MAX16033 Datasheet, PDF (7/21 Pages) Maxim Integrated Products – Low-Power Battery Backup Circuits in Small μDFN Packages

Low-Power Battery Backup
Circuits in Small µDFN Packages
PIN
MAX16033– MAX16037–
MAX16036 MAX16040
(10-pin µDFN) (8-pin µDFN)
1
1
2
—
3
2
4
3
5
4
6
5
7
6
8
7
9
8
10
—
Pin Description
NAME
FUNCTION
RESET
CEIN
PFI
GND
MR
WDI
BATTON
RESETIN
PFO
V_CC
OUT
BATT
CEOUT
Active-Low Reset Output. RESET remains low when V_CC is below the reset
threshold (V_TH), the manual-reset input is low, or RESETIN is low. It asserts low in
pulses when the internal watchdog times out. RESET remains low for the reset
timeout period (t_RP) after V_CC rises above the reset threshold, after the manual-reset
input goes from low to high, after RESETIN goes high, or after the watchdog triggers
a reset event. The MAX160_ _L is an active-low push-pull output, while the
MAX160_ _P is an active-low open-drain output.
Chip-Enable Input. The input to the chip-enable gating circuit. Connect to GND or
OUT if not used.
Power-Fail Input. PFO goes low when V_PFI falls below 1.235V.
Ground
Manual-Reset Input (MAX16033/MAX16037). Driving MR low asserts RESET. RESET
remains asserted as long as MR is low and for the reset timeout period (t_RP) after
MR transitions from low to high. Leave unconnected, or connect to V_CC if not used.
MR has an internal 20kΩ pullup to V_CC.
Watchdog Input (MAX16034/MAX16038). If WDI remains high or low for longer than
the watchdog timeout period (t_WD), the internal watchdog timer runs out and a reset
pulse is triggered for the reset timeout period (t_RP). The internal watchdog clears
whenever RESET asserts or whenever WDI sees a rising or falling edge (Figure 2).
Battery-On Output (MAX16035/MAX16039). BATTON goes high during battery
backup mode.
Reset Input (MAX16036/MAX16040). When RESETIN falls below 1.235V, RESET
asserts. RESET remains asserted as long as RESETIN is low and for at least t_RP
after RESETIN goes high.
Active-Low Power-Fail Output. PFO goes low when V_PFI falls below 1.235V. PFO
stays low until V_PFI goes above 1.235V. PFO also goes low when V_CC falls below
the reset threshold voltage.
Supply Voltage, 1.2V to 5.5V
Output. OUT sources from V_CC when RESET is not asserted and from the greater of
V_CC or BATT when V_CC is below the reset threshold voltage.
Backup Battery Input. When V_CC falls below the reset threshold, OUT switches to
BATT if V_BATT is 40mV greater than V_CC. When V_CC rises above V_BATT, OUT
switches to V_CC. The 40mV hysteresis prevents repeated switching if V_CC falls
slowly.
Chip-Enable Output. CEOUT goes low only when CEIN is low and reset is not
asserted. When CEOUT is disconnected from CEIN, CEOUT is actively pulled up to
OUT.
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