
Analog Integrated Circuit Device Data
Freescale Semiconductor
86
PC34708
Functional Block Requirements and Behaviors
LDO Regulators Description and Application Information
7.5.6.5
VGEN1, VGEN2
General purpose LDOs, VGEN1, and VGEN2, are provided for expansion of the power tree to support peripheral devices, which
could include EMMC cards, WLAN, BT, GPS, or other functional modules. These regulators include programmable set points for
system flexibility. VGEN1 has an internal PMOS pass FET, and is powered from the SW5 buck for an efficiency advantage and
reduced power dissipation in the pass devices. VGEN2 is powered directly from the battery.
VGEN2 has an internal PMOS pass FET, which will support loads up to 50 mA. For higher current capability, drive for an external
PNP is provided. The external PNP is offered to avoid excess on-chip power dissipation at high loads and large differentials
between BP and output settings. The input pin for the integrated PMOS option is shared with the base current drive pin for the
PNP option. The external PNP device is always connected to the BP line in the application. The recommended PNP device is
the ON Semiconductor NSS12100XV6T1G which is capable of handling up to 250 mW of continuous dissipation at minimum
footprint and 75 °C of ambient. For use cases where up to 500 mW of dissipation is required, the recommended PNP device is
the ON Semiconductor NSS12100UW3TCG. For stability, a small minimum ESR may be required.
A short-circuit condition will shut down the VGEN1 and VGEN2 regulators, and generate an interrupt for SCPI.
VDAC ACTIVE MODE – AC
VDACPSRR PSRR - IL = 75% of ILMAX 20 Hz to 20 kHz
VIN = VINMIN + 100 mV
VIN = VNOM + 1.0 V
35
50
40
60
-
dB
VDACNOISE Output Noise Density, VIN = VINMIN IL = 75% of ILMAX
100 Hz – 1.0 kHz
> 1.0 kHz – 10 kHz
> 10 kHz – 1.0 MHz
-
-115
-126
-132
dBV/
√Hz
VDACSPURS Spurs
32.768 kHz and harmonics
-
-120
dB
tON-VDAC
Turn-on Time
Enable to 90% of end value VIN = VINMIN, VINMAX IL = 0
-
1.0
ms
tOFF-VDAC Turn-off Time
Disable to 10% of initial value VIN = VINMIN, VINMAX, IL = 0
0.05
-
10
ms
VDACOS-
START
Start-up Overshoot
VIN = VINMIN, VINMAX IL = 0
-
1.0
2.0
%
VDACLOTRA
NSIENT
Transient Load Response
VIN = VINMIN, VINMAX
-
1.0
2.0
%
VDACLITRAN
SIENT
Transient Line Response
IL = 75% of ILMAX
-
5.0
8.0
mV
tMODE-VDAC Mode Transition Time
From low power to active VIN = VINMIN, VINMAX IL = ILMAXLP
-
100
s
VDACMODE
RES
Mode Transition Response
From low power to active and from active to low power
VIN = VINMIN, VINMAX IL = ILMAXLP
-
1.0
2.0
%
Table 84. VDAC Electrical Specification
Characteristics noted under conditions BP = 3.6 V, VBUS = 5.0 V, -40°C ≤ TA ≤ 85°C, unless otherwise noted. Typical values at
BP = 3.6 V and TA = 25°C under nominal conditions, unless otherwise noted.
Symbol
Characteristic
Min
Typ
Max
Unit
Notes