TC1029 View Datasheet(PDF) - Microchip Technology

Part Name

Description

Manufacturer

TC1029

Linear Building Block – Dual Low Power Op Amp

Microchip Technology 

TC1029

3.0 DETAILED DESCRIPTION

The TC1029 is one of a series of very low power, linear

building block products for low voltage single supply

operations. The TC1029 contains two rail to rail op

amps which operate down to 1.8V with a maximum

supply current of 16µA. The amplifier's input range

extends beyond both supplies by 200mV and the

outputs will swing to within several millivolts of the

supplies, depending on the load current being driven.

The amplifier design is such that large signal gain, slew

rate and bandwidth are largely independent of supply

voltage. The low input bias current and offset voltage of

the TC1029 make it suitable for precision applications.

4.0 TYPICAL APPLICATIONS

The TC1029 lends itself to a wide variety of

applications, particularly in battery powered systems. It

typically finds application in power management,

processor supervisory and interface circuitry.

4.1 Voice Band Receive Filter

The majority of spectral energy for human voices is

found to be in a 2.7kHz frequency band from 300Hz to

3kHz. To properly recover a voice signal in applications

such as radios, cellular phones and voice pagers, a low

power bandpass filter matched to the human voice

spectrum can be implemented, using Microchip’s

CMOS op amps. Figure 4-1 shows a unity gain multi-

pole Butterworth filter with ripple less than 0.15dB in

the human voice band. The lower 3 dB cut-off

frequency is 70Hz (single order response), while the

upper cut-off frequency is 3.5kHz (fourth order

response).

4.2 Supervisory Audio Tone (SAT)

Filter for Cellular

Supervisory Audio Tones (SAT) provide a reliable

transmission path between cellular subscriber units

and base stations. The SAT tone functions much like

the current/voltage used in land line telephone systems

to indicate that a phone is off the hook. The SAT tone

may be one of three frequencies: 5970, 6000 or

6030Hz. A loss of SAT implies that channel conditions

are impaired and if SAT is interrupted for more than 5

seconds a cellular call is terminated.

Figure 4-2 shows high Q (30) second order SAT

detection bandpass filter using Microchip’s CMOS op

amp architecture. This circuit nulls all frequencies

except the three SAT tones of interest.

DS21340B-page 4

© 2002 Microchip Technology Inc.

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