Joulescope JS220 Datasheet#

The Joulescope™ JS220 is a precision DC energy analyzer. It measures current and voltage, then computes power and energy. It measures current over ten orders of magnitude, from amps down to nanoamps, with rapid current range switching and low voltage drop.

  • ±15V voltage range

  • ±3A current range, continuous

  • ±10A current pulses (<10 ms, < 3A average per second)

  • Down to 0.5 nA resolution, equivalent to 34-bits of dynamic range

  • Synchronously measures voltage and current at 2 million samples per second, 16-bit

  • 300 kHz bandwidth

  • Rapid 1 µs switching between shunt resistors

  • Enwavify™ technology for consistent, accurate measurements through current range changes

  • Computes power, energy, and charge

  • Operates with minimal voltage disturbance between Current + and Current – ports

  • Up to ±48V common-mode voltage between USB ground and sensing ports

  • 4 general-purpose inputs and 2 general-purpose outputs

  • 1 BNC trigger configurable for either input or output

  • Programmable on/off for power cycling the target device and measuring inrush currents

  • USB 2.0 high-speed host connectivity with modern USB C connector

  • Host software support for Microsoft® Windows®, Apple® macOS®, and Linux®

  • Host software user interface provides real-time graphs of current, voltage, and power over time

  • Python library and scripting provided

  • Host software is open source and available on GitHub

  • Swappable front panel with open-source designs on GitHub

  • Firmware upgradable

The Joulescope JS220 User’s Guide describes how to use the instrument. The specification values are also available as js220.yaml.

Absolute maximum ratings#

Min

Max

Unit

USB voltage

-0.3

6

V

Max voltage applied between any port (Current +, Current -, Voltage +, Voltage -)

-20

20

V

Max voltage to USB ground from any port (Current +, Current -, Voltage +, Voltage -)

-48

48

V

Input current (powered, burst)

-10

10

A

Input current (powered, sustained)

-3

3

A

Input current (unpowered)

N/A (off)

N/A (off)

A

Storage temperature

-40

80

°C

Operating temperature

0

50

°C

Relative humidity (non-condensing)

0

95

%

Altitude from sea level

-100

2500

m

Max voltage applied to GPI relative to USB ground

-10

10

V

Mechanical#

Instrument only#

Typical

Unit

Weight

190

grams

Width

99

mm

Length (including binding posts and BNC connector)

126

mm

Height

28

mm

Complete product kit#

Typical

Unit

Weight

510

grams

Width

190

mm

Length

200

mm

Height

60

mm

Specification conditions#

Temperature

23 °C ± 10 °C

Humidity

20% to 80% RH, non-condensing

Calibration interval

1 year1

  1. Recommended to comply with industry-standard practices, but the Joulescope JS220 is designed not to need recalibration.

Current measurement specifications#

Range

Accuracy

Resolution

Impedance

Guaranteed

10 A1

±0.25% ±1.50 mA

175 µA

0.01 Ω

±9.7 A

180 mA

±0.25% ±150 µA

15 µA

0.11 Ω

±185 mA

18 mA

±0.25% ±15 µA

1.5 µA

1.11 Ω

±18.5 mA

1.8 mA

±0.25% ±1.5 µA

150 nA

11.1 Ω

±1.85 mA

180 µA

±0.25% ±150 nA

15 nA

111 Ω

±185 µA

18 µA

±0.25% ±30 nA

1.5 nA

1111 Ω

±18.5 µA

  1. Joulescope is designed for 3 A sustained. See the recommended operating conditions for maximum durations for higher currents.

Test current measurement bandwidth by varying the effective load impedance. Due to load capacitance, altering the source voltage is not a valid method of testing current bandwidth.

The JS220 is sensitive to RF radiation which induces real current in test setups. When tested with EN61326-1 and 3 V RMS/m, the JS220 measured up to 10 µA (observed, not guaranteed) of current at several frequencies. The exact frequency susceptibility varies with cable length and configuration.

Voltage measurement specifications#

Range

Accuracy

Resolution

Guaranteed

15 V

±0.1% ±10 mV

1.2 mV

±14.5 V1

2 V

±0.1% ±2 mV

180 µV

±1.98 V

  1. Beta units are limited to ±13.6 V.

The JS220 is sensitive to RF radiation which induces real voltages in test setups. When tested with EN61326-1 and 3 V RMS/m, the JS220 error increased by 10 mV (observed, not guaranteed) at several frequencies. The exact frequency susceptibility varies with cable length and configuration.

General specifications#

Test condition

Min

Typical

Max

Unit

Sampling frequency

25 °C

2000000

sps

Sampling frequency

25 °C

-25

25

ppm

Measurement bandwidth

-3 dB

280

310

350

kHz

Front panel insertions

100

Parasitic effects specifications#

Test condition

Min

Typical

Max

Unit

Current leakage (Voltage + to -)

25 °C, ±3.3V

2

nA

Current leakage (Voltage + to -)

25 °C, ±5V

2

nA

Current leakage (Voltage + to -)

25 °C, ±15V

3

nA

Shunt resistor voltage, max

-2 to 2 A, static

20

21

mV

Burden voltage (Current + to -)

1 A, banana jacks

0

25

35

mV

Burden voltage (Current + to -)

Shunt resistor, < ±2 A

±20

mV

Shunt switching time

Over-range, < 200 ns rise time

0

0.8

1.2

µs

Measurement gap following a current range switch

0

µs

Software-controlled fuse specifications#

Test condition

Min

Typical

Max

Unit

Current leakage (Current + to -)

25 °C, 3.3V

±5

nA

Current leakage (Current + to -)

25 °C, 5V

±7

nA

Current leakage (Current + to -)

25 °C, 15V

±28

±5000

nA

Max fuse engage

5 A

0.293

s

Max fuse engage

10 A

0.050

s

General purpose inputs and outputs#

Test condition

Min

Typical

Max

Unit

Internal 3.3V reference

3.135

3.3

3.465

V

External reference

Vref < (VUSB - 0.5 V)

Vref - 0.1

Vref

Vref + 0.1

V

Input leakage per pin

25 °C

±10

nA

Input leakage per pin

±100

nA

Output voltage high

-100 µA

Vcco - 0.1

V

Output impedance

10 mA

45

50

80

Ω

GPI sample rate

2

MSPS

Continuous output current

Per pin

±50

mA

Total power dissipation

Over output impedance

0.25

W

The Joulescope uses the TI SN74LVC2T45 for both the GPIs and GPOs. See the SN74LVC2T45 datasheet for more information. Both the GPIs and GPOs are protected with the TI TPD4E1U06 for ESD protection.