C8051F99X_10 Datasheet, PDF (49/322 Pages) Silicon Laboratories – Ultra Low Power, 8-2 kB Flash, Capacitive Sensing MCU

C8051F99x-C8051F98x
Table 4.2. Global Electrical Characteristics (Continued)
–40 to +85 °C, 25 MHz system clock unless otherwise specified. See "AN358: Optimizing Low Power Operation of the
‘F9xx" for details on how to achieve the supply current specifications listed in this table.
Parameter
Conditions
Min Typ Max Units
Notes:
1. Based on device characterization data; Not production tested.
2. SYSCLK must be at least 32 kHz to enable debugging.
3. Digital Supply Current depends upon the particular code being executed. The values in this table are obtained
with the CPU executing an “sjmp $” loop, which is the compiled form of a while(1) loop in C. One iteration
requires 3 CPU clock cycles, and the Flash memory is read on each cycle. The supply current will vary slightly
based on the physical location of the sjmp instruction and the number of Flash address lines that toggle as a
result. In the worst case, current can increase by up to 30% if the sjmp loop straddles a 64-byte Flash address
boundary (e.g., 0x007F to 0x0080). Real-world code with larger loops and longer linear sequences will have
few transitions across the 64-byte address boundaries.
4. Includes oscillator and regulator supply current.
5. IDD can be estimated for frequencies < 14 MHz by simply multiplying the frequency of interest by the
frequency sensitivity number for that range, then adding an offset of 84 µA. When using these numbers to
estimate I_DD for > 14 MHz, the estimate should be the current at 25 MHz minus the difference in current
indicated by the frequency sensitivity number. For example: V_DD = 3.0 V; F = 20 MHz, I_DD = 3.6 mA –
(25 MHz – 20 MHz) x 0.088 mA/MHz = 3.16 mA assuming the same oscillator setting.
6. Idle IDD can be estimated by taking the current at 25 MHz minus the difference in current indicated by the
frequency sensitivity number. For example: V_DD = 3.0 V; F = 5 MHz, Idle I_DD = 1.75 mA – (25 MHz –
5 MHz) x 0.067 mA/MHz = 0.41 mA.
Rev. 1.0
49