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PDF AIC1384 Data sheet ( Hoja de datos )
| Número de pieza | AIC1384 | |
| Descripción | DDR Termination Regulator | |
| Fabricantes | Analog Intergrations Corporation | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de AIC1384 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
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FEATURES
Source and Sink Current Capability
Suspend To RAM Functionality
Support DDR (1.25VTT) and DDR (0.9VTT)
Requirements
Low Output Voltage Offset, ±20mV
High Accuracy Output Voltage at Full-Load
Low External Component Count
No external resistor required
Current Limit protection
Thermal Protection
SOP-8 and SOP-8 Exposed Pad (Heat Sink)
Package
APPLICATIONS
Mother board
Graphic cards
DDR and DDR
termination voltage
AIC1384
DDR Termination Regulator
DESCRIPTION
The AIC1384 linear regulator is designed to
deliver 1.5A continuous current and up to 3A
peak transient currents for termination of DDR-
SRAM. The AIC1384 contains a high-speed
operational amplifier to supply superior load
transient response. It also includes a VSENSE to
provide excellent load regulation and VREF
output as a reference for the chipset and
DIMMs. The AIC1384 supply accurate VTT and
VREF without external resistors that save PCB
areas.
The AIC1384 also features an active low
shutdown pin that provides Suspend To RAM
(STR) functionality. The VTT will remain high
impedance when in shutdown, but VREF will
keep active. The advantage of power saving
can be obtained through low 150µA (DDR )
quiescent current.
Built in current limiting in source and sink mode,
with thermal shutdown provide maximal
protection to the AIC1384 against fault
conditions.
TYPICAL APPLICATION CIRCUIT
SD
VREF=1.25V
1
2
3
4
10nF
GND
VTT 8
SD PVIN
VSENSE AVIN
7
6
VREF VDDQ 5
VDDQ=2.5V
AIC1384
VTT=1.25V
Cout
22uF
VIN=2.5V
Cin
47uF
Analog Integrations Corporation
Si-Soft Research Center
3A1, No.1, Li-Hsin Rd. I , Science Park , Hsinchu 300, Taiwan , R.O.C.
TEL: 886-3-5772500
FAX: 886-3-5772510 www.analog.com.tw
DS-1384G-01 073108
1
1 page  
AIC1384
TYPICAL PERFORMANCE CHARACTERISTICS
112
108
104
100
96
92
88
2.0
2.5 3.0 3.5 4.0 4.5 5.0
AVIN (V)
Fig. 1 IQ vs. AVIN in Shutdown
5.5
290
280
270
260
250
240
230
220
210
200
2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
AVIN (V)
Fig.2 IQ vs. AVIN
4.0 1.32
3.5 1.30
3.0 VIH
2.5
1.28
1.26
2.0 VIL
1.5
1.24
1.22
1.0
0.5
2.0
2.5 3.0
Fig.3
3.5 4.0 4.5
AVIN (V)
AVIN vs. VSD
5.0 5.5
1.20
1.18
-30
-20 -10 0 10
IREF (uA)
Fig.4 VREF vs. IREF
20
30
3.0 3.0
2.5 2.5
2.0 2.0
1.5 1.5
1.0 1.0
0.5 0.5
0.0
0 1 2 3 4 56
0.0
0
1 2 3 4 56
VDDQ (V)
VDDQ (V)
Fig.5 VREF vs. VDDQ
Fig.6 VTT vs. VDDQ
5
5 Page 
AIC1384
0.01µF to 0.1µF of ceramic capacitor is
recommended.
VTT
VTT is the regulated output that is used to
terminate the bus resistor, which obtains the
ability of sinking and sourcing current while
regulating the output accurately to VDDQ/2. The
AIC1384 is designed to deliver up to ±3A peak
transient currents with excellent transient
response. The output capacitor should be large
enough to prevent an excessive voltage drop if a
transient is expected to last above the maximum
continuous current rating for a significant amount
of time. AIC1384 is able to provide large transient
output currents, yet it can’t handle for long
durations under all conditions that results from
the standard packages are not able to dissipate
the heat of the internal power loss. If large
currents are required for longer durations, ensure
that the maximum junction temperature is not
exceeded.
Capacitor Selection
The input capacitor of AIC1384 is required for
improved performance during large load
transients to prevent the input rail from dropping.
47µF aluminum electrolytic capacitors or ceramic
capacitor is recommended. If AVIN and PVIN are
separated, the 47µF capacitor should be placed
as close as possible to the PVIN. And AVIN can
bypass a 0.1uF ceramic capacitor to prevent
excessive noise.
220µF aluminum electrolytic capacitor is a
recommendation for output capacitor to improve
load transient response of VTT. And size above
22uF ceramic output capacitor is allowed to
general used for obtain small profile. The value of
ESR is determined by the acceptable maximum
current spike and the output voltage droops.
Thermal Dissipation
The AIC1384 has a thermal-limiting circuitry,
which is designed to protect the device against
overload condition. For continuous load
condition, maximum rating of junction
temperature must not be exceeded. It is
important to pay more attention in thermal
resistance. It includes junction to case, junction
to ambient. The maximum power dissipation of
AIC1384 depends on the thermal resistance of
its case and circuit board, the temperature
difference between the die junction and ambient
air, and the rate of airflow. The thermal
resistance is greatly affected by the package
used, the number of vias, the speed of airflow
and the thickness of copper. When the IC
mounting with good thermal conductivity is used,
the junction temperature will be low even when
large power dissipation applies. So the PCB
mounting pad for GND pin of AIC1384 should
provide maximum thermal conductivity to
maintain low device temperature.
The power dissipation across the device is
P = IOUT (VIN-VOUT).
The maximum power dissipation is:
PMAX
=
(TJ-max - TA )
Rθ JA
Where TJ-max is the maximum allowable junction
temperature (125°C), and TA is the ambient
temperature suitable in application.
Layout Considerations
1. Minimize high current ground loops. Place
the ground of the device, the input capacitor,
and the output capacitor together with short
and wide connection.
2. Connect the bottom-side pad (available in
SOP-8 Exposed Pad) to a large ground
plane. Use as much copper as possible to
decrease the thermal resistance of the
device.
3. A buried layer may be used as a heat
spreader if the large copper around the
11
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet AIC1384.PDF ] | |
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