Datasheet ML6554 Datasheet (Fairchild Semiconductor)

www.fairchildsemi.com

ML6554

3A Bus Termination Regulator

Features

• Can source and sink up to 3A, no heat sink required

• Integrated Power MOSFETs

• Generates termination voltages for DDR SDRAM,
SSTL-2 SDRAM, SGRAM, or equivalent memories

• Generates termination voltages for active termination
schemes for DDR SDRAM, GTL+, Rambus, VME,
LV-TTL, HSTL, PECL and other high speed logic

•V

• Separate voltages for V

• Buffered V

•V

input available for external voltage divider

REF

output

REF

of ±3% or less at 3A

OUT

CCQ

and PV

DD

• Minimum external components

• Shutdown for standby or suspend mode operation

• 0° to +70°C and -40° to +85°C temperature ranges
available

• Thermal Shutdown ≈ 130ºC

Block Diagram

Description

The ML6554 switching regulator is designed to convert volt­age supplies ranging from 2.3V to 4V into a desired output
voltage or termination voltage for various applications. The
ML6554 can be implemented to produce regulated output
voltages in two different modes. In the default mode, when
the V
the voltage applied to V
to produce various user-defined voltages by forcing a voltage
on the VREF
the input VREF
ble of sourcing or sinking up to 3A of current while regulat­ing an output V

The ML6554, used in conjunction with series termination
resisitors, provides an excellent voltage source for active
termination schemes of high speed transmission lines as
those seen in high speed memory buses and distributed
backplane designs. The voltage output of the regulator can
be used as a termination voltage for other bus interface
standards such as DDR SDRAM, SSTL, CMOS, Rambus
GTL+, VME, LV-CMOS, LV-TTL, HSTL and PECL.

pin is open, the ML6554 output voltage is 50% of

REF

pin. In this case, the output voltage follows

IN

voltage. The switching regulator is capa-

IN

voltage to within 3% or less.

TT

. The ML6554 can also be used

CCQ

™

,

11

13

200kΩ

VREF

200kΩ

AGND

D

GND

9

S

R

12

V

DD

Q

Q

SHDN

2

4 58

PV

P

GND1

DD1

7

PV

DD2

V

L1

(V

)

OUT

3

6

V

L2

(V

)

OUT

P

GND2

15

IN

V

CCQ

10

16

–

+

V

V

FB

AV

REF

14

CC

BUFFER

+

–

VREF

OUT

OSCILLATOR/

RAMP

GENERATOR

ERROR AMP

1

V

DD

–

+

RAMP
COMPARATOR

REV. 1.1.3 3/8/02

2

ML6554 PRODUCT SPECIFICATION

Pin Configuration

ML6554

16-Pin PSOP (U16)

Pin Description

Pin Name Function

1V

2PV

3V

4P

5P

6V

7PV

8D

9V

10 V

11 VREF

12 SHDN Shutdown active low. CMOS input level

13 AGND Ground for internal reference voltage divider

14 VREF

15 V

16 AV

DD

DD1

L1

GND1

GND2

L2

DD2

GND

DD

FB

OUT

CCQ

CC

PV

P

GND1

P

GND2

PV

D

V

DD

DD1

V

V

DD2

GND

L1

L2

1

2

3

4

5

6

7

8

TOP VIEW

Digital supply voltage

Voltage supply for internal power transistors

Output voltage/ inductor connection

Ground for output power transistors

Ground for output power transistors

Output voltage/inductor connection

Voltage supply for internal power transistors

Digital ground

Digital supply voltage

Input for external compensation feedback

Input for external reference voltage

IN

Reference voltage output

Voltage reference for internal voltage divider

Analog voltage supply

AV

16

15

14

13

12

11

10

9

CC

V

CCQ

VREF

AGND

SHDN

VREF

V

FB

V

DD

OUT

IN

REV. 1.1.3 3/8/02

∆

PRODUCT SPECIFICATION ML6554

Absolute Maximum Ratings

Absolute maximum ratings are those values beyond which the device could be permanently damaged. Absolute maximum
ratings are stress ratings only and functional device operation is not implied.

Parameter Min. Max. Units

PV

DD

Voltage on Any Other Pin GND – 0.3 V
Average Switch Current (I

) 3.0 A

AVG

4.5 V
+ 0.3 V

IN

Junction Temperature 150 °C
Storage Temperature Range -65 150 °C
Lead Temperature (Soldering, 10 sec) 150 °C
Thermal Resistance ( θ

)(Note 2) 2 °C/W

JC

Output Current, Source or Sink 3.0 A

Operating Conditions

Parameter Min. Max. Units

Temperature Range, CU suffix 0 70 °C
Temperature Range, IU suffix -40 +85 °C
PV

Operating Range 2.0 4.0 V

DD

V

Operating Range 1.4 4.0 V

CCQ

Electrical Characteristics

Unless otherwise specified, AV

Symbol Parameter Conditions Min. Typ. Max. Units

Switching Regulator

V

TT

Output Voltage, SSTL_2
(See Figure 1)

VREF

Z

IN

Internal Resistor Divider I

OUT

V

Reference Pin Input

REF

Impedance

Switching Frequency 650 kHz

V

OFFSET

Offset Voltage V

Supply

I

Q

Quiescent Current I

Buffer

I

REF

Notes

1. Limits are guaranteed by 100% testing, sampling, or correlation with worst-case test conditions.

2. Infinite heat sink

Output Load Current 3 mA

= V

CC

– VREF

TT

DD

= PV

OUT

= 3.3V ±10%, TA = Operating Temperature Range (Note 1)

DD

I

= 0,

OUT

V

= open

REF

I

= ±3A,

OUT

V

= open

REF

= 0 V

OUT

AV

= 2.5V No Load V

CC

= 0, no load

OUT

V

= 2.5V

CCQ

V

= 2.3V 1.12 1.15 1.18 V

CCQ

V

= 2.5V 1.22 1.25 1.28 V

CCQ

V

= 2.7V 1.32 1.35 1.38 V

CCQ

V

= 2.3V 1.09 1.15 1.21 V

CCQ

V

= 2.5V 1.19 1.25 1.31 V

CCQ

V

= 2.7V 1.28 1.35 1.42 V

CCQ

= 2.3V 1.139 1.15 1.162 V

CCQ

V

= 2.5V 1.238 1.25 1.263 V

CCQ

V

= 2.7V 1.337 1.35 1.364 V

CCQ

V

= 0 100 k Ω

CCQ

= 2.5 –20 20 mV

CCQ

I

VCCQ

I

AVCC

I

SD 0.2 0.5 mA

AVCC

I

VDD

I

SD 0.2 1.0 mA

VDD

I

PVDD

610µA

0.5 1.0 mA

0.25 1.0 mA

100 250 µA

REV. 1.1.3 3/8/02

3

4

ML6554 PRODUCT SPECIFICATION

Functional Description

This switching regulator is capable of sinking and sourcing
3A of current without an external heatsink. The ML6554
uses a power surface mount package (PSOP) that includes
an integrated heat slug. The heat can be piped through the
bottom of the device and onto the PCB (Figure 1).

The ML6554 integrates two power MOSFETs that can be
used to source and sink 3A of current while maintaining a
tight voltage regulation. Using the external feedback, the
output can be regulated well within 3% or less, depending on
the external components chosen. Separate voltage supply
inputs have been added to accommodate applications with
various power supplies for the databus and power buses, see
Figure 2.

Outputs

The output voltage pins (V
address, or clock lines via an external inductor. See the
Applications section for recommendations. Output voltage
is determined by the V

Inputs

The input voltage pins (V
output voltages (V
the VREF
V

input. V

CCQ

databus.

IN

L1

pin is floating, the output voltage is 50% of the

can be the reference voltage for the

CCQ

, V

) are tied to the databus,

L1

L2

or VREF

CCQ

or VREF

CCQ

or V

) . In the default mode, where

L2

inputs.

IN

) determine the

IN

Output voltage can also be selected by forcing a voltage at
the VREF
voltage at the VREF

pin. In this case, the output voltage follows the

IN

input. Simple voltage dividers can be

IN

used this case to produce a wide variety of output voltages
between 0.7V and V

DD

–0.7V.

VREF Input and Output

The VREF
outputs (Inputs section, above). The VREF
output pin that is driven by a small output buffer to provide
the V
buffer is capable of driving several output loads. The output
buffer can handle 3mA.

input can be used to force a voltage at the

IN

signal to other devices in the system. The output

REF

OUT

pin is an

Other Supply Voltages

Several inputs are provide for the supply voltages: PV
PV

, AV

DD1

, and VDD.

CC

and PV

provide the power supply to the

DD2

DD2

The PV
power MOSFETs. VDD provides the voltage supply to the
digital sections, while AVCC supplies the voltage for the
analog sections. Again, see the Applications section for
recommendations.

DD1

,

Feedback Input

The VFB pin is an input that can be used for closed loop
compensation. This input is derived from the voltage output.
See application section for recommendation.

Figure 1. Cutaway view of PSOP Package

HEAT SLUG

REV. 1.1.3 3/8/02

PRODUCT SPECIFICATION ML6554

Applications

Using the ML6554 for SSTL Bus Termination

The circuit schematic in Figure 2 shows a recommended
approach for constructing a bus terminating solution for an
SSTL-2 bus. This circuit can be used in PC memory and
Graphics memory applications as shown in Figures 4 and 5.
Note that the ML6554 can provide the voltage reference
(V

) and terminating voltages (VTT). Using the layout

REF

as shown in Figures 6, 7, and 8, and measuring the VTT
performance using the test setup as described in Figure 9,
the ML6554 delivered a V
(see Figure 10). Table 1 provides a recommended parts list
for the circuit in Figure 2.

± 20mV for 1A to 3A loads

TT

Power Handling Capability of the PSOP
Package

Using the board layout shown in Figures 6, 7, and 8; solder­ing the ML6554 to the board at zero LFPM the temperature
around the package measured 55ºC for 3A loads. Note that a
1 ounce copper plane was used in the board construction.

Airflow is not likely to be needed in the operation of this
device (assuming a board layout similar to that described
above). The power handling performance of the PSOP
package is shown by a study of the package manufacturer for
various airflow vs. θ

conditions in Figure 11.

JA

Bus Termination Solutions for Others Buses

Table 3 provides a summary of various bus termination V
& VTT requirements. The ML6554 can be used for those
applications.

R2 100Ω

C8 0.1µF

REF

2.5V TO 4V

TPI

V

TT

TO SDRAMS

C1
820µF
F2V
OS-CON

L1 3.3µH

C2

0.1µF

R1 100Ω

C3 0.1µF

C4 0.1µF

1

V

2

PV

3

V

4

P

5

P

6

V

7

PV

8

D

R4 100kΩ

R5 1kΩ

Figure 2.

C9 0.1µF

ML6554

DD

DD1

L1

GND1

GND2

L2

DD2

GND

U1

VREF

C7 1nF

AV

V

CCQ

OUT

AGND

SHDN

VREF

V

OUT

IN

C5
330µF 330µF

R3

100kΩ

16

CC

15

14

13

12

11

IN

10

V

FB

9

DD

V

CCQ

VREF

SHDN

VREF

C6

GNDGND

REV. 1.1.3 3/8/02 5

ML6554 PRODUCT SPECIFICATION

2.5V TO 4V

C3 10µF

L1 3.3µH

C2

0.1µF

Figure 3. Alternate Application Circuit

V

TT

TO SDRAMS

C1
820µF
F2V
OS-CON

An alternate application circuit for the ML6554 is shown in
Figure 3. The number of external components is reduced
compared to the circuit in Figure 2. This is achieved by
replacing four, 0.1µF bypass capacitors with one, low ESR,
10µF ceramic capacitor placed right next to U1. Two 100Ω
resistors are also eliminated. High value, surface-mount

1

2

3

4

5

6

7

8

R1 100kΩ

R2 1kΩ

C5
330µF 330µF

OUT

IN

V

DD

PV

V

L1

P

GND1

P

GND2

V

L2

PV

D

GND

DD1

DD2

U1

ML6554

VREF

C4 1nF

AV

V

CCQ

AGND

SHDN

VREF

CC

OUT

V

FB

V

DD

R3

100kΩ

16

15

14

13

12

11

IN

10

9

V

CCQ

VREF

SHDN

VREF

MLC capacitors were not available when the original appli­cation circuit (Figure 2) was developed. Both application
circuits offer the same electrical performance but that shown
in Figure 2 has a reduced bill-of-materials. Table 2 shows the
recommended parts list for the circuit of Figure 3.

C6

GNDGND

6 REV. 1.1.3 3/8/02

PRODUCT SPECIFICATION ML6554

168/184/208-PIN DIMM CONNECTORS

AND SDRAM/SGRAM MODULES

TERMINATION

RESISTORS

PC CHIP SET

NORTHBRIDGE

DATA LINE, CLOCK LINES,

ADDRESS LINES, CONTROL LINES

TERMINATION

RESISTORS

VREF

Figure 4. Complete Termination Solution PC Main Memory (PC Motherboard)

SO DIMM

AND MODULES

TERMINATION

RESISTORS

VTT

ML6554

SGRAM

3D

GRAPHIC CHIP

DATA LINE, CLOCK LINES,

ADDRESS LINES, CONTROL LINES

TERMINATION

RESISTORS

VOLTAGE

REGULATOR

5V OR 3.3V

2.5V

AGP/PCI BUS

VREF

ML6554

VTT

Figure 5. Complete Termination Solution Graphics Memory Bus – AGP Graphics Cards

REV. 1.1.3 3/8/02 7

ML6554 PRODUCT SPECIFICATION

Figure 6. Top Silk

Figure 7. Top Layer Figure 8. Bottom Layer

8 REV. 1.1.3 3/8/02

PRODUCT SPECIFICATION ML6554

3.3V POWER
SUPPLY

VA

V

CCQ

SUPPLY

VA

ACTIVE

CLAMP

V

CCQ

Figure 9. Test Circuit Setup

V

ML6554

EVAL

GND

DD

V

TT

CURRENT SOURCE/SINK

POWER SUPPLY

I

TT

VTT VARIANCE WITH VDD@ITT (V

1.29

1.28

(V)

TT

V

1.27

1.26

2.0 2.5 3.0 4.03.5

TESTED WITH EVAL PCB

VDD (V)

Figure 10. VTT Performance for SSTL-2 Bus

CCQ

2.5V)

I

TT

3A SINKING

2A SINKING

1A SINKING

0A SINKING

3A SOURCING

2A SOURCING

1A SOURCING

REV. 1.1.3 3/8/02 9

ML6554 PRODUCT SPECIFICATION

Table 1. Recommend Parts List for SSTL-2 Termination Circuit in Figure 2.

Item Qty Description Manufacturer / Part Number Designator

Resistors

1 2 100Ω1210 SMD Panasonic/ERJ-8ENF1000V R1, R2
211kΩ 1210 SMD Panasonic/ERJ-8ENF1001V R5
3 2 100kΩ1210 SMD Panasonic/ERJ-8ENF1003V R3, R4

Capacitors

4 3 0.1µF 1210 Film SMD Panasonic/ECV3VB1E104K

Panasonic/ECU-V1H104KBW
5 1 820µF 2V Solid Elect. SMD Sanyo/2SV820M Os Con C1
6 2 330µF Tant 6.3V 100mΩ AVX/TPSE337M006R0100 C5, C6
7 1 1nF 1210 Film SMD Panasonic/ECU-V1H102KBM C7
8 2 0.1µF 0805 Film Panasonic/ECJ-2VF1C104Z C3, C4

ICS

9 1 ML6554 Bus Terminator

Power SOP Package

Magnetics

10 1 3.3µH 5A inductor SMD Coilcraft/D03316P-332HC

Other

11 1 Scope probe socket Tektronics/131-4353-00 TP1
12 1 12 Pin breakaway strip Sullins/PTC36SAAN (36 PINS) I/O, standoffs

ML6554CU or ML6554IU U1

Pulse Eng./ P0751.332T

Gowanda/SMP3316-331M

XFMRS inc./XF0046-S4

C2, C8, C9

L1

Table 2. Recommend Parts List for Figure 3.

Item Qty Description Manufacturer / Part Number Designator

Resistors

1 2 100kΩ 0805 SMD Panasonic/ERJ-8ENF1000V R1, R3
211kΩ 0805 SMD Panasonic/ERJ-8ENF1000V R2

Capacitors

3 1 0.1µF, 1210 Film SMD Panasonic/ECV3VB1E104K

Panasonic/ECU-V1H104KBW
4 1 820µF 2V Solid Elect. SMD Sanyo/2SV820M Os Con C1
5 2 330µF Tant 6.3V 100mΩ AVX/TPSE337M006R0100 C5, C6
6 1 1nF 1210 Film SMD Panasonic/ECU-V1H102KBM C4
7 1 10µF 6.3V Ceramic TDK/C2012X5R0J106M C3

ICS

8 1 ML6554 Bus Terminator

Power SOP Package

Magnetics

9 1 3.3µH 5A inductor SMD Coilcraft/D03316P-332HC

Other

10 1 Scope probe socket Tektronics/131-4353-00 TP1
11 1 12 Pin breakaway strip Sullins/PTC36SAAN (36 PINS) I/O, standoffs

ML6554CU or ML6554IU U1

Pulse Eng./ P0751.332T

Gowanda/SMP3316-331M

XFMRS inc./XF0046-S4

C2

L1

10 REV. 1.1.3 3/8/02

PRODUCT SPECIFICATION ML6554

Vendor List

1. AVX [phone]

2. Sanyo [phone]

3. Tektronix [phone]

4. Coilcraft [phone]

5. Pulse [phone]

6. Gowanda [phone]

7. Xfmrs Inc. [phone]

8. Panasonic [phone]

9. Digikey [phone]

60

40

(ºC/W)

JA

θ

20

0

0.0

0.2 1.0 1.4 1.80.6

0.4 1.2 1.6 2.00.8

POWER (W)

NATURAL CONVECTION ΘJA TEST RESULTS

1.27mm PITCH PowerSOP™ 2
SLUG SOLDERED

Figure 11. Graphical Results Summary – 1S2P Test Board

16Ld PSOP2

2.3x3.1mm PAD

1.9mm DIE

60

40

(ºC/W)

JA

Θ

20

16Ld PSOP2

2.3x3.1mm PAD

0

0 200 300 500400100

AIR VELOCITY (LFPM)

FORCED CONVECTION ΘJA TEST RESULTS

1.27mm PITCH PowerSOP™ 2

1.9mm DIE @ 0.8 WATTS

SLUG SOLDERED

REV. 1.1.3 3/8/02 11

ML6554 PRODUCT SPECIFICATION

DRAWING NUMBER ENG-CB-1007 REV A

Applicable Jedec Spec JC 51-X (Note 1)

(Proposed Spec)

Substrate Material FR-4

Dimensions (LxW) (Overall) 114.3 x 76.2mm

Dimensions (LxW) (Metallization) 55 x 65mm

Dimensions (LxW) (Inner Planes) 73 x 73mm

Thickness 1.6 mm

Pitch 1.27mm

Stackup (# Signal Layers, # Cu Planes) 1S2P

Cu Trace Coverage (Signal Layer) 12%

Cu Coverage (Internal Layer) 100%

Trace Width (Spec/Measured) 235.5±25.5/288µm

Trace Cu Thickness (Spec/Measured) 70±14/67µm

Inner Cu Thickness (Spec/Measured) 35±3.5/31µm

Build # C1797

Note 1: Proposed Spec "Thermal Test Board with Two Internal Solid Copper Planes for leaded Surface Mount Packages".

Figure 12. Test Board Layout for ΘJA vs. Airflow

Table 3. Termination Solutions Summary By Buss Type

Driving

Bus Description

GTL+ Gunning

Transceiver
Bus Plus

SSTL_2 Series Stub

Terminated
Logic for 2V

RAMBUS RAMBUS

Signaling
Logic

LV-TTL Low Voltage

TTL Logic or
PECL or

3.3V VME

Method VDDQ VTT V

Open Drain 5v or 3.3V

Note 10

Symmetric

2.5V±10% 0.5x
Drive,
Series

1.5V±10%
Note12

(V

)

DDQ

±3%

Resistance

Open Drain None

2.5V 2.0V ML6553CS;

Specified

Symmetric

3.3±10% V

/2 3.3V ML6553CS;

DDQ

Drive

REF

1.0V±2%
Note 11

ML6554CU;
Mode: V
Input = 1.5V,
VCC = 5V

2.5V ML6554CU
or ML6553CS;
Mode: V
Input = Floating
or Forced,
VCC = 3.3V

Mode: V
Input = Open,
V

CC

Mode: V
Input = Open,
VCC = VDDQ

Fairchild

Solutions

REF

REF

REF

= V

DDQ

REF

Industry

System

Components

300 to 500MHz
Processor;
PC Chipsets;
GTLP 16xxx
Buffers;
Fairchild,
Texas Instr.

SSTL SDRAM;
Hitachi,
Fujitsu,
NEC, Micro,
Mitsubishi

nDRAM,
RAMBUS,
Intel, Toshiba

Processors or
backplanes;
LV-TTL
SDRAM,
EDO RAM

12 REV. 1.1.3 3/8/02

PRODUCT SPECIFICATION ML6554

Mechanical Dimensions

16-Pin PSOP

6.00

PIN ONE

INDICATOR

(0.30)

1.75 MAX

1.45

(R0.10)

(R0.10)

8°
0°

0.70 ± 0.20

9.90 ± 0.10

8.89

16

18

1.27

0.25 C B AM

+0.05
–0.20

+0.10

0.15
–0.05

0.50
X 45°

0.25

GAGE PLANE

SEATING PLANE

(1.04)

DETAIL A

SCALE: 2:1

9

0.36

A

3.90 ± 0.10

0.51

0.35

1.95

B

3.70

C

0.10 C

NOTES: UNLESS OTHERWISE SPECIFIED

0.60

1.75

LAND PATTERN RECOMMENDATION

A) THIS PACKAGE CONFORMS TO JEDEC
MS–012, VARIATION AC, ISSUE C,
DATED MAY 1990.
B) ALL DIMENSIONS ARE IN MILLIMETERS.
C) DIMENSIONS DO NOT INCLUDE MOLD
FLASH OR BURRS.

7.50

1.27

8.89

SEE DETAIL A

2.50

3.50

0.25

0.19

7.40

REV. 1.1.3 3/8/02 13

ML6554 PRODUCT SPECIFICATION

Ordering Information

Part Number Temperature Range Package

ML6554CU 0°C to 70°C 16-Pin PSOP (U16)

ML6554IU -40°C to +85°C 16-Pin PSOP (U16)

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FAIRCHILD SEMICONDUCTOR RESERVES THE RIGHT TO MAKE CHANGES WITHOUT FURTHER NOTICE TO ANY
PRODUCTS HEREIN TO IMPROVE RELIABILITY, FUNCTION OR DESIGN. FAIRCHILD DOES NOT ASSUME ANY
LIABILITY ARISING OUT OF THE APPLICATION OR USE OF ANY PRODUCT OR CIRCUIT DESCRIBED HEREIN; NEITHER
DOES IT CONVEY ANY LICENSE UNDER ITS PATENT RIGHTS, NOR THE RIGHTS OF OTHERS.

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FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES
OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD SEMICONDUCTOR
CORPORATION. As used herein:

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which, (a) are intended for surgical implant into the body,
or (b) support or sustain life, or (c) whose failure to perform
when properly used in accordance with instructions for use
provided in the labeling, can be reasonably expected to
result in significant injury of the user.

2. A critical component is any component of a life support
device or system whose failure to perform can be
reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.

www.fairchildsemi.com

3/8/02 0.0m 002

 2001 Fairchild Semiconductor Corporation

Stock#DS30006554