XC6222D251MR-G Datasheet, PDF (9/26 Pages) Torex Semiconductor – Reverse Current Protection, 700mA High Speed LDO Regulator

XC6222
Series
<Current Limiter, Short-Circuit Protection>
The XC6222 series’ fold-back circuit operates as an output current limiter and a short protection circuit for the output pin.
When the load current reaches the current limit level, the fixed current limiter circuit operates and output voltage drops. When
the output pin is short-circuited to the VSS pin, the current is decreased to a level of 55mA.
<Thermal Shutdown>
When the junction temperature of the built-in driver transistor reaches the temperature limit level (150℃ TYP.), the thermal
shutdown circuit operates and the driver transistor will be turned OFF. The IC resumes its operation when the thermal
shutdown function is released and the IC’s operation is automatically restored because the junction temperature drops to the
level of 125℃ (TYP.) as the thermal shutdown release voltage.
■OPERATIONAL EXPLANATION (Continued)
<C_L Auto-Discharge Function>
XC6222B/D series can discharge the electric charge stored in the output capacitor (CL), when a low signal to the CE pin, which
enables the whole IC circuit to be turned off, is inputted via the N-channel transistor located between the VOUT pin and the VSS
pin (cf. BLOCK DIAGRAM). The CL auto-discharge resistance value is set at 530Ω(TYP.). The discharge time of the output
capacitor (CL) is set by the CL auto-discharge resistance (R) and the output capacitor (CL). By setting the time constant of the
CL auto-discharge resistance value [R_DCHG] and the output capacitor value (CL) as τ(τ=C x R_DCHG), the output voltage after
discharge via the N-channel transistor is calculated by the following formula.
V = VOUT(E) x e ^–t/τ, or t=τIn ( V / VOUT(E) )
where
V: Output voltage after discharge
VOUT (E): Output voltage
t: Discharge time
τ: CL auto-discharge resistance R_DCHG×Output capacitor (CL) value C)
<CE Pin>
The entire XC6222 circuitry can be turned off via the CE pin signal. In shutdown mode, output at the VOUT pin will be pulled
down to the VSS level via R1 & R2. However, with the XC6222B series, the CL auto-discharge resistor is connected in parallel to
R1 and R2 while the power supply is applied to the VIN pin. Therefore, time until the VOUT pin reaches the VSS level is shorter.
For the XC6222A/B series, the output voltage becomes unstable, when the CE pin is left open. If this CE pin voltage is set with
the specified voltage range, the logic is fixed and the IC will operate normally. However, the supply current may increase as a
result of shoot-through current in the IC's internal circuitry when a medium voltage is input to the CE pin. With the XC6222C/D
series, when the CE pin is left open, output voltage is fixed to V_SS level.
■NOTES ON USE
1. Please use this IC within the stated absolute maximum ratings. The IC is liable to malfunction should the ratings be
exceeded.
2. Where wiring impedance is high, operations may become unstable due to noise and/or phase lag depending on
output current.
Please wire the input capacitor (CIN) and the output capacitor (CL) as close to the IC as possible.
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