
Analog Integrated Circuit Device Data
Freescale Semiconductor
17
PC34708
General Product Characteristics
Thermal Characteristics
5.2.1
Power Dissipation
During operation, the temperature of the die should not exceed the maximum junction temperature. To optimize the thermal
management scheme and avoid overheating, the PC34708 PMIC provides a thermal management system. The thermal
protection is based on a circuit with a voltage output that is proportional to the absolute temperature. This voltage can be read
This voltage is monitored by an integrated comparator. Interrupts THERM110, THERM120, THERM125 and THERM130 will be
generated when respectively crossing in either direction the thresholds specified in
Table 6. The temperature range can be
determined by reading the THERMxxxS bits.
Thermal protection is integrated to power off the PC34708 PMIC and disables the charger circuitry in case of over dissipation.
This thermal protection will act above the maximum junction temperature to avoid any unwanted power downs. The protection is
debounced for 8.0 ms in order to suppress any (thermal) noise. This protection should be considered as a fail-safe mechanism
and therefore the application design should be dimensioned such that this protection is not tripped under normal conditions. The
temperature thresholds and the sense bit assignment are listed in
Table 6.
5.2.2
Current Consumption
The current consumption of the individual blocks is described in detail throughout this specification. For convenience, a summary
table follows for standard use cases.
Table 6. Thermal Protection Thresholds
Parameter
Min
Typ
Max
Units
Thermal 110C threshold (THERM110)
105
110
115
°C
Thermal 120C threshold (THERM120)
115
120
125
°C
Thermal 125C threshold (THERM125)
120
125
130
°C
Thermal 130C threshold (THERM130)
125
130
135
°C
Thermal warning hysteresis
(13)2.0
-
4.0
°C
Thermal protection threshold
130
140
150
°C
Notes
13.
Equivalent to approx. 30 mW min, 60 mW max
Table 7. Current Consumption Summary (16) Mode
Description
Typ
Max
Unit
RTC / Power
cut
All blocks disabled, no main battery attached, coin cell is attached to LICELL
(at 25°C only)
RTC Logic
VCORE Module
VSRTC
32 k Oscillator
Clk32KMCU buffer active(10 pF load)
4.0
8.0
μA
OFF (good
battery)
All blocks disabled, main battery attached * Core and RTC module
Digital Core
RTC Logic
VSRTC
32 k Oscillator
CLK32KMCU buffer active (10 pF load)
Charger (detect)
20
55
μA