Philips tda9176 DATASHEETS

INTEGRATED CIRCUITS

DATA SH EET

TDA9176

Luminance Transient Improvement
(LTI) IC

Preliminary specification
Supersedes data of 1995 Jun 13
File under Integrated Circuits, IC02

1996 Jan 30

Philips Semiconductors Preliminary specification

Luminance Transient Improvement (LTI) IC TDA9176

FEATURES

• Luminance transient improvement

• Line width control

• Can be used in 50 and 100 Hz environments

(1FH and 2FH)

• Compensating chrominance delay

• YUV interface

• Black insertion or clamping are selectable

• Amplitude selection for optimum operation with

450 mV (p-p) and 1 V

luminance signals.

bl-wh

GENERAL DESCRIPTION

The TDA9176 is a Luminance Transient Improvement
(LTI) IC which is suitable for operation in both
50 and 100 Hz environments. The device can be used in
conjunction with both LCD and CRT displays.

The TDA9176 also contains chrominance delay lines to
compensate for the luminance delay. The device can be
used as a low-power, cost effective alternative to (but also
in combination with) Scan Velocity Modulation (SVM).
The device operates at a supply voltage of 8 V. The device
is contained in a 16 pin dual in-line package.

QUICK REFERENCE DATA

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

V

CC

I

CC

supply voltage 7.2 8.0 8.8 V
supply current at 1FH − 24 − mA

at 2FH − 30 − mA

V

iY( p-p)

V

iY(bl-wh)

G

Y

V

iU(p-p)

V

iV(p-p)

G

U. V

Y input voltage (peak-to-peak value) low amplitude mode − 0.45 0.63 V
Y input voltage (black-to-white) high amplitude mode − 1.0 1.4 V
Y path gain − 1
U input voltage (peak-to-peak value) − 1.33 1.90 V
V input voltage (peak-to-peak value) − 1.05 1.50 V
U and V path gain − 1 −

ORDERING INFORMATION

PACKAGE

TYPE NUMBER

NAME DESCRIPTION VERSION

TDA9176 DIP16 plastic dual in-line package; 16 leads (300 mil); long body SOT38-1

1996 Jan 30 2

Philips Semiconductors Preliminary specification

Luminance Transient Improvement (LTI) IC TDA9176

BLOCK DIAGRAM

handbook, full pagewidth

YIN

BLI/CL

AMPSEL

SC RT LW

8

SANDCASTLE

DETECTOR

BLACK

4

INSERTION

CLAMP

7
9

14 6 11 5 12 16

TDA9176

DELAY

DELAY DELAY

V

CC

CLAMPS

Fig.1 Block diagram.

2315

LTI

CONTROL

MINMAX

PTAT

CURRENT

SOURCE

R

UOUTVOUT UINVINGND

ext

f

SEL

SHAPER

BAND GAP

1

LTI

13

10

MBE775

YOUT

V

ref

1996 Jan 30 3

Philips Semiconductors Preliminary specification

Luminance Transient Improvement (LTI) IC TDA9176

PINNING

SYMBOL PIN DESCRIPTION

f

SEL

LW 2 vertical line width control input
RT 3 rise time control input
YIN 4 luminance signal input
UIN 5 U input (colour difference signal)
VIN 6 V input (colour difference signal)
BLI/CL 7 black level insertion/clamp mode

SC 8 synchronization input signal
AMPSEL 9 high/low amplitude luminance

V

ref

VOUT 11 V output (colour difference signal)
UOUT 12 U output (colour difference signal)
YOUT 13 luminance signal output
GND 14 ground (0 V)
V

CC

R

ext

1 1FH or 2FH mode selection

selection

signal mode selection

10 internally generated reference

voltage for line width control and
rise time control

15 supply voltage (+8 V)
16 external resistor for PTAT current

source

handbook, halfpage

f

1

SEL

2

LW

3

RT

YIN

4

TDA9176

5

UIN UOUT
VIN

6
7

BLI/CL

8

SC AMPSEL

16
15
14
13
12
11
10

9

MBE776

Fig.2 Pin configuration.

R

ext

V

CC

GND
YOUT

VOUT
V

ref

1996 Jan 30 4

Philips Semiconductors Preliminary specification

Luminance Transient Improvement (LTI) IC TDA9176

FUNCTIONAL DESCRIPTION

The TDA9176 is a Luminance Transient Improvement
(LTI) IC which is suitable for operation in both
50 and 100 Hz environments. The IC also contains
chrominance delay lines to compensate for the luminance
delay. A diagram of the LTI processor is illustrated in Fig.3.

The LTI processor contains a delay line which drives a
minimum/maximum (MINMAX) detector and a control
circuit. When the control circuit discovers a transient, the
LTI shaper switches from the minimum to the maximum
signal (or vice-versa, depending on the sign of the
transient). By mixing the original signal with the switched
signal, a variable transient improvement is obtained.
The 50% crossing point of the transient is not affected by
the LTI circuit.

If the rise time improvement is active, the duty cycle of the
output signal can be varied with the line width control input.
This function delays the rising edge and advances the
falling edge (or vice-versa). This can be used for example
aperture correction. Figures 4 and 5 illustrate some
waveforms of the LTI processor.

For correct operation the LTI circuit requires a number of
fast clamps. To overcome problems where noise is
superimposed on the input signal the device contains an
input clamp that can either clamp to the black level of the
input signal, or, insert a black level. When a black level is
inserted, the internal clamps do not respond to the noise
on the input signal (see Fig.1). When the input signal
already has an inserted black level (e.g. when it is driven
from the TDA9170 picture booster) it is recommended to

set the device to the clamping mode. If no inserted black
level is available on the input signal it is recommended to
select the black insert mode of the input clamp.

The chrominance delay lines compensate for the delay of
the luminance signal in the LTI circuit. This is to safeguard
a correct colour fit.

Two and three level sandcastles can be used as a timing
signal, only the clamp pulse of the sandcastle input is used
in the device.

There are three selection inputs to select the modes of
operation. These selections are as follows:

1. 1FH or 2FH, for the 50 or 100 Hz applications.

2. Amplitude selection, for optimum operation of the
circuit with 450 mV (p-p) or 1 V

luminance signals.

bl-wh

3. Black insertion or clamping of the luminance signal.

The selection inputs must be directly connected to either
ground or the supply rail. The modes are selected as
follows:

Frequency selection: GND = 1FH mode,
VCC= 2FH mode

Amplitude selection: GND = 450 mV (p-p),
VCC=1V

bl-wh

mode

Black insertion/clamp: GND = clamp mode,
VCC= black insert mode.

If the selection pins are left floating, internal 1 MΩ resistors
connected to the pins set the device to, 1FH mode, black
insert mode and 1 V

bl-wh

mode.

handbook, full pagewidth

YIN

1996 Jan 30 5

RT LW

23

LTI

TDA9176

4

DELAY

CLAMPS MINMAX

CONTROL

SHAPER

LTI

13

MBE777

YOUT

Fig.3 Block diagram of the LTI circuit.