Rainbow Electronics ATR0625 - Manual (Page 17)

17
4925A–GPS–02/06
ATR0625 [Preliminary]
4. Power Supply
The baseband IC is supplied with four distinct supply voltages:
• VDD18, the nominal 1.8V supply voltage for the core, the RF-I/O pins, the memory
interface and the test pins and all GPIO-pins not mentioned in next item.
• VDDIO, the variable supply voltage within 1.8V to 3.6V for following GPIO-pins: P1, P2, P8,
P12, P14, P16, P17, P18, P19, P20, P21, P23, P24, P25, P26, P27 and P29 In input mode,
these pins are 5V input tolerant.
• VDD_USB, the power supply of the USB pins: USB_DM and USB_DP.
• VBAT18 to supply the backup domain: RTC, backup SRAM and the pins NSLEEP, NSHDN,
LDO_EN, VBAT18, P9/EXTIN0, P13/EXTINT1, P22/RXD2 and P31/RXD1 and the 32kHz
oscillator. In input mode, the four GPIO-pins are 5V input tolerant.
Figure 4-1 , Figure 4-2 , and Figure 4-3 show examples of the wiring of ATR0625 power supply.
Figure 4-1. External Wiring Example Using Internal LDOs and Backup Power Supply
ATR0625 internal
VDDUSB 0 to 2V or 3V to 3.6V
1.5V to 3.6V
1 µF
(X7R)
ldoout
ldoen
ldoin
LDO18
LDO_IN
1 µF
(X7R)
VDDIO
2.3V to 3.6V
LDO_EN NSHDN
VDD18
LDO_OUT
USB SM and
Transceiver
1.8V to 3.3V
variable IO Domain
RTC
Backup Memory
Core
vbat18
vbat
vdd
ldobat_in
LDOBAT
LDOBAT_IN
VBAT
VBAT18