Ideal for DDR-I, DDR-II and DDR-III VTT Applications
Sink and Source 2A Continuous Current
Integrated Power MOSFETs
Generates Termination Voltage for SSTL_2, SSTL_18,
HSTL, SCSI-2 and SCSI-3 Interfaces.
High Accuracy Output Voltage at Full-Load
Output Adjustment by Two External Resistors
Low External Component Count
Shutdown for Suspend to RAM (STR) Functionality
with High-Impedance Output
Current Limiting Protection
On-Chip Thermal Protection
Available in ESOP-8 (Exposed Pad) Packages
VIN and V
RoHS Compliant and 100% Lead (Pb)-Free
APPLICATIO
Desktop PCs, Notebooks, and Workstations
Graphics Card Memory Termination
Set Top Boxes, Digital TVs, Printers
Embedded Systems
Active Termination Buses
DDR-I, DDR-II and DDR-III Memory Systems
No Power Sequence Issue
CNTL
AP1280MP
DESCRIPTIOON
The AP1280MP is a simple, cost-effective and
high-speed linear regulator designed to generate
termination voltage in double data rate (DDR) memory
system to comply with the JEDEC SSTL_2 and
SSTL_18 or other specific interfaces such as HSTL,
SCSI-2 and SCSI-3 etc. devices requirements. The
regulator is capable of actively sinking or sourcing up to
2A while regulating an output voltage to within 40mV.
The output termination voltage cab be tightly regulated
to track 1/2V
resistors or the desired output voltage can be programmed by externally forcing the REFEN pin voltage.
The AP1280MP also incorporates a high-speed
differential amplifier to provide ultra-fast response in
line/load transient. Other features include extremely low
initial offset voltage, excellent load regulation, current
limiting in bi-directions and on-chip thermal shut-down
protection.
The AP1280MP are available in the ESOP-8
(Exposed Pad) surface mount packages.
Lead Temperature (Soldering, 10sec.) ---------------- 260°C
Thermal Resistance from Junction to Case (R
Note1 : Exceeding the absolute maximum rating may damage the device.
OPERATING RATING
(Note2)
thjc
)
Input Voltage (VIN) ------------------------------------------- 2.5V to 1.5V +3%
CNTL Pin Voltage (V
Junction Temperature Range (T
Ambient Temperature Range (T
Note2 : The device is not guaranteed to function outside its operating conditions.
) --------------------------------- 5.5V or 3.3V +5%
CNTL
) ----------------------- -40 to +125°C
J
) ---------------------- -40 to +85°C
A
ORDERING / PACKAGE INFORMATION
AP1280X-HF
Halogen-Free
MP : ESOP-8
(Note1)
28°C/W
VIN
1
2
3
REFEN
4
VOUT
(
R
= 75oC/W
thja
Top View
GND
ESOP-8
)
8
NC
7
NCGND
6
VCNTL
5
NC
ELECTRICAL SPECIFICATIONS
(VIN=1.8V, V
ParameterSYMTEST CONDITIONMINTYPMAX
Input
VCNTL Operation Current
Standby Current
Output (DDR / DDRII / DDRIII)
Output Offset Voltage
Load Regulation
Protection
Current LimitI
Thermal Shutdown TemperatureT
Thermal Shutdown HysteresisΔT
REFEN Shutdown
Shutdown ThresholdV
Note3. VOS offset is the voltage measurement defined as V
Note4. Regulation is measured at constant junction temperature by using a 5ms current pulse. Devices are tested for load regulation
in the load range from 0A to 2A.
CNTL
=3.3V, V
(Note3)
(Note4)
REFEN
=0.9V, C
=10uF(Ceramic), TA =25oC, unless otherwise specified)
OUT
I
CNTL
I
STBY
V
OS IOUT
ΔV
LIM
SD
V
IH
V
IL
I
= 0A-
OUT
V
< 0.2V (Shutdown), R
REFEN
= 180Ω-
LOAD
= 0A -20 -
I
= 10mA ~ 2A -20 -
Load
OUT
I
= -10mA ~ -2A -20 -
OUT
3.3V < VCNTL < 5V130160-
3.3V < VCNTL < 5V-30-
SD
Enable0.65-Shutdown--0.2
subtracted from V
OUT
REFEN
.
12.5
5090
2.2--
20
20
20
UNITS
mA
uA
mV
o
A
C
2
Advanced Power
M
Electronics Corp.AP1280MP
PIN DESCRIPTIONS
PIN SYMBOLPIN DESCRIPTION
V
IN
GND
V
OUT
V
CNTL
REFEN
BLOCK DIAGRA
Power Input Voltage.
Ground Pin
Output Voltage
Gate Drive Voltage
Reference Voltage Input and Chip Enable
REFEN
VCNTL
Current Limit
Thermal Protection
+
EA
-
VIN
VOUT
APPLICATION INFORMATION
Input Capacitor and Layout Consideration
Place the input bypass capacitor as close as possible to the AP1280MP. A low ESR
capacitor larger than 470uF is recommended for the input capacitor. Use short and wide traces to
minimize parasitic resistance and inductance.
Inappropriate layout may result in large parasitic inductance and cause undesired oscillation
between AP1280MP and the preceding powe converter.
3
Advanced Power
Electronics Corp.AP1280MP
Consideration while designs the resistance of voltage divider
Make sure the sinking current capability of pull-down NMOS if the lower resistance was
chosen so that the voltage on V
is below 0.2V. In addition, the capacitor and voltage divider
REFEN
form the lowpass filter. There are two reasons doing this design; one is for output voltage soft-start
while another is for noise immunity.
Thermal Consideration
AP1280MP regulators have internal thermal limiting circuitry designed to protect the device
during overload conditions.For continued operation, do not exceed maximum operation junction
temperature 125
P
The maximum power dissipation depends on the thermal resistance of IC package, PCB
layout, the rate of surroundings airflow and temperature difference between junction to ambient.
The maximum power dissipation can be calculated by following formula:
P
Where T
temperature and the R
thermal resistance (R
standard JEDEC 51-7 (4 layers, 2S2P) thermal test board. The maximum power dissipation at T
o
C can be calculated by following formula:
25
P
The thermal resistance R
and the PCB design. However, the package design has been decided. If possible, it's useful to
increase thermal performance by the PCB design. The thermal resistance can be decreased by
adding copper under the expose pad of ESOP-8 package. We have to consider the copper couldn't
stretch infinitely and avoid the tin overflow.
J(MAX)
o
C. The power dissipation definition in device is:
= (VIN - V
D
= ( T
D(MAX)
OUT
J(MAX)
) x I
OUT
-TA ) / R
+ VIN x I
thja
Q
is the maximum operation junction temperature 125oC, TA is the ambient
is the junction to ambient thermal resistance. The junction to ambient
thja
is layout dependent) for ESOP-8 package (Exposed Pad) is 75oC/W on
thja
= (125oC - 25oC) / 75oC/W = 1.33W
D(MAX)
of ESOP-8 (Exposed Pad) is determined by the package design