N6781A

The Keysight N6781A is a 2-quadrant Source/Measure Unit (SMU) module specifically designed for battery drain analysis in mobile devices and low-power IoT equipment. It features patented seamless dynamic current measurements, enabling engineers to measure microamp-level sleep currents and amp-level active currents without glitches. Operating within the N6705 DC Power Analyzer or N6700 Modular Power System mainframes, the N6781A combines programmable voltage sourcing, programmable output resistance (battery emulation), and high-speed 18-bit digitizing of voltage and current.

Battery Simulation Battery Testing Source Measure Unit

Specifications

General

Parameter	Value
Interfaces	Via mainframe (USB, LAN with LXI, GPIB)
Display	None (uses mainframe display)
Product Type	Source/Measure Unit (SMU) Module
Number of Channels	1
Mainframe Slot Occupancy	1 slot
Mainframe Compatibility	Keysight N6705A/B/C, N6700B/C, N6701A, N6702A
Calibration Interval	1 Year

Physical

Parameter	Value
Power Supply	Draws power from N6700 series or N6705 mainframe
Operating Temperature	0 to 55 °C
Dimensions (W×H×D)	34.7 mm × 128.4 mm × 290.8 mm
Weight	1.23 kg

Output Ratings

Parameter	Value
Maximum Output Power	20 W
High Voltage Output Range	0 to 20 V
Low Voltage Output Range	0 to 6 V
High Voltage Current Limit	±1 A
Low Voltage Current Limit	±3 A
Operating Quadrants	2-Quadrant (Sources and sinks current)

Measurement Capabilities

Parameter	Value
A/D Converter Resolution	18-bit
Maximum Measurement Sampling Rate	200 kHz
Measurement Interval	5 µs
Simultaneous V & I Measurement	Yes
Seamless Current Range Switching	Yes
Voltage Measurement Ranges	20 V, 6 V, 100 mV
Current Measurement Ranges	3 A, 100 mA, 1 mA, 10 µA

Connectivity & Auxiliary

Parameter	Value
Auxiliary DVM Input	Yes
Auxiliary DVM Input Range	-20 V to +20 V

Battery Emulation

Parameter	Value
Programmable Output Resistance	Yes
Programmable Output Resistance Range	-40 mΩ to 1 Ω

Protection

Parameter	Value
Over-Voltage Protection (OVP)	Yes
Over-Current Protection (OCP)	Yes
Over-Temperature Protection (OTP)	Yes
Isolation Voltage	240 VDC (maximum to chassis ground)

Programming Accuracy

Parameter	Value
Voltage Programming Accuracy (20 V Range)	0.025% + 1.8 mV
Voltage Programming Accuracy (6 V Range)	0.025% + 600 µV
Current Programming Accuracy (3 A Range)	0.04% + 1.5 mA
Current Programming Accuracy (1 A Range)	0.04% + 1 mA

Measurement Accuracy

Parameter	Value
Voltage Measurement Accuracy (20 V Range)	0.025% + 1.2 mV
Voltage Measurement Accuracy (100 mV Range)	0.025% + 75 µV
Current Measurement Accuracy (3 A Range)	0.03% + 250 µA
Current Measurement Accuracy (100 mA Range)	0.025% + 10 µA
Current Measurement Accuracy (1 mA Range)	0.025% + 100 nA
Current Measurement Accuracy (10 µA Range)	0.025% + 8 nA

Auxiliary DVM Accuracy

Parameter	Value
Auxiliary DVM Accuracy (20 V Range)	0.025% + 1.2 mV
Auxiliary DVM Accuracy (1 V Range)	0.025% + 75 µV

Output Characteristics

Parameter	Value
Voltage Ripple & Noise (20 Hz to 20 MHz)	1.2 mV RMS, 12 mV peak-to-peak

Programming Resolution

Parameter	Value
Voltage Programming Resolution (20 V Range)	200 µV
Voltage Programming Resolution (6 V Range)	60 µV
Voltage Programming Resolution (200 mV Range)	2 µV
Current Programming Resolution (3 A Range)	40 µA
Current Programming Resolution (1 A Range)	15 µA

Measurement Resolution

Parameter	Value
Voltage Measurement Resolution (20 V Range)	125 µV
Voltage Measurement Resolution (100 mV Range)	1 µV
Current Measurement Resolution (3 A Range)	8 µA
Current Measurement Resolution (100 mA Range)	250 nA
Current Measurement Resolution (1 mA Range)	2.5 nA
Current Measurement Resolution (10 µA Range)	25 pA

Regulation

Parameter	Value
Load Regulation (Voltage)	700 µV
Load Regulation (Current)	100 µA (3 A range)
Line Regulation (Voltage)	50 µV
Line Regulation (Current)	50 µA (3 A range)

Auxiliary DVM

Parameter	Value
Auxiliary DVM Input Impedance (20 V Range)	10 MΩ
Auxiliary DVM Input Impedance (1 V Range)	> 10 GΩ

Noise and Ripple

Parameter	Value
Current Ripple & Noise (CC RMS)	200 µA (3 A range, 20 Hz to 20 MHz)

Transient Response

Parameter	Value
Transient Voltage Recovery Time	< 30 µs (to within 75 mV for a 1.5 A load step)

Output Terminal Features

Parameter	Value
Maximum Sense Lead Drop Compensation	1 V per lead
Maximum Load Capacitance (Normal Mode)	2.2 µF
Maximum Load Capacitance (High Capacitance Mode)	150 µF

Technology

Source/Measure Unit (SMU)

Applications

Battery Drain Analysis & Battery Emulation