at86rf401 ATMEL Corporation, at86rf401 Datasheet - Page 10

• Manufacturer Part Number: at86rf401
• Description: Smart Rf Wireless Data Microtransmitter
• Manufacturer: ATMEL Corporation

Bandgap Reference
Brown-out Protection/Low
Battery Detection
Brown-out Protection
Low Battery Detection
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AT86RF401
period. A number of registers are available to adjust the performance of the lock detec-
tor. These include lock delay and unlock delay timers as well as a cycle slip counter.
The device uses a 1.2V (nominal) bandgap reference generator to provide consistent
performance over a wide range of input supply voltages. This reference voltage is used
throughout the device.
The brown-out protection and low battery detection functions consist of a voltage refer-
ence, a sampling block and an autozero comparator. The circuit’s primary operating
mode is brown-out protection.
The brown-out protection circuit detects when the level of V
voltage that guarantees proper operation. The brown-out voltage for this device is typi-
cally 1.8 volts.
If a brown-out occurs, the device enters a reset state. It stays in this state until either of
the following occurs:
•
•
The low battery detection feature allows the programmer to select a voltage threshold
(1.5–2.7 volts) for V
warning may be utilized to activate an I/O port or to change the transmitted message.
Additionally, the programmer has the option of defining the amount of hysteresis on this
threshold. More detail can be found in register descriptions for I/O Enable (IO_ENAB,
$30, page 39) and Battery Low Configuration (BL_CONFIG, $35, page 42).
The level of V
the device to enter a warm reboot state.
The level of V
the device into the “cold start” mode of operation, identical to battery insertion.
DD
DD
DD
increases ~0.1–0.2 volts above the brown-out voltage. This causes
drops to ~0 volts, then increases above the POR level. This places
at which a warning flag is issued to the user. For example, this
DD
drops below the minimum
1424F–RKE–12/03