S-882Z Datasheet, PDF (11/24 Pages) Seiko Instruments Inc – ULTRA-LOW VOLTAGE OPERATION CHARGE PUMP IC FOR STEP-UP DC-DC CONVERTER STARTUP

ULTRA-LOW VOLTAGE OPERATION CHARGE PUMP IC FOR STEP-UP DC-DC CONVERTER STARTUP
Rev.1.2_00
S-882Z Series
If the Schottky diode (SD1) has a large reverse current or if a pull-down resistor is added to the OUT pin of the
S-882Z Series, add the current value generated from these to the current consumption (I_VDD) of the step-up
DC-DC converter.
Moreover, if a Schottky diode is added between the OUT pin of the S-882Z Series and the power supply pin (VDD
pin) of the step-up DC-DC converter, set V_CPOUT1 so that it is higher by the amount corresponding to the forward
drop voltage (V_F) of the added Schottky diode in comparison to the discharge start voltage value (V_CPOUT1)
obtained with the above described conditional expression.
Cautions 1.
The S-882Z Series can start up the step-up DC-DC converter more reliably as the discharge
start voltage value (V_CPOUT1) and the startup capacitor value (C_CPOUT) are larger. However,
note that the time from when the input power is input until the step-up DC-DC converter
starts becomes longer in this case.
2. In the S-882Z Series, C_CPOUT can be more lowered as V_CPOUT1 is higher, but note that if V_CPOUT1
≥ 2.2 V, the minimum value of the operation input voltage (the minimum input voltage value
required for power to be output from the OUT pin of the S-882Z Series) rises from 0.3 V to
0.35 V (refer to Table 6).
Discharge Start Voltage
Value
1.8, 2.0 V
1.8 to 2.4 V
Table 6
Minimum Operation Input
Voltage Value
0.3 V
0.35 V
Temperature Range
−30 to +60°C
−40 to +85°C
Caution The above connection diagram and constant will not guarantee
successful operation. Perform thorough evaluation using the actual
application to set the constant.
„ Standard Circuit
CCPOUT
CPOUT
OUT
VIN
S-882Z Series
VM
VSS
Figure 15
Caution The above connection diagram and constant will not guarantee successful operation. Perform
thorough evaluation using the actual application to set the constant.
Seiko Instruments Inc.
11