Product Specification
IXD3235/36/37
CE/MODE Pin Function
The IXD3235/36/37 series enter the shut down mode, when a LOW logic-level signal applies to the CE/MODE pin.
In the shutdown mode, IC current consumption is ~0 μA (Typical value), with the Lx and VOUT pins at high
impedance state. The IC starts its operation when a HIGH logic-level signal applies to the CE/MODE pin.
Intermediate voltage, generated by external resistive divider can be used to select PWM/PFM auto or PWM only
switching modes in respect with the table below.
OPERATION MODE
CE/MODE VOLTAGE LEVEL
IXD3235
IXD3236
IXD3537
Synchronous PWM/PFM auto
switching mode
0.65 V ≤ V CE/MODE ≤ 6.0 V
Synchronous Fixed PWM mode
-
Synchronous PWM/PFM auto
switching mode
VIN – 0.25 V ≤ V CE/MODE ≤ VIN
-
-
0.65 V ≤ V CE/MODE ≤ VIN – 1.0 V
-
-
Synchronous Fixed PWM mode
Standby mode
0 V ≤ V CE/MODE ≤ 0.25 V
Standby mode
Standby mode
Examples of CE/MODE pin use are shown below. Please set the value of each resistor from few hundreds kΩ to
few hundred MΩ. For switches, CPU open-drain I/O port and transistor can be used.
The CE/MODE pin is a CMOS input with a sink current ~ 0 μA.
IXD3235/36 series - Examples of how to use CE/MODE pin
IC STATUS
SW-CE
POSITION
ON
SCHEMATIC A
SCHEMATIC B
Active
Standby
Active
OFF
Standby
IXD3237 series - Examples of how to use CE/MODE pin
IC STATUS
SW-CE
POSITION
SW-PWM/PFM
POSITION
SCHEMATIC A
SCHEMATIC B
PWM/PFM Auto
Switching Mode
PWM Mode
ON
X
Standby
OFF
OFF
ON
OFF
PWM Mode
PWM/PFM Auto
Switching Mode
Standby
Soft Start
Soft start time is available in two options via product
selection.
The soft-start time of IXD3235/36/37 series is optimized by
using internal circuits and it is 1.0 ms (Typically.) for
A/C/D/E series and 0.25 ms for B/F/G series. D and F
series require external resistors and a capacitor to set the
output voltage, so the soft-start time might vary based on
value of those external components. The definition of the
soft-start time is the time when the output voltage goes up
to the 90% of nominal output voltage after the IC is enabled
by CE ”H” signal.
PS034201-0515
PRELIMINARY
12
ZILOG [ ZILOG, INC. ]
