ISL59832 Datasheet, PDF (11/14 Pages) Intersil Corporation – Dual Channel, Single Supply Video Reconstruction Filter with Charge Pump

ISL59832
Typical Performance Curves V_CP = V_S = 3.3V, C_F = 0.1µF, C_S = 0.22µF, C_FIL = 0.4µF, C_IN1= C_IN2 = 0.1µF, R_L1= R_L2 = 150Ω.
TIME SCALE = 20ns/DIV
VERTICAL SCALE = 20mV/DIV
0
V_S = V_CP = +3.3V
-10 _{RL = 150Ω}
-20 ^{VOUT = 0 TO 2VP, SINE WAVE}
-30
-40
-50
f_IN = 500kHz
f_IN = 5MHz
-60
FIGURE 25. CHARGE PUMP FEEDTHROUGH AT AMPLIFIER
OUTPUT
-70
0.5
0.8
1.1
1.4
1.7
2.0
OUTPUT VOLTAGE (V)
FIGURE 26. THD (dBc) vs OUTPUT VOLTAGE (V_P-P)
4.5
4.0
3.5
3.0
2.5
2.0 ^{16 LD TQFN PACKAGE}
4mmx4mm
1.5 θ_JA = +46°C/W
1.0
0.5
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90
AMBIENT TEMPERATURE (°C)
FIGURE 27. PACKAGE POWER DISSIPATION vs AMBIENT TEMPERATURE
Description of Operation and Application Information
Theory of Operation
The ISL59832 is a single supply video driver with a
reconstruction filter and an on-board charge pump. It is
designed to drive SDTV displays with S-video (Y-C) or
composite video (CV) signals. The input signals can be AC
or DC-coupled. When AC-coupled, a sync tip clamp forces
the blank level to ground at the output of Channel 1 and a
keyed clamp forces the average level of Channel 2 to
ground. The ISL59832 is capable of driving two AC- or DC-
coupled standard video loads and has a 4^th order
Butterworth reconstruction filter with nominal -3dB frequency
set to 10MHz, providing 40dB of attenuation at 27MHz. The
ISL59832 is designed to operate with a single supply voltage
range ranging from 3.0V to 3.6V. This eliminates the need for
a split supply with the incorporation of a charge pump
capable of generating a bottom rail as much as 1.5V below
ground; providing a 4.8V range on a single 3.3V supply. This
performance is ideal for NTSC video with negative-going
sync pulses.
Output Amplifier
The ISL59832 output amplifiers provide a gain of +6dB. The
Channel 1 output amplifier is able to drive a 2.8V_P-P video
signal into a 150Ω load to ground, while the Channel 2
amplifier is able to drive a 2.8V_P-P into a 150Ω or 75Ω load to
ground.
The outputs are highly-stable, low distortion, low power, high
frequency amplifiers capable of driving moderate (10pF)
capacitive loads.
Input/Output Range
The ISL59832 inputs have a dynamic range of 0 to 1.4V_P-P.
This allows the device to handle the maximum possible
video signal inputs. As the input signal moves outside the
specified range, the output signal will exhibit increasingly
higher levels of harmonic distortion.
The Charge Pump
The ISL59832 charge pump provides a bottom rail up to
1.5V below ground while operating on a 3.0V to 3.6V power
supply. The charge pump is driven by an internal 13MHz
clock.
To reduce the noise on the power supply generated by the
charge pump connect a lowpass RC-network between
11
FN6267.1
June 11, 2008