EZZE MASS2, Техническое руководство, Страница: 67 / 137

Model MASS 2 Version V_1.0
Prepared by H/W Date 22/01/2008
Subject Technical Manual Page 45/59
The auxiliary analog circuit LDO is a regulator that sources 50 mA (max) with 2.8 V or 3.3 V output voltage
selection based on the VA_SW_SEL register setting (Register F [7]). It can be switched on/off by register control.
10) USB IO LDO (VUSB)
The USB IO LDO is a regulator that sources 20 mA (max) with a 3.3 V output voltage. The LDO output on/off
follows the control bit USB_PWR (Register 1 [3]). When the USB_PWR control bit is set to off, the VUSB output
voltage drops below 0.3 V within 1 ms. (VUSB output is shunt with a 1
μ
F capacitor.)
11) Vibrator LDO (VIBR)
The vibrator LDO is a regulator that sources 200 mA (max) with a 1.8 V or 3.2 V output voltage selection based on
the VIBSEL register setting (Register E [1]). This LDO can be powered on/off by register.
12) Reference Voltage Output (VREF)
The reference voltage output is a low noise, high PSRR and high precision reference with a guaranteed accuracy of
1.5% over temperature. The output is used as a system reference in MT6318 internally. However for accurate specs
of every LDO output voltage, avoid loading the reference voltage; only bypass it to GND with a minimum 100 Nf
capacitance.
Figure 45. Status of Mobile Handset and LDOs.
3. LED Drivers
PMIC provides 4 independent drivers. Three of them use an identical structure to drive 3 different LEDs (R, G, B).
The fourth is dedicated to driving the keypad LEDs. The reason for separating the LED drivers into 2 groups is
phone feature oriented.