Datasheet

Analog Integrated Circuit Device Data
Freescale Semiconductor 52
MC34708
Functional Block Description
Table 40. SW2 Electrical Specifications
Characteristics noted under conditions BP = 3.6 V, V
BUS
= 5.0 V, - 40 C  T
A
 85 C, unless otherwise noted. Typical values
at BP = 3.6
V and T
A
= 25 °C under nominal conditions, unless otherwise noted.
Symbol Characteristic Min Typ Max Unit Notes
SW2 BUCK REGULATOR
V
SW2IN
Operating Input Voltage
• PWM operation, 0 < IL < I
MAX
• PFM operation, 0 < IL < IL
MAX
3.0
2.8
-
-
4.5
4.5
V
V
SW2ACC
Output Voltage Accuracy
• PWM mode including ripple, load regulation, and transients
• PFM Mode, including ripple, load regulation, and transients
Nom-25
Nom-25
Nom
Nom
Nom+25
Nom+25
mV
(48)
I
SW2
Continuous Output Load Current, V
INMIN
< BP < 4.65 V
• PWM mode
• PFM mode
-
-
-
50
1000
-
mA
I
SW2PEAK
Current Limiter Peak Current Detection
•V
IN
= 3.6 V Current through Inductor
- 2.0 -
A
I
SW2
TRANSIENT
Transient Load Change
• 100 mA/µs
- - 0.500
A
V
SW2OS-
START
Start-up Overshoot, IL = 0
- - 25 mV
t
ON-SW2
Turn-on Time
• Enable to 90% of end value IL = 0
- - 500
µs
f
SW2
Switching Frequency
• PLLX = 0
• PLLX = 1
-
-
2.0
4.0
-
-
-
MHz
I
SW2Q
Quiescent Current Consumption
• APS MODE, IL = 0 mA; device not switching
• PFM MODE, IL = 0 mA; device not switching
-
-
160
15
-
-
µA

SW2
Efficiency
•PFM, 0.9 V, 1.0 mA
•PWM, 1.2 V, 120 mA
•PWM, 1.2 V, 500 mA
•PWM, 1.2 V, 1000 mA
-
-
-
-
54
75
83
78
-
-
-
-
%
(49)
Notes:
48. Transient loading for load steps of ILMAX/2.
49. Efficiency numbers at V
IN
= 3.6 V, excludes the quiescent current.