90E32 Datasheet, PDF (66/71 Pages) Integrated Device Technology – Poly-Phase High-Performance Wide-Span Energy Metering IC

90E32
POLY-PHASE HIGH-PERFORMANCE WIDE-SPAN ENERGY METERING IC
7.4 POWER ON RESET TIMING
In most case, the power of 90E32 and MCU are both derived from
220V power lines. To make sure 90E32 is reset and can work properly,
MCU must force 90E32 into idle mode firstly and then into normal mode.
In this operation, RESET is held to high in idle mode and de-asserted by
delay T1 after idle-normal transition. Refer to Figure-18.
DVDD
T0
PM[1:0]
MCU startup
Idle Mode
Normal Mode
T1
RESET
Figure-18 Power On Reset Timing (90E32 and MCU are Powered on Simultaneously)
DVDD
V_H
T1
RESET
Figure-19 Power On Reset Timing in Normal & Partial Measurement Mode
Table-17 Power On Reset Specification
Symbol
Description
Min
Typ
Max
Unit
V_H
Power On Trigger Voltage
2.5
2.7
V
T₀
Duration forced in idle mode after power on
1
ms
T₁
Delay time after power on or exit idle mode
5
16
40
ms
Electrical Specification
66
December 9, 2011