TMC2242C

Features:

• Pin-compatible upgrade of TMC2242B
• User-selectable interpolate d.c. gain, 0 dB or -6 dB
• True unity d.c. gain in all "0 db" modes
• 40 MSPS performance in equal-rate filter modes
• 40 and 60 MSPS speed grades in all other modes
• User-selectable 2:1 decimation, 1:2 interpolation, and equal-rate filter modes, plus unfiltered bypass/delay mode
• Defeatable x/sin(x) compensation filter
• Passband ripple <0.014 dB
• Stopband rejection >56 dB
• Dedicated 12-bit two's complement or unsigned input bus
• 16-bit two's complement or unsigned output bus with user-selectable rounding to 8 to 16 effective bits
• Programmable limiter prevents overflow or clips to CCIR601 levels
• New double-latency modes match Y channel data flow to slower-sampled CB and CR data flows
• New dual-channel interpolation and decimation for YUV422


Pinout




Specifications

Parameter	Conditions	Min	Max	Units
Supply Voltage		-0.5	7.0	V
Input Voltage		-0.5	VDD + 0.5	V
Output Applied Voltage2		-0.5	VDD + 0.5	V
Externally Forced Current3,4		-3.0	+6.0	mA
Short Circuit Duration	Single output in HIGH state to ground		1	sec
Operating Temperature (Case)		-20	110
Junction Temperature			140
Lead Soldering Temperature	10 seconds		300
Storage Temperature		-65	150

Description

The TMC2242C, a linear-phase low-pass half-band digital filter with fixed coefficients, can be used to halve or double the sampling rate of a digital signal. When used as a decimating post-filter with a double-speed oversampling A/D converter, it greatly reduces the cost and complexity of the required analog antialiasing pre-filters. When used as an interpolating pre-filter with a double-speed oversampling D/A converter, it greatly reduces the complexity and cost of the necessary analog post-filter, particularly when its x/sin(x) correction filter is engaged.
The TMC2242C user selects the mode of operation (decimate, interpolate, equal-rate, bypass, x/sin(x))and rounding. The part can accept 12-bit two's complement or unsigned data at up to 60 MHz and can output saturated two's complement or offset binary data rounded to from 8 to 16 bits. Within the speed grade I/O limit, the output sample rate may be 1/2, 1, or 2 times the input sample rate. Two-channel modes permit it to interpolate or to decimate two multiplexed data streams (such as video C B and C R) jointly. The filter response is flat to within±0.014 dB up to 0.21fs (e.g. 5.75MHz at a 27MHz clock rate), with stopband attenuation greater than 56dB above 0.29fs. Symmetric-coefficient filters such as the TMC2242C always have linear phase response. Half-band response is -6 dB.
Fabricated on an advanced submicron CMOS process, the TMC2242C is available in a 44-lead PLCC package. Performance is guaranteed from 0 to 70 and over a power supply range of 4.75 to 5.25V.