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1. Introduction

WizFi250 is a small size wireless module for the highest level of integration, featuring 802.11b/g and 802.11n.
It includes a 2.4 GHz WLAN CMOS power amplifier (PA) that meets the output power requirements of most handheld systems.
Along with the integrated power amplifier, the WizFi250 also includes integrated transmit and receive baluns, further reducing the overall solution cost.
The small size and low profile physical design eases enabling high performance wireless connectivity without space constraint in system designs.
Hardware WAPI acceleration engine, AES, TKIP, WPA and WPA2 are supported to provide your network with the latest security requirements.
For software and driver development, WIZnet provides extensive technical documents and reference software codes for system integration.

2. Features

  • Single band 2.4GHz IEEE 802.11b/g/n
  • Integrated RF power amplifier
  • Supports wireless data rates up to 65Mbit/s
  • 1MB Flash Memory, 128KB SRAM, 1MB Serial Flash
  • Supports per packet Rx Antenna diversity
  • Low power consumption & excellent power management performance to extend battery life.
  • Small size, suitable for low volume system integration.
  • Easy integration into mobile and handheld devices flexible system configuration.
  • 2.412-2.484 GHz two SKUs for worldwide market.
  • Lead Free design supporting Green design requirements, RoHS Compliance.
  • Device Package : 28x20 mm (17x20 mm)
  • Serial Interface : UART, SPI
  • Powerful Web server provides
  • Soft AP
  • Sufficient memory retention
  • Wi-Fi Security (WEP, WPA/WPA2PSK)
  • L2 Switching
  • OTA(Over The Air F/W Upgrading)

3. Block diagram

The WizFi250 module is designed based on WiFi block and MCU block . It supports generic SPI, UART interface to connect WLAN to the host processor. A simplified block diagram of the WizFi250 module is depicted in the Fig. below.

4. Pin description

Pin map

Pin description

Pin NumberPin DefineTypeDescription
2VBAT_WLIBattery supply input
3VBAT_WLIBattery supply input
5VDDIO_3V3_WLIDigital I/O supply.
21SPI_MISOI/OSPI Master In Slave Out
23SPI_MOSII/OSPI Master Out Slave In
24SPI_SSI/OSPI Slave Select
26VDD_3V3IPower supply for I/O and the internal regulator
27VDD_3V3IPower supply for I/O and the internal regulator
29UART2_RTSI/OActive-low request-to-send signal for UART2 interface (Not Used)
30UART2_CTSI/OActive-low clear-to-send signal for UART2 interface (Not Used)
31UART2_RXDISerial data input for UART2 interface (Not Used)
32UART2_TXDOSerial data output for UART2 interface (Not Used)
34RESETIRESET pin (Active Low)
38VBATIPower supply when VDD_3V3 is not present.
41BOOTIBOOT MODE pin (Active low)
48Wi-Fi_STATUSI/OWi-Fi Status pin
50SPI_Data_Ready(GPIO14)I/OIn SPI Mode, It is used to SPI_Data Ready Pin
51JTAG_TRSTIFor normal operation, if JTAG is not used, this pin can be left unconnected (NC)
52JTAG_TDOI/OFor normal operation, if JTAG is not used, this pin can be left unconnected (NC)
53JTAG_TDII/OFor normal operation, if JTAG is not used, this pin can be left unconnected (NC)
54JTAG_TMSIFor normal operation, if JTAG is not used, this pin can be left unconnected (NC)
55JTAG_TCKIFor normal operation, if JTAG is not used, this pin can be left unconnected (NC)
61UART1_RTSI/OActive-low request-to-send signal for UART1 interface (Use)
62UART1_CTSI/OActive-low clear-to-send signal for UART1 interface (Use)
63UART1_RXDISerial data input for UART1 interface (Use)
64UART1_TXDOSerial data output for UART1 interface (Use)

5. Technical Specification

Absolute maximum rating

Supply PowerMax +3.6 Volt
Storage Temperature- 40° to 85° Celsius
Voltage ripple+/- 2% MaxValues not exceeding Operating voltage

Temperature, humidity

The WizFi250 can withstand the operational requirements as listed in the table below.

Operating Temperature-20° to 85° Celsius
Humidity rangeMax 95%, Non condensing, relative humidity
  • The maximum operating ambient temperature can be up to 85°. Exposure to absolute-maximum-rated conditions may cause performance degradation and affect device reliability. For the best performance -20° to 75° is recommended.


Power supply for the WizFi250 module will be provided by the host via power pins.

VBAT_WLpower supply for WizFi2503.03.33.6V
VDDIO_3V3_WLhost Interface power supply3.03.33.6V
VBAT_MICRObackup operating voltage3.03.33.6V
VDD_3V3power supply for MCU3.03.33.6V

Current consumption

The WizFi250 on operation output current consumption :

MCU modeWiFi mode (802.11n)Typ. (RMS)Max.
Normal modeNot Associated14 mA18 mA
Normal modeAssociated67 mA69 mA
Normal modeAssociated
(IEEE Power Save mode)
32 mA65 mA
Stop modeAssociated
(IEEE Power Save mode)
14 mA17 mA
Stop modeNot Associated3 mA23 mA

The WizFi250 on TX mode output current consumption :
(Typical spec is defined @3.3V 25℃ ; MAX. spec is defined @3.0V 70℃)

Current ConsumptionTyp.Max.
Tx output power @16.5 dBm on 11b 1M385 mA430 mA
Tx output power @ 16.5 dBm on 11b 11M370 mA410 mA
Tx output power @ 15 dBm on 11g 6M345 mA380 mA
Tx output power @ 13 dBm on 11g 54M290 mA320 mA
Tx output power @ 14.5 dBm on 11n MCS0315 mA350 mA
Tx output power @ 12 dBm on 11n MCS7265 mA295 mA

The WizFi250 on RX mode current consumption :
(Typical spec is defined @3.3V 25℃; MAX. spec is defined @3.0V 70℃)

Current ConsumptionTyp.Max.
Rx @ 11b 1M120 mA150 mA
Rx @ 11b 11M120 mA150 mA
Rx @ 11g 6M120 mA150 mA
Rx @ 11g 54M120 mA150 mA
Rx @ 11n MCS0120 mA150 mA
Rx @ 11n MCS7120 mA150 mA

Wireless specifications

WizFi250 complies with following features and standards;

WLAN StandardsIEEE 802 11 b/g/n
Antenna Connecter PortOne printed antenna, one U.FL connector for external antenna
Frequency Band2.400 GHz ~ 2.484 GHz
Number of Sub ChannelsCH1 to CH14
Supported data rates11b1, 2, 5.5, 11 (Mbps)
:::11g6, 9, 12, 18, 24, 36, 48, 54 (Mbps)
:::11nHT20 MCS0(6.5Mbps) to HT20 MCS7(65Mbps)

Specifications of WiFi’s output power, evm, sensitivity

The WizFi250 WiFi output power is listed in the table below:

RF Average Output Power, 802.11b CCK Mode1M16.5+/- 1.5dBm
:::11M16.5+/- 1.5dBm
RF Average Output Power, 802.11g OFDM Mode6M15+/- 1.5dBm
:::54M13+/- 1.5dBm
RF Average Output Power, 802.11n OFDM ModeMCS014.5+/- 1.5dBm
:::MCS712+/- 1.5dBm

WiFi TX EVM following the IEEE spec as listed in the table below:

CharacteristicsIEEE SpecUnit
RF Average Output EVM (11b)@1 Mbps-10dB
:::@11 Mbps-10dB
RF Average Output EVM (11g)@6 Mbps-5dB
:::@54 Mbps-25dB
RF Average Output EVM (11n)@ MCS0-5dB
:::@ MCS7-28dB

The WizFi250 Wi-Fi sensitivity as listed in the table below:

Receiver CharacteristicsTyp.Max.Unit
PER < 8%, Rx Sensitivity @ 1 Mbps-96-89dBm
PER < 8%, Rx Sensitivity @ 11 Mbps-88-84dBm
PER < 10%, Rx Sensitivity @ 6 Mbps-90-83dBm
PER < 10%, Rx Sensitivity @ 54 Mbps-74-70dBm
PER < 10%, Rx Sensitivity @ MCS0-89-83dBm
PER < 10%, Rx Sensitivity @ MCS7-71-67dBm

6. I/O port characteristics

WizfFi250 is a small size wireless module. Unless otherwise specified, parameters are given as in the table below.
^Symbol^ Parameter ^Conditions^ Min ^Typ^ Max ^Unit^

VILStandard IO input low level voltage-0.30.28*(VDD-2V)+0.8VV
:::IO FT(1) input low level voltage-0.30.32*(VDD-2V)+0.75VV
VIHStandard IO input high level voltage0.41*(VDD-2V)+1.3VVDD+0.3V
:::IO FT(1) input high level voltageVDD > 2V0.42*(VDD-2V)+1V5.5V
::::::VDD≤ 2V5.2
VhysStandard IO Schmitt trigger voltage hysteresis(2)200mV
:::IOFT Schmitt trigger voltage hysteresis(2)5%VDD(3)mV
IlkgInput leakage current(4)VSS≤VIN≤VDD
Standard I/Os
::::::VIN=5V,I/O FT3
RPUWeak pull-up equivalent resistor(5)VIN=VSS304050k Ω
RPDWeak pull-down equivalent resistor(5)VIN=VDD304050k Ω
CIOI/O pin capacitance5pF

1. FT = Five-volt tolerant. In order to sustain a voltage higher than VDD+0.3 the internal pull-up/pull-down resistors must be disabled.
2. Hysteresis voltage between Schmitt trigger switching levels. Based on characterization, not tested in production.
3. With a minimum of 100 mV.
4. Leakage could be higher than max. if negative current is injected on adjacent pins.
5. Pull-up and pull-down resistors are designed with a true resistance in series with a switchable PMOS/NMOS. The MOS/NMOS contribution to the series resistance is minimum(~10% order).

7. Dimensions, weight and mounting

The following paragraphs provide the requirements for size, weight and mounting of the WizFi250.

- 28 mm (W) x 20 mm (L) x 1.9 mm (H) (+/- 0.1mm) (PCB Antenna, Including metal shielding)

- 17 mm (W) x 20 mm (L) x 1.9 mm (H) (+/- 0.1mm)

Pin out and pin description
Recommend footprint

8. Design Guide

PCB Antenna Guide

Module Location Recommendation

To get better antenna performance, the following two module locations are advised.

-Location 1: Module is recommended to be on the upper right corner of main board.

-Location 2: Module is recommended to be on the upper left corner of main board.

Module Layout Guideline

- Main board antenna area under module printed antenna should be clear or empty.
- No signals, GND or power traces can be routed in antenna area for each layers of the main board.
- Any mental lids, power traces or metal components should be placed far away from the antenna area on the main board.
- Keep GND plane as large as you can on main board.

Antenna Simulation Result

Ant. on right-up cornerAnt. on left-up corner
3D Pattern

Antenna Measurement Setup

Module is on the upper right corner of main board for performance measurement.

Antenna measurement setup as the figure.

Antenna Measurement Results

Firmware Update - Circuit Guide

WizFi250 provides some specific functions according to its firmware. Until now, there is a standard firmware and some customized firmware to specific customers available. It is possible to perform firmware updates.
WizFi250 decides its operating mode according to the input value of the BOOT signal. WizFi250 operates in boot mode when the BOOT input value is “LOW”, otherwise it operates in the standard run mode. WizFi250 communicates with a PC via UART in order to upload another firmware, so you have to connect UART1_RXD and UART1_TXD to the external interface for communicating with PC.
Two different schematics for that connection are listed below.

Case 1

A simple circuit for updating firmware.
If your application MCU has UART communication with WizFi250, there is a possibility that the firmware update with an external PC will fail because of dual use of the one UART interface. In that case WIZnet cannot guarantee a completely successful update.
Therefore, please monitor the signal of BOOT with your MCU by a GPIO. Please stop the UART communication between your MCU and the WizFi250 when the BOOT input value is “LOW”. After that detection of a "LOW" BOOT signal you can succeed firmware update.

Case 2

This circuit selects the UART communication using some extra hardware. If the BOOT SW is ON(GND), it is in BOOT Mode, and if the BOOT SW is OFF(3.3V) it is RUN Mode. The UART signal of the WizFi250 is connected to the firmware update UART (PC) when it becomes BOOT Mode, so firmware updates are made possible. The UART signal of the WizFi250 is only connected on your MCU if the BOOT signal is "High" and WizFi250 goes into the RUN Mode.

The following paragraphs provide the requirements for the size, weight and mounting of the WizFi250.

A-B. Temp.: 150-200℃; soak time:60-120sec.
C. Peak temp: 235~245℃.
D. Time above 220 ℃: 40~90sec.
Suggestion: Optimal cooling rate is <1℃/sec. from peak to 220 ℃.

10. WizFi250 Ref. Schematic

Ref Schematic

Instruction to OEM

This device complies with Industry Canada’s licence-exempt RSSs. Operation is subject to the following two conditions:

(1) This device may not cause interference; and
(2) This device must accept any interference, including interference that may cause undesired operation of the device.

This application and its antenna must not be co-located or operation in conjunction with any other antenna or transmitter. A minimum separation distance of 20cm must be maintained between the antenna and the person for this appliance to satisfy the RF exposure requirements.

Host labeling requirement: "Contains transmitter module IC: 20560-WIZFI250"