Datasheet DS90C385A Datasheet (National Semiconductor)

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PRELIMINARY

DS90C385A
+3.3V Programmable LVDS Transmitter 24-Bit Flat Panel
Display Link-87.5 MHz

DS90C385A +3.3V Programmable LVDS Transmitter 24-bit Flat Panel Display (FPD) Link-87.5 MHz

October 2005

General Description

The DS90C385A is a pin to pin compatible replacement for
DS90C383, DS90C383A and DS90C385. The DS90C385A
has additional features and improvements making it an ideal
replacement for DS90C383, DS90C383A and DS90C385.
family of LVDS Transmitters.

The DS90C385A transmitter converts 28 bits of LVCMOS/
LVTTL data into four LVDS (Low Voltage Differential Signal­ing) data streams. A phase-locked transmit clock is transmit­ted in parallel with the data streams over the fifth LVDS link.
Every cycle of the transmit clock 28 bits of input data are
sampled and transmitted. At a transmit clock frequency of

87.5 MHz, 24 bits of RGB data and 3 bits of LCD timing and
control data (FPLINE, FPFRAME, DRDY) are transmitted at
a rate of 612.5Mbps per LVDS data channel. Using a 87.5
MHz clock, the data throughput is 306.25Mbytes/sec. This
transmitter can be programmed for Rising edge strobe or
Falling edge strobe through a dedicated pin. A Rising edge
or Falling edge strobe transmitter will interoperate with a
Falling edge strobe FPDLink Receiver without any transla­tion logic.

This chipset is an ideal means to solve EMI and cable size
problems associated with wide, high-speed TTL interfaces
with added Spread Spectrum Clocking support.

Features

n Pin-to-pin compatible to DS90C383, DS90C383A and

DS90C385 .

n No special start-up sequence required between

clock/data and /PD pins. Input signals (clock and data)
can be applied either before or after the device is
powered.

n Support Spread Spectrum Clocking up to 100kHz

frequency modulation & deviations of
spread or -5% down spread.

n “Input Clock Detection” feature will pull all LVDS pairs to

logic low when input clock is missing and when /PD pin
is logic high.

n 18 to 87.5 MHz shift clock support
n Tx power consumption

Grayscale

n Tx Power-down mode
n Supports VGA, SVGA, XGA, SXGA(dual pixel),

SXGA+(dual pixel), UXGA(dual pixel).

n Narrow bus reduces cable size and cost
n Up to 2.45 Gbps throughput
n Up to 306.25Megabytes/sec bandwidth
n 345 mV (typ) swing LVDS devices for low EMI
n PLL requires no external components
n Compliant to TIA/EIA-644 LVDS standard
n Low profile 56-lead TSSOP package

<

147 mW (typ)@87.5 MHz

<

60 µW (typ)

±

2.5% center

Block Diagram

DS90C385A

Order Number DS90C385AMT

See NS Package Number MTD56

© 2005 National Semiconductor Corporation DS200702 www.national.com

20070201

Absolute Maximum Ratings (Note 1)

If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.

DS90C385A

Supply Voltage (V

CMOS/TTL Input Voltage −0.5V to (V

LVDS Driver Output Voltage −0.3V to (V

LVDS Output Short Circuit

Duration Continuous

Junction Temperature +150˚C

Storage Temperature −65˚C to +150˚C

Lead Temperature

(Soldering, 4 sec) +260˚C

Maximum Package Power Dissipation Capacity

MTD56 (TSSOP)

Package:

DS90C385AMT 1.63 W

) −0.3V to +4V

CC

CC

CC

+ 0.3V)

+ 0.3V)

@

25˚C

Package Derating:

DS90C385AMT 12.5 mW/˚C above +25˚C

ESD Rating

(HBM, 1.5kΩ, 100pF) 7kV

(EIAJ, 0Ω, 200 pF) 500V

Latch Up Tolerance

@

25˚C

Recommended Operating
Conditions

Min Nom Max Units

Supply Voltage (V

Operating Free Air

Temperature (T

Supply Noise Voltage

)

(V

CC

TxCLKIN frequency 18 87.5 MHz

) 3.0 3.3 3.6 V

CC

) −10 +25 +70 ˚C

A

200 mV

Electrical Characteristics

Over recommended operating supply and temperature ranges unless otherwise specified.

Symbol Parameter Conditions Min Typ Max Units

LVCMOS/LVTTL DC SPECIFICATIONS

V

IH

V

IL

V

CL

I

IN

LVDS DC SPECIFICATIONS

V

OD

∆V

OD

V

OS

∆V

OS

I

OS

I

OZ

TRANSMITTER SUPPLY CURRENT

ICCTW Transmitter Supply Current

High Level Input Voltage 2.0 V

CC

Low Level Input Voltage 0 0.8 V

Input Clamp Voltage ICL= −18 mA −0.79 −1.5 V

Input Current VIN= 0.4V, 2.5V or V

V

= GND −10 0 µA

IN

CC

+1.8 +10 µA

Differential Output Voltage RL= 100Ω 250 345 450 mV

Change in VODbetween

35 mV

complimentary output states

Offset Voltage (Note 4) 1.13 1.25 1.38 V

Change in VOSbetween

35 mV

complimentary output states

Output Short Circuit Current V

Output TRI-STATE®Current Power Down = 0V,

Worst Case

= 0V, RL= 100Ω −3.5 −5 mA

OUT

±

1

V

=0VorV

OUT

R

= 100Ω,

L

= 5 pF,

C

L

Worst Case Pattern

CC

f = 25 MHz 31 45 mA

f = 40 MHz 37 50 mA

±

10 µA

(Figures 1, 3 ) ” Typ ”
values are given for

= 3.6V and TA=

V

CC

f = 65 MHz 48 60 mA

+25˚C, ” Max ” values
are given for V

3.6V and T

A

=

CC

= −10˚C

f = 87.5 MHz 55 65 mA

±

100mA

PP

V

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Electrical Characteristics (Continued)

Over recommended operating supply and temperature ranges unless otherwise specified.

Symbol Parameter Conditions Min Typ Max Units

TRANSMITTER SUPPLY CURRENT

ICCTG Transmitter Supply Current

16 Grayscale

R

L

C

L

= 100Ω,

= 5 pF,
16 Grayscale Pattern
(Figures 2, 3 ) ” Typ ”
values are given for

= 3.6V and TA=

V

CC

+25˚C, ” Max ” values

CC

= −10˚C

A

=

ICCTZ Transmitter Supply Current

Power Down

are given for V

3.6V and T

Power Down = Low
Driver Outputs in TRI-STATE under
Power Down Mode

Note 1: “Absolute Maximum Ratings” are those values beyond which the safety of the device cannot be guaranteed. They are not meant to imply that the device
should be operated at these limits. The tables of “Electrical Characteristics” specify conditions for device operation.

Note 2: Typical values are given for V

Note 3: Current into device pins is defined as positive. Current out of device pins is defined as negative. Voltages are referenced to ground unless otherwise

specified (except V

Note 4: V

OS

and ∆VOD).

OD

previously referred as VCM.

= 3.3V and TA= +25C unless specified otherwise.

CC

f = 25 MHz 29 40 mA

f = 40 MHz 33 45 mA

f = 65 MHz 39 50 mA

f = 87.5 MHz 44 55 mA

17 150 µA

DS90C385A

Recommended Transmitter Input Characteristics

Over recommended operating supply and temperature ranges unless otherwise specified

Symbol Parameter Min Typ Max Units

TCIT TxCLK IN Transition Time (Figure 5) 1.0 6.0 ns

TCIP TxCLK IN Period (Figure 6) 11.42 T 55.55 ns

TCIH TxCLK IN High Time (Figure 6) 0.35T 0.5T 0.65T ns

TCIL TxCLK IN Low Time (Figure 6) 0.35T 0.5T 0.65T ns

TXIT TxIN , and PWR DOWN pin Transition Time

TXPD Minimum pulse width for PWR DOWN pin signal.

1.5 6.0 ns

1us

Transmitter Switching Characteristics

Over recommended operating supply and temperature ranges unless otherwise specified

Symbol Parameter Min Typ Max Units

LLHT LVDS Low-to-High Transition Time (Figure 4) 0.75 1.4 ns

LHLT LVDS High-to-Low Transition Time (Figure 4) 0.75 1.4 ns

TPPos0 Transmitter Output Pulse Position (Figure 12)

(Note 5)

TPPos1 Transmitter Output Pulse Position 5.26 5.71 6.16 ns

TPPos2 Transmitter Output Pulse Position 10.98 11.43 11.88 ns

TPPos3 Transmitter Output Pulse Position 16.69 17.14 17.59 ns

TPPos4 Transmitter Output Pulse Position 22.41 22.86 23.31 ns

TPPos5 Transmitter Output Pulse Position 28.12 28.57 29.02 ns

TPPos6 Transmitter Output Pulse Position 33.84 34.29 34.74 ns

f = 25MHz −0.45 0 +0.45 ns

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Transmitter Switching Characteristics (Continued)

Over recommended operating supply and temperature ranges unless otherwise specified

Symbol Parameter Min Typ Max Units

DS90C385A

TPPos0 Transmitter Output Pulse Position (Figure 12)

(Note 5)

TPPos1 Transmitter Output Pulse Position 3.32 3.57 3.82 ns

TPPos2 Transmitter Output Pulse Position 6.89 7.14 7.39 ns

TPPos3 Transmitter Output Pulse Position 10.46 10.71 10.96 ns

TPPos4 Transmitter Output Pulse Position 14.04 14.29 14.54 ns

TPPos5 Transmitter Output Pulse Position 17.61 17.86 18.11 ns

TPPos6 Transmitter Output Pulse Position 21.18 21.43 21.68 ns

TPPos0 Transmitter Output Pulse Position (Figure 12)

(Note 5)

TPPos1 Transmitter Output Pulse Position 2.00 2.20 2.40 ns

TPPos2 Transmitter Output Pulse Position for Bit 2 4.20 4.40 4.60 ns

TPPos3 Transmitter Output Pulse Position for Bit 3 6.39 6.59 6.79 ns

TPPos4 Transmitter Output Pulse Position 8.59 8.79 8.99 ns

TPPos5 Transmitter Output Pulse Position 10.79 10.99 11.19 ns

TPPos6 Transmitter Output Pulse Position 12.99 13.19 13.39 ns

TPPos0 Transmitter Output Pulse Position (Figure 12)

(Note 5)

TPPos1 Transmitter Output Pulse Position 1.48 1.68 1.88 ns

TPPos2 Transmitter Output Pulse Position 3.16 3.36 3.56 ns

TPPos3 Transmitter Output Pulse Position 4.84 5.04 5.24 ns

TPPos4 Transmitter Output Pulse Position 6.52 6.72 6.92 ns

TPPos5 Transmitter Output Pulse Position 8.20 8.40 8.60 ns

TPPos6 Transmitter Output Pulse Position 9.88 10.08 10.28 ns

TSTC Required TxIN Setup to TxCLK IN

(Figure 6) at 85MHz

THTC Required TxIN Hold to TxCLK IN (Figure 6) at

87.5 MHz

TCCD TxCLK IN to TxCLK OUT Delay. Measure from

TxCLK IN edge to immediately crossing point of
differential TxCLK OUT by following the positive
TxCLK OUT. 50% duty cycle input clock is
assumed. (Figure 7)

Measure from TxCLK IN edge to immediately
crossing point of differential TxCLK OUT by
following the positive TxCLK OUT. 50% duty
cycle input clock is assumed. (Figure 8)

f = 40 MHz −0.25 0 +0.25 ns

f = 65 MHz −0.20 0 +0.20 ns

f = 87.5 MHz −0.20 0 +0.20 ns

2.5 ns

0.5 ns

T

= −10˚,

A

3.086 7.211 ns
and 87.5MHz
for " Min ",

= 70˚, and

T

A

25MHz for "
Max ", V

=

CC

3.6V, R_FB
pin = VCC

T

A

= −10˚,

2.868 6.062 ns
and 87.5MHz
for " Min ",

= 70˚, and

T

A

25MHz for "
Max ", V

=

CC

3.6V, R_FB
pin = GND

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Transmitter Switching Characteristics (Continued)

Over recommended operating supply and temperature ranges unless otherwise specified

Symbol Parameter Min Typ Max Units

SSCG Spread Spectrum Clock support; Modulation

frequency with a linear profile.(Note 6)

TPLLS Transmitter Phase Lock Loop Set (Figure 9) 10 ms

TPDD Transmitter Power Down Delay (Figure 11) 100 ns

Note 5: The Minimum and Maximum Limits are based on statistical analysis of the device performance over process, voltage, and temperature ranges. This
parameter is functionality tested only on Automatic Test Equipment (ATE).

Note 6: Care must be taken to ensure TSTC and THTC are met so input data are sampling correctly. This SSCG parameter only shows the performance of tracking
Spread Spectrum Clock applied to TxCLK IN pin, and reflects the result on TxCLKOUT+ and TxCLKOUT− pins.

f = 25 MHz 100kHz

2.5%/−5%

f = 40 MHz 100kHz

2.5%/−5%

f = 65 MHz 100kHz

2.5%/−5%

f = 87.5 MHz 100kHz

2.5%/−5%

±

±

±

±

DS90C385A

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AC Timing Diagrams

DS90C385A

20070204

FIGURE 1. “Worst Case” Test Pattern (Note 7)

20070205

FIGURE 2. “16 Grayscale” Test Pattern - DS90C385A (Notes 8, 9, 10)

Note 7: The worst case test pattern produces a maximum toggling of digital circuits, LVDS I/O and LVCMOS/LVTTL I/O.

Note 8: The 16 grayscale test pattern tests device power consumption for a “typical” LCD display pattern. The test pattern approximates signal switching needed

to produce groups of 16 vertical stripes across the display.

Note 9: Figures 1, 2 show a falling edge data strobe (TxCLK IN/RxCLK OUT).

Note 10: Recommended pin to signal mapping. Customer may choose to define differently.

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AC Timing Diagrams (Continued)

FIGURE 3. DS90C385A (Transmitter) LVDS Output Load. 5pF is showed as board loading

FIGURE 4. DS90C385A (Transmitter) LVDS Transition Times

DS90C385A

20070230

20070206

20070208

FIGURE 5. DS90C385A (Transmitter) Input Clock Transition Time

20070210

FIGURE 6. DS90C385A (Transmitter) Setup/Hold and High/Low Times with R_FB pin = GND (Falling Edge Strobe)

20070212

FIGURE 7. DS90C385A (Transmitter) Clock In to Clock Out Delay with R_FB pin = VCC

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AC Timing Diagrams (Continued)

DS90C385A

FIGURE 8. DS90C385A (Transmitter) Clock In to Clock Out Delay with R_FB pin = GND

20070235

20070214

FIGURE 9. DS90C385A (Transmitter) Phase Lock Loop Set Time

FIGURE 10. 28 Parallel TTL Data Inputs Mapped to LVDS Outputs - DS90C385A

20070217

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AC Timing Diagrams (Continued)

FIGURE 11. Transmitter Power Down Delay

DS90C385A

20070218

FIGURE 12. Transmitter LVDS Output Pulse Position Measurement - DS90C385A

20070226

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DS90C385A MTD56 (TSSOP) Package Pin Descriptions — FPD Link
Transmitter

Pin Name I/O No. Description

DS90C385A

TxIN I 28 LVTTL level input. This includes: 8 Red, 8 Green, 8 Blue, and 4 control lines — FPLINE,

FPFRAME and DRDY (also referred to as HSYNC, VSYNC, Data Enable).

TxOUT+ O 4 Positive LVDS differentiaI data output.

TxOUT− O 4 Negative LVDS differential data output.

TxCLKIN I 1 LVTTL Ievel clock input. Pin name TxCLK IN.

R_FB I 1 LVTTL Ievel programmable strobe select (See Table 1).

TxCLK OUT+ O 1 Positive LVDS differential clock output.

TxCLK OUT− O 1 Negative LVDS differential clock output.

PWR DOWN

V

CC

GND I 5 Ground pins for LVTTL inputs.

PLL V

CC

PLL GND I 2 Ground pins for PLL.

LVDS V

LVDS GND I 3 Ground pins for LVDS outputs.

CC

I 1 LVTTL level input. When asserted (low input) TRI-STATE the outputs, ensuring low current at

power down.

I 3 Power supply pins for LVTTL inputs.

I 1 Power supply pin for PLL.

I 1 Power supply pin for LVDS outputs.

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Applications Information

The DS90C385A is backward compatible with the
DS90C385, DS90C383A, DS90C383 in TSSOP 56-lead
package, and it is a pin-for-pin replacements.

This device DS90C385A also features reduced variation of
the TCCD parameter which is important for dual pixel appli­cations. (See AN-1084)

This device may also be used as a replacement for the
DS90CF583 (5V, 65MHz) and DS90CF581 (5V, 40MHz)
FPD-Link Transmitters with certain considerations/
modifications:

1. Change 5V power supply to 3.3V. Provide this 3.3V
supply to the V
transmitter.

2. The DS90C385A transmitter input and control inputs
accept 3.3V LVTTL/LVCMOS levels. They are not 5V
tolerant.

3. To implement a falling edge device for the DS90C385A,
the R_FB pin may be tied to ground OR left unconnected
(an internal pull-down resistor biases this pin low). Bias­ing this pin to Vcc implements a rising edge device.

TRANSMITTER INPUT PINS

The TxIN and control input pins are compatible with LVC­MOS and LVTTL levels. These pins are not 5V tolerant.

TRANSMITTER INPUT CLOCK/DATA SEQUENCING

Unlike the DS90C385, DS90C(F)383A/363A, the
DS90C385A does not require any special requirement for
sequencing of the input clock/data and PD (PowerDown)
signal. The DS90C385A offers a more robust input sequenc-

, LVDS VCCand PLL VCCof the

CC

ing feature where the input clock/data can be inserted after
the release of the PD signal. In the case where the clock/
data is stopped and reapplied, such as changing video mode
within Graphics Controller, it is not necessary to cycle the PD
signal. However, there are in certain cases where the PD
may need to be asserted during these mode changes. In
cases where the source (Graphics Source) may be supply­ing an unstable clock or spurious noisy clock output to the
LVDS transmitter, the LVDS Transmitter may attempt to lock
onto this unstable clock signal but is unable to do so due the
instability or quality of the clock source. The PD signal in
these cases should then be asserted once a stable clock is
applied to the LVDS transmitter. Asserting the PWR DOWN
pin will effectively place the device in reset and disable the
PLL, enabling the LVDS Transmitter into a power saving
standby mode. However, it is still generally a good practice
to assert the PWR DOWN pin or reset the LVDS transmitter
whenever the clock/data is stopped and reapplied but it is
not mandatory for the DS90C385A.

SPREAD SPECTRUM CLOCK SUPPORT

The DS90C385A can support Spread Spectrum Clocking
signal type inputs. The DS90C385A outputs will accurately
track Spread Spectrum Clock/Data inputs with modulation
frequencies of up to 100kHz (max.)with either center spread

±

2.5% or down spread -5% deviations.

of

POWER SOURCES SEQUENCE

In typical applications, it is recommended to have V

and PLL VCCfrom the same power source with three

V

CC

CC

, LVDS

separate de-coupling bypass capacitor groups. There is no
requirement on which VCC entering the device first.

DS90C385A

Pin Diagram for TSSOP Packages

DS90C385AMT

20070223

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Typical Application

DS90C385A

Truth Table

TABLE 1. Programmable Transmitter (DS90C385A)

Pin Condition Strobe Status

R_FB R_FB = V

R_FB R_FB = GND or NC Falling edge strobe

CC

Rising edge strobe

20070203

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Physical Dimensions inches (millimeters) unless otherwise noted

DS90C385A +3.3V Programmable LVDS Transmitter 24-bit Flat Panel Display (FPD) Link-87.5 MHz

56-Lead Molded Thin Shrink Small Outline Package, JEDEC

Dimensions in millimeters only

Order Number DS90C385AMT

NS Package Number MTD56

National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves
the right at any time without notice to change said circuitry and specifications.

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