Specifications

Product Technical Specification & Customer Design Guidelines
56 Proprietary and Confidential - Contents subject to change 4114634
USB enumeration
The unit supports single and double USB enumeration with the host:
• Single enumeration—Enumeration starts within maximum
t_pwr_on_seq seconds of power-on.
• Double enumeration—As shown in Figure 5-2:
· First enumeration starts within t_pwr_on_seq seconds of power-on (while
USB_D+ is high)
· Second enumeration starts within 14 seconds of power-on (when USB_D+
goes high again)
Transmit power waveform (GSM)
As shown in Figure 5-3, at maximum GSM transmit power, the input current can
remain at 2.2 A for up to 25% of each 4.6 ms GSM cycle (1.15 ms) after reaching
an initial peak of 2.5 A (average over 100 µs). For class 12 operation, the peak
could remain for 2.3 ms (four timeslots).
The 2.2 A current draw is for 50 ohm systems (1:1 VSWR). For worst-case
antenna designs (3.5:1 VSWR), the current draw could increase to 2.5 A, as
shown in the diagram.
Figure 5-3: GSM transmit power waveform (class 10 operation)
Table 5-6: Power-on timing parameters (double enumeration)
Parameter Typical (s) Maximum (s)
t_pwr_on_seq 0.43 0.5
t_USB_active 0.25 0.3
t_USB_suspend 12 13
Table 5-7: Power-on timing parameters (single enumeration)
Parameter Typical (s) Maximum (s)
t_pwr_on_seq 12 13
2.2
0.15
Current
(A)
2.5A peak
2.5
25 µs
1.15 ms
4.6 ms
3.5:1 VSWR = 2.5A
1:1 VSWR = 2.2A