN
V
OUT
) = 3V
10mA
I
OUT
2.7A
0.15
1.5
%
Dropout Voltage
V
REF
= 1%, I
OUT
= 2.7A
1.150
1.300
V
Current Limit
(V
IN
V
OUT
) = 2V
3.1
4
A
Minimum Load Current
1.5V
(V
IN
V
OUT
)
5.75V
10
mA
Quiescent Current
V
IN
= 5V
4
13
mA
Ripple Rejection
f = 120Hz, C
OUT
= 22
F Tantalum,
(V
IN
V
OUT
) = 3V, I
OUT
= 2.7A
60
72
dB
Thermal Regulation
T
A
= 25
C, 30ms pulse
0.004
0.02
%/W
Temperature Stability
0.5
%
Long-Term Stability
T
A
= 125
C, 1000 hrs.
0.03
1.0
%
RMS Output Noise
(% of V
OUT
)
T
A
= 25
C, 10Hz
f
10kHz
0.003
%
Thermal Resistance,
Junction to Case
TO-220
3
C/W
TO-263, TO-252
3
C/W
Thermal Shutdown
150
C
FAN1589
PRODUCT SPECIFICATION
4
REV. 1.0.3 2/25/02
Typical Performance Characteristics
Figure 1. Dropout Voltage vs. Output Current
Figure 2. Load Regulation vs. Temperature
0.5
1
1.5
OUTPUT CURRENT (A)
DROPOUT VOLTAGE (V)
2
3.0
2.5
0
1.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
T=25
C
T=0
C
T=125
C
JUNCTION TEMPERATURE (
C)
OUTPUT VOLTAGE DEVIATION (%)
-75 -50 -25
0
25
50
75 100 125 150 175
0.10
0.05
0
-0.05
-0.10
-0.15
-0.20
I = 2.7A
Figure 3. Reference Voltage vs. Temperature
Figure 4. Output Voltage vs. Temperature
JUNCTION TEMPERATURE (
C)
REFERENCE VOLTAGE (V)
-75 -50 -25
0
25
50
75 100 125 150 175
1.225
1.220
1.215
1.210
1.205
1.200
1.195
1.190
1.185
1.180
1.175
JUNCTION TEMPERATURE (
C)
REFERENCE VOLTAGE (V)
-75 -50 -25
0
25
50
75 100 125 150 175
1.30
1.20
1.10
1.00
0.90
0.80
V
OUT
SET WITH 1% RESISTORS
Figure 5. Minimum Load Current vs. Temperature
Figure 6. Short-Circuit Current vs. Temperature
JUNCTION TEMPERATURE (
C)
MINIMUM LOAD CURRENT (mA)
-75 -50 -25
0
25
50
75 100 125 150 175
5
4
3
2
1
0
JUNCTION TEMPERATURE (
C)
SHORT-CIRCUIT CURRENT (A)
-75 -50 -25
0
25
50
75 100 125 150 175
5.0
4.5
4.0
3.5
3.0
PRODUCT SPECIFICATION
FAN1589
REV. 1.0.3 2/25/02
5
Typical Performance Characteristics
(continued)
Figure 7. Ripple Rejection vs. Frequency
Figure 8. Maximum Power Dissipation
FREQUENCY (Hz)
RIPPLE REJECTIONS (dB)
10
100
1K
10K
100K
90
80
70
60
50
40
30
20
10
0
(V
IN
V
OUT
)
3V
0.5V
V
RIPPLE
2V
I
OUT
= 2.7A
CASE TEMPERATURE (
C)
POWER (W)
50
60
70
80
90 100 110 120 130 140 150
20
15
10
5
0
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