TC1043 Datasheet, PDF (5/20 Pages) Microchip Technology – Linear Building Block . Low Power Voltage Reference with Dual Op Amp, Dual Comparator, and Shutdown Mode

3.0 DETAILED DESCRIPTION
The TC1043 is one of a series of very low power, linear
building block products targeted at low voltage, single
supply applications. The TC1043 minimum operating
voltage is 1.8V and typical supply current is only 20µA
(fully enabled). It combines two comparators, two op
amps and a voltage reference in a single package. A
shutdown mode is incorporated for easy adaptation to
system power management schemes. During shut-
down, all but one comparator and the voltage reference
are disabled (i.e. powered down with their respective
outputs at high impedance). The “still awake” compar-
ator and voltage reference can be used as a wake-up
timer, power supply monitor, LDO controller or other
continuous duty circuit function.
3.1 Comparators
The TC1043 contains two comparators. The compara-
tors input range extends beyond both supply voltages
by 200mV and the outputs will swing to within several
millivolts of the supplies, depending on the load current
being driven.
The comparators exhibit a propagation delay and sup-
ply current which are largely independent of supply
voltage. The low input bias current and offset voltage
make them suitable for high impedance precision appli-
cations.
Comparator CMPTR1 is disabled during shutdown and
has a high impedance output. Comparator CMPTR2
remains active.
3.2 Operational Amplifiers
The TC1043 contains two rail-to-rail op amps. The
amplifiers’ 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 TC1043 make it suitable for precision applications.
Both op amps are disabled during shutdown and have
high output impedance.
3.3 Voltage Reference
A 2.0% tolerance, internally biased, 1.20V bandgap
voltage reference is included in the TC1043. It has a
push-pull output capable of sourcing and sinking at
least 50µA. The voltage reference remains fully
enabled during shutdown.
TC1043
3.4 Shutdown Input
SHDN at V_IL disables both op amps and one compara-
tor. The SHDN input cannot be allowed to float. When
not used, connect it to V_DD. The disabled comparator’s
output and the two disabled op amp outputs are in a
high impedance state when shutdown is active. The
disabled comparator’s inputs and the two disabled op
amp inputs can be driven from rail-to-rail by an external
voltage when the TC1043 is in shutdown. No latch-up
will occur when the device is driven to its enabled state
when SHDN is set to V_IH.
© 2002 Microchip Technology Inc.
DS21347B-page 5