TS6001
Supply Current
The TS6001 exhibits excellent dc line regulation as
its supply current changes slightly as a function of
the applied supply voltage. Because of a unique bias
loop design, the change in its supply current as a
function of supply voltage (its ΔI
IN
/ΔV
IN
) is less than
0.1μA/V. Since the TS6001 is a series-mode
reference, load current is drawn from the supply
voltage only when required. In this case, circuit
efficiency is maintained at all applied supply
voltages. Reducing power dissipation and extending
battery life are the net benefits of improved circuit
efficiency.
When the applied supply voltage is less than the
minimum specified input voltage of the TS6001 (for
example, during the power-up or “cold-start”
transition), the TS6001 performs an internal
calibration routine and can draw up to 200μA above
its nominal, steady-state supply current. This internal
calibration sequence also dominates the TS6001’s
turn-on time. To ensure reliable power-up behavior,
the input power source must have sufficient reserve
power to provide the extra supply current drawn
during the power-up transition.
Voltage Reference Turn-On Time
With a (V
IN
– V
OUT
) voltage differential larger than
200mV and I
LOAD
= 0mA, the TS6001’s typical
combined turn-on and settling time to within 0.1% of
its 2.5V final value is approximately 340μs.
Output Voltage Hysteresis
Reference output voltage thermal hysteresis is the
change in the reference’s +25°C output voltage after
temperature cycling from +25°C to +85°C to +25°C
and from +25°C to -40°C to +25°C. Thermal
hysteresis is caused by differential package stress
impressed upon the TS6001’s internal bandgap core
transistors and depends on whether the reference IC
was previously at a higher or lower temperature. At
100ppm, the TS6001’s typical temperature
hysteresis is equal to 0.25mV with respect to a 2.5V
output voltage.
Connecting Two or More TS6001s in Stacked
V
OUT
Arrangements
In many applications, it is desired to combine the
outputs of two or more precision voltage references,
especially if the combined output voltage is not
available or is an uncommon output voltage. One
such technique for combining (or “stacking”) the
Page 8
Figure 3:
Connecting Two TS6001-2.5s in a
Stacked V
REFOUT
Arrangement
In this example and powered by an unregulated
supply voltage (V
IN
≥ +5.2V), two TS6001-2.5
precision voltage references are used. The GND
terminal of REFA is connected to the OUT terminal
of REFB. This connection produces two output
voltages, V
REFOUT1
and V
REFOUT2
, where V
REFOUT1
is
the terminal voltage of REFB and V
REFOUT2
is
V
REFOUT1
plus the OUT terminal voltage of REFB. By
implementing this stacked arrangement with a pair
of TS6001-2.5s, V
REFOUT2
is 5V and V
REFOUT1
is 2.5V.
Although the TS6001-2.5s do not specifically require
input bypass capacitors, it is good engineering
practice to bypass both references from V
IN
to the
global GND terminal (at REFB). If either or both
reference ICs are required to drive a load
capacitance, it is also good engineering practice to
route the load capacitor’s return lead to each
reference’s corresponding REF’s GND terminal. The
circuit’s minimum input supply voltage, V
IN
, is
determined by V
REFOUT2
and REFB’s dropout voltage
(75mV, typically).
How to Configure the TS6001 into a General-
Purpose Current Source
In many low-voltage applications, a general-purpose
current source is needed with very good line
regulation. The TS6001-2.5 can be configured as a
grounded-load, floating current source as shown
Figure 4. In this example, the TS6001-2.5’s output
voltage is bootstrapped across an external resistor
(R1 + P1) which, in turn, sets the output current. The
circuit’s total output current is I
OUT
= I
SET
+I
QSC
where
I
QSC
is the TS6001 supply current (up to 35µA). For
outputs of precision voltage references is illustrated
in Figure 3.
TS6001DS r1p0
RTFDS
TOUCHSTONE [ TOUCHSTONE SEMICONDUCTOR INC ]
