ONSEMI NCP5208

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
SO−8 package.
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MARKING
DIAGRAM
8
SO−8
D SUFFIX
CASE 751
8
N5208
ALYW
1
1
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 SO−8 Package
A
L
Y
W
= Assembly Location
= Wafer Lot
= Year
= Work Week
PIN CONNECTIONS
POK 1
8
VTT
GND 2
7
PVIN
VFB 3
6
AVIN
5
VDDQ
SD
4
(Top View)
Typical Applications
• DDR Termination Voltage
• Active Bus Termination (SSTL−2, SSTL−3)
ORDERING INFORMATION
Device
NCP5208DR2
VDDQ
VDDQ
2.5 V
Package
Shipping†
SO−8
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.
SD
AVIN
NCP5208
POK
2.5 V
AVIN
VTT
PVIN
VFB
VTT
1.25 V,
1.5 A
COUT
CIN
GND
Figure 1. Typical Application Circuit
 Semiconductor Components Industries, LLC, 2004
February, 2004 − Rev. 3
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
Symbol
Value
Unit
−
−0.3, 6.0
V
VIO
−0.3, 6.0
V
VPOK
−0.3, 6.0
V
Thermal Characteristics
SO−8 Package
Thermal Resistance, Junction−to−Air
RJA_T
151
°C/W
Operating Junction Temperature Range
TJ
−10 to +150
°C
AVIN, PVIN, VDDQ, VFB, VTT to GND
Input/Output Pins
Open Drain Output Pins
SD
POK
Operating Ambient Temperature Range
TA
0 to +70
°C
Storage Temperature Range
Tstg
−55 to +150
°C
1. This device series contains ESD protection and exceeds the following tests:
Human Body Model (HBM) 2.0 kV per JEDEC standard: JESD22–A114.
Machine Model (MM) 200 V per JEDEC standard: JESD22–A115.
2. Latch–up 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
Symbol
Conditions
Min
Typ
Max
Unit
Analog Supply Input
AVIN
−
1.7
−
5.5
V
Power Supply Input
PVIN
−
1.7
−
AVIN
V
Termination Voltage Output
VTT
AVIN = 2.5 V, VDDQ = PVIN = 1.8 V
IVTT = –0.6 A to +0.6 A
0.870
0.900
0.930
V
AVIN = PVIN = VDDQ = 2.5 V
IVTT = –1.5 A to 1.5 A
1.215
1.250
1.285
V
VDDQ = 1.8 V, IVTT = 0 to +0.6 A
VDDQ = 1.8 V, IVTT = 0 to –0.6 A
−
−18
−
−
15
−
mV
VDDQ = 2.5 V, IVTT = 0 to +1.5 A
VDDQ = 2.5 V, IVTT = 0 to –1.5 A
−
−20
−
−
20
−
mV
IAVIN
No Load
−
−
10
mA
ZVDDQ
−
−
50
−
k
IVFB
Note 3
−
−
20
nA
VSD
−
1.14
1.24
1.34
V
VSDhys
−
0.40
0.55
0.68
V
Shutdown Pin Input Current
ISD
VDDQ = 2.5 V, VSD = 0 V
VDDQ = 2.5 V, VSD = 2.5 V
VDDQ = 2.5 V, VSD = 5.5 V
−15
−
−
−
−
−
−
10
12
A
Shutdown Analog Supply Current
Ishut
VDDQ = 2.5 V, VSD = 0 V
−
−
15
A
VTT Power OK Window Low Threshold
POKLth
Note 4
−
VDDQ ×
(1/2−0.02)
−
V
VTT Power OK Window High Threshold
POKHth
Note 4
−
VDDQ ×
(1/2+ 0.02)
−
V
POK Pull−LOW Resistance
RPOKL
IPOK = 5.0 mA
7.0
−
20
IPOKleak
VDDQ = 2.5 V, VPOK = 6.0 V
−
−
0.1
A
Source Current Limit
ILIMsrc
−
1.65
2.1
2.9
A
Sink Current Limit
ILIMsnk
−
−2.9
−2.0
−1.65
A
TSD
Note 3
120
135
150
°C
TSDhys
Note 3
−
30
−
°C
Load Regulation
Analog Current Consumption
VDDQ Input Impedance
VFB Feedback Pin Input Current
VTT
SHUTDOWN CONTROL
Shutdown Pin Enable Threshold
Shutdown Pin Hysteresis
VTT POWER OK INDICATOR
POK Leakage Current
OVER CURRENT PROTECTION
OVER TEMPERATURE PROTECTION
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
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 Start−up Waveform (VDDQ = 2.5 V)
Figure 15. VTT Start−up 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 SO−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 135C typical, the part will
shutdown. When the junction temperature falls back to
105C 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 pull−up 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 RθJA_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
SO−8
D SUFFIX
CASE 751−07
ISSUE AA
−X−
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.
A
8
5
0.25 (0.010)
S
B
1
M
Y
M
4
K
−Y−
G
C
N
X 45 SEATING
PLANE
−Z−
0.10 (0.004)
H
D
0.25 (0.010)
M
Z Y
S
X
M
J
S
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DIM
A
B
C
D
G
H
J
K
M
N
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
NCP5208
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
liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, consequential or incidental
damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual performance may vary over
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
its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems intended for surgical implant into the body,
or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product could create a situation where personal injury or death
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NCP5208/D