Datasheet
DocID10396 Rev 14 21/28
M41T60 DC and AC parameters
Table 8. Crystal electrical characteristics
Symbol Parameter
(1)(2)
Min Typ Max Unit
f
O
Resonant frequency - 32.768 kHz
R
S
Series resistance
(T
A
= –40 to 70°C, oscillator startup at 2.0 V)
-75
(3)(4)
kΩ
C
L
Load capacitance - 6 pF
1. For the QFN16 package, user-supplied, external crystals are required. The 6 and 7 pF crystals listed in
Table 9 below have been evaluated by ST and have been found to be satisfactory for use with the M41T6x
series RTCs.
2. Load capacitors are integrated within the M41T60. Circuit board layout considerations for the 32.768 kHz
crystal of minimum trace lengths and isolation from RF generating signals should be taken into account.
3. Guaranteed by design.
4. R
S (max)
= 65 kΩ for T
A
= –40 to 85 °C and oscillator startup at 1.5 V.
Table 9. Crystals suitable for use with M41T6x series RTCs
Vendor Order number Package
Manufacturer’s specifications
ESR
max
Temp.
range
(°C)
Rated
tolerance
at 25 °C
Rated
load
cap.
Citizen CMJ206T-32.768KDZB-UB
8.3 x 2.5 mm
leaded SMT
50 kΩ –40/+85 ±20 ppm 6 pF
Citizen CM315-32.768KDZY-UB 3.2 x 1.5 x 0.9 mm SMT 70 kΩ –40/+85 ±20 ppm 7 pF
Ecliptek E4WCDA06-32.768K
(1)
2.0 x 6.0 mm thru-hole 50 kΩ –10/+60 ±20 ppm 6 pF
Ecliptek E5WSDC 07 - 32.768K 7 x 1.5 x 1.4 mm SMT 65 kΩ –40/+85 ±20 ppm 7 pF
ECS ECS-.327-6-17X-TR 3.8 x 8.5 x 2.5 mm SMT 50 kΩ –10/+60 ±20 ppm 6 pF
ECS ECS-.327-7-34B-TR 3.2 x 1.5 x 0.9 mm SMT 70 kΩ –40/+85 ±20 ppm 7 pF
ECS ECS-.327-7-38-TR 7 x 1.5 x 1.4 mm SMT 65 kΩ –40/+85 ±20 ppm 7 pF
Epson MC-146 32.7680KA-AG: ROHS
(2)
7 x 1.5 x 1.4 mm SMT 65 kΩ –40/+85 ±20 ppm 7 pF
Fox 298LF-0.032768-19 1.5 x 5.0 mm thru-hole 50 kΩ –20/+60 ±20 ppm 6 pF
Fox 299LF-0.032768-37 2.0 x 6.0 mm thru-hole 50 kΩ –20/+60 ±20 ppm 6 pF
Fox 414LF-0.032768-12 3.8 x 8.5 x 2.5 mm SMT 50 kΩ –40/+85 ±20 ppm 6 pF
Fox 501LF-0.032768-5 7 x 1.5 x 1.4 mm SMT 65 kΩ –40/+85 ±20 ppm 7 pF
Micro
Crystal
MS3V-T1R 32.768KHZ 7PF 20PPM
6.7 x 1.4 mm
leaded SMT
65 kΩ –40/+85 ±20 ppm 7 pF
Pletronics SM20S - 32.768K - 6pF 3.8 x 8.5 x 2.5 mm SMT 50 kΩ –40/+85 ±20 ppm 6 pF
Seiko SSPT7F-7PF20PPM 7 x 1.5 x 1.4 mm SMT 65 kΩ –40/+85 ±20 ppm 7 pF
Seiko VT200F-6PF20PPM 2.0 x 6.0 mm thru-hole 50 kΩ –10/+60 ±20 ppm 6 pF
1. ST has been informed that this crystal has been terminated by the vendor.
2. Epson MC-146 32.7680KA-E: ROHS is 6 pF version.