TDA4882 Datasheet, PDF (11/28 Pages) NXP Semiconductors – Advanced monitor video controller for OSD

Philips Semiconductors
Advanced monitor video controller for OSD
Product specification
TDA4882
SYMBOL
PARAMETER
CONDITIONS
MIN. TYP. MAX. UNIT
t_r(CL), t_f(CL)
t_w(clamp)
t_d(Vblank)
rise and fall time for clamping pulse note 19; Fig.17
width of clamping pulse
delay between vertical blanking
input and internal blanking
note 19; Fig.17
−
−
75
ns/V
0.6 −
−
µs
260 320 380 ns
Notes to the characteristics
1. Definition of levels:
a) Artificial black level: internal signal level behind input emitter follower during input clamping and signal clipping.
This level is inserted instead of the input signal during blanking.
b) Reference black level: DC voltage during output clamping at voltage outputs, not influenced by brightness,
contrast or gain setting, adjustable by cut-off stabilization.
c) Cut-off level: corresponding DC voltage at CRT cathode in closed feedback loop.
d) Black level: actual signal black level at either the voltage outputs or cathode, it can be adjusted by
(brightness × gain), it refers to reference black level or cut-off level.
e) Ultra-black level, switch-off level: lowest adjustable reference black level, lowest signal level at voltage outputs.
f) The minimum guaranteed control range for reference black level is 0.1 to 1 V. The ultra-black level is dependent
on the external resistor R_O at pins 13, 16 and 19 (voltage outputs) to ground.
g) V_bl(SO) ≈ -3---.--5-----k--R-_Ω---^o---₊-----R-----_o × 4.65 V
2. Linear control range is 1 to 6 V for V_i(BC), independent of supply voltage.
3. Linear control range is 1 to 6 V for V_i(CC), independent of supply voltage. Open pin 6 leads to maximum contrast
setting. It is recommended not to exceed V_i(CC) = V_P − 1 V to avoid saturation of internal circuitry. For
V_i(CC) < V_i(CC)(min) ≈ 0.7 V a small negative signal (≈ −40 dB) will appear. For frequency dependency of contrast
control see note 15.
4. Definition for nominal output signals: input V_i(b-w) = 0.7 V, gain pins 3 and 11 open-circuit, contrast control
V_i(CC) = V_i(CC)(nom).
5.
∆ G_track
=
20 × maximum of



log



A--A---₁^-1-₀^-
×
A--A---_2-2-0-



;
log



A--A---₁^-1-₀^-
×
A--A---_3-3-0-



;

log 

A--A---₂^-2-₀^-
×
A--A---_{3-3-0- }



dB
A_x: signal output amplitude in channel x at any contrast setting between 1 and 6 V.
A_x0: signal output amplitude in channel x at nominal contrast and same gain setting.
6. Typical step in contrast voltage and response at signal outputs for nominal input signal V_i(b-w) = 0.7 V
(OSD fast blanking input/output).
7. Linear control range is 1 to 6 V for V_i(GC), independent of supply voltage.
8. The internal reference voltage can be measured at pins 18, 15 and 12 (channel feedback inputs) during output
clamping (V_i(HBL) = 2 V) in closed feedback loop.
9. Slow variations of video supply voltage V_CRT (Fig.1) will be suppressed at CRT cathode by cut-off stabilization.
Change of V_CRT by 5 V leads to specified change of cut-off voltage.
10. The test mode allows testing without input and output clamping pulses. The signal inputs have to be biased via
resistors to the previously measured clamp voltages of approximately 3 V (artificial black level + V_BE). Signal and
brightness blanking is not possible during test mode. The current outputs should be adjusted by resistors >> R₀ from
voltage outputs to a positive voltage (e.g. V_P).
1997 Sep 04
11