ON NCP5208 Ddr−i/ii termination regulator Datasheet

NCP5208
DDR−I/II Termination
Regulator
The NCP5208 is a linear regulator specifically designed for the
active termination of DDR−I/II SDRAM. The device can be operated
from a single supply voltage as low as 1.7 V. For DDR−I
applications, the device is capable of sourcing and sinking current up
to 1.5 A with the output voltage regulated to within "3% or better. A
separate voltage feedback pin ensures superior load regulation
against load and line changes.
Protective features include soft−start, source/sink current limits
and thermal shutdown. Open−drain VTT OK output (POK) is added
for system monitoring. The shutdown pin can tri−state the regulator
output for Suspend To RAM (STR) state. This device is available in a
SOIC−8 package.
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SOIC−8
D SUFFIX
CASE 751
1
MARKING DIAGRAM
Features
•
•
•
•
•
•
•
•
•
•
•
•
Supports Both DDR−I and DDR−II SDRAM Requirements
Single Supply Voltage Operation as Low as 1.7 V
Integrated Power MOSFETs
Few External Components Needed
Source and Sink Current Up to 1.5 A
Load Regulation Within "3%
Both Source and Sink Current Limits
Open−Drain VTT OK (POK) Pin
Shutdown Pin
Thermal Shutdown
Housed in SOIC−8 Package
Pb−Free Package is Available
Typical Applications
• DDR Termination Voltage
• Active Bus Termination (SSTL−2, SSTL−3)
8
N5208
ALYW
G
1
A
L
Y
W
G
PIN CONNECTIONS
POK 1
8
VTT
GND 2
7
PVIN
VFB 3
6
AVIN
5
VDDQ
SD
VDDQ
SD
ORDERING INFORMATION
AVIN
Device
NCP5208
NCP5208DR2
POK
2.5 V
4
(Top View)
VDDQ
2.5 V
= Assembly Location
= Wafer Lot
= Year
= Work Week
= Pb−Free Package
AVIN
VTT
PVIN
VFB
VTT
NCP5208DR2G
1.25 V,
1.5 A
COUT
CIN
Package
Shipping†
SOIC−8
2500/Tape & Reel
SOIC−8
(Pb−Free)
2500/Tape & Reel
†For information on tape and reel specifications,
including part orientation and tape sizes, please
refer to our Tape and Reel Packaging Specifications
Brochure, BRD8011/D.
GND
Figure 1. Typical Application Circuit
© Semiconductor Components Industries, LLC, 2006
May, 2006 − Rev. 5
1
Publication Order Number:
NCP5208/D
NCP5208
VDDQ
AVIN
VDDQ
PVIN
AVIN
PVIN
AVIN
R
POK
−
+
M0
EN
SD
EN
+
VTT
VTT
R/50
−
AVIN
COUT
M1
EN
R
VFB
GND
Figure 2. Simplified Functional Block Diagram
PIN FUNCTION DESCRIPTION
Pin
Symbol
Description
1
POK
Open−drain VTT Power OK output
2
GND
Ground
3
VFB
Remote sensing Feedback pin for regulating VTT
4
SD
Active low shutdown pin to tri−state VTT output, this pin is pulled high internally
5
VDDQ
6
AVIN
Analog supply input, this powers all the internal control circuitry
7
PVIN
Power supply input, this provides the rail voltage for the VTT output
8
VTT
Termination Regulator output
Reference input for VTT regulator
MAXIMUM RATINGS
Rating
AVIN, PVIN, VDDQ, VFB, VTT to GND
Symbol
Value
Unit
−
−0.3, 6.0
V
VIO
−0.3, 6.0
V
VPOK
−0.3, 6.0
V
RJA_T
151
°C/W
Operating Junction Temperature Range
TJ
−10 to +150
°C
Operating Ambient Temperature Range
TA
0 to +70
°C
Storage Temperature Range
Tstg
−55 to +150
°C
Input/Output Pins
SD
Open Drain Output Pins
POK
Thermal Characteristics
SOIC−8 Package − Thermal Resistance, Junction−to−Air
Stresses exceeding Maximum Ratings may damage the device. Maximum Ratings are stress ratings only. Functional operation above the
Recommended Operating Conditions is not implied. Extended exposure to stresses above the Recommended Operating Conditions may affect
device reliability.
1. This device series contains ESD protection and exceeds the following tests:
Human Body Model (HBM) v2.0 kV per JEDEC standard: JESD22–A114.
Machine Model (MM) v200 V per JEDEC standard: JESD22–A115.
2. Latchup Current Maximum Rating: "150 mA per JEDEC standard: JESD78.
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NCP5208
ELECTRICAL CHARACTERISTICS (AVIN = 2.5 V, PVIN = 2.5 V, VDDQ = 2.5 V, COUT = 220 F, for typical values TA = 25°C, for
min/max values TA = 0 to 70°C, unless otherwise noted.)
Characteristic
Analog Supply Input
Power Supply Input
Termination Voltage Output
Conditions
Symbol
Min
Typ
Max
Unit
−
AVIN
1.7
−
5.5
V
−
PVIN
AVIN = 2.5 V, VDDQ = PVIN = 1.8 V
IVTT = –0.6 A to +0.6 A
VDDQ = 1.8 V, IVTT = 0 to +0.6 A
VDDQ = 1.8 V, IVTT = 0 to –0.6 A
VTT
VDDQ = 2.5 V, IVTT = 0 to +1.5 A
VDDQ = 2.5 V, IVTT = 0 to –1.5 A
Analog Current Consumption
−
AVIN
V
0.900
0.930
V
1.215
1.250
1.285
V
−
−18
−
−
15
−
mV
−
−20
−
−
20
−
mV
VTT
AVIN = PVIN = VDDQ = 2.5 V
IVTT = –1.5 A to 1.5 A
Load Regulation
1.7
0.870
No Load
IAVIN
−
−
10
mA
−
ZVDDQ
−
50
−
k
(Note 3)
IVFB
−
−
20
nA
Shutdown Pin Enable Threshold
−
VSD
1.14
1.24
1.34
V
Shutdown Pin Hysteresis
−
VSDhys
0.40
0.55
0.68
V
VDDQ = 2.5 V, VSD = 0 V
VDDQ = 2.5 V, VSD = 2.5 V
VDDQ = 2.5 V, VSD = 5.5 V
ISD
−15
−
−
−
−
−
−
10
12
A
VDDQ = 2.5 V, VSD = 0 V
Ishut
−
−
15
A
VTT Power OK Window Low Threshold
(Note 4)
POKLth
−
VDDQ ×
(1/2−0.02)
−
V
VTT Power OK Window High Threshold
(Note 4)
POKHth
−
VDDQ ×
(1/2+ 0.02)
−
V
IPOK = 5.0 mA
RPOKL
7.0
−
20
VDDQ = 2.5 V, VPOK = 6.0 V
IPOKleak
−
−
0.1
A
VDDQ Input Impedance
VFB Feedback Pin Input Current
SHUTDOWN CONTROL
Shutdown Pin Input Current
Shutdown Analog Supply Current
VTT POWER OK INDICATOR
POK Pull−LOW Resistance
POK Leakage Current
OVER CURRENT PROTECTION
Source Current Limit
−
ILIMsrc
1.65
2.1
2.9
A
Sink Current Limit
−
ILIMsnk
−2.9
−2.0
−1.65
A
Thermal Shutdown Temperature
(Note 3)
TSD
120
135
150
°C
Thermal Shutdown Hysteresis
(Note 3)
TSDhys
−
30
−
°C
OVER TEMPERATURE PROTECTION
3. Values are not tested in production, guaranteed by design only.
4. Production test performed for AVIN = PVIN = VDDQ = 2.5 V only, 1.8 V performance guaranteed by design.
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NCP5208
TYPICAL OPERATING CHARACTERISTICS
1.300
AVIN = 2.5 V
PVIN = VDDQ = 1.8 V
TA = 25°C
0.925
VTT, Output Voltage (V)
VTT, Output Voltage (V)
0.950
0.900
0.875
0.850
−0.8
0.4
−0.6 −0.4
−0.2
0
0.2
0.6
IVTT, OUTPUT LOAD CURRENT (A)
0.8
1.275
1.250
1.225
1.200
−1.8
VTT, Sink Current Load Regulation (mV)
VTT, Source Current Load Regulation (mV)
0
VDDQ = 1.8 V, IVTT = 0.6 A
−4
−6
VDDQ = 2.5 V, IVTT = 1.5 A
−8
−10
−12
−14
−16
−18
−20
PVIN = VDDQ, = AVIN = 2.5 V
0
10
60
20
30
40
50
TA, AMBIENT TEMPERATURE (°C)
1.8
70
20
PVIN = VDDQ, = AVIN = 2.5 V
18
16
14
12
VDDQ = 2.5 V, IVTT = 1.5 A
10
8
6
4
VDDQ = 1.8 V, IVTT = 0.6 A
2
0
0
Figure 5. Source Current Load Regulation vs.
Ambient Temperature
10
60
20
30
40
50
TA, AMBIENT TEMPERATURE (°C)
70
Figure 6. Sink Current Load Regulation vs.
Ambient Temperature
10
IAVIN, Analog Input Current (mA)
2.5
ILIM, Over Current Protection Limit (A)
−1.4 −1.0 −0.6 −0.2 0.2
0.6 1.0 1.4
IVTT, OUTPUT LOAD CURRENT (A)
Figure 4. VTT Output Voltage vs. Load Current
(VDDQ = 2.5 V)
Figure 3. VTT Output Voltage vs. Load Current
(VDDQ = 1.8 V)
−2
AVIN = 2.5 V
PVIN = VDDQ = 2.5 V
TA = 25°C
Source Current
2.0
Sink Current
1.5
1.0
0.5
PVIN = AVIN = VDDQ = 2.5 V
0
PVIN = AVIN = VDDQ = 2.5 V
IVTT = 0 A
8
6
4
2
0
0
10
20
30
40
50
60
TA, AMBIENT TEMPERATURE (°C)
70
0
Figure 7. Over Current Protection Limit vs.
Ambient Temperature
10
20
30
40
50
60
TA, AMBIENT TEMPERATURE (°C)
Figure 8. Analog Input Current vs. Ambient
Temperature
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70
NCP5208
TYPICAL OPERATING CHARACTERISTICS
ZVDDQ, VDDQ Input Impedance ()
55
52
49
46
PVIN = AVIN = VDDQ = 2.5 V
IVTT = 0 A
43
40
0
10
20
30
40
50
60
TA, AMBIENT TEMPERATURE (°C)
70
Figure 9. VDDQ Input Impedance vs. Ambient
Temperature
TYPICAL OPERATING WAVEFORMS
0.4 ms ON, 1.6 ms OFF
0.4 ms ON, 1.6 ms OFF
(PVIN = AVIN = VDDQ = 1.8 V)
Upper Trace: VTT Output Waveform, 50 mV/Division, AC Coupled
Lower Trace: Loading Current, IVTT, 500 mA/Division
(PVIN = AVIN = VDDQ = 1.8 V)
Upper Trace: VTT Output Waveform, 50 mV/Division, AC Coupled
Lower Trace: Loading Current, IVTT, 500 mA/Division
Figure 10. VTT Current Source Transient
Figure 11. VTT Current Sink Transient
0.4 ms ON, 1.6 ms OFF
0.4 ms ON, 1.6 ms OFF
(PVIN = AVIN = VDDQ = 2.5 V)
Upper Trace: VTT Output Waveform, 50 mV/Division, AC Coupled
Lower Trace: Loading Current, IVTT, 1 A/Division
(PVIN = AVIN = VDDQ = 2.5 V)
Upper Trace: VTT Output Waveform, 50 mV/Division, AC Coupled
Lower Trace: Loading Current, IVTT, 1 A/Division
Figure 12. VTT Current Source Transient
Figure 13. VTT Current Sink Transient
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NCP5208
TYPICAL OPERATING WAVEFORMS
(PVIN = AVIN = VDDQ = 2.5 V, IVTT = 0 A)
Upper Trace: VTT Output Waveform, 500 mV/Division
Middle Trace: VTT Power OK Output, 2 V/Division
Lower Trace: Shut−down Signal, 1 V/Division
Time Scale: 500 s/Division
(PVIN = AVIN = VDDQ = 1.8 V, IVTT = 0 A)
Upper Trace: VTT Output Waveform, 500 mV/Division
Middle Trace: VTT Power OK Output, 2 V/Division
Lower Trace: Shut−down Signal, 1 V/Division
Time Scale: 500 s/Division
Figure 14. VTT Startup Waveform (VDDQ = 2.5 V)
Figure 15. VTT Startup Waveform (VDDQ = 1.8 V)
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NCP5208
DETAILED OPERATING DESCRIPTIONS
General
Termination Voltage Output Regulation
The NCP5208 is a linear regulator with both sink and
source current capabilities used for active termination of
fast switching logic, DDR−I/II SDRAM terminations and
active buses termination of SSTL−2/3 logic. This device
can be operated from a single supply voltage as low as 1.7
V. For DDR−I applications, the device is capable of
sourcing and sinking current up to 1.5 A with output
voltage regulated to within ±3%. The separate voltage
remote feedback pin ensures superior load and line
regulation with fast tracking capability.
Protective features include Soft−Start, Source/Sink
Current Limits and internal Thermal Shutdown.
Additionally, an open−drain VTT OK output signal (POK)
is provided for system monitoring. The shutdown pin (SD)
can be used to tri−state the regulator output for Suspend To
RAM (STR) state. This device is available in a low profile,
space saving SOIC−8 package.
The NCP5208 includes a simple linear series regulator
with a pair of control error amplifiers, which takes care of
the current source and sink operations separately. The error
amplifiers control a pair of MOSFETs to maintain the
output voltage equal to the internal reference voltage for
both current sink and source conditions. In order to avoid
the MOSFETs turning on at the same time, a dead−band is
implemented internally for safe operation.
Regulator Shutdown Function
The operation of the NCP5208 can be suspended by
pulling the Shutdown (SD) pin to ground. When the device
is stopped, the regulator output will be tri−stated for
Suspend To RAM (STR) state in PC applications. The
shutdown pin is internally pulled high by a small current
source, if this feature is not used, this pin can be left open.
VTT Power OK for System Monitoring
NCP5208 provides an additional VTT power OK signal
for system monitoring. The VTT Power OK (POK) pin
goes low when the VTT voltage is in regulation and has
settled within the allowed window. For memory
termination applications, the system can check this pin to
ensure the termination voltage quality before accessing the
memory. The POK output is connected to a open−drain
switching FET and the designer is free to pull this pin to any
logic voltage level externally. When the VTT output is in
regulation, the internal FET is turned on and pulls the
power OK pin to ground.
Supply Voltage Inputs
For added flexibility, separate input pins are provided for
each required supply input. AVIN is the device operating
voltage, VDDQ is used to generate the internal reference
for VTT output voltage control and PVIN is the power rail
for the linear regulator. The device will regulate the output
voltage, VTT, with respect to the internal voltage reference
generated from VDDQ input and track the VDDQ changes
closely. The separate PVIN pin allows the designer to
isolate the high current PVIN line changes from coupling
into the noise sensitive AVIN and VDDQ inputs. Since the
AVIN supplies the control to the output power MOSFETs,
PVIN should always be lower than or equal to AVIN.
Over−current Protection for Sink and Source Operation
In order to provide protection for the internal power
MOSFETs, bi−directional current limit protection circuits
are implemented. Current limit levels are internally set at
2.1 A typical for current source and 2.0 A typical for current
sink at 2.5 V operation.
Generation of Internal Reference Voltage
The prime function of a termination regulator is to
provide a termination voltage, VTT at its output, which can
track the mid−point of the logic voltage level closely, i.e.
½(VDDQ). The VTT voltage is used to terminate the bus
resistors. The NCP5208 generates a precise reference
voltage internally with a built in dead−band to avoid upper
and lower MOSFET shoot through.
Thermal Shutdown with Hysteresis
To guarantee safe operation, NCP5208 provides on−chip
thermal shutdown protection. When the chip junction
temperature exceeds 135_C typical, the part will
shutdown. When the junction temperature falls back to
105_C typical, the device resumes normal operation.
Remote Voltage Feedback Sensing
The NCP5208 has a separate feedback pin to monitor the
output voltage at the remote point. With this capability, the
output voltage can be controlled precisely at the output
capacitor so that any noise and fluctuations along the power
path can be eliminated.
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NCP5208
APPLICATIONS INFORMATION
Typical Application Circuit
Thermal Dissipation
The NCP5208 is a highly integrated termination
regulator. For most applications, an input and output
capacitor and a pullup resistor for the power OK output, are
the only external components needed. For typical
application circuit, refer to Figure 1.
The NCP5208 is a linear regulator, any current flow
from/to VTT will result in internal power dissipation and
generating heat. In order to prevent un−wanted shutdown
of the device during operation, care should be taken to
de−rate the power capability according to the maximum
expected ambient temperature and power dissipation. The
maximum allowable internal temperature rise, TR−MAX
can be calculated from the equation in below:
AVIN and VDDQ Supply
AVIN provides power for the device to operate. This
voltage must be kept clean and free from transients. A small
capacitor, 1.0 F is recommended at this input to provide
the required supply filtering and ripple rejection. VDDQ is
primarily used to generate the internal voltage reference, so
any noise or transient at this pin will be directly reflected
at the VTT output. In order to avoid undesired interference
injected into this pin, appropriate de−coupling and careful
design of PCB layout is required.
TR−MAX + TJ−MAX * TA−MAX
Where TJ−MAX is the maximum allowable junction
temperature and TA−MAX is the maximum expected
ambient temperature.
The maximum allowable power dissipation for a specific
condition is given by:
T
PD−MAX + R−MAX
RJA_T
Input Capacitor Selection
The NCP5208 does not require an input capacitor for
stability, however it is still recommended for better overall
performance during large load transients that can cause
sudden drop of the power rail voltage. The input capacitor
must be located as close as possible to the PVIN pin to
avoid a transient voltage dip affecting the quality of AVIN
and VDDQ. For typical DDR−I applications, a low ESR
electrolytic capacitor of 100 F or larger is recommended.
By adding a small ceramic capacitor of 0.1 F in parallel,
the best high frequency transient filtering will result. If the
device is located near the main supply bulk capacitors, the
input capacitance can be reduced accordingly.
Where PD−MAX is the maximum allowable power
dissipation and RJA_T is Junction−to−Air thermal
resistance for specific package.
The thermal handling capability depends on several
variables. Increasing the thickness and area of the copper
and adding vias and airflow can improve the thermal
performance.
Output Capacitor Selection
The NCP5208 is internally compensated and stable for any
output capacitor with capacitance greater than 220 F and
with ESR ranging from 2 m to 400 m The choice for this
output capacitor is determined solely by the application and
the requirements for load transient characteristic of VTT
output. As a general recommendation, the capacitance should
be larger than 220 F with low ESR for SSTL and DDR
memory applications.
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NCP5208
PACKAGE DIMENSIONS
SOIC−8 NB
CASE 751−07
ISSUE AH
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DIMENSION A AND B DO NOT INCLUDE
MOLD PROTRUSION.
4. MAXIMUM MOLD PROTRUSION 0.15 (0.006)
PER SIDE.
5. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. ALLOWABLE DAMBAR
PROTRUSION SHALL BE 0.127 (0.005) TOTAL
IN EXCESS OF THE D DIMENSION AT
MAXIMUM MATERIAL CONDITION.
6. 751−01 THRU 751−06 ARE OBSOLETE. NEW
STANDARD IS 751−07.
−X−
A
8
5
0.25 (0.010)
S
B
1
M
Y
M
4
K
−Y−
G
C
N
DIM
A
B
C
D
G
H
J
K
M
N
S
X 45 _
SEATING
PLANE
−Z−
0.10 (0.004)
H
D
0.25 (0.010)
M
Z Y
S
X
M
J
S
MILLIMETERS
MIN
MAX
4.80
5.00
3.80
4.00
1.35
1.75
0.33
0.51
1.27 BSC
0.10
0.25
0.19
0.25
0.40
1.27
0 _
8 _
0.25
0.50
5.80
6.20
INCHES
MIN
MAX
0.189
0.197
0.150
0.157
0.053
0.069
0.013
0.020
0.050 BSC
0.004
0.010
0.007
0.010
0.016
0.050
0 _
8 _
0.010
0.020
0.228
0.244
SOLDERING FOOTPRINT*
1.52
0.060
7.0
0.275
4.0
0.155
0.6
0.024
1.270
0.050
SCALE 6:1
mm Ǔ
ǒinches
*For additional information on our Pb−Free strategy and soldering
details, please download the ON Semiconductor Soldering and
Mounting Techniques Reference Manual, SOLDERRM/D.
ON Semiconductor and
are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further notice
to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC assume any
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time. All operating parameters, including “Typicals” must be validated for each customer application by customer’s technical experts. SCILLC does not convey any license under
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