TS30111 Datasheet, PDF (8/23 Pages) List of Unclassifed Manufacturers – High Efficiency 700mA Current-Mode Synchronous Buck DC/DC Converter, 1MHz

TS30111
Version 1.0
Switching output, VSW
This is the switching node of the regulator. It should be connected directly to the 3.3uH inductor with a wide, short trace and to
one end of the Bootstrap capacitor. It is switching between VCC and PGND at the switching frequency.
Ground, GND
This ground is used for the majority of the device including the analog reference, control loop, and other circuits.
Power Ground, PGND
This is a separate ground connection used for the low side synchronous switch to isolate switching noise from the rest of the
device. (Figure 23)
Enable, high-voltage, EN
This is the input terminal to activate the regulator. The input threshold is TTL/CMOS compatible. It also has an internal pull-
up to ensure a stable state if the pin is disconnected.
Power Good Output, PG
This is an open drain, active low output. The switched mode output voltage is monitored and the PG line will remain low until
the output voltage reaches the V_OUT-UV threshold. Once the internal comparator detects the output voltage is above the desired
threshold, an internal delay timer is activated and the PG line is de-asserted to high once this delay timer expires. In the event
the output voltage decreases below V_OUT-UV, the PG line will be asserted low and remain low until the output rises above V_OUT-UV
and the delay timer times out. See Figure 2 for the circuit schematic for the PG signal.
INTERNAL PROTECTION DETAILS
Internal Current Limit
The current through the high side FET is sensed on a cycle by cycle basis and if current limit is reached, it will abbreviate the
cycle. In addition, the device senses the FB pin to identify hard short conditions and will direct the VSW output to skip 4 cycles
if current limit occurs when FB is low. This allows current built up in the inductor during the minimum on time to decay
sufficiently. Current limit is always active when the regulator is enabled. Soft start ensures current limit does not prevent
regulator startup.
Under extended over current conditions (such as a short), the device will automatically disable. Once the over current
condition is removed, the device returns to normal operation automatically. (Alternately the factory can configure the device’s
NVM to shutdown the regulator if an extended over current event is detected and require a toggle of the Enable pin to return
the device to normal operation.)
Thermal Shutdown
If the temperature of the die exceeds 170°C (typical), the VSW outputs will tri-state to protect the device from damage. The PG
and all other protection circuitry will stay active to inform the system of the failure mode. Once the device cools to 160°C
(typical), the device will start up again, following the normal soft start sequence. If the device reaches 170°C, the
shutdown/restart sequence will repeat.
Reference Soft Start
The reference in this device is ramped at a rate of 4ms to prevent the output from overshoot during startup. This ramp restarts
whenever there is a rising edge sensed on the Enable pin. This occurs in both the fixed and adjustable versions. During the soft
start ramp, current limit is still active, and will still protect the device in case of a short on the output.
Output Overvoltage
If the output of the regulator exceeds 103% of the regulation voltage, the VSW outputs will tri-state to protect the device from
damage. This check occurs at the start of each switching cycle. If it occurs during the middle of a cycle, the switching for that
cycle will complete, and the VSW outputs will tri-state at the beginning of the next cycle.
VCC Under-Voltage Lockout
The device is held in the off state until VCC reaches 4.3V (typical). There is a 300mV hysteresis on this input, which requires the
input to fall below 4V (typical) before the device will disable.
Specifications subject to change
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