AP1705/6/7
Processor Supervisory Circuits
Features
General Description
The AP1705/6/7 family of supervisors provides circuit
initialization and timing supervision, primarily for DSP
and processor-based systems.
During power-on, RESET is asserted when supply
voltage VCC becomes higher than 1.1V. Thereafter, the
supply voltage supervisor monitors VCC and keeps
- Power-on reset generator with fixed delay time of
200ms (AP1705/6/7)
- Manual reset input (AP1705/7)
- Reset output available in active-Low (AP1705/6/7),
active-high (AP1706/7)
- Supply voltage supervision range 2.5V, 3V, 3.3V,
5V
RESET active as long as VCC remains below the
threshold voltage VIT-. An internal timer delays the return
of the output to the inactive state (high) to ensure proper
system reset. The delay time ,td, starts after VCC has
risen above the threshold voltage VIT-. When the supply
voltage drops below the threshold voltage VIT-, the
output becomes active (low) again. No external
components are required. All the devices of this family
have a fixed-sense threshold voltage VIT- set by an
internal voltage divider.
- Watchdog timer (AP1705/6/7)
- Supply current of 25µA (Typ.)
- SOT23-5, SOT23-6 ,TSOT23-5 and TSOT23-6
Pb-Free Package
- Temperature range: -40°C to 85°C
Applications
The AP1705/7 devices incorporate a manual reset input,
- Applications Using DSPs, Microcontrollers, or
Microprocessors
MR . A low level at MR causes RESET to become
active. The AP1706/7 devices include a high-level
output RESET. AP1705/6/7 have a watchdog timer that
is periodically triggered by a positive or negative
transition at WDI. When the supervising system fails to
retrigger the watchdog circuit within the time-out interval,
- Industrial Equipment
- Programmable Controls
- Automotive Systems
- Portable/Battery-Powered Equipment
- Intelligent Instruments
ttout, RESET becomes active for the time period td.
This event also reinitializes the watchdog timer. Leaving
WDI unconnected disables the watchdog.
- Wireless Communications Systems
- Notebook/Desktop Computers
In applications where the input to the WDI pin may be
active (transitioning high and low) when the AP1705/6/7
asserting RESET , the AP1705/6/7 does not return to a
non-reset state when the input voltage is above Vt. If
the application requires that input to WDI is active when
Ordering Information
RESET is asserted, WDI must be decoupled from the
active signal. This can be accomplished by using an
N-channel FET in series with the WDI pin, with the gate
AP170X X X
of the FET connected to the RESET output as shown
Part No.
Voltage
A: 4.63
Package
in Figure 1.
5: AP1705
6: AP1706
7: AP1707
W5:SOT23-5
AP1706
B: 4.38 W6:SOT23-6
TW5:TSOT23-5
TW6:TSOT23-6
C: 4.00
D: 3.08
E: 2.93
F: 2.63
G: 2.25
WDI
WDI External
RESET
Figure 1.
The product spectrum is designed for supply voltage of
2.5V, 3V, 3.3V and 5V. The circuits are available in a
SOT23-5L, SOT23-6L, and TSOT23-5L,TSOT23-6L
packages. The AP1705/6/7 devices are characterized
for operation over a temperature range of -40oC to 85oC.
This datasheet contains new product information. Anachip Corp. reserves the rights to modify the product specification without notice. No liability is assumed as a result of the use of this
product. No rights under any patent accompany the sale of the product.
Rev. 1.0 Nov. 17, 2005
1/13