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Analog Devices DS1305E+T&R — DC-DC Power Modules

DS1305E+T&R RTC Clock/Calendar, SPI, 96B NVSRAM, 20-TSSOP

MPNDS1305E+T&R
End of Life

Maxim Integrated DS1305E+T&R, Clock/Calendar RTC, SPI interface, 96B NVSRAM, Alarm/Leap Year/Trickle-Charger, 2V-5.5V supply, 0°C-70°C, 20-TSSOP package, Tape & Reel.

$6.58Ref. price · indicative, final on quote
Packaging20-TSSOP (0.173", 4.40mm Width)
RoHSROHS3 Compliant
Independent supplier — new & surplus stockAuthenticity-screened · ESD-safe packingListing updated Aug 2026

Specifications

DS1305E+T&R specifications
ParameterValue
TypeClock/Calendar
MountingSurface Mount
Voltage2V ~ 5.5V
Voltage - supply, battery2V ~ 5.5V
Current - timekeeping25.3µA ~ 81µA @ 2V ~ 5V
InterfaceSPI
Operating temperature0°C ~ 70°C
PackageTape & Reel (TR); Cut Tape (CT)
FeaturesAlarm, Leap Year, NVSRAM, Trickle-Charger
Date formatYY-MM-DD-dd
Memory size96B
Time formatHH:MM:SS (12/24 hr)
Case20-TSSOP (0.173\", 4.40mm Width)

Product details

SPI RTC with onboard NVSRAM and trickle charger

The Maxim Integrated DS1305E+T&R is a serial real-time clock/calendar that communicates over SPI, carrying 96 bytes of NVSRAM for user data that survives a main power loss. It includes a trickle-charger for a backup battery or supercap, plus alarm and leap-year compensation. The 2 V to 5.5 V supply range and 0°C to 70°C operating temperature suit it for indoor equipment, instrumentation, and embedded controllers where a battery-backed timebase and a small scratchpad are needed on one SPI bus.

Timekeeping current and battery life

Timekeeping current ranges from 25.3 µA to 81 µA depending on supply voltage.

20-TSSOP footprint and surface-mount assembly

It mounts on the board alongside the MCU and passives, with no special handling beyond normal SMT reflow. The Tape & Reel option suits automated pick-and-place; the Cut Tape variant works for prototypes or small runs.

Active lifecycle and ROHS compliance

Frequently asked questions

What is the difference between DS1305 and DS1307?

The DS1305 uses an SPI interface, while the DS1307 uses I2C. The DS1305 also includes 96 bytes of NVSRAM and a trickle-charger — the DS1307 has neither. If your MCU has a free SPI port and you need battery-backed user RAM, the DS1305 is the better fit.

Does the DS1305E+T&R have a built-in trickle charger?

Yes, the trickle-charger is an integrated feature. It can charge a supercapacitor or rechargeable battery from the main supply when power is present, and the charged element backs up the RTC and NVSRAM during main power loss.