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FAN1654
1.5A LDO, DDR Bus Termination Regulator
Features
•
•
•
•
•
•
•
•
Sinks and sources 1A continuous, 1.5A peak
-40°C to +125°C Operating Range
Load regulation: (VDDQ/2) ± 40mV
5mA VREF buffer tracks VTT
On-chip thermal limiting
Power-enhanced eTSSOP™-16 package
Low Current Shutdown Mode
Output Short Circuit Protection
Description
The FAN1654 is a low-cost bi-directional LDO specifically
designed for terminating DDR memory bus. It can both sink
and source up to 1A continuous, 1.5A peak, providing
enough current for most DDR applications. Load regulation
meets the JEDEC spec, VTT = (VDDQ/2) ± 40mV.
The FAN1654 includes a buffered reference voltage capable
of supplying up to 5mA current. On-chip thermal limiting
provides protection against a combination of power overload
and ambient temperature that would create an excessive
junction temperature. A shutdown input puts the FAN1654
into a low power mode for laptop computer applications.
The FAN1654 regulator is available in a power-enhanced
eTSSOP™-16 package, and the standard SOIC-14
Applications
• DDR terminators
Block Diagram
VDDQ
200k
-
VREFOUT
VREFIN
+
VTTFORCE
+
VTTFORCE
-
200k
VTTSENSE
FAN1655
VSSQ
VSS
VSS
VSS
VDD
VDD
VDD
SHDN
REV. 1.0.5 4/17/02
PRODUCT SPECIFICATION
FAN1654
Pin Assignments
VDD
VDD
VTTFORCE
VSS
VSS
VTTFORCE
VDD
VSS
1
2
3
4
5
6
7
8
FAN1654
16
15
14
13
12
11
10
9
NC
VDDQ
VREFOUT
VSSQ
SHDN
VREFIN
VTTSENSE
NC
VSSQ
VREFOUT
VDDQ
VDD
VDD
VTTFORCE
VSS
1
2
3
4
5
6
7
FAN1654
14
13
12
11
10
9
8
SHDN
VREFIN
VTTSENSE
VSS
VDD
VTTFORCE
VSS
16-Lead Plastic eTSSOP-16
θ
JC
= 4˚C/W*
*With package power slug soldered to 0.5 square inch
copper area over backside ground plane of internal
power plane
14-Lead Plastic SOIC
θ
JC
= 37˚C/W,
θ
JA
= 88˚C/W
Pin Definitions
Pin Number*
1, 2, 7 (4, 5, 10)
3, 6 (6, 9)
4, 5, 8 (7, 8, 11)
10 (12)
11 (13)
12 (14)
Pin Name
VDD
VTTFORCE
VSS
VTTSENSE
VREFIN
SHDN
VTT Force Output.
Power Ground.
VTT Sense
. Feedback for remote sense of the VTT voltage.
VREFIN
. Alternative input for direct control of VTTOUT and VREFOUT.
Shutdown.
This active low shutdown turns off both VTT and VREFOUT. This
pin has an internal pull-down, and must be externally driven high for the IC to be
on.
Signal Ground.
Buffered Voltage Reference Output.
VDDQ Input.
Attach this pin to the VDDQ supply to generate VTT and
VREFOUT.
No Internal Connection
Pin Function Description
VDD.
Input power for the LDO.
13 (1)
14 (2)
15 (3)
9,16
VSSQ
VREFOUT
VDDQ
NC
* Pin Numbers in brackets are for the SOIC-14 package
Typical Application
VDDQ
VDD
VTTFORCE
470µF
1
2
3
4 FAN1654
5
6
7
8
10µF
16
15
14
13
12
11
10
9
1nF
10k
10µF
VREFOUT
SHDN
VTTSENSE
GND
100µF
6V
1nF
(connect to VTTFORCE
at the load)
GND
Figure 1. (eTSSOP pinout shown)
2
REV. 1.0.5 4/17/02
FAN1654
PRODUCT SPECIFICATION
Typical Performance Characteristics
Quiescent Current vs. Temperature
3.5
V
REF
Output Change vs. I
REF
1.0
3
QUIESCENT CURRENT (mA)
V
DD
= V
DDQ
= 2.5V
T
A
= 25˚C
0.5
∆
V
REFOUT
(mV)
2.5
2
1.5
R
OUT
= 0.2Ω
0
-0.5
1
.5
0
-60
-1.0
-6
-40
-20
0
20
40
60
80
100 120
140
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
V
REF
LOAD CURRENT (mA)
AMBIENT TEMPERATURE (˚C)
Figure 2
Figure 3
V
TT
Load Current
1.260
V
DD
= V
DDQ
= 2.5V
T
A
= 25°C
1.255
V
TT
OUTPUT (V)
1.250
1.245
1.240
-1500
-1000
-500
0
500
1000
1500
V
TT
Load Current (mA)
Figure 4
REV. 1.0.5 4/17/02
3
PRODUCT SPECIFICATION
FAN1654
Absolute Maximum Ratings
Supply Voltage VDD, VDDQ
Junction Temperature, T
J
Storage Temperature
Lead Soldering Temperature, 10 seconds
Power Dissipation, P
D
6V
150°C
-65 to 150°C
300°C
1.4W
Recommended Operating Conditions
Parameter
Supply Voltage VDD
Supply Voltage VDDQ
Ambient Operating Temperature
VREFIN
Conditions
Min.
2.3
2.2
-40
1.1
1.25
Typ.
2.5
2.5
Max.
3.6
3.0
125
1.5
Units
V
V
°C
V
Electrical Characteristics
(VDD = VDDQ = 2.5V ± 0.2V, and T
A
= 25˚C using circuit in Figure 1, unless otherwise noted.)
The • denotes specifications which apply over the specified operating temperature range.
Parameter
VTT Output Voltage
Conditions
I
OUT
= 0A, VREFIN = open
VDDQ = 2.3V
VDDQ = 2.5V
VDDQ = 2.7V
I
OUT
= +1A, VREFIN = open
VDDQ = 2.3V
VDDQ = 2.5V
VDDQ = 2.7V
Cload = 10µF
SHDN = 0V
Min.
•
•
•
1.135
1.235
1.335
1.110
1.210
1.310
Typ.
1.150
1.250
1.350
1.150
1.250
1.350
0.1
•
-50
±2
100
No load
VREFIN = 1.150V •
VREFIN = 1.250V •
VREFIN = 1.350V •
VDDQ = 2.3V
•
•
SHDN = 0V
•
•
No load, SHDN = 2.7V
•
SHDN = 0V
•
SHDN = 0V
•
SHDN = 2.7V
•
1.145
1.245
1.345
-5
-10
1.667
1.150
1.250
1.350
1.155
1.255
1.355
5
10
0.800
10
10
50
75
V
V
V
mA
µA
V
V
mA
µA
µA
µA
°C
°C
50
Max.
1.165
1.265
1.365
1.190
1.290
1.390
Units
V
V
V
V
V
V
V/µsec
µA
A
K
Ω
VTT Output Slew Rate
VTT Leakage Current
VTT Current Limit
VREFIN Input Impedance
VREFOUT Output Voltage
VREFOUT Output Current
VREFOUT Leakage Current
SHDN Logic High
SHDN Logic Low
IDD Supply Current
VDDQ Leakage Current
VDD Leakage Current
SHDN Input Current
Over-Temperature Shutdown
Over-Temperature Hysteresis
3
6
3
50
155
30
4
REV. 1.0.5 4/17/02
FAN1654
PRODUCT SPECIFICATION
Mechanical Dimensions
16 Lead eTSSOP
0.10 TYP
16
5.0
±
0.1
9
-A-
4.00
-B-
16
9
6.4
4.4
±
0.1
3.40
3.2
4.16
7.72
1
8
0.2 C B A
ALL LEAD TIPS
PIN #1 IDENT.
(1.78)
1
8
1.2 MAX
ALL LEAD TIPS
0.1 C
+0.15
(0.90) –0.10
0.65 TYP
0.42 TYP
LAND PATTERN RECOMMENDATION
-C-
0.65 TYP
0.10±0.05 TYP
(0.19–0.30)
0.10
M
C B A
SEE DETAIL A
(0.09–0.20)
1.7 MIN
9
16
1.5 MIN
12° TOP & BOTTOM
R0.09MIN
0°–8°
GAGE PLANE
0.25
8
1
BOTTOM VIEW
0.75
0.45
(1.00)
SEATING PLANE
DETAIL A
NOTES:
A. CONFORMS TO JEDEC REGISTRATION MO-153, VARIATION ABT,
DATED 10/97.
B. DIMENSIONS ARE IN MILLIMETERS.
C. DIMENSIONS ARE EXCLUSIVE OF BURRS, MOLD FLASH,
AND THE BAR EXTENSIONS.
D. DIMENSIONS AND TOLERANCES PER ASME Y14.5M, 1994.
REV. 1.0.5 4/17/02
5
