
Analog Integrated Circuit Device Data
Freescale Semiconductor
77
PC34708
Functional Block Requirements and Behaviors
LDO Regulators Description and Application Information
7.5
LDO Regulators Description and Application Information
7.5.1
Introduction
This section describes the linear regulators provided. For convenience, these regulators are named to indicate their typical or
possible applications, but the supplies are not limited to these uses and may be applied to any loads within the specified regulator
capabilities.
A low power standby mode controlled by STANDBY is provided for the regulators with an external pass device in which the bias
current is aggressively reduced. This mode is useful for deep sleep operation, where certain supplies cannot be disabled, but
active regulation can be tolerated with lesser parametric requirements. The output drive capability and performance are limited
in this mode.
All regulators use the main bandgap as reference. The main bandgap is bypassed with a capacitor at REFCORE. The bandgap
and the rest of the core circuitry are supplied from VCORE. The performance of the regulators is directly dependent on the
performance of VCOREDIG and the bandgap. No external DC loading is allowed on VCOREDIG or REFCORE. VCOREDIG is
kept powered as long as there is a valid supply and/or coin cell.
VSWBSTLINE
AREG
Average Line Regulation
3.0 V < VIN < 4.5 V IL = ILMAX
-
50
-
mV
ISWBST
Continuous Load Current
3.0 V < VIN < 4.5 V, VOUT = 5.0 V
-
380
-
mA
ISWBSTPEAK Peak Current Limit
At SWBSTIN, VIN = 3.6 V
-
1800
-
mA
VSWBSTOS-
START
Start-up Overshoot, IL = 0 mA
-
500
mV
tON-SWBST Turn-on Time
Enable to 90% of VOUT IL = 0
-
2.0
ms
fSWBST
Switching Frequency
-
2.0
-
MHz
VSWBSTRAN
SIENT
Transient Load Response, IL from 1.0 to 100 mA in 1.0 s
Maximum transient Amplitude
-
300
mV
VSWBSTRAN
SIENT
Transient Load Response, IL from 100 to 1.0 mA in 1.0 s
Maximum transient Amplitude
-
300
mV
VSWBSTRAN
SIENT
Transient Load Response, IL from 1.0 to 100 mA in 1.0 s
Time to settle 80% of transient
-
500
s
VSWBSTRAN
SIENT
Transient Load Response, IL from 100 to 1.0 mA in 1.0 s
Time to settle 80% of transient
-
20
ms
Efficiency, IL = ILMAX
65
80
-
%
ISWBSTBIAS Bias Current Consumption
PFM or Auto mode
-
35
-
A
ILEAK-SWBST NMOS Off Leakage
SWBSTIN = 4.5 V, SWBSTMODE [1:0] = 0
-
1.0
5.0
A
Notes:
59.
VIN is the low side of the inductor that is connected to BP.
Table 75. SWBST Electrical Specifications
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