Datasheet
SLVS216B − JUNE 1999 − JUNE 2008
13
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
detailed description (continued)
shutdown
Driving ENABLE low places the device in shutdown mode. This disables all switches, the oscillator, and control
logic. The device typically draws 0.05-µA (1-µA max) of supply current in this mode. Leakage current drawn from
the output is as low as 1 µA max. The device exits shutdown once ENABLE is set high level. The typical no-load
shutdown exit time is 20 µs. When the device is in shutdown, the load is isolated from the input and the output
is high impedance.
external clock signal
If the device operates at a user-defined frequency, an external clock signal can be used. Therefore, SYNC needs
to be connected to IN and the external oscillator signal can drive CLK. The maximum external frequency is
limited to 800 kHz. The switching frequency of the converter is half of the external oscillator frequency. It is
recommended to operate the charge pump in constant-frequency mode if an external clock signal is used so
that the output noise contains only well-defined frequency components.
IN
IN
C1+
C1−
ENABLE
OUT
OUT
FB
C2+
C2−
SYNC
SKIP COM CLK
PGND GND
INPUT
2.7 V to 5.4 V
C
IN
4.7 µF
OUTPUT
5 V 150 mA
C
O
= 33 µF
C
2F
1 µF
C
1F
1 µF
+
OFF/ON
TPS60111
+
External Clock
Figure 28. Typical Operating Circuit TPS60111 With External Synchronization