R
EM MICROELECTRONIC -
MARIN SA
EM1537
Low Power 32 kHz Circuit for Analog Quartz Watches
Description
The EM1537 is an integrated circuit in a low power CMOS
technology for battery operated wristwatches with bipolar
stepping motors. Time base is a 32 kHz crystal oscillator.
It has a very low current consumption of typ. 100 nA in a
wide voltage range of 1.2 to 3.6 Volt.
The IC is available in two voltage ranges - 1.2 to 1.8 Volt
and 1.8 to 3.6 V.
Motor pulse width is programmable from 0.098 ms to
14.65 ms in steps of 0.98 ms by metal mask.
Motor period is programmable from 2 x 1s to 2 x 60 s in
steps of 1 s selectable by metal mask.
Motor pulse chopping is programmable from 1/8 to 8/8 in
steps of 1/8 with chopping frequencies of 1024 Hz or 2048
Hz selectable by metal mask.
Motor period in Motor test mode is selectable 2 x 31.25
ms or 2 x 62.5 ms by metal mask
Input and output capacitors are integrated on chip and
also programmable by metal mask.
With a fully debounced RESET pad the motor can be
stopped.
A multi-functional bidirectional pad MTEST acts as output
for a 32 Hz or 512 Hz for frequency tuning - if open, or – if
connected to Vp – accelerates the motor period by a
factor of 16 or 32.
Features
Low power 32 kHz Quartz oscillator
Operating voltage ranges 1.55V and 3 Volt.
Very low current consumption typ. 100 nA at 1.5V.
Motor pulse width motor period and motor pulse
chopping is programmable in a wide range by metal
mask and don’t require additional bonds.
Fully debounced RESET input for accurate time setting
and power saving during shelf life.
Integrated capacitors, mask selectable is steps of 1 pF up to
35 pF.
Operation temperature range: -10°C to +60°C
Available in chip form, SO8 package
Applications
Analog watches
Driver for bipolar stepping motors
Functional Diagram
RESET
Vn
Vn
RESET
V
P
V
P
MOT1
C
TR
H1537
OSCIN
MOT2
Rm
(Stepping Motor)
OSCOUT
V
P
V
P
Operating range of Trimmer Capacitance:
3pF
≤
C
TR
≤
30 pF
Copyright
©
2006, EM Microelectronic-Marin SA
10/06 – rev.A
1
www.emmicroelectronic.com
EMMICRO [ EM MICROELECTRONIC - MARIN SA ]
