LTC6652AHMS8-1.25-PBF LINER [Linear Technology], LTC6652AHMS8-1.25-PBF Datasheet - Page 12

• Manufacturer Part Number: LTC6652AHMS8-1.25-PBF
• Description: Precision Low Drift Low Noise Buffered Reference
• Manufacturer: LINER [Linear Technology]

LTC6652
In Figure 8, ripple momentarily appears just after the
leading edge of powering on. This brief one time event is
caused by calibration circuitry during initialization. When
an output capacitor is used, the ripple is virtually undetect-
able as shown in Figure 9.
Shutdown Mode
Shutdown mode is enabled by tying SHDN low which
places the part in a low power state (i.e., <2µA). In shut-
down mode, the output pin takes the value 20k • (rated
output voltage). For example, an LTC6652-2.5 will have
12
applications inForMation
Figure 9. Start-Up Response with 1µF Output Capacitor
Figure 8. Start-Up Response without Output Capacitor
2V/DIV
1V/DIV
2V/DIV
1V/DIV
V
V
OUT
OUT
V
V
IN
IN
C
C
OUT
OUT
= 0µF
= 1µF
100µs/DIV
100µs/DIV
6652 F08
6652 F09
an output impedance of 20k • 2.5 = 50kΩ. For normal
operation, SHDN should be greater than or equal to 2.0V.
For use with a microcontroller, use a pull-up resistor to
V
10. The LTC6652’s response into and out of shutdown
mode is shown in Figure 11.
The trip thresholds on SHDN have some dependence on the
voltage applied to V
Characteristics section. Be careful to avoid leaving SHDN
at a voltage between the thresholds as this will likely cause
an increase in supply current due to shoot-through current.
IN
2.8V ≤ V
and an open-drain output driver as shown in Figure
1V/DIV
1V/DIV
SHDN
V
OUT
Figure 11. Shutdown Response with 5mA Load
IN
≤ 13.2V
Figure 10. Open-Drain Shutdown Circuit
I
LOAD
TO µC
= 5mA
IN
C1
1µF
as shown in the Typical Performance
2N7002
R1
20k
1ms/DIV
SHDN
LTC6652-2.5
GND
V
IN
V
6652 F10
OUT
6652 F11
C2
1µF
V
OUT
6652fd