AT73C237 Atmel, AT73C237 Datasheet - Page 23

• Manufacturer Part Number: AT73C237
• Description: IC POWER MANAGEMENT UNIT 16QFN
• Manufacturer: Atmel

Specifications of AT73C237

• Applications: Wireless
• Current - Supply: 250µA
• Voltage - Supply: 2.8 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-QFN
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

9.8
9.9
9.10
9.11
9.12
6362A–PMAAC–01-Jul-08
State Machine
Oscillator
Power-On-Reset
Supply Monitor
Digital Control
An Internal State Machine supervises the start up of the regulators connected to VDD1, VDD2
and VDD3. The startup configuration is in the following order LDO3 then LDO1 then LDO2.
A voltage must be present on VDD4 to supply LDO4.
An Internal Oscillator (RCOSC) is used to generate the internal master clock which synchronizes
the state machine controlling the start up of the LDOs and HPBG.
A Power-On-Reset (POR) monitors the output of LDO4 (VO4) and generates an internal signal
to enable the trimming registers to be loaded for LDO1, LDO2, LDO3 output voltage program-
ming, as well as for the reference voltages and internal oscillator trimming. This internal signal is
released when VO4 is higher then 1.5V ± 300 mV.
A Supply Monitor is set on VDD3 and generates an internal signal to enable state machine to
startup the LDOs and to generate the XRESO signal. The threshold has been set to 2.7V when
rising up and 2.6V when falling down.
On AT73C237, the pins TWCK, TWD are respectively the clock and data lines of a true two-wire
interface, allowing to activate and disable the output voltage delivered by the regulators LDO1,
LDO2, LDO3 and also to change their output voltage value.
AT73C237
23